Comparison of Postoperative Delirium in Patients Anaesthetised With Isoflurane and Desflurane During Spinal Surgery
Phase: PHASE4
Conditions: Postoperative Delirium
Sponsor: Post Graduate Institute of Medical Education and Research, Chandigarh

 
1
TITLE: 
Comparison of postoperative delirium in patients anaesthetised with 
Isoflurane and Desflurane during spinal surgery 
  NCT02925611            Date-31 December 2015 
 
BY 
DR. STEVE JOYS 
Junior Resident 
Department of Anaesthesia and Intensive care 
PGIMER, Chandigarh 
 
GUIDE                                                                                         CO GUIDE 
DR. HEMANT BHAGAT                                                               DR. TANVIR SAMRA 
Additional Professor                                                                            Assistant Professor 
Department of Anaesthesia &                                                Department of Anaesthesia & 
Intensive Care                                                                                   Intensive Care 
PGIMER, Chandigarh                                                                    PGIMER, Chandigarh 
 
CO GUIDES 
 
Dr. HBS SODHI                      DR. MANJU MOHANTY             DR. VISHAL KUMAR 
Assistant Professor                       Associate Professor                        Assistant Professor 
Dept. of Neurosurgery                Dept. of Neurosurgery                    Dept. of Orthopedics 
      PGIMER                                       PGIMER                                        PGIMER 
    Chandigarh                                   Chandigarh                                     Chandigarh 
 

 
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TABLE OF CONTENTS 
                             
CONTENTS 
PAGE NO. 
ABBREVIATIONS 
3 
INTRODUCTION 
4 
REVIEW OF LITERATURE 
6 
AIMS OF THE STUDY 
11 
MATERIALS AND METHODS 
12 
STATISTICAL ANALYSIS 
15 
ORGANISATION OF WORK ELEMENTS 
16 
ETHICAL JUSTIFICATION 
18 
INFORMATION TO THE PARTICIPANTS 
19 
CONSENT FORM 
22 
REFERENCES 
26 
 
 
 

 
3
 
ABBREVIATIONS 
ASA-American Society of Anaesthesiologists 
BP-Blood pressure 
CAM-Confusion assessment method 
CBF- Cerebral blood flow 
CDT-Clock drawing test 
CMR- Cerebral metabolic rate 
CMRO2 -Cerebral metabolic rate of Oxygen consumption 
CNS-Central nervpus system 
GA-General anaesthesia 
GCS- Glasgow Coma Scale  
Hb-Hemoglobin 
MAC-Mean alveolar concentration 
MMSE-Mini mental state examination 
NMT-Neuromuscular transmission 
NRS-Numerical rating score 
POD-Post operative delirium                                                                                                                                      

 
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INTRODUCTION 
In simple words delirium is defined as a temporary state of confusion . It is characterized byacute 
onset, fluctuating course, inattention, disorganized thinking, altered level of consciousness, 
perceptual disturbances, psychomotor disturbances, altered sleep-wake cycle, and  emotional 
disturbances1.Postoperative delirium (POD ) is disturbance of consciousness seen 24 to 72 hours 
after surgery. Its incidence varies from 5% to 15% but in high-risk groups such as cardiac and 
orthopedic patients,the range is 16–62%2. Postoperative delirium is not only distressing for patient 
but also for family members. It is associated with functional decline, need for prolonged nursing 
care and prevent functional recovery. Hence it leads to prolonged duration of hospital stay and 
adds to morbidity and mortality in the long term. Exact mechanism responsible for POD is not 
known but several risk factors are found to be associated with POD.  This includes patient 
related,surgery related and anesthesia related factors. 
The incidence of POD in spine surgery in previous studies was found to be between 3.3% to 
3.8%3,4.Spine surgeries are associated with significant postoperative pain,blood loss, long duration 
of surgery and all these factors may be associated with POD after spine surgeries2,5,6,7,8. But for 
the smooth conduct of spine surgery general anesthesia (GA) is required. During general 
anesthesia either inhalational volatile agents or intravenous hypnotic agents are used. However 
effect of the type of anesthetic agents in spine surgeries on postoperative delirium have not been 
studied previously. Both isoflurane and desflurane are commonly used inhalational agents. Now a 
days many centers prefer to use desflurane over isoflurane due to its low blood gas solubiltity 
which results in faster emergence.Among the inhalational volatile agents, previous studies have 

