Comparison of Clinical Performance of LMA Protector Cuff Pilot and LMA Supreme Among Anaesthetised, Non-Paralysed Patients
Phase: NA
Conditions: Anesthesia
Sponsor: Liu Chian Yong

 
 
 
 
 
 
 
 
 
COMPARISON OF CLINICAL PERFORMANCE OF LMA PROTECTOR™ CUFF 
PILOTTM AND LMA SUPREME™ AMONG ANAESTHETISED, NON-PARALYSED 
PATIENTS 
 
DR. CHAN WENG KEN 
M.D. (UNIMAS) 
 
UNIVERSITI KEBANGSAAN MALAYSIA 
 
14 JULY 2018 
 
 
 

 
 
2
INTRODUCTION 
 
The inception of supraglottic airway (SGA) has revolutionized the anaesthetist’s 
airway armamentarium. It was invented by Dr Archie Ian Jeremy Brain in 1982 and was 
commercially made available in 1987.1 It offers the advantage of avoiding endotracheal 
intubation, shorter insertion time, lower incidence of post-operative pharyngeal pain and 
better haemodynamic stability during induction and emergence.2 An ideal SGA placement 
should provide sufficient perilaryngeal seal to allow ventilation of the lungs without injuring 
pharyngeal mucosa and able to prevent or provide early detection of gastric aspiration. It can 
be classified based on its function into 1st, 2nd and 3rd generation3 or via its sealing 
mechanism.4  
 
 
LMA Supreme™ is a single use, second generation SGA introduced in 2005. It is 
made of polyvinyl chloride (PVC). It has the advantage of anatomically shaped airway tube, 
presence of an integral bite block and a drain tube to facilitate placement of gastric tube.5 
According to manufacturer, it is a high volume low pressure cuff which can generate high 
seal pressure up to 37 cmH2O.6  
 
 
LMA Protector™ is the latest second generation SGA introduced in 2015. It is a 
single use device made of silicon and is both latex and phthalate free. It is similar to LMA 
Supreme™ that has a dynamic curve, which conforms to the anatomical contour of the 
pharynx, hence allowing rapid insertion. LMA Protector™ also has an integral bite block and 
dual gastric access. In addition, LMA Protector™ Cuff PilotTM has an integrated cuff pressure 
monitor to ensure the SGA is properly inflated.7  
 
 
The common complications of SGA are malposition, sore throat, dysphagia and 
laryngeal nerve injury.8 Instruction leaflet for LMA Supreme™ states a maximum cuff 
volume of 20 ml, 30 ml and 40 ml of air for size 3, 4, and 5 respectively. It also recommends 
maximum intra-cuff pressure of 60 cmH2O.5 However, inflating the maximum recommended 
cuff volume often results in intra-cuff pressure higher than 60 cmH2O.9,10 Saraçoğlu et al. 
reported that professional experience does not contribute to obtaining optimal cuff pressure 
without measuring it.11 Hence, this calls for a need to introduce cuff manometer into our 
routine anaesthetic practice.  
 

 
 
3
 
The new LMA Protector™ Cuff PilotTM was designed to reduce the risk of 
overinflating. It has a cuff pilot valve to allow user to monitor the intra-cuff pressure of the 
SGA through visual means that are colour coded. Optimal intra-cuff pressure of 40-60 
cmH2O will place the cuff pilot valve in green zone whereas underinflating and overinflating 
will place it either in yellow or red zone respectively. As it is made of silicone, it also offers 
more flexibility and potentially less traumatic than LMA Supreme™.12  
 
 
A search of ‘LMA Protector, laryngeal mask airway protector’ in PubMed Central 
only yielded six results, whereas 'laryngeal mask airway supreme' yielded 160 results in 
PubMed and 188 results in PubMed Central respectively. Only two papers mentioned LMA 
Protector™’s clinical performance whereas another three were case reports. Hence, this calls 
for more study on LMA Protector™ Cuff PilotTM especially in regards to its clinical 
performance.  
 
 

 
 
4
OBJECTIVES 
 
Primary objective: 
To assess the oropharyngeal leak pressure (OLP) of LMA Protector™ Cuff PilotTM and LMA 
Supreme™. 
 
Secondary objectives: 
1. To compare the mean time to insertion between LMA Protector™ Cuff PilotTM and LMA 
Supreme™.  
2. To compare the ease of gastric tube insertion between LMA Protector™ Cuff PilotTM and 
LMA Supreme™.  
3. To compare the laryngeal view of LMA Protector™ Cuff PilotTM and LMA Supreme™. 
4. To compare the complications in patients using LMA Protector™ Cuff PilotTM and LMA 
Supreme™. 
 
