Xenon and Cooling Therapy in Babies at High Risk of Brain Injury Following Poor Condition at Birth: A Randomised Pilot Outcomes Study (COOLXENON3 Study)
Phase: PHASE2
Conditions: Hypoxic Ischaemic Encephalopathy
Sponsor: University Hospitals Bristol and Weston NHS Foundation Trust

 
 
 
 
Neonatal Xenon Study 3_St. Michael’s Hospital, Bristol   
 
Second Site, Imperial /Hammersmith, London 
  
 
 
 
CLINICAL STUDY PROTOCOL 
 
 
 
 
 
 
 
UHB R & I REFERENCE NUMBER: CH/2013/4414 
University of Bristol ref no: 2112 
 
 
XENON AND COOLING THERAPY IN BABIES AT HIGH RISK OF  
BRAIN INJURY FOLLOWING POOR CONDITION AT BIRTH:  
A RANDOMISED OUTCOME STUDY 
(COOLXENON3 STUDY) 
 
 
 
  
18 September 2019             Issue 2 Revision 3 
 
 
 
 
Study Sponsor: 
 
University Hospitals Bristol NHS Foundation Trust 
Research and Innovation, Level 3 
UH Bristol Education & Research Centre 
Upper Maudlin Street 
Bristol   BS2 8AE 
Tel: 0117 342 0233 
 
 
 
 
 
 
 
The information in this document is confidential and is the property of University Hospitals Bristol NHS 
Foundation Trust. The information may be provided only to Investigators, Co-Investigators, appropriate trial 
personnel, members of the Research Ethics Committee and personnel of the authorities to which it is 
submitted. This protocol may not be photocopied or discussed with third parties not involved in the clinical 
study without prior written authorisation from University Hospitals Bristol NHS Foundation Trust. 
 
 
 
 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
Second Site, Imperial /Hammersmith, London 
 
 
 
 
 
 
 
 
 
 
 
 
Confidentiality Statement 
 
The confidential information in the following document is provided to you as an Investigator, potential 
Investigator, or Consultant for review by you, your staff and an appropriate Independent Ethics Committee.  
By accepting the document you agree that the information contained herein will not be disclosed to others 
without written authorisation from University Hospitals Bristol NHS Foundation Trust except to the extent 
necessary to obtain informed consent from those persons to whom the products may be administered. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
Second Site, Imperial /Hammersmith, London 
Protocol Summary 
Title 
XENON AND COOLING THERAPY IN BABIES AT HIGH RISK OF  
BRAIN INJURY FOLLOWING POOR CONDITION AT BIRTH: 
RANDOMISED PILOT OUTCOMES STUDY 
(COOLXENON3 STUDY) 
Investigators 
Professor Marianne Thoresen (Chief Investigator) 
e-mail: marianne.thoresen@bristol.ac.uk Mob: 0047 90885956 
Dr Ela Chakkarapani (Principal Investigator) - Bristol 
Email: Ela.Chakkarapani@bristol.ac.uk 
Dr Sudhin Thayill (Principal Investigator Second Site) – Hammersmith 
s.thayyil@imperial.ac.uk  
Dr John Dingley (Co-Investigator) 
e-mail: JohnDingley98@gmail.com  Mob: 07735 379471 
Study Centres 
1. Primary Site – Bristol 
2. Second Site - London 
1. St Michael’s Hospital 
2. Hammersmith Hospital /  
 
Southwell Street 
 
Imperial Neonatal Service  
 
Bristol 
 
Du Cane Road, London 
 
BS2 8EG 
 
W12 0HS 
Test Article 
Xenon Neonatal Breathing Device  
Objectives 
Primary Objective:  
This is a randomised two group pilot outcomes study comparing Bayley 
III neurodevelopmental outcome scores between;  
i) the established treatment of cooling the body down to 33.5 °C 
for 3 days; to  
ii) Xenon inhalation for 18 hours in combination with whole body 
cooling to 33.5 °C for 3 days  
 
This will be applied in term newborn babies who are at moderate or 
high risk of brain injury following poor condition around the time of 
birth. 
 
 
Secondary Objectives:  
Potential outcome predictors are based on a combination of: 
1) Time in hours after birth when background activity as recorded by 
amplitude integrated EEG (aEEG: from single channel EEG)1 and onset 
of sleep wave cycling (SWC).  
2) Cerebral MRI lesions in T1W and T2W sequences2 and MRI 
biomarkers including absolute thalamic N-acetyl aspartate (NAA) 
quantification, 
lactate/NAA 
peak-area 
ratio 
from 
proton 
spectroscopy3 and whole brain white matter water-diffusion 
fractional anisotropy analysed with tract-based spatial statistics4 
from two MR images performed around 48 hours of age and around7 
days of life.  
3) Peak value of Lactate Dehydrogenase within the first 72h of life5, was 
a good predictor in cooled infants. 
4) Age in hours when plasma lactate has fallen to 5mmol/l 
5) Resistance Index (RI).6 
 
Tertiary Objectives: 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
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We will monitor a number of variables before/during and after the 
period of Xenon delivery. This group of physiological and biochemical 
parameters includes those recorded during both our CoolXenon1 and 
CoolXenon2 studies.  
Parameters for which data will be collected are: 
  
i. 
Gas exchange: Transcutaneous oxygen saturation, end-
tidal carbon dioxide concentration, blood gas data 
(from 
arterial 
sample), 
mechanical 
ventilation 
requirements (rate, peak inspiratory pressure, PEEP 
settings).  
ii. 
Haemodynamic: Systolic, mean and diastolic arterial 
pressure, heart rate.  
iii. 
Any problems during weaning and extubation, such as 
post-extubation stridor, use of steroids. 
iv. 
Coagulopathy (INR >2, APTT> 50) 
v. 
Inotrope requirement, cardiac Troponin T 
vi. 
Hepatic impairment, (raised Alanine aminotransferase > 
40, Alkaline phosphatase > 100, peak Lactate 
dehydrogenase within 72h of age) 
vii. 
Renal impairment, oliguria (urine output < 1 ml/kg/h after 
day 1 of life and  raised creatinine > 100) 
viii. 
Infection (culture proven, need for antibiotics > 5 days, 
raised CRP ~ within  the first 24h  and at 4 days of life of 
life 
ix. 
Estimation of sedation with validated sedation scale N-
PASS and plasma morphine concentrations. 
x. 
Estimation of adrenocortical function during xenon 
inhalation and hypothermia using plasma, salivary and 
urine 
cortisol 
measurements 
and 
plasma 
adrenocorticotropic hormone. 
xi. 
Number of anticonvulsive drugs needed to treat seizures 
xii. 
Length of hospital stay 
xiii. Time to full oral feed by bottle or breast  
xiv. MRI assessment by T1 and T2 weighted images using the 
scoring system by Rutherford et al.2  
xv. In some infants when the 3Tesla MRI scanner is available 
assessment of brain metabolites using magnetic 
resonance spectroscopy (MRS) where the ratio 
Lactate/N-acetyl aspartate has been shown to be a 
good early biomarker for outcome.3 
xvi. Safety 
Patient Population 
Newborn infants >/=36 weeks gestation which satisfy all St Michael’s 
Hospital standard inclusion criteria for cooling (i.e. at risk of brain injury 
following poor condition at birth) and which additionally satisfy the 
inclusion criteria of this study for the administration of Xenon by 
inhalation.  
Cooling should be started within 3h of age and Xenon within 5h.7  
Use of a shorter treatment delay in these entry criteria will optimise the 
possibility of finding an effect if there is one.  

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
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Population Size 
52 babies in total  
Structure 
Prospective randomised comparative outcome study 
Duration of Participation 
Xenon administration period of 18 hours.  
Recruitment period up to two years from start of study.  
Short and long term monitoring until 18 months of age.  
Therefore total study duration 3.5 years. 
Definition of End of study 
The end of the trial as a whole will be when all recruited participants 
have completed the treatment and follow-up period and all data has 
been collected and analysed, with data queries answered. 
Method of Assignment 
Neonates meeting all entry criteria can be included. 
Randomisation 
Patients will be randomised between cooling (standard treatment) and 
Xenon+cooling groups on a 1:1 basis.  
Statistical Analysis 
This is a randomised pilot outcomes study.  
The statistician for this study is Professor Lars Walloe who has also 
advised on all the preliminary experimental Xenon work and the 
previous two clinical feasibility studies and a recent clinical evaluation 
of the Bayley examination which is used in this study.8-11 
Adverse Events 
Volunteered and Elicited 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
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SECTION 
CONTENTS 
 
PAGE 
 
Confidentiality Statement 
2 
 
Protocol Summary 
3 
 
Approvals 
11 
 
Declarations and Signatures of Investigators 
12 
 
Schematic of Study Design 
13 
 
Study Administration 
14 
 
List of Abbreviations 
15 
1.0 Overview 
17 
2.0 Background and Introduction 
18 
2.1 
Background 
18 
2.2 
Review of Literature  
18 
2.3 
Rationale for the Study 
19 
3.0 Objectives 
20 
3.1 
Primary Objective 
20 
3.2 
Primary Endpoint 
20 
3.3 
Secondary Endpoint 
20 
3.4 
Tertiary Endpoint 
21 
4.0 Study Design 
22 
4.1 
Study design and procedures 
22 
4.1.1 
St Michael’s hospital standard inclusion criteria for cooling 
22 
4.1.2 
Exclusion criteria for cooling in the CoolXenon2 study 
23 
4.1.3 
Additional inclusion criteria for Xenon 
23 
4.2 
Consent 
23 
4.2.1 
Which of the parents can consent to letting the child enter the trial? 
24 
4.3 
Randomisation 
24 
4.4 
Clinical Management 
24 
4.4.1 
Specific clinical management of cooling group 
24 
4.4.2 
Specific clinical management of Xenon+cooling group 
24 

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4.5 
Further information on the oxygen fraction in the breathing gas mixture 
25 
4.6 
Vigilance and monitoring 
26 
4.6.1 
Action to be taken with respect to typical problems in this patient group 
26 
4.7 
Risks/benefits and risk minimisation 
27 
4.7.1 
Potential risks from Xenon 
27 
4.7.2 
Potential risks from breathing system 
28 
4.7.3 
Use of cuffed tracheal tube 
28 
4.7.4 
Experience with cuffed tube in neonates with Xenon 
29 
4.7.5 
Cleaning/disinfection 
29 
4.8 
Potential benefit to research participants 
29 
4.9 
Follow Up 
29 
4.9.1 
Short term information and investigations (before discharge from hospital) 
29 
4.9.2 
Short term assessment neurological evaluation 
30 
4.9.3 
Long term follow up (at 18 months) 
30 
4.9.3.1 
Additional follow up 
30 
4.10 
Groups size calculation 
31 
4.11 
Justification of Treatment/Procedure 
31 
5.0 Study Therapies 
31 
5.1 
Test Article: Description 
31 
5.2 
Test Article: Principles of Operation 
31 
5.2.1 
Gas delivery to breathing system 
33 
5.3 
Test Article: Clinical Development 
35 
5.3.1 
Proof-of-Concept Pre-clinical Studies 
35 
5.3.2 
Proof-of-Concept and Pilot Clinical Studies 
35 
5.4 
Test Article: Regulatory Status 
35 
5.5 
Test Article: Packaging and Labelling 
35 
5.6 
Test Article: Component Tracking 
35 
5.7 
Control/Comparator Therapy 
35 
6.0 Patient Selection 
36 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
Second Site, Imperial /Hammersmith, London 
6.1 
Which of the parents can consent to letting the child enter the trial? 
36 
6.2 
Inclusion Criteria 
36 
6.2.1 
St Michael’s Hospital standard inclusion criteria for cooling 
37 
6.2.2 
Additional inclusion criteria for Xenon 
37 
6.3 
Exclusion Criteria 
37 
6.3.1 
Exclusion criteria for cooling 
37 
6.3.2 
Additional exclusion criteria for Xenon 
37 
6.4 
Prohibited Therapies 
38 
7.0 Subject Assignment to Treatment Group 
38 
8.0 Methods and Procedures 
38 
8.1 
Informed Consent 
38 
8.2 
Pre-Study 
39 
8.3 
Screening 
39 
8.4 
Initial Assessment 
39 
8.4.1 
Demographics 
39 
8.4.2 
Patient History and Physical 
39 
8.4.3 
Concomitant Medications 
39 
8.5 
Study Phases 
39 
8.5.1 
Phase 1 
39 
8.5.2 
Phase 2 
40 
8.5.3 
Phase 3 
40 
8.5.4 
Patient Follow-up 
40 
8.5.4.1 
Short term 
40 
8.5.4.2 
Short term assessment neurological evaluation will include 
40 
8.5.4.3 
Long term follow up (at 18 months) 
41 
8.5.4.4 
Additional follow up 
41 
8.6 
Study Data 
41 
8.7 
GP Notification 
41 
8.8 
Definition of End of Study 
41 

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9.0 Assessment of Safety 
41 
9.1 
Data Review Group 
41 
9.2 
Composition of IDRG 
42 
9.3 
Criteria for stopping the study 
42 
9.3.1 
Reasons for stopping Xe delivery before the 18h timepoint 
42 
9.3.2 
Stopping rule 
43 
9.4 
Adverse events (AE’s) 
43 
9.5 
AE Definitions 
43 
9.5.1 
Assessment of causality 
43 
9.6 
AE Classification 
44 
9.7 
AE Recording 
44 
9.8 
AE Reporting 
44 
9.9 
Reporting Responsibilities to Regulatory Authorities, Investigators and Ethics 
Committees 
44 
10.0 Data Analysis and Statistical Plan 
44 
10.1 
Statistical Analysis 
44 
10.2 
Interim analysis and stopping rules 
45 
11.0 Withdrawal of Subjects from Study 
45 
12.0 Modification of Protocol 
45 
13.0 Discontinuation of Study 
45 
14.0 Administrative Requirements, Ethical and Regulatory Aspects and Quality 
Assurance 
45 
14.1 
Study Approvals: MHRA, Research Ethics Committee (REC) and NHS Trust R&D 
Approval 
45 
14.2 
Responsibilities of the Investigator 
45 
14.3 
Subject Information 
45 
14.4 
Subject Consent 
46 
14.5 
Source Data and Subject Files 
46 
14.6 
Reporting and Recording of Data 
46 
14.7 
Monitoring 
46 
14.8 
On-Site Audits 
47 
14.9 
Record Storage and Retention 
47 

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14.10 
Indemnity 
47 
15.0 Study Funding 
47 
16.0 Publication 
47 
17.0 References 
47 
APPENDICES 
 
 
A1: Summary of study procedures 
52 
 
A2: Laboratory technical feasibility study 
53 
 
A3: Data from CoolXenon study 
63 
 
A4: SPA abstract 2013 
69 
 
A5: Patient information sheet (Abbreviated and full versions) 
70 
 
A6: Informed consent document 
76 
 
A7: Declaration of Helsinki 
77 
 
 
 
 
 
 
 
 
 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
Second Site, Imperial /Hammersmith, London 
APPROVALS 
 
Protocol Approval Signatures 
 
Sponsor 
 
 
 
 
University Hospitals Bristol NHS Foundation Trust 
Research and Innovation, Level 3 
UH Bristol Education & Research Centre 
Upper Maudlin Street 
Bristol    
BS2 8AE 
Date 
 
Diana Benton/Katharine Wale 
Research Projects Manager 
 
Chief Investigator 
 
 
 
Department of Neonatal Neuroscience  
Level D 
St Michael's Hospital 
Southwell Street 
Bristol   
BS2 8EG 
Date 
19 September 2019 
Professor Marianne Thoresen 
Professor of Neonatal Neuroscience 
 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
Second Site, Imperial /Hammersmith, London 
Declarations and Signatures of Chief Investigator and Chair of Data Review Committee 
 
I confirm that I have carefully read and understood this protocol and agree to conduct this clinical trial as outlined in this 
protocol, according to current Good Clinical Practice and local laws and requirements. 
 
I have received and read all trial-related information provided to me. 
 
The objectives and content of this protocol as well as the results derived from it will be treated confidentially and will not 
be made available to third parties without prior written authorisation from University Hospitals Bristol NHS Foundation 
Trust. 
 
 
Chief Investigator 
 
Professor Marianne Thoresen 
Neonatal Neuroscience 
Level D 
St Michael's Hospital 
Southwell Street 
Bristol   
BS2 8EG 
 
Signature 
 
 
Date   19 September 2019 
 
Chair of Data Review Committee 
 
Dr David Evans 
Consultant Neonatologist 
North Bristol NHS Trust 
Neonatal Intensive Care Unit  
Southmead Hospital 
Bristol      
BS10 5NB  
 
Signature 
 
 
 
 
Date   9 October 2019 
 

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SCHEMATIC OF STUDY DESIGN  
 
 
 
 
 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
Second Site, Imperial /Hammersmith, London 
STUDY ADMINSTRATION 
 
Chief Investigator 
Professor Marianne Thoresen  
Neonatal Neuroscience 
Level D  St Michael's Hospital 
Southwell Street 
Bristol        BS2 8EG 
UK 
Tel: 0117 342 5226 (Carol Bond, PA to Professor Thoresen) 
Tel:  +47 90885956 
 
Co-Investigator 
Dr John Dingley 
Department of Anaesthetics and Intensive Care 
Morriston Hospital 
Swansea      SA6 6NL 
Tel: 01792 703280 (NHS secretary) 
 
Principal Investigator (Bristol) 
Principal Investigator (London - second site) 
Dr Ela Chakkarapani 
Dr Sudhin Thayill 
NICU and Neonatal Neuroscience   
Hammersmith Hospital / Imperial College 
Level D, St Michael’s Hospital 
Du Cane Road 
Southwell street 
London    W12 0HS 
Bristol. BS2 8EG. 
Tel: 01173425711 
Tel: 02033138515 
 
Study Sponsor 
University Hospitals Bristol NHS Foundation Trust 
Research and Innovation, Level 3 
UH Bristol Education & Research Centre 
Upper Maudlin Street 
Bristol     BS2 8AE  
 
Contact: Diana Benton 
Tel: 0117 342 0233 
 
Study Monitor 
 Sandra MulliganEmail:   Sandra.mulligan@uhbristol.nhs.uk 
Tel: 0117 342 0578   
 
Data Management 
Professor Lars Walløe 
Professor Marianne Thoresen  
 
Statistician 
Data Review Committee Chair 
Professor Lars Walløe  
Dr David Evans 
Department of Physiology,  
Consultant Neonatologist 
Institute of Basic Medical Sciences,  
North Bristol NHS Trust 
University of Oslo 
Neonatal Intensive Care Unit 
P.O. Box 1103 Blindern, 
Southmead Hospital 
NO-0317 Oslo 
Bristol  BS10 5NB 
Norway 
Tel: +47 22851218, +47 90967531 
 
  
 
 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
Second Site, Imperial /Hammersmith, London 
LIST OF ABBREVIATIONS 
 
AE 
Adverse Event 
aEEG 
Amplitude integrated EEG 
AEs 
Adverse Events 
ALT 
Alanine Transaminase 
AP 
Alkaline Phosphatase 
APTT 
Activated Partial Thromboplastin Time 
ARs 
Adverse Reactions 
AST 
Aspartate Aminotransferase 
BMI 
Basal Metabolic Index 
CF 
Consent Form 
CI 
Chief Investigator 
CRFs 
Case Report Forms 
CRO 
Contract Research Organisation 
CRP 
C Reactive Protein 
CT 
Computerised Tomography 
cTnT 
increased cardiac Troponin T 
DoB 
Date of Birth 
DQ 
Developmental quotients 
ECG 
Electrocardiograph 
EDD 
Expected Date of Delivery 
EEG 
Electroencephalograph 
EN  
European Norm 
ETCO2 
End Tidal carbon dioxide 
EU MDD 
European Union Medical Device Directives 
FBC 
Full Blood Count 
FDA 
Food and Drug Administration 
FiO2 
Fraction Inspired Oxygen 
GCP 
Good Clinical Practice 
Hb 
Haemoglobin 
Hct 
Haematocrit 
HI 
hypoxic-ischaemic 
HIE 
Hypoxic-Ischaemic Encephalopathy 
HT 
Hypothermia 
ICH 
International Committee on Harmonisation 
IDRG 
Independent Data Review Group 
INR 
International Normalised Ratio 
ISO 
International Standards Organisation  
LDH 
Lactate Dehydrogenase 
LMP 
Last Menstrual Period 
MHRA 
Medicines and Healthcare products Regulatory Agency 
MRI 
Magnetic Resonance Imaging 
MRS 
Magnetic Resonance  Spectroscopy 
NHS 
National Health Service 
NICHD 
National Institute of Child Health and Human Development 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
Second Site, Imperial /Hammersmith, London 
NICU 
Neonatal Intensive Care Unit 
NNT 
Number Needed to Treat 
NXBD 
Neonatal Xenon Breathing Device 
pCO2 
Partial pressure carbon dioxide 
PEEP 
Positive End Expiratory Pressure 
PIS 
Patient Information Sheet 
PPV 
Positive Predictive Value 
QoL 
Quality of Life 
R&D 
Research and Development 
RBC 
Red Blood Cells 
REC 
Research Ethics Committee 
RI 
Resistance Index 
SAE 
Serious Adverse Event 
SaO2 
Oxygen saturation 
SUSAR 
Suspected Unexpected Serious Adverse Reaction 
SWC 
Sleep Wave Cycling 
TT 
Tracheal tube 
UAR 
Unexpected Adverse Reaction 
WBC 
White Blood Cells 
Xe 
Xenon 
Xe-HT 
Xenon-hypothermia 
 
 
 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
Second Site, Imperial /Hammersmith, London 
1.0 
Overview 
 
This is a prospective randomised pilot outcomes study to be undertaken at St Michael’s Hospital, Bristol and 
Hammersmith Hospital, London. A short delay for recruitment is included to optimise the effectiveness of hypothermia 
(cooling, HT) and potentially Xenon. Cooled infants that are ≤3h old and start Xenon within ≤5h of age can be accepted 
into the study. In an experimental study, adding xenon with HT when both were commenced 5 hours after the insult did 
not provide any additional neuroprotection compared to HT alone7; however, 2h delayed Xenon when HT was started 
immediately was more effective than HT alone.8 With the Xenon delivery system mounted in the ambulance we can start 
the Xe treatment in the local hospital and continue treatment during transport, thus starting Xe within 5h after birth. 
Since >90% of patients are retrievals from regional units within the network, the ability to reliably recruit to xenon within 
the 5h limit is now possible and has been demonstrated as one of the findings of the CoolXenon2 study. Preliminary data 
from the CoolXenon2 study show that the groups were well balanced with respect to severity of HI. Time to recovery of 
normal EEG trace is the best single early predictor of outcome1 and is monitored in all infants. In CoolXenon2 we have 
found that this does not function as an early predictor as xenon suppresses the aEEG for the entire 18h period of xenon 
administration and for a short period afterwards. This means that analysed the traditional way, aEEG is not reliable as an 
outcome predictor during the whole of the Xenon administration periods and a few hours afterwards. Mortality was low, 
7% in each group. 
 