 
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compared the incidence of postoperative delirium with sevoflurane and desfluraneespecially in 
children and elderly individuals.But no study has compared the incidence of postoperative delirium 
with isoflurane and desflurane in middle aged adults undergoing spine surgery . 
Desflurane is associated with faster emergence and lesser incidence of postoperative cognitive 
dysfunction compared to isoflurane9,10. Animal studies have shown that prolonged exposure to 
isoflurane to be neurotoxic11,12,13,14,15.  We hypothesize that the adverse neurological outcomes 
associated with isoflurane compared to desflurane may be associated with an increased incidence 
of postoperative delirium. Hence we are conducting this study to compare the occurrence of 
postoperative delirium with Isoflurane and Desflurane in spine surgery patients. 
 
 
 
 
 
 
 
 
 
 
 

 
6
 
REVIEW OF LITERATURE 
 
Brain functions are known to be affected during immediate postoperative period after exposure to 
anesthesia. These effects vary from depressed levels of consciousness with impairment of attention 
and memory to complete amnesia for several hours. Cognitive disturbances commonly seen in 
postoperative period are delirium and cognitive disturbances. 
Prolonged exposure to anesthetics can lead to neuroapoptosis and neurocognitive 
problems11,12,13,14,15. However, other studies suggest that even low nonapoptotic concentrations of 
general anesthetics may inhibit normal synapse formation and damage developing neuronal 
networks16.Mechanisms underlying neurodevelopmental toxicity are potentially linked to the same 
ion channels hypothesized to mediate general anesthesia. General anesthetic actions are attributed 
in part to both antagonism of N-methyl-d-aspartate receptor and potentiation of GABA-A receptor 
signal transduction, and drugs with either or both of these activities damage developing 
brains17,18,19. 
 
POST OPERATIVE DELIRIUM- 
American Psychiatric Association defines delirium as an acute change in cognition or disturbance 
of consciousness that cannot be attributed to a pre-existing medical condition, substance 
intoxication or medication. However various conditions such as age, functional status and 
substance abuse influence the risk of immediate and post operative delirium. Delirium in the 

 
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postoperative period can be divided into emergence delirium and post operative delirium 
depending on the time of presentation. Emergence delirium or emergence agitation is usually 
observed immediately after GA and is related to anesthetic drugs. It is common in children with 
peak age being 2-4 years. It is accompanied by psychomotor agitation which includes a series of 
unintentional and purposeless motion like pacing around a room, wringing ones hands, pulling off 
clothing, and self-extubation. It usually occurs within the first 10 minutes of recovery and resolves 
within minutes to hours without long term neurological effects. It is more commonly associated 
with less soluble inhalational anaesthetics like sevoflurane and desflurane. 
Postoperative Delirium(POD) usually presents 24-72 hours following a lucid interval. It usually 
resolves within hours to days. Post operative delirium can have lasting effects beyond the 
perioperative period. POD has also been associated with postoperative depression, posttraumatic 
stress disorder-like syndrome which may impede recovery. As a result, delirium may have long-
term mental health complications20.  
POD has been previously reported to occur following several kinds of surgery, including general 
surgery , head and neck cancer surgery, cardiac surgery , vascular surgery , hip fracture and joint 
replacement surgery21,22,23,24,25,26,27,.The incidence of post operative delirium(POD) in various 
studies ranges from 5% to 15%.Within certain high-risk groups such as hip fracture patients, the 
range is 16–62% with an average of 35%2. The incidence of POD in spine surgery in previous 
studies was found to be between 3.3% to 3.8%3,4. 
RISK FACTORS FOR POSTOPERATIVE DELIRIUM- 
The mechanism of postoperative delirium is not clear. However ,studies have shown that major 
risk factors include age >70 years, pre-existing cognitive impairment, preoperative use of narcotics 