STUDY HYPOTHESIS 
 
We hypothesised that LMA Protector™ Cuff PilotTM has similar OLP to LMA Supreme™, is 
easily inserted with faster insertion time, and lesser complication. 
 
MATERIALS AND METHODS 
 
 
This prospective, single blinded, randomised controlled trial will be submitted for the 
approval of the Research Committee of Department of Anaesthesiology & Intensive Care, 
Universiti Kebangsaan Malaysia Medical Centre (UKMMC) and the Medical Research & 
Ethics Committee, UKMMC. 
 
 
Patient information sheet (in Malay and English) will be given out and explained to 
patients. Written informed consent will be obtained from patients recruited into the study, 
which will be conducted by a single operator who has experience in insertion of both LMAs. 
 
Study Site:  
This proposed study will be carried out in operation theatres of Universiti Kebangsaan 
Malaysia Medical Centre. 

 
 
5
 
Inclusion Criteria: 
1. Patients aged 18-65 years old. 
2. Patients planned for general anaesthesia without muscle relaxant usage via SGA. 
 
Exclusion Criteria: 
1. Patients with body mass index (BMI) > 35 kg/m2. 
2. Patients with likelihood of difficult intubation (Simplified Airway Risk Index score ≥ 
4).13 
3. Patients with increase risks of aspiration (gastro-oesophageal reflux disease, obstetric 
patients, hiatus hernia).  
 
Methodology: 
 
 
Patients who consented to the study will be randomized into 2 groups, Group P or 
Group S using an online Random Sequence Generator (https://www.random.org/sequences/). 
Patients in Group P will have LMA Protector™ Cuff PilotTM inserted during general 
anaesthesia whereas patients in Group S will receive LMA Supreme™. The selection of SGA 
sizes will be done according to manufacturer’s recommendation based on participant's 
weight. At the operating theatre, patients will be placed in supine position with a head rest. 
Standard monitoring consisting of pulse oximeter, non-invasive blood pressure (NIBP) and 3 
lead electrocardiogram (ECG) will then be applied.  
 
 
Both groups will receive similar induction regime which are: preoxygenation to 
achieve end-tidal fractional oxygen concentration > 0.85; intravenous (IV) fentanyl 1-2 
mcg/kg; IV propofol 1.5-2.5 mg/kg and anaesthesia maintained with sevoflurane at minimum 
alveolar concentration (MAC) of 0.8-1.2 via manual mask ventilation with adjustable 
pressure limiting (APL) valve closed at < 20 cmH2O. Each SGA will be fully deflated and its 
posterior surface will be lubricated with water-based gel prior to placement. SGA will be 
inserted once participant's both pupils are in the centre and loss of motor response to jaw 
thrust. Both LMA Protector™ Cuff PilotTM and LMA Supreme™ will be inserted using the 
single-handed rotational technique in the semi-sniffing position as recommended by 
manufacturer.  
 

 
 
6
 
After insertion, the cuff in Group P will be insufflated with air till the cuff pilot valve 
is located in the centre of the green zone (estimated cuff pressure between 40-60 cmH2O). In 
Group S, the cuff will be insufflated with air in accordance to manufacturer’s 
recommendation to 60 cmH2O by using a hand-held analog cuff pressure gauge (VBM 
Medizintechnik GmbH, Germany). The time to insertion - that is defined as duration from 
picking up the study device to presence of capnography tracing - will be recorded. The 
number of attempts will also be recorded. Any participant which require more than three 
attempts will be considered a fail attempt and will subsequently be managed appropriately by 
the attending anaesthetist.  
 
 
After placement, a size 12-F gastric tube will be lubricated at the distal tip with water 
based lubricant and then inserted via the gastric channel of both groups. The number of 
attempt to insert a gastric tube will be recorded. Correct placement of the gastric tube will be 
determined by the detection of injected air through epigastric auscultation.  
 