In CoolXenon 1 we demonstrated that it is technically feasible to deliver xenon in this patient group without adverse 
effects on physiology and in CoolXenon2 preliminary analyses we have found that i) Early recruitment losses due to the 
short birth to treatment-start time limits we have set were then successfully minimised by commencing xenon during 
retrieval, ii) As in CoolXenon1 there are no adverse physiological effects of giving xenon in this patient group and iii) one 
planned predictive early marker of outcome, aEEG, has not functioned as expected. 
  
The study is a therefore a natural extension of, and includes lessons learned from, the previous studies we have 
undertaken (CoolXenon 1 and CoolXenon2) and examines the effect of inhaled Xenon gas in the treatment of newborn 
infants with hypoxic-ischaemic encephalopathy (HIE), in combination with cooling which is the standard treatment for 
this condition. The hypothesis is that the Xenon+cooling combination will produce better neuroprotection than the 
standard treatment, cooling-alone, as assessed at 18m using the established Bayley Scales of Infant Development, Xenon, 
a rare anaesthetic gas, is almost side-effect free and shows great promise as a method of enhancing the neuroprotection 
offered by cooling. It is, however, extremely expensive at £25-50/L. 
 
Based on experience and clinical data from our previous trials, we now propose to study 52 full term infants with 
moderate or severe HIE who require mechanical ventilation and hypothermia for 72 hours. HT will be routinely applied if 
the standard existing criteria for this are met except recruitment will be earlier, ≤3h rather than 6h as in our standard 
institutional cooling protocol. We have recently shown that cooling ≤3h gives better outcome12:  Time Is Brain: Starting 
Therapeutic Hypothermia within Three Hours after Birth Improves Motor Outcome in Asphyxiated Newborns.  Thoresen 
M, Tooley J, Liu X, Jary S, Fleming P, Luyt K, Jain A, Cairns P, Harding D, Sabir H. Neonatology. 2013 Sep 12;104(3):228-
233.  
Candidates for the study will be randomly assigned to one of two groups: (i) the standard treatment for this condition, 
72 hours of cooling, i.e. the treatment they are already receiving, or (ii) addition of 50% Xenon concentration in the 
breathing gas from the mechanical ventilator for 18 hours in combination with the existing cooling regime, with cooling 
continuing to 72 hours.  
 
All efforts will be made to commence delivery of the Xenon and cooling as soon as possible after birth, with maximum 
delay of 5 hours for Xenon and 3 hours for cooling. In the event that a baby is retrieved from another local hospital to the 
study centre, an assigned research team member will accompany or meet the retrieval team and commence Xenon 
delivery at the local hospital or during the return transfer of the baby to Bristol. Xenon will be given in the breathing gas 
mixture via a special delivery system situated between the ventilator and airway of the infant. This device has been 
specifically developed to eliminate Xenon wastage,9 without which this putative therapy would be completely unfeasible 
on cost grounds. It has recently been successfully used for Xenon delivery to a total of 28 babies with the same entry 
criteria (MHRA approved CoolXenon10 and CooXenon2 studies),. 
 
As in the CoolXenon2 study, an Independent Data Review Group (IDRG) will be convened. The IDRG will meet after the 

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recruitment of every 8th baby during enrolment of infants to the Xenon+cooling group and also review all serious adverse 
events occurring throughout the study. 
 
2.0 
Background and Introduction 
2.1 
Background 
HIE is a major cause of severe cognitive and motor disability in term infants. Until 2005, there was no effective treatment 
for HIE. Since 1993 we have developed moderate HT as a neuroprotective treatment culminating in a successful clinical 
feasibility study in Bristol 1998-9 (10 infants). This experimental work led to the “CoolCap” trial13 followed by the UK 
“TOBY” trial14. In both trials Bristol was a major recruiting centre. 
 
The trials have shown that HT significantly reduced disability and cooling has now become standard treatment.  As 
protection from clinically delayed HT (by 4.5h) is only partial, (absolute risk reduction 15%),15 enhancing its effectiveness 
as well as starting earlier is paramount. More recent clinical trials have also shown effectiveness of HT.16  
 
Since 2003 we have demonstrated that immediate Xenon and immediate hypothermia in combination, increase cerebral 
protection from 35% (HT alone) to 70% in newborn rats and pigs.17,18 In 2011 we completed a human neonatal 
feasibility/safety study of 14 patients undergoing standard cooling therapy for moderate or severe perinatal asphyxia 
using a Xenon delivery system of the same design. A pilot study, comparing standard cooling to standard cooling plus 
Xenon, has also been successfully undertaken (CoolXenon2), examining technical ability to recruit with short birth to 
treatment delays, physiological effects and possible early predictors of outcome. There have been no technical problems 
due to the breathing system, use of the Xenon gas nor any adverse effects related to these in any of the human studies 
we have conducted to date. (Protocol CH/2011/3799. Xenon AND cooling therapy in babies at high risk of brain injury 
following poor condition at birth: RANDOMISED PILOT STUDY (COOLXENON2 STUDY). MHRA reference CI/2011/0061). 
 
2.2 
Review of Literature 
Critical lack of oxygen delivery to the foetus during labour and delivery results in HIE in 1-3 per 1000 births at term.  60-
70% of infants with moderate/severe HIE die or survive with serious disability such as cerebral palsy and/or learning 
difficulties. Some of the survivors are unable to walk, sit up, control head movement, feed or communicate. Until 2005 
there was no treatment that had been shown to improve outcome in such infants.  
 
Since 1993 Marianne Thoresen’s group have taken moderate HT as a neuroprotective treatment through all the steps of 
therapeutic development starting with small (rat) 19,20 and large (pig) 21,22, animal models to a clinical feasibility study in 
Bristol (body or head cooling in 10 infants).23In collaboration with others our experimental work and clinical pilot led to 
the American funded “CoolCap” trial where Bristol was a major recruiting centre. The results were published in 2005 and 
showed a therapeutic benefit from hypothermia.13 There are few cardiovascular effects of cooling and there may be some 
cardiac protection in addition23,24. This study was followed by the American National Institute of Child Health and 
Development body cooling trial which also showed reduced mortality and improved neurological outcome in the cooled 
group25  We and colleagues in the UK (PI Denis Azzopardi) received MRC funding to carry out the largest of all the cooling 
trials, the “TOBY” trial recruiting a total of 325 infants. St. Michael’s Hospital was a major centre in these trials and MT is 
one of the principal investigators and grant holders for the TOBY trial.14 We have received further MRC funding to carry 
out long term follow up of this cohort which is on-going.  Other trials in Europe26and Australia (ICE trial)27 have also shown 
significant improvement in cooled infants.  
 
In these 5 big trials13,14,25-27, HT reduced death or disability from 66% to 51%. The number needed to treat (NNT) to prevent 
death or disability is 7.16 Hypothermia has also been shown to be effective in adults after cardiac arrest and is being 
considered for other conditions where brain injury is the major problem (e.g. stroke, head trauma). 
 
At the end of 2006, we finished recruiting to the TOBY trial and HT became standard of care in Bristol. Our local incidence 
of poor outcome in this group has been further reduced to 39%1, and more recently as low as 34%, as compared to 48% 
for the cooled group in “TOBY”). Compared to our own historical controls using the same entry criteria where the 
incidence of poor outcome was 63% without active treatment, our Bristol cooling protocol has reduced the risk of a poor 
outcome by 38%. Thus HT improves outcome but does only partly abolish death or disability. There is clearly a need to 
 
 Principal Investigator: Marianne Thoresen 

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explore other therapies that can be combined with HT to further improve outcome in this devastating condition. 
 
For the past 8 years our research group has been investigating the rare anaesthetic noble gas Xenon, which is showing 
great promise as a neuroprotectant in HIE. Despite being considered “noble” because it is almost inert in conventional 
chemical reactions, Xenon is not completely inert in biological systems and has been known as an anaesthetic for decades. 
The group has built upon the initial work in cell cultures28,29 by conducting both small and large animal studies of 
Xenon+cooling with positive results. In particular a suitable delivery and monitoring system capable of providing Xenon 
to the inhaled gas mixture of a mechanically ventilated infant in the neonatal intensive care unit has been developed and 
evaluated in a pig model of global HIE – replicating the clinical scenario in pigs of similar weight to human neonates. This 
has been developed by Dr John Dingley, Reader in Anaesthetics, a member of the Thoresen collaborative group and 
honorary consultant at University Hospital Bristol. The group has recently used this system in the first human neonatal 
feasibility/safety trial of Xenon + cooling in this group of neonates, which was carried out in Bristol over 12 months and 
successfully completed in September 2012 (including 18m follow-up) (See Appendix 4). The safety of Xenon has been 
further demonstrated by Sabir et al,30 who showed there was no increased apoptosis after breathing Xenon for 24 hours, 
compared to a 10x increase when breathing isoflurane in a piglet model. 
 
2.3 
Rationale for the Study 
We have undertaken a series of experiments since 2003 using Xenon with different dosages, durations and delays before 
treatment onset in our neonatal rat brain injury model and found that Xenon approximately doubles the neuroprotective 
effect in combination with hypothermia, compared to hypothermia alone17,31,32. Since 2006 we have investigated Xenon-
hypothermia (Xe-HT) in our newborn piglet model of global hypoxia-ischemia.18,33 With this model we have extensively 
examined the effect of Xe-HT, Xe alone, HT alone as compared to no treatment. We have examined the effect on the 
brain and all organs, in particular the heart, liver, kidney and lungs. We have also examined the biochemical changes in 
the blood throughout the treatment period in all the treatment groups.  
 
In brief, we have not found any adverse effect of Xenon in the piglet model – and we can document: 
- 
Improved neuroprotection compared to HT alone18 
- 
Better cardiovascular stability (reduced need for inotropic support)34  
- 
No extubation delay18 
- 
No increase in oxygen requirements18 
 
Our large animal trial of Xe-HT in piglets recently concluded with a very positive outcome supporting the result we found 
in rats, i.e. adding Xenon to HT doubles the neuroprotection in both animal models. Also we found in both studies that 
HT and Xenon had additive effects with no interaction. 
 
A human neonatal feasibility study combining cooling (the established treatment) with Xenon inhalation via mechanical 
ventilation was completed by this group on April 5th 2011 (The CoolXenon study). This small scale safety study was a 
necessary requirement before a randomised clinical trial of cooling+Xenon that would examine neurological outcomes 
could be conducted. The findings were similar to those listed above and have been documented. The design was such 
that the Xenon duration increased from 2h to 18h, and 3 patients received the maximal duration of 18h Xenon which has 
been shown to be neuroprotective in the pig model. Increasing the duration had no adverse effect on the physiological 
parameters. Furthermore, the data from this study have confirmed that it is appropriate to start ventilation with Xe as 
early as 5h post-birth.  
 
A second study (CoolXenon2) has also been successfully undertaken. This study initially was for 24 babies, 12 in each 
group. One main aim was to establish if we could recruit sufficient neonates within the 5h time limit from birth to Xenon. 
During this period, when Xe was started only after arrival in Bristol, we lost approximately 40% of potential recruits due 
to not being able to meet this ambitious time limit. After starting to run the Xe delivery system in the dedicated retrieval 
ambulance, we applied for an extension to the CoolXe2 study to evaluate the impact on recruitment this would have (8 
additional patients, 4 per group) and from that point we have had no missed recruitment due to the 5h time interval. 
The CoolXenon2 study revealed an unknown and unforeseen effect of Xenon; Xenon in itself depresses the aEEG trace 
during delivery  which means it is unreliable as an early outcome predictor until the treatment has finished which will for 
most infants say ≥25h of age (5h  old when starting xe +18h treatment +  at least 1h recovery). We observed that Xenon 
depresses seizure activity per se (SPR abstract 2013, Appendix 4) and we observed that if Xenon was stopped very fast 

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seizures could occur on stopping Xenon. This means that there is a period where “time to recovery of normal trace” may 
or may not be affected by Xenon. These data illustrate the importance of examining a small dataset like CoolXenon2 when 
a new treatment is administered. This means that when analysed the traditional way, aEEG is not reliable as an outcome 
predictor   during the whole of the Xenon administration periods and a few hours afterwards. Since we cannot quantify 
the aEEG response we do not have a validated early outcome predictor from which we can make a power calculation. 
 
Therefore, in CoolXenon3 we will record all the same data as in CoolXenon2 and we will use Bayley III converted to Bayley 
II as appropriate.11 The Bayley clinical neurodevelopmental examination at 18months of age is the primary outcome 
measure. In the standard treatment, all cooled babies currently undergo MRI brain assessment between 7-10 days of life 
to confirm the diagnosis of HIE by demonstrating the brain lesions consistent with hypoxia-ischaemia and to 
prognosticate long-term outcome for parents. In routine clinical practice, some of the cooled babies undergo MRI brain 
examination around 48 hours of life, when there are concerns of poor recovery of aEEG and abnormal neurology to 
estimate the severity of brain injury. Undertaking MRI brain assessment around 48 hours of age for all babies during 
cooling in both cooling and xenon+cooling arms of the study (after completion of xenon) will offer valuable data including 
early predictors of long-term outcome, assessing the severity of brain injury and progression of brain injury and early 
effect of xenon on brain injury. Our team is very experienced in looking after the cooled babies during transport and MRI 
examination. Other putative short-term predictors will continue to be recorded as secondary outcomes. With this 
enhanced dataset we will be able to validate any early predictors in infants cooled early with or without added Xenon. 
 
There have been no technical problems due to the breathing system, use of the Xenon gas, nor any adverse effects related 
to these in any of the human studies we have conducted to date. 
 
The safety of Xenon for the immature brain has been demonstrated by no increase in apoptosis30 after 24 hours of 
breathing the gas in a neonatal piglet model; in comparison breathing isoflurane for the same duration resulted in a 10x 
increase in apoptotic cell death 
 
3.0 
Objectives 
 
The aim of this study is to examine the potential neuroprotective effects of the cooling+xenon combination when 
compared to cooling alone. 
 
3.1 
Primary Objective  
Our hypothesis is that the Bayley Scales of Infant and Toddler Development (Bayley III) scores at 18m of age will show a 
trend towards an enhanced neuroprotective effect of the Xenon-cooling combination over cooling alone.  
 
3.2 
Primary Endpoint 
This is a randomised two group pilot outcomes study comparing Bayley scores between;  
1) Xenon inhalation for 18 hours in combination with whole body cooling to 33.5 °C for 3 days, and  
2) the established treatment of cooling the body down to 33.5 °C for 3 days.  
 
This will be applied in term newborn babies who display signs indicating moderate or severe brain injury following poor 
condition at birth. 
 
3.3 
Secondary Endpoint 
The following potential predictors of outcome will be used: 
a. Time to recovery after birth of a normal aEEG1 
b. MRI scan around 48hours and around day 7 of life, to assess lesions consistent with hypoxic-ischaemia,2 
absolute quantification of thalamic NAA and white matter fractional anisotropy using tract based spatial 
statistics.3,4,35  
c. 
Peak LDH value within 72h of life5,36  
d. Resistance Index (RI). 
We will also collect data on: 
e. Plasma glucose at birth (in cord blood) 
f. 
Age in hours after birth when plasma lactate has fallen to 5mmol/L 
g. Different  inotropic  drugs  needed and the total duration in hours of any inotropic support 

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h. Number of anticonvulsants given 
i. 
Amount and duration of sedation (e.g. plasma morphine level), stress level (plasma, salivary, urine cortisol 
level and adrenocorticotropic hormone) 
j. 
Age at full oral feeds (breast or bottle or tube) 
k. Neonatal hearing screening result before 14 days of life 
l. 
Clinical examination at birth, at 7 days of age and at discharge including weight and head circumference 
 
Neurodevelopmental follow up is a part of the routine follow up of infants with HIE, Bayley III examination at 18 months 
of age. 
 
Disability will be defined as any of: 
m. Bayley III Cognitive Composite score less than 85.11 
n. Bayley III Motor Composite score less than 85  (Bayley scores will also be expressed as a Developmental Quotient 
(DQ) calculated from developmental age scores as this allows a larger range of scores for those functioning at a 
low level)37  
o. Bilateral cortical visual impairments 
p. Hearing loss needing amplification > 40dB. 
 
In addition any Adverse Events will be recorded and criteria have been devised for stopping the study early if necessary. 
The IDRG will review data when 8, 16 and 24 infants have undergone Xenon treatment. 
 
3.4 
Tertiary Endpoint 
A series of variables that are among the most relevant for evaluation of safety were examined closely in our previous 
studies. In both groups we will continue to routinely monitor and record the same set of physiological variables in the 
proposed study, for a subset of data for a longer time period until after rewarming. 
 
• 
Endpoint 1 – defined as Mechanical ventilation and gas exchange parameters 
➢ 
The following will be measured before (from start cooling), during and after Xenon administration (for 
12h or until 12h after end of cooling  hours pending  which variable): 
▪ 
transcutaneous  oxygen saturation 
▪ 
end-tidal carbon dioxide concentration 
▪ 
blood gas data 
▪ 
mechanical ventilation requirements (rate, peak inspiratory pressure, inspiratory time, PEEP 
settings) 
▪ 
FiO2 
▪ 
average percentage Xenon in inspired gas mixture (when applicable) 
▪ 
tracheal tube cuff pressure. 
• 
Endpoint 2 – defined as Haemodynamic parameters 
➢ 
The following will be measured before, during and after Xenon administration: 
▪ 
systolic, mean and diastolic arterial pressures; and heart rate variability 
• 
Endpoint 3 – defined as Inotropic drug requirements 
➢ 
The following will be recorded before, during and after Xenon administration until 12h after end of 
cooling: 
▪ 
drug, dose and duration 
• 
Endpoint 4 – defined as Marker of myocardial impairment/insult 
➢ 
The following will be recorded before and after Xenon administration:  
▪ 
plasma levels Troponin T (marker of myocardial cell death) recorded before and after Xenon 
administration until 12h after end of cooling: 
• 
Endpoint 5 – defined as timecourse  and peak value of  Markers of hepatic impairment 
➢ 
The following will be recorded before and after Xenon administration until 12h after end of cooling:  
▪ 
alanine aminotransferase , alkaline phosphatase and lactate dehydrogenase 
• 
Endpoint 6 – defined as  timecourse and peak value of Markers of renal impairment 

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➢ 
The following will be recorded before, during and after Xenon administration until 12h after end of 
cooling: 
▪ 
oliguria - defined as urine output < 1 ml/kg/h -  from age > 24h 
▪ 
raised creatinine > 100 at > 24h of age. 
• 
Endpoint 7 – defined as Evidence of infection 
➢ 
The following will be recorded:  
▪ 
culture proven 
▪ 
need for antibiotics for 5 or more days 
▪ 
raised CRP occurring within 24h or later. 
• 
Endpoint 8 – defined as Length of hospital stay including duration of stay in local hospital after discharge from St 
Michaels hospital 
➢ 
This will be recorded 
• 
Endpoint 9 – defined as age when full oral feeding was achieved by breast or bottle or tube 
➢ 
This will be recorded 
• 
Endpoint 10 – defined as Haematology measurements 
➢ 
The following will be recorded before and after Xenon administration (routinely recorded 24 hrly): 
▪ 
Coagulopathy  - INR > 2 and/or APTT> 50 
▪ 
FBC 
• 
Endpoint 11 – defined as Serum chemistry measurements 
➢ 
The following will be recorded before and after Xenon administration 
▪ 
serum sodium, potassium, chloride, magnesium, phosphate, calcium, (urea, creatinine as 
above), glucose, (liver enzymes as above), bilirubin, albumin  
▪ 
drug levels may be analysed  on clinical indication  (Gentamicin levels, Phenobarbital levels)   
• 
Endpoint 12 – defined as aEEG background pattern and Evidence of seizures 
➢ 
The following will be recorded before, during and after Xenon administration until 12h after end of 
cooling:  
▪ 
evidence from continuous aEEG/EEG recording 
▪ 
any anticonvulsant treatments given. 
 