 
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or benzodiazepines, previous history of POD, alcohol abuse, breast and abdominal surgeries, long 
duration of surgery and preoperative cognitive dysfunction2,6,7,8.Precipitating factors include: the 
use of physical restraints, malnutrition, the use of a urinary bladder catheter and electrolyte and 
fluid abnormalities.Specific perioperative risk factors include greater intraoperative blood loss, 
more postoperative transfusions, and postoperative haematocrit of <30%. 
Severe acute pain regardless of the method of analgesia (opioid type, method and dose) is 
associated with POD . Certain types of injury, particularly hip fractures, and serious illness 
requiring intensive care are also associated with a high incidence of delirium2.Several factors with 
positive correlation with POD may also suggest an association with preoperative anxiety. 
Incidence of POD was greater with inhalational anesthetic agents than with propofol2. Other risk 
factors  of delirium include vision impairment, severe illness, cognitive impairment, and serum 
urea nitrogen: creatinine ratio of 18 or greater,vascular risk factors (tobacco use and vascular 
surgery ), decreased cerebral perfusion , low preoperative executive scores and depressive 
symptoms , pre-existing attentional deficits in non-demented patients2. Previous history of illness 
and long term treatment with antidepressants were associated with a decreased risk for POD2,3,4. 
 
PHARMACOLOGY OF ISOFLURANE- 
Isoflurane is a volatile anaesthetic  agent.Chemically it is 2-chloro-2-(difluoromethoxy)-1,1,1-
trifluoro-ethane.It has a boiling point of 48.5 degree Celsius and a vapour pressure of 238 mm Hg. 
The blood /gas partition coefficient of isoflurane is 1.4 at 37 degree Celsius and MAC – immobility 
is 1.28 mm Hg. At concentrations greater than 1 MAC, isoflurane increases CBF and intracranial 

 
9
pressure. Isoflurane reduces cerebral metabolic oxygen requirements, and at 2 MAC, it produces 
an electrically silent electroencephalogram(EEG). 
Many animal studies have demonstrated the neurotoxic effects of isoflurane- 
Studies have demonstrated that there was increased apoptotic cellular degeneration and 
neurodegenration following isoflurane exposure in neonatal mice and rhesus monkeys11,12,14,15.Liu 
J. et al demonstrated that in young adult mice,isoflurane  may cause neurotoxicity by inducing 
caspase activation and apoptosis with the anesthetic concentration increased and duration 
prolonged. High concentration of isoflurane exceeding 4 hours may induce a decline of NR2B and 
ratio of pERK1/2 to ERK1/2 resulting in cognitive impairment13. 
There are studies which have also demonstrated neuroprotective effects of isoflurane. Liu J. et al 
demonstrated that in young adult mice ,low concentration of isoflurane in 2 hours can induce a 
hippocampus-specific elevation of NR2B subunit composition and ratio of p-ERK1/2 to total 
ERK1/2,thereby producing hippocampal-dependent cognitive improvement13.Engelhard K et al 
demonstrated that desflurane and isoflurane improve neurological outcome after incomplete 
cerebral ischaemia in rats28.Milner E et al demonstrated improved neurological outcome in 
subarachnoid haemorrhage in mice with isoflurane29. 
PHARMACOLOGY OF DESFLURANE- 
Desflurane ,a volatile anesthetic agent was introduced into clinical practice in 1992. Chemically it 
is fluorinated methyl ethyl ether. Two most important physical properties of desflurane are that it 
has a boiling point of 22.80 C and a vapour pressure of 664 mmHg. So it boils at room temperature 
and hence a special vaporizer is required to deliver desflurane. It has a blood/gas partition 
coefficient of  0.45 at 37 degree Celsius which is the least among the inhalational agents and a 
MAC- immobility of  6.0 mmHg. This  favors rapid achievement of alveolar concentration 

 
10
necessary for production of anesthesia followed by rapid recovery on discontinuation. This 
anesthetic property makes it a favourable anesthetic agent for neurosurgery. 
Central nervous system (CNS) actions: Desflurane decreases cerebral metabolic rate (CMR) by 
35%.  Cerebral blood flow(CBF) may increase or decrease depending on concentration used.At 1 
minimum alveolar concentration (MAC), desflurane decreased CMRO2 by 50%, CBF by 22% and 
at the same time cerebrovascular reactivity is preserved. Desflurane has been found to be 
neuroprotective in certain animal studies28.The mechanism of neuroprotection involves reduction 
of glutamate, potentiation of GABA receptors, regulation of intracellular calcium responses and 
activation of potassium channels. However it may raise ICP more than isoflurane, hence it should 
be used cautiously in patients with unstable ICP. 
 