 
The position of SGA after insertion in relation to laryngeal inlet will be verified by 
passing an intubating bronchoscope to a position just proximal to the end of the SGA. The 
laryngeal view obtained at this point will be scored according to Keller et al.: Grade 1, clear 
view of the vocal cords; Grade 2, view of the arytenoids only; Grade 3, view of the epiglottis 
only; Grade 4, no laryngeal structures visible.14 
 
 
Oropharyngeal leak pressure (OLP) will be assessed by setting the APL valve of the 
circle system at 40 cmH2O with fresh gas flow of 3 L/min. The OLP will be determined by 
observing the airway pressure at equilibrium until an audible noise is heard over the mouth 
with a stethoscope. For safety reasons, the maximum allowable OLP is 40 cmH2O.  
 
 
Intraoperatively, anaesthesia will be maintained with sevoflurane at MAC of 0.8 to 
1.2 in a mixture of 50% oxygen and 50% medical air with total flow of 2 L/min. Subsequent 
anaesthetic management including analgesia and anti-emetic will be in accordance to the 
discretion of the anaesthetist-in-charge.  
 
 
SGA will be removed once patient awake and obeying simple commands. Presence of 
blood stain over the SGA will be recorded. Participants will be followed up in the recovery 

 
 
7
and 6 hours after discharged from recovery to assess for presence of sore throat and 
hoarseness of voice. 
 
 
 
 

 
 
8
STATISTICAL ANALYSIS 
 
Sample size calculation: 
For the primary objective, we need 26 participants in each group to detect the difference of 
4.5 cmH2O (20.7 vs 25.2 cmH2O) 15 with standard deviation of 5.7 at 80% power and alpha 
value of 0.05 using Power and Sample Size Calculation version 3.1.2.16 With anticipation of 
15% dropout rate, we decided to take a total of 60 participants. 
 
Statistical test: 
All data will be entered into Microsoft Excel 2016 and analysed in Statistical Package for 
Social Science (SPSS) version 20.0. Result for the respective objectives will be analysed 
using the following statistical test and as appropriate. A value of p < 0.05 will be considered 
statistically significant. 
 
Results 
Statistical analysis 
Assessing OLP 
Student t-test 
Comparing mean insertion time 
Student t-test 
Comparing ease of gastric tube insertion 
Mann Whitney 
Comparing laryngeal view 
Mann Whitney 
Comparing complications 
Chi square 
 
 
 
 
 

 
 
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Patient planned for operation under Genaral Anaesthesia using SGA
- Patients aged 18-65 years old
- Less than 2 hours
Written consent
Random group allocation 
- Standard monitoring: pulse oximeter, NIBP, ECG
- Induction: preoxygenation, IV Fentanyl 1-2 mcg/kg, IV Propofol 
1.5-2.5 mg/kg 
- Anaesthesia maintained with Sevoflurane to MAC 0.8-1.2 in 50% 
oxygen and 50% air with total flow 2L/min
- SGA and Gastric tube inserted
- Adequate analgesia as per Anaesthetist's discretion
Group P:
- Cuff will be insufflate with air till 
the cuff pilot valve is located in the 
middle of green zone
- Check intra-cuff pressure, 
laryngeal view and OLP
Group S:
- Cuff will be insufflate with air 
based until intra-cuff pressure is 
60 cmH2O 
- Check laryngeal view and OLP
- SGA removed at the end of operation
- Check for presence of blood stain on SGA
- Postoperative follow up in recovery and 6 hous post discharge from 
recovery to assess for post-operative pharyngeal pain
- High risk of difficult 
ventilation via SGA 
- Increase risks of aspiration
Excluded
FLOW CHART 
 
 
 
 
 
 
 
 

 
 
10
GANTT CHART 
 
 
Activity 
Sep   
17 
Oct - 
Nov 
17 
Dec 17 
- May 
18 
June - 
Nov 
18 
Dec  
18 
Jan  
19 
Feb - 
Mar 
19 
Apr  
19 
May - 
Jun 19 
Oct   
19 
Proposal 
presentation 
 
  
 
  
 
  
 
  
 
  
Quotation from 
LMA company 
 
  
 
  
 
  
 
  
 
  
Proposal 
editing and 
submission 
 
  
 
  
 
  
 
  
 
  
Preparing 
research 
materials 
 
  
 
  
 
  
 
  
 
  
Data collection 
 
  
 
  
 
  
 
  
 
  
Data entry 
 
  
 
  
 
  
 
  
 
  
Data analysis 
 
  
 
  
 
  
 
  
 
  
Study write up 
 
  
 
  
 
  
 
  
 
  
Preliminary 
report 
 
  
 
  
 
  
 
  
 
  
Final report 
presentation 
 
  
 
  
 
  
 
  
 
  
Thesis 
submission 
  
  
  
  
  
  
  