4.0 
Study Design 
 
This is a prospective randomised comparative clinical outcome study conducted in St Michael’s Hospital, Bristol and 
Hammersmith Hospital, London. 
 
 
4.1  
 Study design and procedures 
Infants will be eligible for Xenon if the St Michael’s hospital standard inclusion criteria for cooling are met and additional 
inclusion criteria for Xenon administration are met. 
 
4.1.1 
St Michael’s hospital standard inclusion criteria for cooling 
Standard Hypothermia Treatment Criteria for 72 hrs of cooling — all of criteria A, B and C. 
A:  
Infants ≥ 36.0 weeks gestation (estimated or clinical assessment) with at least ONE of the following:  
i. Apgar score of ≤5 at ten (10) minutes after birth  
ii. Continued need for resuscitation, including tracheal or mask ventilation, at ten minutes after 
birth  
iii. Acidosis defined as either umbilical cord pH or any arterial, venous or capillary pH within 60 
minutes of birth less < 7.00 
iv. Base deficit ≥16 mmol/L in umbilical cord blood sample or any blood sample within 60 minutes 
of birth (arterial or venous blood). If the infant meets criterion A then assess for neurological 
abnormality using criterion B and C (by trained personnel): 
 
 
B:  
Moderate or severe encephalopathy as evidenced by any of the following:  

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i. Altered state of consciousness (reduced or absent responses or pathological irritability and 
hyper responsive and at least ONE or more of the following: 
ii. Hypotonia 
iii. Abnormal reflexes including oculomotor or pupillary abnormalities  
iv. Absent or weak suck  
v. Clinical seizures, as recorded by trained personnel  
                                              AND  
C:  
At least 30 minutes duration of amplitude-integrated electroencephalography (aEEG) recording that 
shows abnormal background aEEG activity. The decision to cool is based on the worst 30 min section of 
the aEEG, not the best38 or seizures (clinical or electrical) thus meeting ONE of the following:  
i. Normal background with some (> 5 min)  electrical seizure activity  
ii. Moderately abnormal activity (upper margin of trace >10μV and lower margin <5μV) 
iii. Suppressed activity (upper margin of trace <10μV and lower margin of trace <5μV) 
iv. Definite seizure activity 
 
4.1.2 
Exclusion criteria for cooling in the CoolXenon3 study 
a. Infants expected to be greater than 3 hours of age at the time of starting cooling treatment. 
b. Futility. Where prognosis is considered to be hopeless e.g. no cardiac output for 20 minutes. 
   
4.1.3 
Additional inclusion criteria for Xenon 
Before being considered for additional inhaled Xenon therapy via the breathing gas mixture, the infant would need to 
meet further additional entry criteria (all must be met): 
i. 
Intubated, ventilated, sedated, being cooled. 
ii. 
≤5 hours old 
iii. 
Any seizures under control. 
iv. 
Weight > 2nd centile for gestational age 
v. 
Stable cardiovascular parameters; Mean arterial pressure >40mmHg. 
vi. 
Oxygen requirement via mechanical ventilator < 40%. 
vii. 
Positive End Expiratory Pressure (PEEP) requirement ≤ 8cm H2O 
viii. 
Arterial/capillary/venous pCO2 <7.0kPa (ideally arterial). Venous can be higher if peri-arrest and tissues 
have been very recently Ischaemic 
ix. 
Postnatal age ≤5 hours 
x. 
Absence of major congenital abnormalities, imperforate anus and in particular any bowel obstruction, 
congenital abnormalities suggestive of chromosomal anomaly or other syndromes that include brain 
dysgenesis. Congenital syndromes affecting the brain should be excluded when diagnosed. 
 
4.2 
Consent  
Informed written consent will be obtained from a parent (only the mother can consent if parents are not married) after 
a full verbal and written explanation of the study by a named physician or trained nurse like an advanced nurse 
practitioner. Such staff will also meet with parents during the intervention period to ensure that they understand the 
study procedures and continue to consent to participate in the study. Information can be given by local trained staff and 
consent can also be taken over the phone with the mother if she is unable to be available for the consent process (e.g. 
cannot be moved shortly after Caesarean Section). 
 
Approval for the study is being obtained from the Regional South West Research Ethics Committee covering St Michael’s 
Hospital. 
 
Most of the patients (61%) will be born outside the study hospital (Outborn) and brought to the hospital by a dedicated 
retrieval team and ambulance. 
 
The local delivery hospitals will have medical staff (e.g. consultants, specialist registrars, advanced nurse practitioners) 
trained in consenting for the CoolXenon3 trial. A training log with signatures, a short CV and competency approval will 
be kept centrally. 
 

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Parents will receive a written information leaflet (1 page, short version) when the infant is eligible for cooling treatment. 
Staff will discuss CoolXenon3 with parents as soon as practically possible. Parents will be able to speak on the phone to a 
member of the treatment team if they need further information and help with the consent process. Parents will also be 
offered the opportunity to speak to members of the treatment team that are picking up the baby for transport. 
 
Trained staff on the transport team can take consent for the study. 
 
A more detailed information sheet regarding the trial will be given to parents after the first conversation or at the earliest 
suitable time. 
4.2.1 
Which of the parents can consent to letting the child enter the trial? 
• 
Either parent if they are married. 
• 
If the parents are not married, only the mother can consent - provided she is awake and understanding (e.g. not 
under the influence of anaesthetic drugs)  
If the mother is not in a state to understand the situation and the biological father does currently not have legal parental 
responsibility he can assent for the trial until the mother is awake/understanding the child’s condition and able to decide 
on consent.  
 
A parent who is eligible to consent can, at any time and without a specific reason, withdraw the child from the study. In 
this situation, Xenon treatment will then be stopped as soon as possible and medically safe (within minutes). 
 
4.3 
Randomisation  
The babies entered into the study will be randomised into two groups on a 1:1 basis. Randomisation will be via sealed 
opaque envelopes containing details of treatment allocation and [an] identifying adhesive label(s) to be attached to the 
CRF binder. Neonates meeting all the entry criteria can be included. In this study early randomisation before 5h of age is 
paramount. The maximum target delay before starting cooling is before 3h of age and for Xenon this value is 5h of age. 
These are maximum delay values however, so consent and randomisation need to take place as early as possible. 
 
4.4 
Clinical management 
The neonates would be sedated, mechanically ventilated and cooled according to the protocol for cooling listed above, 
as this is standard treatment. In the case of retrieved babies, cooling is always started before transfer to Bristol (active or 
passive cooling). If not before, active cooling starts when the transport team arrives. Antibiotics, fluid management and 
sedative drugs used would be unmodified. 
 
Neonates would be entered into the study according to the set criteria within a maximum of 5hrs of birth with respect to 
adding Xenon to the existing underlying standard cooling regime which has started within 3 hrs (passive or active). 
 
4.4.1 
Specific clinical management of cooling group 
This group will be cooled according to the normal protocols of the hospital as this is standard treatment. In standard care, 
some of the cooled babies will undergo MRI brain assessment around 48 hours of life in addition to the routine MRI brain 
assessment around 7 days of life, to provide early information about severity of brain injury. In the study, all the babies 
will undergo MRI brain examination around 48 hours of age. At this time point the babies will be continuing the cooling 
therapy. Our team is experienced in looking after the cooled babies during transport and MRI examination with least 
discomfort to the babies. Moreover, all the babies will receive continuous morphine infusion to keep them comfortable 
during cooling, as part of their standard protocol. 
  
 
4.4.2 
Specific clinical management of Xenon+cooling group 
After initial resuscitation and attainment of a stable state, and inclusion in the study, the tracheal tube would be replaced 
with a cuffed commercially available tracheal tube (Kimberley-Clark microcuff) of the same or 0.5mm smaller size as the 
existing one and the cuff inflated until leakage of gas around the cuff had ceased audibly and according to the ventilator 
monitor. This particular tube has a high volume, low pressure cuff and is specifically designed for long term use on the 
paediatric or neonatal intensive care unit. The cuff pressure will be monitored and recorded at the time of initial inflation, 
during Xenon administration every 2 hours and just prior to final deflation. If there are any post extubation adverse events 
such as stridor, or extubation fails secondary to vocal cord, nerve or subglottic damage, these will be recorded. In our 

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recent studies, of the 28 babies given Xenon, one developed post-extubation stridor requiring steroids.  
 
1. 
The dose (fraction of Xenon in breathing gas) planned for each patient in the Xenon+cooling group will be 50%. 
It will be applied for 18 hours. It will be commenced as soon as is practicable but no later than 5h after birth 
once all the entry criteria / consent requirements have been met.  
2. 
If a baby is being retrieved from another local hospital to the study centre (Bristol) using the existing Bristol-
provided retrieval team and ambulance, AND they have been consented and randomised to receive Xenon AND 
if it is deemed probable that the delay between birth and the start of Xenon in Bristol would exceed an interval 
of 5 hours, then if logistically possible an assigned research team member will  accompany or meet the retrieval 
team and commence Xenon delivery at the local hospital or during the return transfer of the baby to Bristol. 
3. 
Full data sets will be acquired in two groups of 26 patients. The mortality rate in the patients referred for cooling 
to Bristol is 10.3%.  
4. 
Cooling will be for 72 hours using the clinically chosen cooling device in both groups, as is current standard 
practice for cooling. 
5.         In standard care, some of the cooled babies will undergo MRI brain assessment around 48 hours of life in addition 
to the routine MRI brain assessment around 7 days of life, to provide early information about severity of brain 
injury. In the study, all babies will undergo MRI brain examination around 48 hours of life. At this time point, 
babies will have completed the xenon therapy and will continue with cooling therapy. Babies will be kept 
comfortable with continuous morphine infusion as per the standard local protocol. Our team is experienced in 
transporting cooled babies to the MRI and looking after the cooled babies during MR examination. This MRI will 
provide valuable data regarding the severity of brain injury, early effect of xenon on brain injury and determine 
the progression of brain injury with xenon+cooling compared with cooling alone. 
 
4.5 
Further information on the oxygen fraction in the breathing gas mixture 
The Xenon we intend to use (LenoXe) is currently licensed for anaesthesia in adults. The LenoXe SmPC specifies that 
Xenon should be administered (for adult anaesthesia) with at least 30% oxygen in the breathing gas mixture.  
 
It is our intention in this study to administer an oxygen fraction in the breathing gas to ensure adequate oxygenation of 
the blood of the neonate, but not to give an excess, as there is also a real risk of hyperoxic brain damage in this group of 
neonates if the oxygen fraction is too high. Consequently, in a neonate with normal lungs being sedated and ventilated 
for cooling rather than for any lung problems, the inspired oxygen fraction could be lower than 30% (air is 21% for 
example). The lowest fraction of oxygen in the breathing gas will always be used, sufficient to maintain an oxygen 
saturation on blood gas analysis or pulse oximetry of at least 96%, especially as hyperoxia is considered to be very harmful 
to the brain in infants who have just had a hypoxic-ischaemic insult. 
 
The reason the LenoXe SmPc specifies 30% oxygen is following the normal practice of anaesthesia using other gases and 
vapours, because during anaesthesia in adults the ventilation/perfusion mismatch in the lungs becomes very slightly less 
efficient than in the awake state. This is due to changes in muscle tone, diaphragm position/shape and effects of gravity 
on distribution of blood flow through regions of the lung. Although humans are designed to breathe air (21% oxygen), a 
patient with normal lungs under anaesthesia would traditionally be given approximately 30% oxygen (more if there were 
any lung problems as clinically indicated). 
 
It should be noted that this anaesthetic tradition to use a slightly higher inspired oxygen fraction than might strictly be 
required developed before it became commonplace and later mandatory to use pulse oximetry to continuously monitor 
oxygen saturation of the blood and end-expired carbon dioxide monitoring to continuously monitor the adequacy of 
ventilation (in terms of carbon dioxide removal from the blood) which became widespread in the late 1980’s / early 
1990’s. 
 
In the neonates of this study the situation is different as they have all recently suffered a hypoxic-ischaemic (HI) insult to 
the brain and other organs around birth. Ventilating them with a gas mixture containing an oxygen fraction even slightly 
higher than necessary is considered highly undesirable as in this situation it can actually worsen the subsequent brain 
 
 In a recent very large study of cuffed tracheal tubes for anaesthesia in infants and neonates, the use of a cuffed tube did not increase risk of post-
extubation stridor. In 2246 children, post-extubation stridor was noted in 4.4% of those with a cuffed tracheal tube and 4.7% of those with uncuffed 
tubes, with a much lower tube exchange rate in the cuffed tube group. 

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injury. This explains recent changes to resuscitation equipment for the newborn where the 100% oxygen supplies have 
been replaced with air/oxygen blenders.  The new ILCOR Resuscitation Guidelines39 state that term newborns should first 
be resuscitated in air, then with a higher concentration of oxygen if pulse oximetry or clinical signs suggest poor 
oxygenation. 
 
It is worth noting that variations in ventilation/perfusion throughout the regions of a healthy neonatal lung are less 
affected by anaesthesia/sedation than in a (much larger) adult so the physiological (anaesthetic) justification for 
automatically using 30% oxygen is weaker in the neonate. 
 
However the more relevant points with respect to this study are that although in anaesthesia practice it may be normal 
and quite harmless to set an inspired oxygen fraction slightly higher than strictly necessary, in neonates that have suffered 
a hypoxic-ischaemic insult to the brain and other organs around birth, it is considered highly undesirable to administer 
an inspired oxygen fraction that is any higher than the amount required for adequate oxygen delivery to the organs.  We 
have recently shown experimentally that 30 min of 100% oxygen after hypoxia-ischaemia increased injury40. 
Consequently,  
- 
we monitor oxygen saturation of the blood of the neonate using continuous pulse oximetry (with audible and 
visual alarms),  
- 
we continuously monitor adequacy of ventilation with a neonatal end-expired carbon dioxide monitor which 
reflects the systemic arterial carbon dioxide content. While mandatory in adult intensive care practice this is not 
yet the case in neonatal practice due to unavailability of suitable monitors for neonates, a situation which is now 
changing. 
- 
We also routinely monitor oxygen saturation of the blood periodically in ventilated neonates by analysing arterial 
blood samples using a blood gas analyser. In neonates that have experienced an HI insult around birth the 
attending physicians are not only checking that the oxygen content is not too low but also they are checking it is 
not too high. A slight elevation that would normally be acceptable is not acceptable in this particular group of 
babies and if too high they will actively request that the inspired oxygen fraction in the breathing gas be reduced. 
- 
As a result of the above, the inspired breathing gas might contain a theoretical maximum oxygen fraction of 40% 
as stated in the protocol if clinically required due to lung problems , but also this may for the above reasons be 
deliberately set as low as is required to maintain an oxygen saturation of >=96% if the lungs are normal. 
 
The desired inspired Xenon fraction is to be set at 50% as per the protocol. The “balance gas” in situations where a 
moderate oxygen fraction is being used will be nitrogen. This will simply be room air which although containing 21% 
oxygen is otherwise mainly composed of nitrogen. 
 
4.6 
Vigilance and monitoring 
This will be ongoing during every case and include: 
- 
Blood gases 2-4 hourly or as clinically indicated 
- 
Cardiac echo /Doppler (where available) 
- 
Blood Pressure 
- 
Heart rate 
- 
Haemodynamic Monitoring. Lidco Plus, Advantech, Ref HM 71-02, model PPC-150M. Lidco Ltd. 16 Orsman Road, 
London, N1 5QJ 
- 
Oxygen saturation by pulse oximeter (SaO2) 
- 
Xe concentration and O2 concentration in gas mixture 
- 
End Tidal CO2 (ETCO2) (End expired carbon dioxide will be measured using a commercial medical monitor (ETCO2 
monitor) designed to monitor adequacy of ventilation in neonatal intensive care patients which displays the 
exhaled carbon dioxide as a value, but additionally as a waveform and uses a mainstream sensor in the breathing 
circuit) 
 
4.6.1 
Action to be taken with respect to typical problems in this patient group 
1) 
Hypotension or inadequate cardiac output:  
• 
10ml/kg 0.9% Saline (or occasionally 4% human albumin or blood) as required (x2) 

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• 
Dopamine infusion commenced (up to 20mcg/kg/min) followed by Dobutamine (up to 20mcg/kg/min), 
then Hydrocortisone up to 2.5mg/kg 6 hourly or other inotrope as indicated 
• 
If not effective then Xe delivery will be stopped and conventional ventilation/gas mixture resumed. 
2) 
Low SaO2 or low oxygen partial pressure on blood gas analysis: 
• Increased oxygen fraction in breathing gas mixture as required up to maximum of 40% 
• If not effective, then Xe delivery stopped and conventional ventilation/gas mixture resumed. If reason 
for high FiO2 is easily solved, e.g. improved by surfactant delivery or changed ventilation settings or 
clearing a blocked tube, then Xenon can be resumed. 
3) 
High ETCO2 or CO2 partial pressure on blood gas analysis: 
• Increase peak pressure and/or breathing rate settings on mechanical ventilator 
• If not effective then Xe delivery stopped and conventional ventilation/gas mixture resumed. This is 
readily achieved by disconnecting the ventilator hoses from their point of attachment to the Xenon 
breathing system and connecting them directly to the tracheal tube of the neonate. 
 
At the end of the prescribed period of Xe delivery the tracheal tube would be reconnected directly to the mechanical 
ventilator and normal ventilation and gas mixtures set as clinically appropriate. The cuff of the tracheal tube would be 
deflated. This tracheal tube would be replaced with an uncuffed tube at a later timepoint as clinically indicated or kept 
until the patient was extubated after rewarming. Cooling regimes last for 72hrs before slow rewarming commences (0.1-
0.4°C per hour). The standard cooling protocol would continue for many more hours after cessation of the additional 
Xenon regime. 
 
4.7 
Risks/benefits and risk minimisation 
4.7.1 
Potential risks from Xenon 
The known effects of Xenon in humans have all been derived from adult anaesthesia studies. Xenon is known to have 
minimal effects on the strength of the heart contractions or the blood pressure41-44. A slight slowing of pulse rate has 
been seen in some studies but this is often not statistically significant. 
 
Xenon is analgesic and causes sedation. These might be considered useful properties in a sedated baby on an Intensive 
Care Unit. 
 
Xenon is a dense gas. Erring on the side of caution we would not use it in this early study in any baby with airway narrowing 
or similar lung problems, the exclusion criteria reflect this. Note that the use in piglets weighing 1.5 kg and small airways 
did not display any ventilation/airway problems (Appendix 4). As with other anaesthetic gases it can diffuse into gas filled 
cavities in the body such as the bowel. This happens only slowly in adults, and more slowly than with other anaesthetic 
gases such as nitrous oxide, however for this reason it would not be used in any situation where the bowel was obstructed 
(our Xenon inclusion criteria reflect this). 
 
In animal neonatal studies, there have been no side effects and we can document: 
- 
Improved neuroprotection18 
- 
Better cardiovascular stability34  
- 
No extubation delay (delay coming off the mechanical ventilator)18 
- 
No increase in oxygen requirements18 
 
From studies using Xenon as an anaesthetic in adults, of which there are many, the experience is that Xenon has 
remarkably few side effects and in particular produces minimal haemodynamic disturbance compared to conventional 
anaesthetics41-44. 
 
As Xenon is almost chemically inert, it is eliminated from the body completely unchanged – it is eliminated from body 
tissues via the circulation and lungs at the end of the procedure. Xenon, although uncommonly used due to its high cost, 
does therefore have a license for use as an anaesthetic in adults in several countries, including the UK. 
 
In 2010/2011 our group undertook and successfully completed the first human neonatal feasibility/safety study of 
Xenon+cooling, mainly 50% Xenon for periods of up to 18hrs. All survivors underwent a Bayley examination at 18 months 
of age. From this study, in terms of safety, we can document: 
• 
It is feasible to give 50% Xenon for up to 18h in infants undergoing therapeutic hypothermia10 

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• 
Only 0.2-0.3L/hour Xenon was used with a closed loop Xenon breathing system 
• 
A cuffed tube did not adversely affect ease of extubation 
• 
Xenon is sedative and other sedation is needed when Xenon is discontinued 
• 
No significant cardiovascular or respiratory changes before, during and after Xenon 
• 
In one child with abnormal/immature lungs, Xenon did not increase FiO2 requirement. 
 
See Appendix 3 
 
From the perspective of babies who may already be unwell, the main points to note therefore are: 
i) 
Xenon is not broken down to any “by products” by the metabolism of the body as many other drugs are, as it is 
an almost chemically “inert” elemental gas. 
ii) 
Xenon is very free of side-effects in the adult experience, which may be due to this “inert” nature, but perhaps 
most importantly: 
• 
Xenon is eliminated from the body completely unchanged via the lungs within a few breaths. This means 
that if there is any problem, unlike the situation with any drug injected into a vein, Xenon is a reversible 
treatment, ie, it can be easily removed completely, rapidly and unchanged from the body at any time. 
This ability to reverse application of Xenon and rapidly eliminate it unchanged from the patient in the 
event of any problem is, although unusual, a key factor from the perspective of safety. When the Xenon 
is being administered, a special breathing circuit will be connected to the ventilator designed for this 
purpose. It will be operated by a member of the team who has documented experience running and 
troubleshooting with this equipment.  
 