 
 
 
 
 
 
 
 
 

 
11
 
 
AIMS OF THE STUDY- 
1)To compare the incidence of postoperative delirium with isoflurane and desflurane on adults 
undergoing spine surgery . 
2)To determine the perioperative factors which can influence postoperative delirium. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
12
 
 
MATERIALS AND METHODS 
The proposed study will be a prospective randomized clinical trial. It will be  be carried out for a 
period of 15 months from Januray 2016 to June 2017 in  60 adult patients scheduled for  spine 
surgery at PGIMER, Chandigarh. Ethical clearance will be sought from the human and ethics 
committee of the institute. Written informed consent will be taken from all the patients. The 
patients will be randomly divided into two groups of 30 each - Group I (Isoflurane) and  Group D 
(Desflurane) prior to surgery. 
Selection of patients- 
Inclusion criteria 
• Patients scheduled for  spine surgery. 
• Age between 18-65 years 
• American Society of Anaesthesiologists (ASA) Grade I and II patients 
• Patients with Glasgow Coma Scale (GCS) of 15 
• Postoperative Aldrette score > 9 
         Exclusion criteria 
• Cardiorespiratory disorders 
• Associated cerebral  disease 
• Psychiatric illness 
• Electrolyte and hormonal imbalance 
• History of drug abuse 

 
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• Postoperative meningitis 
• Administration of high dose steroids  
Randomization and blinding 
Randomization will be done using computer-generated random numbers. The patient will be 
randomized to receive isoflurane or desflurane anaesthesia prior to surgery. All the patients 
involved in the study will be blinded to group allocation. The physician administering anaesthesia 
will be presented with envelopes containing the random numbers with the assigned groups just 
prior to surgery. The investigator will be blinded to group allocation. 
Anaesthesia Protocol 
All the preoperative medications will be continued on the day of surgery. Anaesthesia will be 
induced with propofol 2-2.5 mg/kg and fentanyl 2 ug/kg.  Vecuronium 0.1 mg/kg will be to 
facilitate endotracheal intubation. All the patients will be monitored with 5 lead electrocardiogram, 
pulse oximeter, non-invasive  blood pressure, temperature, airway gas levels , end–tidal carbon-
dioxide concentartion and  urine output . Maintainence of anaesthesia will be carried out with 
either isoflurane or desflurane as per the randomization. The depth of anaesthesia will be 
monitored using entropy (to keep state entropy between 40 and 60) . Analgesia will be maintained 
with fentanyl 0.5-2 ug/kg/hour and Vecuronium 0.06 mg/kg will be used intermittently for 
neuromuscular blockade to maintain less than two twitch response on neuromuscular 
transmission(NMT) monitoring.  Replacement fluid will consist of normal saline. Intraoperative 
haemodynamics, oxygen saturation, temperature and blood loss will be recorded and compared 
among the two groups. The patients will be administered an antiemetic intraoperatively. At the 
end of the procedure neuromuscular blockade will be antagonized with neostigmine (0.05mg/kg) 

 
14
and glycopyrrolate (0.01mg/kg). The patients who cannot be extubated at the end of the procedure 
will followed up in the postoperative period. The patients who cannot be extubated within forty-
eight hours following surgery will be excluded from the study.  
 