4.7.2 
Potential risks from breathing system 
We are using the same breathing circuit to deliver this gas as in previous MHRA approved studies; CoolXenon and 
CoolXenon2 (MHRA study references CI/2009/0043, CI/2011/0061 respectively). This has been developed over many 
years by a Consultant Anaesthetist who is a co-researcher on this team and world leader on this subject. Prior to use in 
these human studies, it has been tested extensively in laboratory neonatal pig simulations of the condition (see section 
4.3.1). 
 
To minimise risk of any technical problems: 
 
a. The equipment meets all necessary international medical device safety and quality standards. It has been 
professionally constructed using medical grade materials. 
b. The design is such that the Xenon system is placed between the standard mechanical ventilator and the baby. 
This means that if there is any technical problem, the ventilator can be immediately connected directly to the 
baby and the Xenon system removed in one simple intuitive operation. 
c. 
The gas composition, in particular oxygen, of the circuit gas will be continuously measured, as will Xenon and 
the ETCO2 (which reflects the arterial value). 
d. The breathing system has an overpressure release valve in the event of any mishap. 
e. Furthermore, if there were any problem due to the Xenon gas itself, reconnection directly to the ventilator would 
also allow all the Xenon to be breathed out from the baby within a few breaths, i.e. the Xenon treatment is 
rapidly reversible.  
f. 
The Xenon will be delivered by trained personnel who have also been involved with laboratory trials using Xenon 
in animal models and previous MHRA approved clinical trials involving the device. 
g. The possibility of interaction between the Xenon gas and the materials of the breathing circuit has been 
considered. As Xenon is chemically “inert” i.e. does not form chemical compounds except in the most extreme 
circumstances, there is no perceived risk. 
h. A full risk assessment in accordance with standard medical device regulatory requirements has been undertaken 
and thoroughly documented. 
i. 
The device meets all of the Essential Requirement of the EU Medical Device Directives, with the exception of 
those being evaluated in the study. 
 
This design of breathing system has now been evaluated in two MHRA approved studies with this patient population. 
Summary data from the CoolXenon2 study: 

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Cooling only (n=14) 
Cooling + Xenon (n=14) 
Birth weight, gram 
3648 ± 503 
3455 ± 394 
Gestational age, weeks 
40.7 ± 1.3 
40.1 ± 1.3 
Female, nr (%) 
8 (57) 
8 (57) 
Outborn, nr (%) 
9 (64) 
8 (57) 
Apgar 1 minute 
2 (0-2.25) 
1 (1-3.25) 
Apgar 5 minutes 
4 (3-5.25) 
4 (2.5-6) 
Apgar 10 minutes 
6 (3.75-7) 
5 (3-8.25) 
Cord pH 
7.03 ± 0.17 
7.00 ± 0.19 
Cord BE 
-12.9 ± 5.2 
-12.3 ± 8.7 
Received anticonvulsants,  
8 of 14 
9 of 14 
Received inotropes, % 
71 
57 
Table 1: Summary preliminary data from CoolXenon2 study (BW, GA, Cord pH and BE are mean±SD apart, Apgar is median with IQR) 
 
4.7.3 
Use of cuffed tracheal tube 
After onset of cooling and attainment of a stable state, the tracheal tube would be replaced with a commercially available 
cuffed tracheal tube (TT) (Kimberley-Clark microcuff) of the same or 0.5mm smaller size as the existing one.  
To minimise the gas pressure in the cuff:  
i) It would be inflated until leakage of gas around the cuff had just ceased audibly and also according to the ventilator 
monitor.  
ii) This particular tube has a high volume, low pressure cuff and is specifically designed for long term use on the paediatric 
or neonatal intensive care unit. Publication of a large scale randomised multicentre trial of uncuffed versus modern cuffed 
tracheal tubes in small children (0-5yrs, n=2246) has recently taken place. The incidence of complications was no greater 
than that seen with uncuffed tubes. The conclusions were “The use of cuffed TTs in small children provides a reliably 
sealed airway at cuff pressures of <or=20 cm H2O, reduces the need for TT exchanges, and does not increase the risk for 
post-extubation stridor compared with uncuffed TTs”45.  
iii) The cuff pressure will be monitored and recorded at the time of initial inflation, during Xenon administration every 2 
hours and just prior to final deflation. It will also be minimised to typically 8-10 cm.H2O pressure (maximum permitted 
cuff pressure in above quoted study was 20 cm.H2O). 
Any Adverse Events at or around the time of extubation, such as stridor or failure of extubation secondary to vocal cord, 
nerve or subglottic damage will be recorded. In this way any theoretical risk of post-extubation stridor will be minimised.  
 
4.7.4 
Experience with cuffed tube in neonates with Xenon  
In 2010/2011 our group successfully undertook and completed the first human neonatal feasibility/safety study of 
Xenon+cooling, mainly 50% Xenon for periods of up to 18hrs. From this study, in terms of safety of the cuffed tube we 
can document: 
- 
Babies were reintubated with a cuffed tube 0.5mm smaller than the uncuffed tube that had been in place 
previously. Cuff pressure was measured frequently during the period of Xenon delivery and the cuff was 
deflated post-Xenon delivery. 
- 
The target cuff pressure was the lowest cuff pressure we could achieve without there being any gas leakage 
past the cuff. This was typically 11cm H2O, - much lower than the maximum of 20 cm H2O used in the above 
randomised tracheal tube study 
- 
We observed stridor post-extubation in 1 of the 14 babies.  
 
In the CoolXenon2 study we have observed stridor post-extubation in 2 of the 28 babies recruited to the study; one in 
the cooling only group and one in the cooling+Xenon group. These episodes of stridor were iatrogenic (due to head 
positioning and sedation effects from morphine) and not related to the cuffed endotracheal tube or Xenon. We aim to 
maintain the infants head in the midline and slightly extended. Infants are turned every 8 hours maintaining the midline 
position with slight extension.  
 
4.7.5 
Cleaning/disinfection 
The entire circuit is single-use. Between patients, the entire breathing circuit and hoses will be replaced with a fresh item.  
 
4.8 
Potential benefit to research participants 

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The hypothesis is that babies enrolled into the study may derive additional neurological benefit from the Xenon/cooling 
combination exceeding that seen from cooling alone, following the pattern seen in all the in-vivo small and large animal 
studies performed so far. 
  
4.9 
Follow Up 
4.9.1 
Short term information and investigations (before discharge from hospital) 
These are part of routine clinical practice. 
1. 
Survival 
2.  
Duration of hospitalisation 
3. 
Time to full oral feeds, breast or bottle or tube 
4. 
Hypoxic-ischaemic or other injury2 and MRI biomarkers such as absolute NAA quantification in 
Thalamus and white matter fractional anisotropy using tract based spatial statistics4 on MRI scan, which 
includes Magnetic Resonance Spectroscopy, undertaken around 48 hours and around day7 of life.   
5.  
Intracranial or intraventricular haemorrhage (on MRI, CT or ultrasound) 
6.  
Major venous thrombosis (on MRI or ultrasound) 
7. 
Resistance Index (Doppler examination of cerebral blood flow velocities) 
8. 
Amplitude integrated EEG (aEEG) continuously recorded until after rewarming. Assessment of time to 
normalisation of background activity, seizure occurrence and duration 
9.  
Pulmonary hypertension needing treatment 
10.  
Pulmonary haemorrhage  
11.  
Pneumonia 
12.  
Pulmonary air leak 
13.  
Systemic hypotension needing inotropic support 
14.  
Prolonged blood coagulation time assessed before Xenon and at ~24 hours and/or at clinically indicated 
timepoints 
15.  
Cardiac arrhythmia (not temperature induced low Heart Rate) 
16.  
Thrombocytopenia (platelets <100,000/ul) 
17.  
Culture proven sepsis 
18.  
Necrotising enterocolitis, medical, radiological or surgically proven  
19. 
Plasma markers of global (increased lactate dehydrogenase (LDH)) or cardiac compromise (increased 
cardiac Troponin T (cTnT)) 
20.  
Renal failure treated with dialysis 
 
4.9.2 
Short term assessment neurological evaluation 
1) 
Time to recovery after birth of a normal aEEG1 
2) 
MRI scan undertaken around 48-hours of life and around day 7 of life2,4,35,46 
3) 
Peak LDH value within 72h of life5,36  
4) 
First plasma glucose after birth (usually from cord blood) 
5) 
Age in hours after birth  when plasma lactate has declined to <5mmol/l 
6) 
Number and type of inotropic drugs needed during stay on the neonatal intensive care unit (typically 
the period from birth to 3-5 days of age) and the total duration in hours of any inotropic support. 
7) 
Number of anticonvulsant drugs given during stay on the neonatal intensive care unit. 
8) 
Amount and duration of sedation (e.g. plasma morphine levels) and stress levels (saliva, plasma and 
urine cortisol and Adrenocorticotropic hormone) while ventilated mechanically on the neonatal 
intensive care unit. 
9) 
Age at full oral feeds (breast or bottle or tube) 
10) 
Outcomes of neonatal hearing screening before 14 days of life 
11) 
Clinical examination at birth, at 7 days of age and at discharge including weight and head 
circumference 
 
4.9.3 
Long term follow up (at 18 months) 

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Neurodevelopmental follow up is a part of the routine follow up of infants with Neonatal Encephalopathy.  Bayley III 
examination at 18 months of age is used to compare the results from this study with our large local patient database and 
previous randomised controlled trials (CoolCap, Gluckman 2005; TOBY, Azzopardi 2009)13,14 where Bayley II was also used: 
we were a main recruiting centre for these trials. 
 
Disability will be defined as any of: 
• 
Bayley III Cognitive and Language Composite score less than 85. 
• 
Bayley III Motor Composite score less than 85.   
o 
Bayley III  will also be expressed as  developmental quotients (DQ) calculated from Developmental Age 
scores as this allows a larger range of score for those functioning at a low level37. In this study a Bayley III 
assessment11 will be undertaken and data will be converted to Bayley II MDI and PDI for comparison with 
historical controls.                                
• 
Bilateral cortical visual impairments.  
• 
Hearing loss needing amplification > 40 dB. 
 
4.9.3.1 Additional follow up 
We will do both short-term (14 days) and long-term (18 months survival) follow-up.  In cooled babies we have shown that 
short-term predictors such as MRI at day 82, time to normal aEEG1 and peak LDH before 72h5 predict long-term outcome 
with a positive predictive value of 84%, 92% and 80% respectively. Absolute quantification of N-acetyl aspartate in 
Thalamus and white matter fractional anisotropy using tract based spatial statistics4 predict long term outcome. In this 
study we will continue as a secondary outcome to examine these potential predictors for cooled babies receiving Xenon 
treatment.   
 
4.10 
Group size 
Twenty-six babies will be recruited into each group (cooling+Xenon vs. cooling alone) at random. The cooling will be 
applied as standard treatment if cooling criteria are met. Addition of Xenon in combination with this underlying cooling 
will take place in the group randomised to receive cooling + Xenon. 
 
4.11 
Justification of Treatment / Procedure 
Even with the best available treatment (hypothermia) infants with HIE have a considerable risk of death or disability of 
<40%. This study offers an additional treatment which has been shown in two animal species to improve (double) brain 
protection over and above the protection from cooling alone. Our large animal trial of Xenon-hypothermia in piglets 
conducted with a delivery system of the same design as proposed for this study concluded with a very positive outcome18 
supporting the result we found in rats, i.e. adding Xenon to HT doubles the neuroprotection17,31. 
 
This equipment has been successfully and safely used to deliver Xenon to a total of 32 human neonates to date in the 
MHRA approved studies, CI/2009/0043, CI/2011/0061; CooXenon1 and CoolXenon2 respectively.  
 
5.0 
Study Therapies 
 
5.1 
Test Article: Description 
The neonatal Xenon breathing device (NXBD) is a gas delivery circuit with some similarities to an anaesthesia circuit that 
is temporarily placed between a standard mechanical ventilator and the tracheal tube of a neonate to deliver Xenon as a 
therapy in the breathing gas. It is designed for use in neonates who already require mechanical ventilation in this manner 
on a neonatal intensive care unit. Its purpose is to provide a gas mixture to the lungs that contains not only an appropriate 
oxygen concentration to maintain life, but also to provide a concentration of up to 50% Xenon in this mixture. The reason 
for this is that Xenon shows great promise as a neuroprotectant and has been shown to reduce neurological damage in 
both small and large laboratory in-vivo models of neonatal hypoxia-ischaemia (birth asphyxia for example). By re-
circulating the exhaled gases after removal of carbon dioxide then, as the uptake of Xenon by a neonate is very low and 
the system does not “vent” any exhaled gas to the environment, it provides a very economical method of Xenon delivery. 
Such economy will be essential for any future clinical use of Xenon as this gas is both limited in availability and extremely 
expensive at approximately £20/litre. While the (minimal) Xenon uptake is replaced manually by the operator, the 
breathing device automatically adds oxygen as required to match metabolic uptake by the patient. This is not achieved 

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by complex sensors and electronics but by a straightforward mechanical mechanism for reliability. Furthermore, if Xenon 
replacement is stopped, the inspired oxygen concentration will tend to very slowly increase i.e. it will not fall as the 
patient consumes oxygen from the circuit – these are both inherent safety features. The most important and intuitive 
safety feature is that in the event of any problem, the mechanical ventilator patient connector can be disconnected from 
the breathing system and reconnected directly to the tracheal tube of the neonate, instantly restoring normal ventilation 
and also allowing any Xenon to very rapidly dissipate from the tissues of the neonate. 
 
5.2 
Test Article: Principles of Operation 
If no fresh oxygen is supplied to a conventional anaesthesia circle system the patient will consume all oxygen present 
until a hypoxic mixture develops. Therefore in a closed circle system, fresh gases must be added at a rate exactly matching 
patient uptake of each gas. There are various ways to achieve this. In the simplest of closed underwater diving systems, 
the user will breathe pure oxygen around a circuit similar to an anaesthesia circle. In time, by metabolic oxygen 
consumption, the reservoir bag will completely collapse part-way through an inspired breath. At this point, by continued 
inspiratory effort, a demand valve on an attached oxygen cylinder will open, providing the missing volume of oxygen to 
complete the inspiration phase. If we now imagine this circle to contain a mixture of Xenon (slow patient uptake) and 
oxygen (metabolic uptake) a different situation develops. It can be envisaged that substitution of these two uptake 
volumes with pure oxygen at each end-inspiration would produce a slowly increasing inspired oxygen fraction (FiO2). 
 
We have incorporated these concepts into a ventilator driven closed circuit where a standard Neonatal Intensive Care 
Unit (NICU) ventilator, set to deliver 100% oxygen in each breath to the circuit, provides not only the motive power but 
also, via a special volume substitution valve, the required oxygen replenishment in place of the demand valve in the diving 
example. 
 
When delivering a Xenon/oxygen mixture there would then be a background tendency for the FiO2 to slowly increase 
while the inspired Xenon concentration decreases at a similar rate. This provides a degree of hypoxic mixture protection 
without use of oxygen sensor and computer software controlled electronic valves. In other words, adequate oxygen 
supply, the most critical function of any breathing system, is not entirely dependent on correct functioning of sensors, 
software and electronic dosing valves, as would be the case with an electronically controlled system. 
 
Against this inherent safety feature of a very slowly increasing the FiO2, and the minimal Xenon uptake of a neonate from 
the closed loop circle breathing system, Xenon can then be delivered to the circle in small volumes under manual control 
to offset this trend, replacing the minimal patient Xenon uptake. 
 
The design of a breathing circuit to achieve these design aims is described in Figures 1a and 1b.  
 
Figure 1a. Diagram of the breathing system 
 

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Figure 1b. Views of breathing system (without hoses) 
The Xenon delivery system is designed to be fitted between a conventional NICU mechanical ventilator (SLE 2000, SLE, 
South Croydon, UK) and the tracheal tube. The latex-free bag in the lower chamber has a volume of 500ml, larger than a 
neonatal tidal volume, providing free space to accommodate added Xenon bolus volumes without overspill. The 
removable soda-lime canister has a volume of 510ml permitting long periods of ventilation without replacement. 
 
In this design, a small aliquot of oxygen enters the closed circle upper part of the circuit at each end-inspiration from a 
lower bag-in-bottle chamber (where it is present as the driving gas from the ventilator) via a dedicated oxygen 
substitution valve. Modern NICU ventilators maintain a bias gas flow throughout the breathing cycle. At end-expiration 
this displaces any residual CO2 from the “Y” connector reducing CO2 rebreathing. However with a closed circuit, the 
absence of a bias flow combined with small neonatal tidal volumes means that an efficient self-closing, leak free, low 
opening pressure inspiratory valve was required to prevent rebreathing. A unidirectional valve performs this function. A 
similar valve design is used as the expiratory valve and as the oxygen substitution valve.  
 
5.2.1 
Gas delivery to breathing system  
Oxygen consumed by the neonate from the circle is replaced automatically via the oxygen substitution valve as described 
above and in Figure 1. The slow-rising FiO2 tendency (a condition of inherent safety against the development of accidental 
hypoxic mixtures) is then deliberately offset by occasional manual delivery of Xenon boluses to the circle, so maintaining 
the target Xenon concentration – the combination of closed circuit, low patient weight and low Xenon uptake making 
these Xenon doses very infrequent (<200ml Xe per hour from laboratory data). 
 

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Figure 1c. Details of exact medical components used to construct the hoses of the breathing circuit, with part numbers. Hoses, humidification 
chamber and connectors all manufactured by Armstrong Medical Ltd, UK 
 
Key to identified parts in Figure 1c. 
1372 
 
 
Connector 
1410/2/3  
Corrugated hose 
AMCA1142 
 
 
Water chamber to fit Fischer-Paykel humidifier base unit (an industry-standard humidification system for 
adult and neonatal ventilation systems). 
12/001 
 
 
Connector with port for Fischer-Paykel proximal temperature sensor and female socket to take power 
cable from Fischer-Paykel base unit for the heated wire system. 
1375 
 
 
Corrugated hose with heated wire. 
1374 
 
Connector with port to take distal temperature sensor of the Fischer-Paykel humidifier base unit. 
1410/2/0  
Corrugated hose link. 
1375 
 
 
Connector. Passy-Muir: Unidirectional valve 
1374 
 
 
Connector 
1410/2/1  
Corrugated hose link to tracheal tube connector. 
1105 
 
 
Tracheal tube connector. 
1302/1 
 
 
Cap for pressure monitoring port. 
1526 
 
 
Connector to fit pressure monitoring port 1302/1 
1331 
 
Male Luer fitting. 
1330 
 
 
Pressure monitoring hose. 
1331 
 
 
Male Luer fitting. 
1332 
 
 
Double female Luer connector. 
5200 
 
 
Filter 
1410/2/1  
Corrugated hose link from tracheal tube connector. 
1372/1374 
 
Hose connectors. 
1410/2/4  
Corrugated hose. 
1204 
 
 
Expiratory limb water trap. 

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1410/2/4  
Corrugated hose. 
1375 
 
 
Connector. Passy-Muir: Unidirectional valve. 
7055 
 
 
Bacterial filter with side mounted Luer port, where fresh gas is delivered to the system. 
1331/1330/1331 
Hose for connection to 7055 Luer port. 
 
We have previously delivered Xenon using high pressure Xenon cylinders with electronic valves actuated by both 
computer and manual control. After using servo control in the past we realised that due to the slow uptake of Xenon, 
manual addition of Xenon boluses would not be particularly onerous facilitating this more straightforward design devoid 
of any computer control systems. 
 
The manual Xenon dosing mechanism is designed to function at ambient pressure for additional simplicity and safety, so 
eliminating any risk of the circle “flooding” with Xenon due to a cylinder/regulator/electronic malfunction (Figure 2). 
 
Figure 2. 
 
A flexible bulb and valve arrangement allows manual addition of ~50ml Xenon boluses to the circle breathing system, 
from a previously filled reservoir bag of Xenon at ambient pressure. These are added to the expiratory limb of the circuit 
to allow maximum mixing with existing gases in the circle before entering the lungs. The small flexible bulb volume of 
50ml was selected because the small bulb volume combined with its slow refill properties further aids even gas mixing, 
it being impossible to rapidly add a large Xenon bolus. Erring on the side of caution, our circuit was primed with oxygen. 
The Xenon/oxygen monitors are constantly observed as in the conduct of a conventional anaesthetic. Deviations in Xenon 
concentration of more than 2-4% from target are corrected by the operator adding Xenon to the circuit, each 50ml bolus 
typically producing a 2% increase in Xenon concentration. These corrections offset the inherent tendency of this circuit 
design to generate a very slowly increasing oxygen concentration (O2 + minimal Xe consumptions being replaced with 
equal volume of oxygen via substitution valve). 
 
The overall design aims were that this breathing system should (i) be driven by a standard NICU ventilator, (ii) have 
inherent hypoxic mixture prevention properties not dependent on electronics (iii) provide the user with the most intuitive 
treatment reversal method; reconnection of the neonate directly to the NICU ventilator. It performs all these functions. 
  
5.3 
Test Article: Clinical Development 
A technical evaluation of the Xenon delivery system and the use of inhaled Xenon in an in-vivo laboratory model that 
replicated the human clinical scenario of; global hypoxic ischemic insult in a neonate followed by cooling (the standard 
treatment) and concurrent Xenon administration was published in 2010.18 It describes the early clinical development and 
performance of the delivery system and is attached in full as Appendix A2. 
 
5.3.1 
Proof-of-Concept Pre-clinical Studies 
Extensive pre-clinical work18 has been undertaken. These data were provided to the UK Competent Authority during the 
review process for the CoolXenon1 and CoolXenon2 studies. 
 
5.3.2 
Proof-of-Concept and Pilot Clinical Studies 

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The Bristol group has undertaken two studies involving the use of inhaled Xenon. A clinical feasibility/safety study in 14 
human neonates of inhaled Xenon in combination with cooling using this equipment design to deliver Xenon was 
successfully completed in March 2011. A further study has recruited 28 infants. In the CoolXenon1 or CoolXenon2 studies 
there were no significant physiological or biochemical changes or other problems attributable to the Xenon gas or the 
use of the NXBD. 
 
5.4 
Test Article: Regulatory Status 
The NXBD is not CE marked in Europe and therefore any UK clinical study involving its use requires review by, and approval 
from, the UK Competent Authority, the Medicines and Healthcare products Regulatory Agency (MHRA). Ethical approval 
for the study will also be obtained from an appropriate Research Ethics Committee (REC) prior to commencement. 
 
5.5 
Test Article: Packaging and Labelling 
The NXBD requires no packaging and will be clearly labelled in compliance with the requirements of the EU Medical 
Devices Directive. Devices used in any clinical trial will clearly be marked “Exclusively For Clinical Investigations”. 
 
5.6 
Test Article: Component Tracking 
Use of the NXBD will be tracked and reconciled throughout and upon completion of the study. Any complications with 
the device or components of the device should be managed by contacting the study Sponsor via the following telephone 
numbers: 
• Mary Perkins, R and D Dept Lvl 3,  Education & Research Centre, Bristol BS2 8AE. Tel 0117 3420233  (office hours) 
• Dr John Dingley Mobile: 07735 379471  (all other times) 
 
5.7 
Control/Comparator Therapy 
This is a randomised comparative outcomes study. The control group will receive the standard treatment for this 
condition which is whole body cooling for 72h as it would be unethical to withhold the normal treatment from the control 
group. The treatment group (experimental group) will also receive an identical cooling regime but in addition will receive 
50% Xenon within 5h of age in the breathing gas mixture via the NXBD breathing circuit for a period of 18h. 
 
 
6.0 
Patient Selection 
 
Potential study participants will be identified via the existing identification system used at St Michaels for administration 
of their (standard) cooling regime for the region. 
 
There is good evidence that the earlier cooling (now standard treatment) is started, the greater the ultimate benefit. 
Consequently neonates are often allowed to passively cool during retrieval to Bristol, where active cooling is then 
continued, in a bid to start the process as early as possible. This argument is also likely to be true for Xenon and there is 
in-vivo laboratory data to support this. Parents of potential participants in study therefore need to be approached as 
early as possible after birth if their baby meets entry criteria for the study. 
 
Therefore they will first be approached by a trained medical member of the clinical team. This person will briefly explain 
the study to the parents of the neonate with the aid of the information sheet, and later a member of the team will obtain 
written consent where this has been agreed.  
 
Informed written consent will be obtained from a parent (only the mother can consent if parents are not married) after 
a full verbal and written explanation of the study by a named physician or trained nurse such as an advanced nurse 
practitioner. Such staff will also meet with parents during the intervention period to ensure that they understand the 
study procedures and continue to consent to participate in the study. Information can be given by local trained staff and 
consent can also be taken over the phone with the mother if she is unable to be available for the consent process (e.g. 
cannot be moved shortly after Caesarean Section). 
 
Approval for the study is being obtained from the Regional South West Research Ethics Committee covering St Michael’s 
Hospital. 
 
Most of the patients will be born outside the study hospital (Outborn) and will constitute >90% of patients. They are 
brought to the hospital by a dedicated retrieval team and ambulance from Bristol. The local delivery hospitals will have 

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medical staff (e.g. consultants, specialist registrars, advanced nurse practitioners) trained in consenting for the 
CoolXenon3 trial. A training log with signatures, a short CV and competency approval will be kept centrally. 
 
Parents will receive a written information leaflet (1 page, short version, Appendix 5) when the infant is eligible for cooling 
treatment. Staff will discuss CoolXenon3 with parents as soon as practically possible. Parents will be able to speak on the 
phone to a member of the treatment team if they need further information and help with the consent process. Parents 
will also be offered the opportunity to speak to members of the treatment team that are picking up the baby for transport. 
 
Trained staff on the transport team can take consent for the study. 
 
A more detailed information sheet regarding the trial will be given to parents after the first conversation or at the earliest 
suitable time. 
 
6.1 
Which of the parents can consent to letting the child enter the trial? 
• 
Either parent if they are married 
• 
If the parents are not married, only the mother can consent - provided she is awake and understanding (e.g. not 
under the influence of anaesthetic drugs)  
• 
If the mother is not in a state to understand the situation (and the parents are living together but are not 
married) the father can consent on behalf of the mother.  The consent process must be repeated with the mother 
as soon as she is able to understand the child’s condition. 
 
A parent who is eligible to consent can, at any time and without a specific reason, withdraw the child from the study. In 
this situation, Xenon treatment will then be stopped as soon as possible and medically safe (within minutes). 
 
6.2 
Inclusion Criteria  
Patients meeting the following criteria will be considered eligible for the study: 
 
Infants will be eligible for inclusion in this study if the St Michael’s hospital standard inclusion criteria for cooling are met 
and additional inclusion criteria for Xenon administration are met. 
 
6.2.1 
St Michael’s Hospital standard inclusion criteria for cooling 
Standard Hypothermia Treatment Criteria for 72 hrs of cooling — all of criteria A, B and C. 
A:  
Infants ≥ 36.0 weeks gestation (estimated or clinical assessment) with at least ONE of the following:  
v. Apgar score of ≤5 at ten (10) minutes after birth  
vi. Continued need for resuscitation, including tracheal or mask ventilation, at ten minutes after 
birth  
vii. Acidosis defined as either umbilical cord pH or any arterial, venous or capillary pH within 60 
minutes of birth less < 7.00 
viii. Base deficit ≥16 mmol/L in umbilical cord blood sample or any blood sample within 60 minutes 
of birth (arterial or venous blood). If the infant meets criterion A then assess for neurological 
abnormality using criterion B and C (by trained personnel): 
 
 
B:  
Moderate or severe encephalopathy as evidenced by any of the following:  
vi. Altered state of consciousness (reduced or absent responses or pathological irritability and 
hyper responsive and at least ONE or more of the following: 
vii. Hypotonia 
viii. Abnormal reflexes including oculomotor or pupillary abnormalities  
ix. Absent or weak suck  
x. Clinical seizures, as recorded by trained personnel  
                                              AND  
C:  
At least 30 minutes duration of amplitude-integrated electroencephalography (aEEG) recording that 
shows abnormal background aEEG activity. The decision to cool is based on the worst 30 min section of 
the aEEG, not the best35 or seizures (clinical or electrical) thus meeting ONE of the following:  
v. Normal background with some (> 5 min)  electrical seizure activity  
vi. Moderately abnormal activity (upper margin of trace >10μV and lower margin <5μV) 
vii. Suppressed activity (upper margin of trace <10μV and lower margin of trace <5μV) 

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viii. Definite seizure activity 
   
6.2.2 
Additional inclusion criteria for Xenon 
Before being considered for additional inhaled Xenon therapy via the breathing gas mixture, the infant would need to 
meet further additional entry criteria (all must be met): Before being considered for additional inhaled Xenon therapy via 
the breathing gas mixture, the infant would need to meet further additional entry criteria (all must be met): 
i. 
Intubated, ventilated, sedated, being cooled. 
ii. 
<5 hours old 
iii. 
Any seizures under control. 
iv. 
Weight > 2nd centile for gestational age 
v. 
Stable cardiovascular parameters; Mean arterial pressure >40mmHg. 
vi. 
Oxygen requirement via mechanical ventilator < 40%. 
vii. 
Positive End Expiratory Pressure (PEEP) requirement ≤ 8cm H2O 
viii. 
Arterial/capillary/venous pCO2 <7.0kPa (ideally arterial). Venous can be higher if peri-arrest and tissues 
have been very recently Ischaemic 
ix. 
Postnatal age <5 hours 
x. 
Absence of major congenital abnormalities, imperforate anus and in particular any bowel obstruction, 
congenital abnormalities suggestive of chromosomal anomaly or other syndromes that include brain 
dysgenesis. Congenital syndromes affecting the brain should be excluded when diagnosed. 
 
6.3 
Exclusion Criteria 
6.3.1 
Exclusion criteria for cooling  
a. Infants expected to be greater than 3 hours of age at the time of starting cooling treatment. 
b. Futility. Where prognosis is considered to be hopeless e.g. no cardiac output for 20 minutes. 
 
6.3.2 
Additional exclusion criteria for Xenon 
i. 
Failure to meet any of the additional inclusion criteria for Xenon listed in section 5.1. 
ii. 
Patients meeting the following criteria are NOT eligible for the study: 
iii. 
Presence of any of: 
a. Major congenital abnormalities 
b. imperforate anus and in particular any bowel obstruction 
c. 
congenital abnormalities suggestive of chromosomal anomaly 
d. other syndromes that include brain dysgenesis. (Neonates with congenital syndromes affecting the 
brain should be excluded when diagnosed). 
 
6.4 
Prohibited Therapies 
Not Applicable. 
 
7.0 
Subject Assignment to Treatment Group 
 
The babies entered into the study will be randomised into groups; Xenon+cooling or cooling (standard treatment) alone. 
Neonates meeting all the entry criteria can be included. 
 
Immediately after enrolment, the patient will be assigned a study ID number, chronologically, from a specified series on 
an enrolment log specific to the Investigational Site. The Subject's study number and date of enrolment will be entered 
onto the enrolment log in the Study Binder. 
 
The babies entered into the study will be randomised into two groups on a 1:1 basis. Randomisation will be via sealed 
opaque envelopes containing details of treatment allocation and [an] identifying adhesive label(s) to be attached to the 
CRF binder. Neonates meeting all the entry criteria can be included. 
 
8.0 
Methods and Procedures 

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8.1 
Informed Consent 
Informed written consent will be obtained from a parent (only the mother can consent if parents are not married) after 
a full verbal and written explanation of the study by a named physician or trained nurse such as an advanced nurse 
practitioner. Such staff will also meet with parents during the intervention period to ensure that they understand the 
study procedures and continue to consent to participate in the study. Information can be given by local trained staff and 
consent can also be taken over the phone with the mother if she is unable to be available for the consent process (e.g. 
cannot be moved shortly after Caesarean Section). 
 
Approval for the study is being obtained from the Regional South West Research Ethics Committee covering St Michael’s 
Hospital. 
 
Most of the patients (>90%) will be born outside the study hospital and are brought to the hospital by a dedicated retrieval 
team and ambulance from Bristol. The local delivery hospitals will have medical staff (e.g. consultants, specialist 
registrars, advanced nurse practitioners) trained in consenting for the CoolXenon3 trial. A training log with signatures, a 
short CV and competency approval will be kept centrally. 
 
Parents will receive a written information leaflet (1 page, short version, Appendix 5) when the infant is eligible for cooling 
treatment. Staff will discuss CoolXenon3 with parents as soon as practically possible. Parents will be able to speak on the 
phone to a member of the treatment team if they need further information and help with the consent process. Parents 
will also be offered the opportunity to speak to members of the treatment team that are picking up the baby for transport. 
 
Trained staff on the transport team can take consent for the study. 
 
A more detailed information sheet regarding the trial will be given to parents after the first conversation or at the earliest 
suitable time. 
 
Which of the parents can consent to letting the child enter the trial? 
• 
Either parent if they are married 
• 
If the parents are not married, only the mother can consent - provided she is awake and understanding (e.g. not 
under the influence of anaesthetic drugs) 
• 
If the mother is not in a state to understand the situation  and the biological father does currently not have legal 
parental responsibility he can assent for the trial until the mother is awake/understanding the child’s condition 
and able to decide on consent. 
 
A parent who is eligible to consent can, at any time and without a specific reason, withdraw the child from the study. In 
this situation, Xenon treatment will then be stopped as soon as possible and medically safe (within minutes). 
 
8.2 
Pre-Study   
Consent will be obtained as described above from parents of the neonates. Prior to this consent they will have been given 
an information leaflet describing the study and the discussion will have taken place with a Consultant Neonatologist 
involved in the study or a trained member of the Transport Team. 
 
8.3 
Screening 
All infants born in St. Michael’s Hospital or retrieved by ambulance from other centres to St. Michael’s Hospital Neonatal 
ICU will have undergone a basic screen of their condition at birth as part of standard procedures, the commonest example 
being the APGAR scoring system, cord blood analysis and clinical examination. Any infant suspected of being in a poor 
condition at birth will, by  locally present  neonatal staff, be assessed for possible cooling as a treatment to limit brain 
injury using the  approved entry criteria (as used in CoolCap and TOBY). Local hospitals will typically contact the St 
Michael’s team within 1 h of age to discuss eligibility, start cooling, transport and potential inclusion in Xenon study. At 
this point on advice from Bristol, information on the Xenon study can be given to parents.  
 
8.4 
Initial Assessment 
The following information will be recorded: 
 
8.4.1 
Demographics 
PATIENT 

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• Date of birth   
• LMP last menstrual period 
• EDD expected date of delivery 
• Gestational age  weeks, days e.g. 40 weeks, 3 days 
• Race  
• Gender 
• Weight 
MATERNAL 
• Years in education 
• Labour induced on maternal indication? 
• Maternal medical treatment during pregnancy 
 
8.4.2 
Patient History and Physical 
• 
Delivery and resuscitation details , Review of Systems,  Transport details if retrieved from another centre, 
Current  diagnoses 
•              Clinical examination 
 
8.4.3 
Concomitant Medications 
All concomitant medications will be recorded as follows: 
• Medication; Start (and Stop date(s) if applicable); Indication; Dose   
 
8.5  
Study Phases 
The study consists of 3 phases.  
 
8.5.1 
Phase 1  
Identification of potential subjects – initially using same identification method used in St. Michael’s Hospital Bristol to 
identify infants who would benefit from cooling.  
 
Compliance with all inclusion/exclusion criteria for use of Xenon in addition to cooling (the standard treatment).  
 
8.5.2 
Phase 2  
Formal recruitment, information supplied to / discussions with parents. 
Consent. 
 
8.5.3 
Phase 3  
Completion of all screening / demographics / baseline data collection immediately pre-Xenon, reintubation with cuffed 
tube, x-ray for tube placement and blood gas  
 
Administration of 50% Xenon for 18 hours to infant according to randomisation protocol. 
 
Completion of all data collection, serum chemistry and examinations immediately post-Xenon and post-cooling. 
 
8.5.4 
Patient Follow-up 
8.5.4.1 Short term information and investigations (before discharge from hospital): 
These are part of routine clinical practice. 
1. 
Survival 
2.  
Duration of hospitalisation 
3. 
Time to full oral feeds, breast, bottle or tube. 
4. 
Hypoxic-ischaemic or other injury2 and MRI biomarkers including quantification of NAA in thalamus and 
fractional anisotropy in white matter using tract based spatial statistics4 on MRI scan, which includes 
Magnetic resonance spectroscopy, undertaken around 48 hours of life and around day 7 of life.  
5.  
Intracranial or intraventricular haemorrhage (on MRI, CT or ultrasound) 
6.  
Major venous thrombosis (on MRI or ultrasound) 
7. 
Resistance Index (Doppler examination of cerebral blood flow velocities) 
8. 
Amplitude integrated EEG (aEEG) continuously recorded until after rewarming, or 82h in cooled-only 
infants. Assessment of time to normalisation of background activity, seizure occurrence and duration 

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9.  
Pulmonary hypertension needing treatment 
10.  
Pulmonary haemorrhage  
11.  
Pneumonia 
12.  
Pulmonary air leak 
13.  
Systemic hypotension needing inotropic support 
14.  
Prolonged blood coagulation time assessed before Xenon and at ~24 hours and/or at clinically indicated 
timepoints 
15.  
Cardiac arrhythmia (not temperature induced low Heart Rate) 
16.  
Thrombocytopenia (platelets <100,000/ul) 
17.  
Culture proven sepsis 
18.  
Necrotising enterocolitis or intestinal perforation, medical, radiological or surgically proven  
19. 
Plasma markers of global (increased lactate dehydrogenase (LDH)) or cardiac compromise (increased 
cardiac Troponin T (cTnT)) or plasma lactate 
20.  
Renal failure treated with dialysis 
 
8.5.4.2 
Short term assessment neurological evaluation will include 
1. Time to recovery after birth of a normal background aEEG1   
2. MRI scan before 14 days of life2,4,35 
3. Peak LDH value within 72h of life5,36  
4. First plasma glucose after birth (usually from cord blood) 
5. Age in hours after birth  when plasma lactate has declined to <5mmol/l 
6. Number and type of inotropic drugs needed during stay on the neonatal intensive care unit (typically the 
period from birth to 3-5 days of age) and the total duration in hours of any inotropic support 
7. Number of anticonvulsant drugs given during stay on the neonatal intensive care unit. 
8. Amount and duration of sedation (e.g. plasma morphine levels) while ventilated mechanically on the 
neonatal intensive care unit. 
9. Stress levels (saliva, plasma and urinary cortisol and adrenocorticotropic hormone) 
10. Age at full oral feeds (breast or bottle or tube) 
11. Outcomes of neonatal hearing screening before 14 days of life 
12. Clinical examination at birth, at 7 days of age and at discharge including weight and head circumference 
 
8.5.4.3 Long term follow up (at 18 months) 
Neurodevelopmental follow up is a part of the routine follow up of infants with Neonatal Encephalopathy.  Bayley III 
examination at 18 months of age is used to compare the results from this study with our large local patient database and 
previous randomised controlled trials (CoolCap, Gluckman 2005; TOBY, Azzopardi 2009)13,14 where Bayley II was also used: 
we were a main recruiting centre for these trials. 
 
Disability will be defined as any of: 
• 
Bayley III Cognitive and Language Composite score less than 85. 
• 
Bayley III Motor Composite score less than 85  
o 
Bayley III will also be expressed as developmental quotients (DQ) calculated from Developmental Age 
scores as this allows a larger range of score for those functioning at a low level37In this study a Bayley III 
assessment11 will be undertaken and data will be converted to Bayley II MDI and PDI for comparison 
with historical controls.                                
• 
Bilateral cortical visual impairments.  
• 
Hearing loss needing amplification > 40 dB. 
 
8.5.4.4  
Additional follow up 
We will do short-term (14 days), intermediate (6 months) and long-term (18 months survival) follow-up.  
 
8.6 
Study Data 
All the patient study information will be coded by patient study number, anonymised and securely stored until the study 
is complete. Electronic data will be stored on a secure portion of a Hospital Trust computer. The Chief Investigator will 
ensure that all the patient identifying details have been removed prior to statistical analyses being undertaken. 

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The identification key linking study numbers to patient details will be kept by the CI (Prof Marianne Thoresen) in a locked 
filing cabinet in a locked office in the Neonatal Neuroscience office of St. Michael's Hospital Bristol, which also has two 
separate secure swipe card entry systems. 
 
8.7 
GP Notification 
The General Practitioner will be informed via a letter of the participation of the infant in the study when the infant is 
discharged from hospital. 
 
8.8 
Definition of End of Study 
 
The end of the trial as a whole will be when all recruited participants have completed the treatment and follow-
up period and all data has been collected and analysed, with data queries answered. 
 
9.0 
Assessment of Safety 
 
9.1  
Data Review Group 
An IDRG will be set up and appropriately constituted with clearly defined terms of reference. Their role will be to 
independently review the safety of the study after every 8th Xenon patient has been recruited and in the light of this make 
appropriate recommendations to the study team. 
 
The IDRG will also meet in the event of a death, regardless of cause.  This meeting will take place within ~14 days of the 
death and recruitment into the study will continue in the meantime.  This meeting could be in person or take the form of 
a teleconference. In our initial study of Xenon+cooling a partial external committee met at intervals of every other baby 
enrolled. For the CoolXenon2 study, the IDRG met after every 4th Xenon patient had been recruited.  
 
In the CoolXenon1 or CoolXenon2 studies there were no significant physiological or biochemical changes or other 
problems attributable to the Xenon gas or the use of the NXBD. An identical NXBD will be used in this study.  
 
Given the excellent safety record of the previous two studies involving Xenon use and the NXBD, it is considered 
appropriate that for this study the IDMG should meet after every 8th Xenon patient is recruited. 
 
 
 
9.2 
Composition of IDRG 
External Members (not involved with delivering the treatment) 
 
Dr David Evans BM BCh (Oxon) MA (Cantab) MRCP(UK) FRCPCH 
Consultant Neonatologist 
North Bristol NHS Trust 
Neonatal Intensive Care Unit  
Southmead Hospital  
  
Bristol    BS10 5NB UK 
Contact details: 
david.evans@nbt.nhs.uk 
david.evans@bristol.ac.uk 
 
 
 
Professor Colin Morley 
Professor of Neonatal Medicine (Retired) 
23 High St 
Great Shelford 
Cambridge   CB22 5EH UK 
Contact details: 
Mobile: 07591 647097 
Home: 01223 846944 
colin@morleys.net 
 
 
Dr Steven Jones MB FRCPCH 
Director  
Southwest Neonatal Network 
Consultant Neonatologist  
Royal United Hospitals  
Coombe Park 
Bath  BA1 3NG 
Contact details: 
Tel: 01225 825405 
Steve.Jones@RUH.nhs.uk 
 
 

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Neonatal Xenon Breathing Study. St. Michael’s Hospital, Bristol. 
          