Study protocol 
The screening for preoperative cognitive dysfunction will be done using the mini-cog test which 
includes a three word recall test and clock drawing test. The patients with preoperative cognitive 
dysfunction will also be included. The primary outcome variable will be assessment of delirium at 
day  one and day three following surgery. Post operative delirium will be diagnosed using the 3D- 
CAM(Confusion Assessment Method) which tests for four features with a series of questions. The 
features include 1) acute onset and fluctuating course,2) inattention,3) disorganized  thinking and 
4) altered level of consciousness. Diagnosis of delirium is made if features 1 and 2 and either 3 or 
4 are present. Similarly the severity of POD will be assessed on day one and day three following 
surgery. Severity of postoperative delirium will be assessed using the CAM-S long form delirium 
severity 
score.It 
asseses 
ten 
features 
including 
1) 
acute 
onset 
and 
fluctuating 
course,2)inattention,3)disorganized  thinking , 4)altered level of consciousness, 5) disorientation, 
6)memory impairment ,7)perceptual disturbances ,8)psychomotor agitation, 9)psychomotor 
retardation and 10) altered sleep-wake cycle. The scores range from 0 to 19. 
The demographic data of the patients,type and site of surgery will be noted. Preoperative 
hemoglobin, serum electrolytes, blood urea and serum creatinine will be recorded. The average of 
3 blood pressure (BP) readings measured preoperatively will be recorded as baseline. 
Intraoperative hemodynamics will be monitored using non invasive blood pressure monitoring. 
Systolic BP <30% of baseline will be recorded as hypotension and systolic BP >30% will be 

 
15
recorded as hypertension. The management of intraoperative hypotension and hypertension will 
be at the discretion of the attending anaesthesiologist. The intraoperative factors like duration of 
surgery and anaesthesia, use of intravenous fluids , blood loss, number blood units transfused and 
opioid use will be studied at the time of surgery. The time to emergence and extubation following 
the completion of surgery will be noted. Emergence time will be the time from cessation of 
anesthetic agent to the time the patient responds to verbal commands. Extubation time will be the 
time interval between cessation of anesthetic agent and extubation of trachea. 
The postoperative factors like postoperative pain, nausea and vomiting, fever, hemoglobin, serum 
electrolytes, blood urea and serum creatinine will be noted. 
Preoperative and postoperative pain will be assessed using the numerical rating score on a scale of 
one to ten. 
The association of various preoperative, intraoperative and postoperative factors with POD will be 
determined. 
 
 
STATISTICAL ANALYSIS- 
Sample size calculation- 
Incidence of POCD was 0% and 27% in a previously conducted study with 15 patients in each 
group with the use of  desflurane and isoflurane respectively and the reported p value was 0.028.6 
We used these results to calculate sample size in our study to prove superiority of desflurane over 

 
16
isoflurane with a margin of atleast 5 percent using an alpha error of 0.05 and power of 85%.The 
estimated sample size was 60 with 30 in each arm. 
STATISTICAL ANALYSIS 
All analysis will be done using SPSS version 22 (SPSS Inc., Chicago, IL, version 16.0 for 
Windows). Descriptive statistics will be obtained for demographic patient related and treatment 
related variables. The variance between both the treatment groups will be analysed using two way 
ANOVA. The primary end points will be compared between the two groups using chi square 
statistics. As a secondary outcome measure, univariate and multivariate analysis will be done to 
identify the factors that may influence post operative delirium. 
 
ORGANIZATION OF WORK ELEMENTS 
 
1. Preoperative Workup 
a) Recruitment of patients as per the inclusion-exclusion criteria 
b) Informed written consent from patient for participation in the study 
c) The patient will be assigned a computer generated random number for allocation to 
the study group. 
d) Demographic details and relevant details will be recorded. 
e) Pain scores will be assessed using the numerical rating score 
f) Cognitive function will be assessed using the mini-cog test. 
g) Hemoglobin, serum electrolytes, blood urea and  serum creatinine will be noted. 
             2. Intraoperative Period 

 
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a) The attending anaesthesiologist will be briefed about the anaesthesia protocol. The 
random number sealed envelope containing the randomized study group will be 
handed over to the anaesthesiologist. 
b) The attending anaesthesiologists will administer the anaesthetic agent as per the 
randomization. 
c) Factors including  duration of surgery and anaesthesia, intravenous fluids used, 
intra operative blood loss, number of blood units transfused, intra operative 
hemodynamics, intra operative opioid use ,time to emergence and time to 
extubation will be noted. 
3. Postoperative Period 
The patients will be followed up on day one and day three following surgery. The patient will be 
subjected to psychological tests for evaluating delirium. Pain scores will be assessed using the 
numerical rating score. Postoperative factors like nausea and vomiting, fever, hemoglobin, serum 
electrolytes, blood urea and serum creatinine will be noted. 
 