Second Site, Imperial /Hammersmith, London 
Dr Steven Sale MB ChB FRCA 
  
Paediatric Anaesthetist 
University Hospitals Bristol NHS Foundation Trust 
Bristol Royal Hospital for Children 
 
Upper Maudlin Street 
Bristol   BS2 8BJ 
Contact details: 
steven.sale@uhbristol.nhs.uk 
 
 
Lay member: 
Paula Windsor  BMedSci (Hons)  
SR Paramedic 
School House 
Peter Street  
Frocester 
Glos      GL10 3TQ 
Contact details: 
Tel: 01453 822833 
paulaascott@hotmail.com 
 
  
The IDMG should invite at least one member from the research team to attend their meeting. 
 
9.3 
Criteria for stopping the study (stopping rule) have been developed according to the following logic: 
The underlying mortality is approximately 10.3% in this cohort of infants (without Xenon). Usually care is redirected based 
on futility, i.e. the clinical condition and state of the brain is such that no meaningful life can be expected. 
 
9.3.1 
Reasons for stopping Xe delivery before the 18h timepoint 
Cardiovascular problems sometimes present as untreatable hypotension. In this situation the heart has also suffered 
hypoxia-ischaemia and sometimes it is impossible to maintain a perfusion pressure even with the use of maximum 
inotropic support. 
 
Another problem would be if the neonate develops a very high oxygen fraction (up to 100%) in the breathing gas over 
time, >40% according to the study entry criteria. An example would be those who have aspirated meconium.                       
9.3.2 
Stopping rule 
Mortality since cooling became standard of care at St Michaels hospital (inborn and outborn) fell from 34%to 10.3% (17 
out of 165 infants born since December 2006 and undergoing cooling died). If, with this (10.3%) underlying mortality, the 
two first infants receiving Xenon die, the probability that this is a random event is very small (p=0.01) and recruitment 
should be stopped and the protocol reviewed. The same applies if 2 out of the first three babies randomised to Xenon 
die (p=0.03). 
 
Thereafter, (n is the number of ‘Xenon’ babies included in the study):  
 
n 
Number of Deaths 
Action 
2 
2 of 2 
Stop study and review 
3 
2 of 3 
Stop study and review 
4 
3 of 4 
Stop study and review 
5 
3 of 5 
Stop study and review 
6 
3 of 6 
Stop study and review 
7 
3 of 7 
Stop study and review 
8 
3 of 8 
Stop study and review 
9-14 
4 
Stop study and review 
15-22 
5 
Stop study and review 
23-26 
6 
Stop study and review 
This stopping rule is based on two considerations:  
 
i. 
Probabilities given 10.3 % mortality without Xe 
ii. 
Stricter rule with more babies included 

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9.4 
Adverse Events (AEs) 
Adverse events will be recorded in accordance with UH Bristol’s Research Safety Reporting SOP and standard national 
regulatory requirements. 
 
9.5 
AE Definitions 
Adverse Event (AE) 
“Any untoward medical occurrence in a patient or clinical trial subject administered a medicinal product and which does 
not necessarily have a causal relationship with this treatment” 
 
Adverse Reactions (ARs) 
“All untoward and unintended responses to an investigational product related to any dose administered” 
 
Serious Adverse Event (SAE) 
“Any untoward medical occurrence or effect that at any dose results in death, is life – threatening, requires hospitalisation 
or prolongation of existing hospitalisation, results in persistent or significant disability or incapacity or is a congenital 
anomaly or birth defect.” 
 
Unexpected Adverse Reaction (UAR) 
“An adverse reaction, the nature or severity of which is not consistent with the applicable product information (e.g. 
investigator’s brochure for an unauthorised medicinal product or summary of product characteristics for an authorised 
product)” 
 
9.5.1 
Assessment of causality 
1. Not related – temporal relationship of the onset of the event, relative to the administration of the product, is 
not reasonable or another cause can by itself explain the occurrence of the event. 
2. Unlikely 
3. Possibly related – temporal relationship of the onset of the event, relative to administration of the product, is 
reasonable but the event could have been due to another, equally likely cause. 
4. Probably related – temporal relationship of the onset of the event, relative to the administration of the product, 
is reasonable and the event is more likely explained by the product than by another cause. 
5. Definitely related – temporal relationship of the onset of the event, relative to the administration of the product, 
is reasonable and there is no other cause to explain the event or a re-challenge (if feasible) is positive. 
 
 Of the above definitions,  
“possibly”, “probably” and “definitely” related to an investigational medical product are considered adverse reactions 
“unlikely” and “not related” do not qualify as a causal relationship. 
 
The severity and causality of a serious adverse event, adverse event or SUSAR (Suspected Unexpected Serious Adverse 
Reaction) should be assessed by a qualified medical practitioner, usually (but not always) the Chief Investigator (CI). 
 
Adverse events or reactions that are not life threatening and do not result in death or hospitalisation may also be 
considered serious if they jeopardise the subject or require intervention. 
 
All adverse events must be reported to the sponsor immediately, unless they are identified as not requiring this in the 
trial protocol. It is then the responsibility of the sponsor to report the incident to the MHRA. 
 
9.6 
AE Classification 
The Investigator(s) will establish the causality of AEs. 
 
9.7 
AE Recording 
All Adverse Events volunteered by study Patients or elicited by the Investigator must be recorded on the AE forms 
provided.  All AEs must be recorded whether or not considered drug / treatment related. 
 
9.8 
AE Reporting 
The Investigator must report by telephone all serious AEs to the Sponsor immediately upon discovery, and forward the 
completed AE form as soon as it is available.  If the event has been classified serious / severe, or there is any suspicion 

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that the AE was caused by a test article, details of medical history, concomitant medication and an assessment of 
compliance with therapy should accompany the AE form.  The Investigator must also report the resolution reported AEs 
promptly.  
 
Non-serious AEs should be reported at the next routine contact. 
The time period allowed for reporting such events to the MHRA are as follows: 
Reaction which is fatal or life threatening, as soon as possible but no later than 7 days after first occurrence 
Reaction which results in hospitalisation /disability/congenital anomaly, as soon as possible, but no later than 15 days 
after first occurrence 
 
9.9 
Reporting Responsibilities to Regulatory Authorities, Investigators and Ethics Committees 
The study will be performed subject to Research Ethics Committee (REC) approval, including any provisions of Site Specific 
Assessment (SSA), and local Research and Development (R&D) approval.  The Sponsor will send appropriate safety 
notifications to regulatory authorities in accordance with applicable laws and regulations. 
 
The Investigator must comply with any applicable site-specific requirements related to the reporting of SAEs involving 
his/her subjects to the REC that approved the trial. 
 
In accordance with ICH GCP guidelines, the Sponsor will inform the Investigator of “findings that could adversely affect 
the safety of subjects, impact the conduct of the trial or alter the REC approval to continue the trial”. 
 
10.0 
Data Analysis and Statistical Plan 
 
10.1 
Statistical Analysis 
This is a prospective randomised comparative outcome study. Data presentation will include descriptive statistics only. 
These will be compared in the 2 treatment groups but also to recordings of the same variables in a similar group of 45 
infants (recruited to cooling only from the same entry criteria) recently treated in our department (historical control 
data). Differences between the groups will be estimated 
 
Sample size is 26 infants in each group. The advisory statistician for this study is Professor Lars Walløe who has also 
advised on all aspects of the Xenon work (pre-clinical and clinical) undertaken to date. 
 
10.2 
Interim Analysis and Stopping Rules 
No interim analyses are planned. Stopping rules are detailed in Section 9.3.1. 
 
11.0 
Withdrawal of Subjects from Study 
 
Patients may be withdrawn from the study for any of the following reasons: 
• 
Experiences clinically significant Adverse Event as determined by the Chief Investigator 
• 
Requests to be withdrawn from the study  
• 
Is unable to complete the study because of unforeseen circumstances 
• 
Develops other conditions for which, in the Investigator’s opinion, it is in the Patient’s best interest to be withdrawn 
from the study 
 
12.0 
Modification of Protocol 
Any amendments to this protocol must be approved by MHRA, the appropriate REC, the Sponsor and Investigators. 
 
13.0 
Discontinuation of Study 
See Section 9.3.1. 
 
14.0 
Administrative Requirements, Ethical and Regulatory Aspects and Quality Assurance 

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14.1 
Study Approvals: MHRA, Research Ethics Committee (REC) and NHS Trust R&D Approval 
Before the study can begin the Chief Investigator must provide the Sponsor with: 
i. 
a signed copy of a letter of “No Objection” from the MHRA 
ii. 
a copy of the approval notice for the protocol from the appropriate Research Ethics Committee, signed by the 
Chairperson;  
iii. 
a copy of the research governance approval from the  University Hospitals Bristol NHS Foundation Trust. 
 
This study will be conducted in accordance with:  
• 
The Medicine for Human Use (Clinical Trial) Regulations 2004. 
• 
The EU Medical Device Directive, 93/42/EEC of 14 June 1993 
• 
BS EN ISO 14155 (2011) Clinical investigation of medical devices for human subjects. Good clinical practice 
• 
International Conference for Harmonisation of Good Clinical Practice (ICH GCP) guidelines. 
• 
Research Governance Framework for Health and Social Care  
 
14.2 
Responsibilities of the Investigator 
The Investigator shall be responsible for ensuring that the clinical study is conducted in accordance with the protocol, the 
ethical principles enshrined in the Declaration of Helsinki (Appendix 9), ICH guidance on Good Clinical Practice and all 
applicable regulatory requirements.  
In all cases the informed consent of subjects or their legal representatives is an essential precondition for participation in 
any clinical study. 
 
14.3 
Subject Information 
An unconditional prerequisite for a subject participating in the clinical study is his/her written informed consent. 
Therefore, adequate information must be given to the subject by the Investigator (in this case parent) before informed 
consent is obtained. A subject information sheet will be provided by the Sponsor for the purpose of obtaining informed 
consent. In addition to this written information, the Investigator will verbally inform the subject. The wording used in the 
information sheet will be such that it can be fully and readily understood by laypersons. The subject information sheet 
will be revised whenever new information becomes available that is relevant to the consent of the subjects. 
14.4 
Subject Consent 
The written informed consent of the subject (in this case subject’s representative – a parent) to participate in the clinical 
study has to be given before any study-related activities are carried out. It must be signed and dated by the subject and 
by the Investigator or person designated by the Investigator to conduct the informed consent discussion. 
 
14.5 
Source Data and Subject Files 
The Investigator must keep a written subject file for every subject participating in the clinical study. In this subject file, 
the available demographic and medical information of a subject has to be documented, in particular the following: name, 
DOB, sex, height, weight, medical history, concomitant diseases and medications (including changes during the study), 
statement of entry into the study, study identification, randomisation number (if applicable), date of informed consent, 
all study visit dates, predefined performed examinations and clinical findings, observed AEs and reason(s) for withdrawal 
from the study, if applicable. 
 
It should be possible to verify the inclusion and exclusion criteria for the study from the available data in the file. It must 
be possible to identify each subject by using this subject file.  
 
Additionally, any other documents with source data have to be filed. This includes ECG tracings, X-ray films, CT and MRI 
scans, laboratory value listings and QoL questionnaires. All these documents have to contain a subject identifier and 
details of the study procedure to which the document belongs.  
 
14.6 
Reporting and Recording of Data 
The data recorded during the course of this study must be documented on the Case report Forms (CRFs) and forwarded 
to the Sponsor. The Investigator must ensure the CRFs do not contain the names of any study subjects. All fields on the 
CRFs must be completed.  
 
All study data will be recorded on the CRFs.  All CRF’s must be made available to the Study Monitor as soon as they have 
been completed so that the validity and completeness of the forms can be determined.  Where possible all CRF data 

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should originate from a verifiable medical record.  All data should be recorded in black ink on the CRF for ease of 
duplication, interpretation and analysis. 
 
Any corrections should be made by scoring through the original value with a single line and writing the new value next to 
the original entry with the Investigator initialling and dating the new entry.  Only the Investigator or designated staff may 
amend or otherwise alter any data entered onto the CRF.  In addition any changes must be made on all copies of the 
document so that there is no difference between copies. If the reason for the correction is not obvious then, when 
appropriate, a brief explanation of the reason for the correction should be made.  Correction fluids should never be used 
on any document.  Before providing copies of completed CRF’s to the Study Monitor, the Investigator should review their 
completeness, accuracy and legibility. The Chief Investigator must always retain a copy of all completed CRF’s in the site 
Study Master File. 
 
14.7 
Monitoring 
The study will be monitored and audited in accordance with UH Bristol’s policy. All trial related documents will be made 
available on request for monitoring and audit by UH Bristol, the relevant Research Ethics Committee and for inspection 
by the Medicines and Healthcare products Regulatory Authority or other licensing bodies. 
 
The Chief Investigator will permit the Study Monitor to visit the Investigational Site at regular intervals to review all the 
CRFs, study management and GCP compliance. 
 
During monitoring visits, the Study Monitor will: 
• 
Help resolve any problems 
• 
Examine CRFs for omission of data, compliance and possible AEs 
• 
Discuss inconsistencies in the study data 
• 
Ensure that all study materials are correctly stored and dispensed 
• 
Check adherence to the obligations of the Investigator 
• 
Review consent forms, in particular the date of consent and signature 
• 
Perform source data verification as described below 
In line with ICH guidelines, monitoring will include verification of data entered in the CRF against original subject records. 
This verification will be performed by direct access to the original subject records and the Sponsor guarantees that subject 
confidentiality will be respected at all times. Participation in this study will be taken as agreement to permit direct source 
data verification. The Study Monitor must be kept informed of all issues pertinent to the study.   
 
At the final monitoring visit the Study Monitor must resolve any outstanding data deficiencies and retrieve all used and 
unused test articles.  
 
14.8 
On-site Audits 
The various National Regulatory Authorities, and the Sponsor, in the person of a scientifically trained and properly 
authorised employee, have the right to inspect all study records, including source documents. In the event of a 
notification of audit being received, the Chief Investigator should immediately notify the Sponsor. 
 
14.9 
Record Storage and Retention 
Data will be collected and retained in accordance with the Data Protection Act 1998. Study documents (paper and 
electronic) will be retained in a secure location during and after the trial has finished. All source documents will be 
retained for a period of 15 years following the end of the study. Where trial related information is documented in the 
medical records - those records will be identified by a 'Do not destroy before dd/mm/yyyy' label where date is 15 years 
after the last patient last visit.  Good clinical practice requires that a copy of all study data and documentation must be 
retained in the files of the responsible Investigator for a minimum of 15 years following notification by Sponsor that all 
Investigations (not merely the Investigators’ portion) are completed, terminated, or discontinued. If the Chief Investigator 
retires, relocates, or for other reasons withdraws from the responsibility of keeping the study records, custody must be 
transferred to a person who will accept responsibility.  
 
14.10 
Indemnity 
This is an NHS-sponsored research study. For NHS sponsored research HSG(96)48 reference no. 2 refers. If there is 
negligent harm during the clinical trial when the NHS body owes a duty of care to the person harmed, NHS Indemnity 

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covers NHS staff, medical academic staff with honorary contracts, and those conducting the trial.  
 
NHS Indemnity does not offer no-fault compensation and is unable to agree in advance to pay compensation for non-
negligent harm.  Ex-gratia payments may be considered in the case of a claim. 
 
15.0 
Study Funding 
All costs related to the standard care of treating a newborn infant suffering from hypoxic-ischaemic brain damage with 
therapeutic hypothermia will be borne by the University Hospitals Bristol NHS Foundation Trust. Any additional costs 
related to this study will be funded by the Moulton charitable foundation (breathing circuits, xenon, research staff). 
 
16.0 
Publication 
The results of the study will be reported / disseminated in the following ways: 
• 
Peer reviewed scientific journals 
• 
Internal report 
• 
Conference presentations 
• 
Publication on website 
 
17.0 
References 
 
1 
Thoresen M, Hellström-Westas L, Liu X, de Vries LS. 
Effect of hypothermia on amplitude-integrated electroencephalogram in infants with asphyxia. 
Pediatrics 2010; 126: e131-139. Epub 2010 Jun 21. 
2 
Rutherford M, Ramenghi LA, Edwards AD, Brocklehurst P, Halliday H, Levene M, Strohm B, Thoresen M, 
Whitelaw A, Azzopardi D. 
Assessment of brain tissue injury after moderate hypothermia in neonates with hypoxic-ischaemic 
encephalopathy: a nested substudy of a randomised controlled trial. 
Lancet Neurol 2010; 9: 39-45. Epub 2009 Nov 5 
3 
Thayyil S, Chandrasekaran M, Taylor A, Bainbridge A, Cady E.B, Chong W.K, Murad S, Omar R.Z, Robertson 
NJ. 
Cerebral magnetic resonance biomarkers in neonatal encephalopathy: a meta-analysis 
Pediatrics 2010;125:e382-95. 
4 
Tusor N, Wuathoff C, Smee N, Merchant N, Arichi T, Allsop JM, Cowan FM, Azzopardi A, Edwards A.D, 
Counsell S.J. 
Prediction of neurodevelopmental outcome after hypoxic-ischemic encephalopathy treated with 
hypothermia by diffusion tensor imaging analysed using tract-based spatial statistics 
Pediatr Res 2012:72:63-9. 
5 
Karlsson M, Wiberg-Itzel E, Chakkarapani E, Blennow M, Winbladh B, Thoresen M. 
Lactate dehydrogenase predicts hypoxic ischaemic encephalopathy in newborn infants: a preliminary 
study. 
Acta Paediatr 2010; 99: 1139-1144. Epub 2010 Mar 19. 
6 
Elstad M, Whitelaw A, ,Thoresen M.  
Cerebral Resistance index is less predictive in hypothermic encephalopathic newborns.   
Acta Paediatr 2011; 100: 1344-1349 e-pub 18.5.2011 
7 
X. Liu, J. Dingley, E. Chakkarapani, N. Hoque, C. Hobbs, M. Thoresen. 
Xenon combined hypothermia treatment after HIE is still neuroprotective starting after a 5h delay. 
Pediatric Academic Societies’ Annual Meeting. Baltimore, Maryland, USA 2009. 
8 
Thoresen M, Hobbs CE, Wood T, Chakkarapani E, Dingley J. 
Cooling combined with immediate or delayed Xenon inhalation provides equivalent long-term 
neuroprotection after neonatal hypoxia-ischemia. 
J Cereb Blood Flow Metab 2009; 29: 707-714. Epub 2009 Jan 14. 

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Chakkarapani E, Thoresen M, Hobbs CE, Aquilina K, Liu X, Dingley J. 
A closed-circuit neonatal Xenon delivery system: a technical and practical neuroprotection feasibility study 
in newborn pigs. 
Anesth Analg 2009; 109: 451-60 
10 
Thoresen M, Liu X, Tooley J, Chakkarapani E, Dingley J.  
First Human Use of 50% Xenon Inhalation during Hypothermia for Neonatal Hypoxic-Ischemic 
Encephalopathy: The “CoolXenon” Feasibility Study.  
Pediatric Academic Societies’ Annual Meeting. Denver, Colorado, USA, 2011. 
11 
Jary S, Whitelaw A, Walløe L, Thoresen M. Comparison of Bayley-2 and Bayley-3 scores at 18 months in term 
infants following neonatal encephalopathy and therapeutic hypothermia. 
Devlpmtl Med Child Neurol 2013; Aug 9. doi: 10.1111/dmcn.12208. [Epub ahead of print] 
12 
Time Is Brain: Starting Therapeutic Hypothermia within Three Hours after Birth Improves Motor Outcome in 
Asphyxiated Newborns.  Thoresen M, Tooley J, Liu X, Jary S, Fleming P, Luyt K, Jain A, Cairns P, Harding D, 
Sabir H. Neonatology. 2013 Sep 12;104(3):228-233.  
13 
Gluckman PD, Wyatt JS, Azzopardi D, Ballard R, Edwards AD, Ferriero DM, Polin RA, Robertson CM, 
Thoresen M, Whitelaw A, Gunn AJ.  
Selective head cooling with mild systemic hypothermia after neonatal encephalopathy: multicentre 
randomised trial.  
Lancet 2005; 365: 663-70. 
14 
Azzopardi D, Strohm B, Edwards A, Dyet L, Halliday H, Juszczak E, Kapellou O, Levene M, Marlow N, Porter 
E, Thoresen M, Whitelaw A, Brocklehurst P.  
Moderate Hypothermia to Treat Perinatal Asphyxial Encephalopathy.  
N Engl J Med 2009;  361: 1349-1358 
15 
Edwards AD, Brocklehurst P, Gunn AJ, Halliday H, Juszczak E, Levene M, Strohm B, Thoresen M, Whitelaw 
A, Azzopardi D.  
Neurological outcomes at 18 months of age after moderate hypothermia for perinatal hypoxic ischaemic 
encephalopathy: synthesis and meta-analysis of trial data.  
BMJ 2010; 340: c363. doi: 10.1136/bmj.c363. 
16 
Jacobs SE, Berg M, Hunt R, Tarnow-Mordi WO, Infer TE, Davis PG. Cooling for newborns with hypoxic 
ischaemic encephalopathy. 
Cochrane Database Syst Rev. 2013; 1: CD003311. doi: 10.1002/14651858.CD003311.pub3. 
17 
Hobbs C, Thoresen M, Tucker A, Aquilina K, Chakkarapani E, Dingley J. 
Xenon and hypothermia combine additively, offering long-term functional and histopathologic 
neuroprotection after neonatal hypoxia/ischemia.  
Stroke 2008; 39: 1307-1313 
18 
Chakkarapani E, Dingley J, Liu X, Hoque N, Aquilina K, Porter H, Thoresen M.  
Xenon enhances hypothermic neuroprotection in asphyxiated newborn pigs. 
Annals of Neurology. 2010; 68:330-41. 
19 
Thoresen M, Bagenholm R, Loberg EM, Apricena F, Kjellmer I. 
Posthypoxic cooling of neonatal rats provides protection against brain injury.  
Arch Dis Child Fetal Neonatal Ed 1996; 74: F3-9 
20 
Bona E, Hagberg H, Loberg EM, Bagenholm R, Thoresen M. 
Protective effects of moderate hypothermia after neonatal hypoxia-ischemia: short- and long-term 
outcome.  
Pediatr Res 1998; 43: 738-745 
21 
Thoresen M, Penrice J, Lorek A, Cady EB, Wylezinska M, Kirkbride V, Cooper CE, Brown GC, Edwards AD, 
Wyatt JS, Reynolds EO. 
Mild hypothermia after severe transient hypoxia-ischemia ameliorates delayed cerebral energy failure in 
the newborn piglet.  
Pediatr Res 1995; 37: 667-70 
22 
Tooley JR, Satas S, Porter H, Silver IA, Thoresen M.  