 
 
 
 
 

 
18
ETHICAL JUSTIFICATION 
 
The anesthetic agents that will be used in our study have been in use for many years and 
have been largely safe. Use of isoflurane and desflurane in surgery has been practiced extensively 
and has not been found to be detrimental to the patients. 
 
 
(1) 
The patients involved in the research project will be informed of the methods, anticipated 
benefits and potential risks of the study and the discomfort it may cause and the remedies 
thereof. 
(2) 
Written informed consent will be obtained. 
(3) 
Every precaution will be taken to respect the privacy of the patient, the confidentiality of 
the patient. 
(4) 
The patient has right to abstain from the study or to withdraw consent to participate at any 
time of the study without reprisal. 
(5) 
Due care and caution will be taken at all stages to ensure that the patient is put to minimum 
risk or suffer from irreversible side effects and probably benefit from study. 
 
 
 
 
 

 
19
INFORMATION TO THE PARTICIPANTS 
Investigator`s Name:  Dr. Steve Joys 
Name of Participant: ________________________________________ 
TITLE:  
‘Comparison of postoperative delirium in patients anaesthetised with Isoflurane and 
Desflurane during spinal surgery’ 
 
You are invited to take part in this research study. The information in this document is meant to 
help you decide whether or not to take part. Please feel free to ask if you have queries or concerned. 
You are being asked to participate in this study being conducted in PGIMER because you satisfy 
our eligibility criteria. 
Purpose of the research: 
To compare the effect of isoflurane and desflurane in patients undergoing spine surgery. 
After being posted for spine surgery, you will be given either isoflurane or desflurane,which are 
commonly used for maintenance of anaesthesia in spine surgery. We have obtained permission 
from the Institutional Ethics Committee for conducting this study.      
Study Procedure:  
Once you are enrolled in the study you will be assessed for  
(a) 
Pre-operative Cognitive Dysfunction pain 
(b) 
Intra-operative hemodynamic parameters 
(c) 
Post-operative delirium and pain 
Possible risks to you:  

 
20
Some of the side effects of general anesthesia like nausea and vomitting. 
Possible benefits to you:  
You may not get any benefit from being on this research study, other than treatment benefit 
and better  monitoring but the result of this study may provide benefits to the society in terms of 
advancement of medical knowledge and /or therapeutic benefit to future patients. 
The alternatives you have:  
If you do not wish to participate, you have the alternative of getting the standard treatment 
for your condition. 
What should you do in case of injury or a medical problem during this research study? 
Your safety is the prime concern of our research. If you are injured or have a medical 
problem as a result of being in this study, you should contact one of the people listed at the end of 
the consent form. You will be provided the required care/treatment. You will be entitled to your 
legal rights besides this.  
Confidentiality of the information obtained from you:  
You have the right to confidentiality regarding the privacy of your medical information 
(personal details, results of physical examinations, investigations, and your medical history). By 
signing this document, you will be allowing the research team investigators , other study personnel, 
institutional ethics committee and any person or agency required by law like the Drug Controller 
of India to view your data, if required. The results of clinical assessments and therapy performed 
as part of this research may be included in your medical record. The information from this study, 
if published in scientific journals or presented at scientific meetings, will not reveal your identity. 
How will your decision to not participate in the study affect you: 

 
21
Your decision not to participate in this research will not affect your medical care or your 
relationship with the investigator or the institution. Your doctor will still take care of you and you 
will not lose any benefits to which you are entitled. 
Can you decide to stop participating in the study once you start? 
The participation in this research is purely voluntary and you have the right to withdraw 
from this study at any time during the course of the study without giving any reasons. However, 
though advisable that you will give investigators the reason for withdrawing, it is not mandatory. 
Can the investigator take you off the study?  
 