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Head cooling with mild systemic hypothermia in anesthetized piglets is neuroprotective.  
Ann Neurol 2003; 53: 65-72 
23 
Thoresen M, Whitelaw A.  
Cardiovascular changes during mild therapeutic hypothermia and rewarming in infants with hypoxic-
ischemic encephalopathy.  
Pediatrics 2000; 106: 92-99 
24 
Liu X, Tooley J, Løberg E, Suleiman S, Thoresen M.  
Immediate hypothermia reduces cardiac troponin I following hypoxic-ischemic encephalopathy in newborn 
pigs.   
Ped Res e-pub 17 June. DOI: 10.1203/PDR.0b013e31822941ee 
25 
Shankaran S, Laptook AR, Ehrenkranz RA, Tyson JE, McDonald SA, Donovan EF, Fanaroff AA, Poole WK, 
Wright LL, Higgins RD, Finer NN, Carlo WA, Duara S, Oh W, Cotten CM, Stevenson DK, Stoll BJ, Lemons JA, 
Guillet R, Jobe AH:  
Whole-body hypothermia for neonates with hypoxic-ischemic encephalopathy.  
N Engl J Med 2005; 353: 1574-1584 
26 
Simbruner G, Mittal RA, Rohlmann F, Muche R; neo.nEURO.network Trial Participants. 
Systemic hypothermia after neonatal encephalopathy: outcomes of neo.nEURO.network RCT. 
Pediatrics 2010 Oct; 126: e771-8. Epub 2010 Sep 20. 
27 
Jacobs SE, Morley CJ, Inder TE, Stewart MJ, Smith KR, McNamara PJ, Wright IM, Kirpalani HM, Darlow BA, 
Doyle LW; Infant Cooling Evaluation Collaboration. 
Whole-body hypothermia for term and near-term newborns withhypoxic-ischemic encephalopathy: a 
randomized controlled trial.  
Arch Pediatr Adolesc Med 2011; 165: 692-700. Epub 2011 Apr 4. 
28 
Petzelt C.  
Prevention of neurotransmitter over-release by Xenon.  
Journal fur Anasthesie und Intensivbehandlung 2002; 2: S117 
29 
Petzelt C, Blom P, Schmehl W, Muller J, Kox WJ. 
Prevention of neurotoxicity in hypoxic cortical neurons by the noble gas Xenon.  
Life Sci 2003; 72: 1909-1918 
30 
Sabir H, Bishop S, Cohen N, Maes E, Liu X, Dingley J, Thoresen M.   
Neither Xenon nor Fentanyl Induce Apoptosis In The Newborn Pig Brain.   
Anesthesiology 2013; 119: 345-357 
31 
Dingley J, Tooley J, Porter H, Thoresen M.  
Xenon provides short-term neuroprotection in neonatal rats when administered after hypoxia-ischemia.  
Stroke 2006; 37: 501-506 
32 
Thoresen M, Hobbs C, Wood T, Chakkarapani E, J. D. 
Cooling combined with immediate or delayed Xenon inhalation provides equivalent long-term 
neuroprotection after neonatal hypoxia-ischemia. 
 Journal of Cerebral Blood Flow and Metabolism 2009; 29: 707-14 
33 
Thoresen M, Haaland K, Loberg EM, Whitelaw A, Apricena F, Hanko E, Steen PA. 
A piglet survival model of posthypoxic encephalopathy.  
Pediatric Res 1996; 40: 738-48 
34 
Chakkarapani E, Liu X, Dingley J, Thoresen M.   
Xenon enhances cardiostability in hypothermic asphyxiated newborn pigs.  
J Int Care Med; e-pub 13.12.11 DOI: 10.1007/s00134-011-2442-7 
35 
Counsell SJ, Tranter SL, Rutherford MA. 
Magnetic resonance imaging of brain injury in the high-risk term infant. 
Semin Perinatol 2010 ; 34: 67-78 
36 
Thoresen M, Liu X, Jary S, Brown E, Sabir H, Stone J, Cowan F, Karlsson M.  
Lactate dehydrogenase: a valid outcome- predictor in hypothermia treated newborn infants with hypoxic 
ischemic encephalopathy.   

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Acta Paediatr 2012; 101: 1038-1044 
37 
Jary S, Kmita G, Whitelaw A.  
Differentiating Developmental Outcome between Infants with Severe Disability in Research Studies: The 
Role of Bayley Developmental Quotients.  
J Pediatr 2011; 159: 211-214.e1. Epub 2011 Mar 10. 
38 
al Naqeeb N, Edwards AD, Cowan FM, Azzopardi D.  
Assessment of neonatal encephalopathy by amplitude-integrated electroencephalography.  
Pediatrics 1999 Jun; 103: 1263-71. 
39 
Perlman JM, Wyllie J, Kattwinkel J, Atkins DL, Chameides L, Goldsmith JP, Guinsburg R, Hazinski MF, Morley 
C, Richmond S, Simon WM, Singhal N, Szyld E, Tamura M, Velaphi S; Neonatal Resuscitation Chapter 
Collaborators. 
Neonatal resuscitation: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency 
Cardiovascular Care Science with Treatment Recommendations. 
Pediatrics 2010; 126: e1319-44. Epub 2010 Oct 18. 
40 
Dalen ML, Liu X, Elstad M, Løberg EM, Saugstad OD, Rootwelt T, Thoresen M. 
Resuscitation with 100% Oxygen Counteracts the Neuroprotective Effect of Therapeutic Hypothermia in 
the Neonatal Rat.  
Pediatr Res 2012; 71: 247-252 
41 
Francis RC, Philippi-Höhne C, Klein A, Pickerodt PA, Reyle-Hahn MS, Boemke W. 
Xenon/remifentanil anesthesia protects against adverse effects of losartan on hemodynamic challenges 
induced by anesthesia and acute blood loss. 
Shock 2010; 34: 628-635 
42 
Hanss R, Bein B, Turowski P, Cavus E, Bauer M, Andretzke M, Steinfath M, Scholz J, Tonner PH. 
The influence of Xenon on regulation of the autonomic nervous system in patients at high risk of 
perioperative cardiac complications. 
Br J Anaesth 2006; 96: 427-436. Epub 2006 Feb 24. 
43 
Marx T, Froeba G, Wagner D, Baeder S, Goertz A, Georgieff M. 
Effects on haemodynamics and catecholamine release of Xenon anaesthesia compared with total i.v. 
anaesthesia in the pig  
Br J Anaesth 1997; 78: 326-327 
44 
Goto T, Hanne P, Ishiguro Y, Ichinose F, Niimi Y, Morita S.  
Cardiovascular effects of Xenon and nitrous oxide in patients during fentanyl-midazolam anaesthesia. 
Anaesthesia  2004; 59: 1178-1183 
45 
Weiss M, Dullenkopf A, Fischer JE, Keller C, Gerber AC; European Paediatric Endotracheal Intubation Study 
Group. 
Prospective randomized controlled multi-centre trial of cuffed or uncuffed endotracheal tubes in small 
children. 
Br J Anaesth 2009; 103: 867-873. Epub 2009 Nov 3. 
46 
Martinez-Biarge M, Diez-Sebastian J, Kapellou O, Gindner D, Allsop JM, Rutherford MA, Cowan FM.  
Predicting motor outcome and death in term hypoxic-ischemic encephalopathy. 
Neurology 2011; 76: 2055-2061 
 
Publications currently in submission to journals 
 
Liu X, Dingley J, Scull-Brown E,Thoresen M Delayed Hypothermia-Xenon Treatment Improves Function but not Brain 
Pathology in Neonatal Rats Surviving to Adulthood. 
Submitted for publication: Ped Res 
 

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18.0 
Appendices 
 
Appendix A1 
 
Summary of Study Procedures 
 
1) Initial screening process using St. Michael’s Hospital existing screening protocol for administration of therapeutic 
cooling (now standard treatment in this group of infants). 
 
2) Additional screening: inclusion/exclusion criteria for administration of xenon. 
 
3) Discussion with parent(s) of infant. Patient information sheet 
 
4) Informed consent. 
 
5) Pre-xenon data collection: 
i) Collection of demographic information. 
ii) Documentation of concomitant medications. 
iii) Collection of baseline data pre-xenon, i.e. vital signs, mechanical ventilation requirements, serum chemistry, full 
blood count, arterial blood gases. 
 
6) Delivery of xenon according to protocol for 18 hours. 
 
7) Post-xenon data collection: 
i) Full blood count. 
ii) Serum chemistry. 
iii) Assessment of level of consciousness, tone, reactions. 
 
8) Follow up. Bayley clinical neurodevelopmental score at 18m. 
 
 

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Appendix A2 Pre-clinical technical feasibility study in pigs. 
 
 
 

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Appendix A3    Additional details on the conduct of the previous human clinical 
feasibility/safety study are given below, a summary of physiological effects is provided, a large 
quantity of physiological data from the cooled and xenon+cooling groups is also supplied. 
 
Single centre prospective non-randomised clinical feasibility study “CoolXenon” 
 
http://www.controlled-trials.com/ISRCTN75602528 
 
UK MHRA Medicines and Healthcare products Regulatory Agency 
 
MHRA approval for clinical use of the xenon delivery system 
MHRA approval to give 50% xenon for up to 18h as a potential neuroprotective drug to babies    
 
 Entry criteria 
       -  Undergo cooling therapy for perinatal asphyxia  
      -   Needing <35% oxygen (Xenon is a heavy gas) 
      -   Parental written consent for added Xenon & re-intubation with cuffed tube 
 
 
       Patient 1             20% Xe for 3h 
       Patient 2             50% Xe for 3h 
       Patient 3-4          50% Xe for 6h 
       Patient 5-11        50% Xe for 12h 
       Patient 12-14      50% Xe for 18h 
 
      For every 2 patients recruitment was paused 
      External review panel to review all patient data before commence recruitment 
 
Objective:  
    Add up to 18 hours of 50% xenon inhalation to the established treatment of 72h of WBC cooling to 33.5°C  
Hypothesis: 
Observe no changes in those clinical and biochemical markers that we routinely monitor in infants who receive cooling 
therapy 
 
It is technically feasible and cost effective to use our closed loop xenon delivery system 
 
 

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Results 
n=14 
 
13 of the 14 babies were outborn (retrieved from other centres). 
 
Demographics 
Patient criteria n=14   
female=7 
Median (range) 
Weight kg 
3.438 
Gestation weeks 
40.2 (36-42)  
Apgar 1 min   & 10min 
1.0   & 5.5 
Cord Ph 
6.86  
(6.72-7.03) 
aEEG  before start cooling 
90% Burst Suppression 
Seizure before cooling 
60% 
Pheno before cool 
Number of   AED doses 
50% 
2.5 (2.0) 
 
 
 

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Physiological changes during and after Xenon 
 
Haemodynamic changes at onset of xenon. 
 
 
Haemodynamic changes at cessation of xenon. 
 

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Xenon is sedative in 50%  concentration 
Depresses the aE E G which recovers when xe is 
discontinued
S tart 50%  Xe
S top 50%  Xe

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Example of cardio-respiratory physiology throughout an entire 18hr study peri
 
Summary of cardio-respiratory variables before (B) during (D) and after (A) xenon. 
 
 
 
Xe B aby 13
Time (minutes)

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SUMMARY 
• 
It is feasible to give 50% xenon for up to 18h in infants undergoing therapeutic hypothermia 
• 
Only 0.2-0.3L/hour xenon was used with a closed loop xenon recycling system 
• 
Xenon is sedative and other sedation is needed when xenon is discontinued 
• 
No significant cardiovascular or respiratory changes before, during and after xenon 
• 
In one child with abnormal lungs, xenon did not increase FiO2 requirement. 
 
 
 
 

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Appendix A4 
 
[1400.6] 50% Xenon Significantly Reduces aEEG Background Activity in Healthy Newborn 
Pigs 
 
Hannah Gill, John Dingley, Elisa Smit, Xun Liu, Damjan Osredkar, Hemmen Sabir, Marianne 
Thoresen. School of Clinical Sciences, University of Bristol; St Michael's Hospital, Bristol, United 
Kingdom; Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, 
Norway; Medical School, Swansea University, Swansea, United Kingdom. 
 
BACKGROUND: Some inhalation anesthetics reduce EEG background activity and EEG voltage-
range has been used to monitor the depth of anesthesia in children1. The noble gas xenon is an 
inhalation anesthetic, which augments neuroprotection when combined with therapeutic hypothermia 
(HT) after hypoxic-ischemic brain injury. However, when used in its proven neuroprotective dosage 
(50%) xenon does not have full anesthetic potency. 
OBJECTIVE: This current study aimed to examine the effect of 50% inhaled xenon on amplitude 
integrated EEG (aEEG) background activity in healthy newborn pigs. 
DESIGN/METHODS: Six healthy newborn pigs aged <24h, receiving i.v. fentanyl sedation, were 
ventilated for 24h with 50% inhaled xenon at normothermia (rectal temperature 38.5°C). The 50% 
xenon concentration was achieved within 10min. aEEG (CFM, Natus, Seattle, USA) was recorded 
for 30min before the onset of xenon delivery and throughout the 24h period. Background voltage 
changes were analyzed. 
RESULTS: Shortly after the onset of 50% xenon delivery, the aEEG background voltage range was 
significantly reduced in 5 pigs (Figure) and unchanged in one. Mean arterial blood pressure, heart 
rate and oxygen saturation were not influenced by the delivery of xenon. Throughout ventilation with 
50% xenon, aEEG background voltage was constant (Figure). Fentanyl did not appear to change 
aEEG background voltage. 
 
CONCLUSIONS: 50% xenon significantly reduces aEEG background voltage in healthy newborn 
pigs throughout prolonged delivery. As aEEG background voltage recovery predicts outcome in 
cooled asphyxiated newborns2, care must be exercised when interpreting the background voltage in 
neonates also receiving xenon. 
First Author is a Ph.D. Student 
 
E-PAS2013:1400.6 
Session: Platform Session: Neonatal Hypoxic Ischemic Encephalopathy & Neuroprotection (10:30 
AM - 12:30 PM) 
Date/Time: Saturday, May 4, 2013 - 11:45 AM 
Room: Ballroom B - Walter E. Washington Convention Center 
Course Code: 1400 
 
 

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Appendix A5.  Patient Information sheets (abbreviated and full). 
University Hospitals Bristol Foundation Trust  
 
                                 
 
 
Xenon and cooling therapy in babies at 
high risk of brain injury following poor 
condition at birth: A randomised 
outcome study  
(CoolXenon3 study) 
 
Version 1.5  22 July 2015 
 
 
 
 
Information for parents 
(Abbreviated version)  
 
 

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Xenon and cooling therapy in babies at risk of brain injury following  
poor condition at birth:  
A randomised outcome study (CoolXenon3).  Version 1.5 
 
We know that your baby is very unwell and that this is a very difficult time for you. Your doctor will have explained what 
has happened and that your baby will benefit from being looked after on the Neonatal Intensive Care Unit. 
 
Being poorly immediately after birth often occurs when a baby’s supply of oxygen is reduced during pregnancy, labour 
and/or delivery. This can lead to injury to the brain and a risk of later disability. 
  
Your baby is receiving full support of all bodily functions in the intensive care unit. We also give specific treatment to 
protect the brain by reducing the temperature of the body (and brain) from 37 to 33.5°C. Cooling has been proven to 
reduce the risk of later disability and has now been widely introduced as standard treatment for these babies. Your baby 
will receive intensive care and be cooled for 3 days (72 hours), then slowly returned to normal temperature However, 
this treatment does not help all infants. 
 
As part of your baby’s intensive care their breathing is currently being helped by a breathing machine (ventilator). The 
ventilator delivers the amount of air and oxygen your baby needs.  
 
What is the aim of our study ?  The aim of our study is to find out if adding Xenon gas to the air and oxygen mixture 
a baby breathes for the first 18 hours of the cooling treatment will improve the brain protection already produced by the 
cooling treatment and improve a baby’s chances of making a full recovery.  
 
What is Xenon? Xenon is a gas found in tiny amounts in the air that we breathe. In higher concentrations (above 50%) 
it makes us sleepy. Xenon has been used in adult anaesthesia and has not been found to have any side effects. There has 
been very limited use of Xenon in newborns so far. We have previously given Xenon to 30 babies and no negative side 
effects were seen.  
 
Why am I being asked to take part? To find out if breathing xenon is helpful we will give it to a small group of babies 
like yours in combination with their normal cooling treatment as part of a randomised research study (all babies in the 
study will be cooled; half the babies will also receive xenon). Your baby may be suitable to be included in this study.  
 
What would being in the study mean? Your baby will be looked after in the Neonatal Intensive Care Unit as with 
any other baby that is cooled for 72 hours. If you do decide to take part in the CoolXenon3 study, your baby will be 
allocated to receive either ‘cooling alone’ or ‘cooling and xenon’. This treatment allocation is decided randomly (by 
chance).All babies in the trial, whether treated with cooling or cooling and Xenon will receive the same careful 
monitoring, examinations and follow up. Xenon will be added to the breathing gas from a specially designed breathing 
circuit, in a concentration of 50% for 18 hours. Trained staff will be present throughout the cooling-xenon treatment 
and they will stop the treatment immediately if they experience any problems. As part of their normal care, all cooled 
babies have a brain scan (known as an ‘MRI scan’) when they are one week old. Babies in our research study will also 
receive an MRI scan at around two days old: this scan is sometimes, but not always, something that a cooled baby 
would have as part of their standard care. 
 
Your participation in this study is voluntary and you may withdraw your baby from the study at any time without giving 
us a reason. This will not affect the care or treatment of your baby in any way.  
 
All the information we gather about you and your baby will be stored securely. Neither you nor your baby will be identified 
in any of the study reports or scientific and medical papers that we will write following completion of the study. 
 
Who is running this study? The Chief Investigator is Professor Marianne Thoresen, a Consultant Neonatologist. 
Principal investigator at St Michael’s Hospital, Bristol site is Dr Ela Chakkarapani, a Consultant Senior Lecturer in 
Neonatology who had undertaken the laboratory study with xenon and cooling. Principal Investigator at the 
Hammersmith, London site is Dr Sudhin Thayyil, Consultant and Reader in Neonatology. Co-Investigator is Dr John 
Dingley, a Consultant Anaesthetist who developed the Xenon delivery system. Both Professor Thoresen and Dr Dingley 
have conducted previous studies on babies using a xenon delivery system at St Michael’s Hospital 
What happens now? If you decide to take part in this study you will be asked to sign a consent form. We will describe 
the study and go through a fuller version of this information sheet with you. You are free to withdraw at any time, without 
giving a reason. This would not affect the standard of care your baby will receive. 
 
 
 

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Xenon and cooling therapy in 
babies at high risk of brain injury 
following poor condition at birth: A 
randomised outcome study 
(CoolXenon3 study) 
 
Version 1.4  22 July 2014 2015 
 
 
 
 
Information for parents 
(Full version)  
 
 

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Xenon and cooling therapy in babies at risk of brain injury following  
poor condition at birth:  
A randomised outcome study (CoolXenon3).  Version 1.4 
Background Information 
We know that your baby is very unwell and that this is a very difficult time for you. Your doctor will have explained what 
has happened and that your baby will benefit from being looked after on the Neonatal Intensive Care Unit. 
 
Being poorly immediately after birth often occurs when a baby’s supply of oxygen is reduced during pregnancy, labour 
and/or delivery. We do not always know what causes this decrease in oxygen supply but we do know that it can affect 
the ability of the whole body, particularly the brain, to function properly. This can lead to injury to the brain and a risk of 
later disability.  
 
The only treatment available at present that is known to benefit these babies is to reduce your baby’s body temperature 
from the normal level (37°C) to lower than normal body temperature (33.5°C) for 3 days (72 hours) and then slowly bring 
the body back to normal temperature. Trials of this cooling treatment have been shown to give some protection to the 
brain and to reduce the risk of later disability. This cooling treatment has now been widely introduced as a standard 
treatment for these babies. 
 
Your baby is already receiving intensive care treatment. The specialist staff caring for your baby know from the tests they 
have performed that your baby has suffered from a lack of oxygen around the time of birth and that cooling treatment is 
suitable for your baby. 
 