You may be taken off the study without your consent if you do not follow the instructions 
of the investigators or the research team or if the investigator thinks that further participation may 
cause harm. 
Right to new information:  
 
If the research team gets any new information during this research study that may affect 
your decision to continue participating in this study, or may raise some doubts, you will be told 
about that information.  
 
 
 
 
 
 

 
22
CONSENT FORM 
Name of the participant: _________________________ Age/ Sex: _________ 
C.R. No. __________________ 
Name of the Investigator : Dr. Steve Joys 
Name of the Institution : Post Graduate Institute of Medical Education and Research 
Documentation of the informed consent 
I, _________________________________ have read the information in this form (or it has been 
read to me). I was free to ask any questions and they have been answered. I am over 18 years of 
age and exercising my free power of choice, hereby give my consent to be included as a participant 
in the study “Comparison of postoperative delirium in patients anaesthetised with Isoflurane and 
Desflurane during spinal surgery”. 
1.  
I have read and understood this consent form and the information provided to me.  
2. 
I have had the consent document explained to me.  
3. 
I have been explained about the nature of the study. 
4. 
My rights and responsibilities have been explained to me by the investigator.  
5. 
I have been advised about the risks associated with my participation in the study.  
6. 
I have informed the investigator of all the treatments I am taking or have taken in the past 
_______ months/years including alternate treatment.  
7. 
I agree to co-operate with the investigator. 
8. 
I have not participated in any research study within past ____ months. 
9. 
I am aware of the fact that I can opt out of any time without having to give any reason and 
this will not affect my future treatment in the hospital. 

 
23
10. 
I am also aware that the investigators may terminate my participation in the study at any 
time, for any reason, without my consent.  
11. 
I hereby give permission to the investigators to release the information obtained from me 
as a result of participation in this study to the sponsors, regulatory authorities, Government 
agencies and ethics committee. I understand that they may inspect my original records.  
12. 
My identity will be kept confidential if my data are publicly presented.  
13. 
If despite the following instructions, I am physically harmed because any substance or any 
procedure as stipulated in any plan (my treatment will be carried out free of cost at the 
investigational site/the sponsor will bear all the expenses), if they are not covered by my 
insurance agency or by a government program or any third party.  
14. 
I have had my questions answered to my satisfaction and have decided to be in the research 
study.  
I am aware, that if I have any questions during this study, I should contract at one of the addresses 
below. By signing this consent form, I attest that the information given in this document has been 
clearly explained to me and understood by me.  
Name and signature / thumb impression of participant / legal representative  
____________________________ (Name)____________________(Signature) 
________________ (Date) ______________ (Time) 
 
Name and signature of impartial witness (for illiterate patients) 
____________________________ (Name)____________________(Signature) 

 
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________________ (Date) ______________ (Time) 
Address 
and 
contact 
number 
of 
the 
impartial 
witness: 
____________________ 
_______________________________________________________________ 
Name and signature of the Investigator or his representative obtaining consent: 
____________________________ (Name)____________________(Signature) 
________________ (Date) ______________ (Time) 
Investigator certificate 
I certify that all the elements including the nature, purpose and possible risks of the above study 
as described in this consent form have been explained to the subject. In my judgement, the 
participant possesses the legal capacity to give the informed consent to participate in this research 
and is voluntarily and knowingly giving informed consent to participate.  
Signature of the investigator : _____________________________________ 
Name of the investigator : ________________________________________ 
Dated : _________________ 
 
CONTACT PERSONS 
For further information / questions, you can contact us at the following address: 
Principal investigator: 

 
25
Dr. Steve Joys 
Junior Resident 
Department of Anaesthesia 
PGIMER, Chandigarh 
 
7087617352 
 
Others: 
Dr.Hemant Bhagat 
Additional Professor 
Department of Anaesthesia and Intensive Care, 
PGIMER, Chandigarh 
 
 
 
 
 
 
 
 
 

 
26
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delirium in spine surgery. Spine J 2006;6:164–69. 
 4)Gao R ,Yang ZZ ,Li M ,Shi ZC ,Fu Q. Probable risk factors for postoperative delirium in 
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