Cooling does not help all children and it is therefore important to investigate whether another treatment combined with 
cooling can give more protection to the brain. 
 
What is the aim of the study? 
The aim of our study is to find out if breathing Xenon gas for the first 18 hours of the cooling treatment will improve the 
brain protection already produced by the cooling treatment and improve a baby’s chances of making a full recovery. 
 
What is Xenon? 
Xenon is a gas found in tiny amounts in the air that we breathe. In higher concentrations (above 50%) it makes us sleepy 
and it can be used to provide anaesthesia. In our laboratory studies we have shown that xenon may improve the brain 
protection produced by the cooling treatment following a lack of oxygen.  
 
How is the Xenon given? 
Your baby’s breathing is currently being helped by a breathing machine (ventilator) which provides air and extra oxygen 
if required. If your baby is allocated to the ‘Cooling and Xenon’ group, 50% Xenon will be added to the air and/or 
additional oxygen your baby is breathing using a safe and efficient delivery and monitoring system we have developed. 
 
Does my baby have to take part in the study? 
Your baby does not have to take part in this study. If you decide not to take part, your baby will receive the same intensive 
care treatment they are already receiving, which includes the cooling treatment from the specialist staff in the Neonatal 
Intensive Care Unit. 
 
If you do choose to take part in the study you may withdraw your baby from the study at any time without giving a reason. 
Your decision to take part or not will not affect the care of your baby in any way. 
 
What will happen to my baby if I agree to take part? 
Your baby is already receiving intensive care treatment. 
 
If you do decide to take part in the study your baby will be treated either with ‘cooling’ or ‘cooling and Xenon’. It is 
important to realise that taking part in the study does not mean that your baby will definitely receive Xenon; half the 
babies will receive cooling treatment and half will receive cooling treatment and Xenon. 
 
How is the treatment chosen? 

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This study is a ‘randomised study’. This type of study is the best way to compare two different treatments. Patients are 
split into two different groups; one group is treated in the standard way and the other has an added treatment, in this 
case, the Xenon. To make sure the two groups of babies are the same at the beginning the allocation to the groups is 
made randomly or ‘by chance’. There is an equal chance of your baby being allocated to the ‘Cooling’ group or the ‘Cooling 
and Xenon’ group. This is essential so that a fair comparison can be made between the groups. 
 
Neither you nor the doctors or nurses are able to choose which treatment your baby receives. 
 
If your baby is allocated to the ‘Cooling’ group they will be looked after by the staff in the Neonatal Intensive Care Unit. 
They will be given standard cooling treatment as already described and any problems associated with your baby’s 
condition will be monitored and treated accordingly. 
 
If your baby is allocated to the ‘Cooling and Xenon’ group, your baby will receive the same intensive care treatment as 
above and in addition, the ventilator that is currently helping with your baby’s breathing will deliver air (and oxygen as 
required) plus Xenon gas at a concentration of 50% for a period of 18 hours. 
 
In order to give the Xenon to your baby we will replace the existing breathing tube that has been placed into your baby’s 
windpipe and attached to the ventilator with a different type of tube. The new one has a small balloon which can be 
gently inflated to fit the windpipe and prevent Xenon leaking from around the tube. A special breathing circuit will be 
connected to the ventilator to deliver Xenon to your baby. Trained staff from the clinical study will be present throughout 
the Xenon treatment to monitor its delivery. 
 
When the 18 hours of Xenon treatment is over the balloon of the breathing tube is deflated and the Xenon breathing 
circuit disconnected. The ventilator will continue to help your baby with its breathing by delivering air and oxygen for as 
long as your baby needs it. 
 
What are the possible side effects of xenon? 
Xenon has been used as an anaesthetic gas for adults and has not been found to have any side effects. There has been 
very limited use of xenon in newborn infants so far. The risks of unwanted side effects are expected to be low due to the 
lack of side effects in adult anaesthesia experience. Knowledge of side effects in infants is limited to the 30 babies we 
have previously given xenon to, where no negative side-effects were seen. 
 
Ongoing medical care of your baby 
All babies taking part in this study will be monitored very carefully by the highly skilled staff in the Neonatal Intensive 
Care Unit. The unit has much experience in caring for babies who are undergoing cooling treatment. All necessary care 
will be given to ensure your baby is kept in a stable condition that will promote recovery. If the doctors caring for your 
baby feel that the xenon (if your baby is in the xenon group) or indeed the cooling needs to be stopped, they will do this 
immediately.  
 
As part of their normal care, all cooled babies have a brain scan (known as an ‘MRI scan’) when they are one week old. 
Babies in our research study will also receive an MRI scan at around two days old, while they are still being cooled.  This 
scan does no harm and may, in fact, be something that a cooled baby would have as part of their standard care.  It is very 
important for parents and doctors to have as much information as possible at an early stage and the additional scan may 
help to show whether there has been any brain injury and if so, the severity of this. 
 
Will my taking part in the study be kept confidential? 
All the information we gather about you and your baby will be stored securely and only members of the study team will 
be able to see it. The information we need for the study includes details about your pregnancy and about your baby’s 
stay in the neonatal unit, as well as details of your family doctor. We routinely follow up all babies who are unwell at birth 
and we need your name, your address and other contact details in order to do this. Your GP will also be informed of your 
baby’s participation in this study. Data will be shared between the collaborators at the Imperial College London and the 
University Hospitals Bristol Foundation NHS Trust, Bristol to aid the analysis of MRI and other outcome measures. 
 
What will happen to the results of the study? 
The study will run for approximately 18 months with another 18 months for follow-up of the babies in outpatient clinic. 
We would also like possibly to contact you at a future time when your child is in the early school years to see how they 
are doing; this would be entirely voluntary on your part. At the end of the study the results will be made available to 
doctors and nurses caring for babies like yours throughout the world. Neither you nor your baby will identified in any of 

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the study reports or scientific and medical papers that will be written. If you wish, we will also send you a copy of the 
final results of the study. This is unlikely to be before 2016. At any time you can contact the Chief investigator of the 
study, Professor Marianne Thoresen. 
 
What happens if something goes wrong? 
If anything goes wrong as a consequence of taking part in the trial because negligence has occurred, University Hospitals 
Bristol NHS Foundation Trust will compensate you.  Negligence would include, for example, a situation in which injury is 
caused by us not following the written study protocol properly.   This means that if your child is harmed and this is due 
to someone's negligence then you may have grounds for a legal action for compensation against the United Bristol 
Hospitals NHS Trust but you may have to pay your legal costs. The normal National Health Service complaints mechanisms 
will always be available to you (if appropriate). 
In the event that your child is harmed during the research study and this is not due to someone’s negligence there are no 
special compensation arrangements. University Hospitals Bristol NHS Foundation Trust, which is sponsoring the study, 
cannot offer no-fault compensation and is unable to agree in advance to pay compensation for non-negligent harm. Ex-
gratia payments may be considered in the case of a claim. 
Who is organising, leading and funding the research? 
The Chief Investigator is Professor Marianne Thoresen a Researcher and Consultant Neonatologist at St Michael’s Hospital 
Neonatal Intensive Care Unit.  Professor Thoresen's research has made a large contribution to cooling treatment over the 
past two decades, leading to it being introduced in the UK, and many other countries, as a standard treatment for babies 
who have suffered from a lack of oxygen at birth. Co-Investigator Dr John Dingley is a Consultant Anaesthetist and 
Researcher responsible for the development and design of the Xenon breathing circuit. The study is sponsored by the 
University Hospitals Bristol NHS Foundation Trust. The study is part-funded by MOULTON, a UK charity supporting new 
treatments for medical problems in children and by the children’s charity SPARKS. 
 
Who has reviewed/approved the study? 
The study has been Reviewed and approved by the NRES Committee South West - Central Bristol Research Ethics 
Committee and the UH Bristol Research and Innovation Department. The use of xenon and the equipment developed to 
deliver it have been reviewed in depth and approved by the UK regulatory authority, the Medicines and Healthcare 
products Regulatory Agency (MHRA). The study will be continuously monitored by an independent group of experts. 
 
What happens now? 
Thank you for reading this information leaflet. If you wish to discuss anything about the study please speak to the doctors 
or nurses looking after your baby. If you decide to take part in this study you will be asked to sign a consent form. We will 
describe the study and go through this information sheet with you. You are free to withdraw at any time, without giving 
a reason. This would not affect the standard of care your baby would receive. 
 
Contact details: 
 
Professor and Neonatal Consultant, Marianne Thoresen (Chief Investigator)  Tel: 0117 34 25607/25226/25733  
 
St Michael’s Hospital, Bristol                                             
Hammersmith Hospital, London  
 
Dr Ela Chakkarapani, (Principal Investigator),                       
Dr Sudhin Thayyil (Principal investigator – second site) 
Consultant Neonatologist and Senior Lecturer                 
Consultant Neonatologist and Weston Reader 
Tel: 01173425711                                                                          Tel: 02033138515.  
Dr John Dingley, (Co-Investigator) 
 
Consultant Anaesthetist and Reader in Anaesthesia            
Tel: 01792 703491 
 
Mrs Emma Scull-Brown (Trial administrator, Bristol)  
Ms Vânia Oliveira (Trial administrator, London) 
Tel: 0117 342 5733 
Tel: 02033132473 
 
 

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Appendix A6     Informed consent document 
STUDY ID nr  
 
CONSENT FORM 
Title of Project:  
 
XENON AND COOLING THERAPY IN BABIES AT HIGH RISK OF  
BRAIN INJURY FOLLOWING POOR CONDITION AT BIRTH:  
A RANDOMISED OUTCOME STUDY (COOLXENON3 STUDY) 
Version 1.4  22/7/2015 
 
Name of Patient 
 
_______________________________  
                                                                                                 Parent, please initial box    
1. I confirm that I have read and understand the information sheet dated 22 July 
2015 version 1.4 (Full version) for the above study and I have been given a 
copy 
 
 
2. I understand that my participation is voluntary and that I am free to withdraw 
my child at any time without my medical or legal rights being affected 
 
 
3. For the purpose of this trial I am willing to allow access to my child’s medical 
records by members of the research team and data to be shared between the 
collaborators but understand that strict confidentiality will be maintained. The 
purpose of this is to check that the study is being carried out correctly and aid 
analysis of investigations. 
 
4.   
For the purposes of this trial, I am willing to be contacted and asked about 
participation in further follow up when my child is in the early school years. 
 
 
5. I give permission for my GP Dr…………………………………....to receive 
details of my child’s participation in this study 
 
 
6. I agree to my child taking part in the above study. 
 
 
7. I understand that data collected from this study may be transferred to, and 
viewed by, appropriate authorities for regulatory purposes. Any data that are 
transferred to such authorities will not identify me or my child nor will it contain 
any means of enabling me or my child to be identified. I give permission for 
such authorities and their designated representatives to have access to my 
data from this study. 
 
 
 
Name of parent 
 
Date 
 
Signature (parent) 
Name & designation of 
person taking consent 
 
Date 
 
Signature 
Name of Researcher 
 
Date 
 
Signature  
One copy to be retained by parent, one to be retained by investigator, one to be filed in patient’s medical records 

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Appendix A7            Declaration of Helsinki 
 
WORLD MEDICAL ASSOCIATION DECLARATION OF HELSINKI 
Ethical Principles for Medical Research Involving Human Subjects 
Adopted by the 18th WMA General Assembly, Helsinki, Finland, June 1964, and amended by the: 
29th WMA General Assembly, Tokyo, Japan, October 1975 
35th WMA General Assembly, Venice, Italy, October 1983 
41st WMA General Assembly, Hong Kong, September 1989 
48th WMA General Assembly, Somerset West, Republic of South Africa, October 1996 
52nd WMA General Assembly, Edinburgh, Scotland, October 2000 
53rd WMA General Assembly, Washington 2002 (Note of Clarification on paragraph 29 added) 
55th WMA General Assembly, Tokyo 2004 (Note of Clarification on Paragraph 30 added) 
59th WMA General Assembly, Seoul, October 2008 
 
A. INTRODUCTION 
1. The World Medical Association (WMA) has developed the Declaration of Helsinki as a statement of ethical principles 
for medical research involving human subjects, including research on identifiable human material and data. 
The Declaration is intended to be read as a whole and each of its constituent paragraphs should not be applied without 
consideration of all other relevant paragraphs. 
2. Although the Declaration is addressed primarily to physicians, the WMA encourages other participants in medical 
research involving human subjects to adopt these principles. 
3. It is the duty of the physician to promote and safeguard the health of patients, including those who are involved in 
medical research. The physician's knowledge and conscience are dedicated to the fulfilment of this duty. 
4. The Declaration of Geneva of the WMA binds the physician with the words, “The health of my patient will be my first 
consideration,” and the International Code of Medical Ethics declares that, “A physician shall act in the patient's best 
interest when providing medical care.” 
5. Medical progress is based on research that ultimately must include studies involving human subjects. Populations that 
are underrepresented in medical research should be provided appropriate access to participation in research. 
6. In medical research involving human subjects, the well-being of the individual research subject must take precedence 
over all other interests. 
7. The primary purpose of medical research involving human subjects is to understand the causes, development and 
effects of diseases and improve preventive, diagnostic and therapeutic interventions (methods, procedures and 
treatments). Even the best current interventions must be evaluated continually through research for their safety, 
effectiveness, efficiency, accessibility and quality. 
8. In medical practice and in medical research, most interventions involve risks and burdens. 
9. Medical research is subject to ethical standards that promote respect for all human subjects and protect their health 
and rights. Some research populations are particularly vulnerable and need special protection. These include those who 
cannot give or refuse consent for themselves and those who may be vulnerable to coercion or undue influence. 
10. Physicians should consider the ethical, legal and regulatory norms and standards for research involving human 
subjects in their own countries as well as applicable international norms and standards. No national or international 
ethical, legal or regulatory requirement should reduce or eliminate any of the protections for research subjects set forth 
in this Declaration. 
B. PRINCIPLES FOR ALL MEDICAL RESEARCH 
11. It is the duty of physicians who participate in medical research to protect the life, health, dignity, integrity, right to 
self-determination, privacy, and confidentiality of personal information of research subjects. 
12. Medical research involving human subjects must conform to generally accepted scientific principles, be based on a 
thorough knowledge of the scientific literature, other relevant sources of information, and adequate laboratory and, as 
appropriate, animal experimentation. The welfare of animals used for research must be respected. 
13. Appropriate caution must be exercised in the conduct of medical research that may harm the environment. 
14. The design and performance of each research study involving human subjects must be clearly described in a research 
protocol. The protocol should contain a statement of the ethical considerations involved and should indicate how the 
principles in this Declaration have been addressed. The protocol should include information regarding funding, sponsors, 
institutional affiliations, other potential conflicts of interest, incentives for subjects and provisions for treating and/or 
compensating subjects who are harmed as a consequence of participation in the research study. The protocol should 
describe arrangements for post-study access by study subjects to interventions identified as beneficial in the study or 
access to other appropriate care or benefits. 

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15. The research protocol must be submitted for consideration, comment, guidance and approval to a research ethics 
committee before the study begins. This committee must be independent of the researcher, the sponsor and any other 
undue influence. It must take into consideration the laws and regulations of the country or countries in which the research 
is to be performed as well as applicable international norms and standards but these must not be allowed to reduce or 
eliminate any of the protections for research 
subjects set forth in this Declaration. The committee must have the right to monitor ongoing studies. The researcher 
must provide monitoring information to the committee, especially information about any serious adverse events. No 
change to the protocol may be made without consideration and approval by the committee. 
16. Medical research involving human subjects must be conducted only by individuals with the appropriate scientific 
training and qualifications. Research on patients or healthy volunteers requires the supervision of a competent and 
appropriately qualified physician or other health care professional. The responsibility for the protection of research 
subjects must always rest with the physician or other health care professional and never the research subjects, even 
though they have given consent. 
17. Medical research involving a disadvantaged or vulnerable population or community is only justified if the research is 
responsive to the health needs and priorities of this population or community and if there is a reasonable likelihood that 
this population or community stands to benefit from the results of the research. 
18. Every medical research study involving human subjects must be preceded by careful assessment of predictable risks 
and burdens to the individuals and communities involved in the research in comparison with foreseeable benefits to 
them and to other individuals or communities affected by the condition under investigation. 
19. Every clinical trial must be registered in a publicly accessible database before recruitment of the first subject. 
20. Physicians may not participate in a research study involving human subjects unless they are confident that the risks 
involved have been adequately assessed and can be satisfactorily managed. Physicians must immediately stop a study 
when the risks are found to outweigh the potential benefits or when there is conclusive proof of positive and beneficial 
results. 
21. Medical research involving human subjects may only be conducted if the importance of the objective outweighs the 
inherent risks and burdens to the research subjects. 
22. Participation by competent individuals as subjects in medical research must be voluntary. Although it may be 
appropriate to consult family members or community leaders, no competent individual may be enrolled in a research 
study unless he or she freely agrees. 
23. Every precaution must be taken to protect the privacy of research subjects and the confidentiality of their personal 
information and to minimize the impact of the study on their physical, mental and social integrity. 
24. In medical research involving competent human subjects, each potential subject must be adequately informed of the 
aims, methods, sources of funding, any possible conflicts of interest, institutional affiliations of the researcher, the 
anticipated benefits and potential risks of the study and the discomfort it may entail, and any other relevant aspects of 
the study. The potential subject must be informed of the right to refuse to participate in the study or to withdraw consent 
to participate at any time without reprisal. Special 
attention should be given to the specific information needs of individual potential subjects as well as to the methods used 
to deliver the information. After ensuring that the potential subject has understood the information, the physician or 
another appropriately qualified individual must then seek the potential subject’s freely-given informed consent, 
preferably in writing. If the consent cannot be expressed in writing, 
the non-written consent must be formally documented and witnessed. 
25. For medical research using identifiable human material or data, physicians must normally seek consent for the 
collection, analysis, storage and/or reuse. There may be situations where consent would be impossible or impractical to 
obtain for such research or would pose a threat to the validity of the research. In such situations the research may be 
done only after consideration and approval of a research ethics committee. 
26. When seeking informed consent for participation in a research study the physician should be particularly cautious if 
the potential subject is in a dependent relationship with the physician or may consent under duress. In such situations 
the informed consent should be sought by an appropriately qualified individual who is completely independent of this 
relationship. 
27. For a potential research subject who is incompetent, the physician must seek informed consent from the legally 
authorized representative. These individuals must not be included in a research study that has no likelihood of benefit 
for them unless it is intended to promote the health of the population represented by the potential subject, the research 
cannot instead be performed with competent persons, and the research entails only minimal risk and minimal burden. 
28. When a potential research subject who is deemed incompetent is able to give assent to decisions about participation 
in research, the physician must seek that assent in addition to the consent of the legally authorized representative. The 
potential subject’s dissent should be respected. 
29. Research involving subjects who are physically or mentally incapable of giving consent, for example, unconscious 
patients, may be done only if the physical or mental condition that prevents giving informed consent is a necessary 

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characteristic of the research population. In such circumstances the physician should seek informed consent from the 
legally authorized representative. If no such representative is available and if 
the research cannot be delayed, the study may proceed without informed consent provided that the specific reasons for 
involving subjects with a condition that renders them unable to give informed consent have been stated in the research 
protocol and the study has been approved by a research ethics committee. Consent to remain in the research should be 
obtained as soon as possible from the subject or a legally authorized representative. 
30. Authors, editors and publishers all have ethical obligations with regard to the publication of the results of research. 
Authors have a duty to make publicly available the results of their research on human subjects and are accountable for 
the completeness and accuracy of their reports. They should adhere to accepted guidelines for ethical reporting. Negative 
and inconclusive as well as positive results should be published or otherwise made publicly available. Sources of funding, 
institutional affiliations and conflicts of interest should be declared in the publication. Reports of research not in 
accordance with the principles of this Declaration should not be accepted for publication. 
 
C. ADDITIONAL PRINCIPLES FOR MEDICAL RESEARCH COMBINED WITH MEDICAL CARE 
31. The physician may combine medical research with medical care only to the extent that the research is justified by its 
potential preventive, diagnostic or therapeutic value and if the physician has good reason to believe that participation in 
the research study will not adversely affect the health of the patients who serve as research subjects. 
32. The benefits, risks, burdens and effectiveness of a new intervention must be tested against those of the best current 
proven intervention, except in the following circumstances: 
• The use of placebo, or no treatment, is acceptable in studies where no current proven intervention exists; or 
• Where for compelling and scientifically sound methodological reasons the use of placebo is necessary to determine the 
efficacy or safety of an intervention and the patients who receive placebo or no treatment will not be subject to any risk 
of serious or irreversible harm. Extreme care must be taken to avoid abuse of this option. 
33. At the conclusion of the study, patients entered into the study are entitled to be informed about the outcome of the 
study and to share any benefits that result from it, for example, access to interventions identified as beneficial in the 
study or to other appropriate care or benefits. 
34. The physician must fully inform the patient which aspects of the care are related to the research. The refusal of a 
patient to participate in a study or the patient’s decision to withdraw from the study must never interfere with the 
patient-physician relationship. 
35. In the treatment of a patient, where proven interventions do not exist or have been ineffective, the physician, after 
seeking expert advice, with informed consent from the patient or a legally authorized representative, may use an 
unproven intervention if in the physician's judgement it offers hope of saving life, re-establishing health or alleviating 
suffering. Where possible, this intervention should be made the object of research, designed to evaluate its safety and 
efficacy. In all cases, new information should be recorded and, where appropriate, made publicly available.