  
  
  
 
 

 
 
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DATA COLLECTION SHEET 
 
Study No: 
 
 
 
 
 
    Contact no: 
 
1. Demographic Data: 
Name: 
 
Age: 
              Gender:   Male   /   Female 
RN: 
              ASA:   I   /   II   /   III 
Weight:  __________ kg 
              Height:  __________ cm 
Diagnosis: 
 
Operation: 
 
 
2. Please circle the supraglottic airway device (SGA) used:  
LMA Supreme™  
/ 
 LMA Protector™ Cuff PilotTM 
 
3. Duration of Insertion 
Time 
Attempt No. 1 
Attempt No. 2 
Attempt No. 3 
Duration (seconds) 
 
 
 
 
4. Laryngeal view grade: __________ 
 
5. Oropharyngeal Leak Pressure (OLP):  __________ cmH2O 
 
6. Gastric tube insertion attempt(s): __________ 
 
7. Total anaesthetic time (From induction to removal of SGA):  _______________  
 
8. Postoperative Data 
a) Presence of blood stain on the SGA after removal:  
Yes 
/ 
No 
b) Pharyngeal pain within 6 hours post op:  
 
 
Yes 
/ 
No 
 
 
 

 
 
12
REFERENCES 
 
1.  
Van Zundert TCR V, Brimacombe JR, Ferson DZ, Bacon DR, Wilkinson DJ. Archie 
Brain: Celebrating 30 years of development in laryngeal mask airways. Anaesthesia. 
2012;67(12):1375–85.  
2.  
Brimacombe J. The advantages of the LMA over the tracheal tube or facemask: a 
meta-analysis. Can J Anaesth. 1995;42(11):1017–23.  
3.  
Cook T, Howes B. Supraglottic airway devices: Recent advances. Contin Educ 
Anaesthesia, Crit Care Pain. 2011;11(2):56–61.  
4.  
Miller DM. A proposed classification and scoring system for supraglottic sealing 
airways: A brief review. Anesth Analg. 2004;99(5):1553–9.  
5.  
Teleflex. LMA SupremeTM A Second Generation SAD with and innovative Second 
SealTM [Internet]. 2014 [cited 2017 Sep 19]. p. 1–2. Available from: 
http://www.teleflex.com/emea/documentLibrary/documents/940689-000001_31817-
LMA-TF-Supreme-A4_1403_PDF.pdf 
6.  
Verghese C, Ramaswamy B. LMA-SupremeTM - A new single-use LMATM with 
gastric access: A report on its clinical efficacy. Br J Anaesth. 2008;101(3):405–10.  
7.  
Teleflex. LMA ProtectorTM Instructions for use [Internet]. 2015 [cited 2017 Sep 19]. p. 
1–16. 
Available 
from: 
http://www.lmaco-
ifu.com/sites/default/files/node/1928/ifu/revision/3285/pbe2100000b-lma-protector-
ifuuk.pdf 
8.  
Bick E, Bailes I, Patel A, Brain AIJ. Fewer sore throats and a better seal: why routine 
manometry for laryngeal mask airways must become the standard of care. Anaesthesia 
[Internet]. 2014;69(12):1304–8. Available from: http://doi.org/10.1111/anae.12902 
9.  
Asai T, Howell TK, Koga K, Morris S. Appropriate size and inflation of the laryngeal 
mask airway. Br J Anaesth. 1998;80(4):470–4.  
10.  
Tiefenthaler W, Eschertzhuber S, Brimacombe J, Fricke E, Keller C, Kaufmann M. A 
randomised, non-crossover study of the GuardianCPV??? Laryngeal Mask versus the 
LMA Supreme??? in paralysed, anaesthetised female patients. Anaesthesia. 
2013;68(6):600–4.  
11.  
Saracoglu A, Dal D, Pehlivan G, Gögüs FY. The Professional Experience of 
Anaesthesiologists in Proper Inflation of Laryngeal Mask and Endotracheal Tube Cuff. 
Turkish 
J 
Anesth 
Reanim 
[Internet]. 
2014;42(5):234–8. 
Available 
from: 
http://jtaics.org/jvi.aspx?pdir=tard&plng=eng&un=TARD-87487&look4= 

 
 
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12.  
Van Zundert AAJ, Skinner MW, Van Zundert TCR V, Luney SR, Pandit JJ. Value of 
knowing physical characteristics of the airway device before using it. Br J Anaesth. 
2016;117(1):12–6.  
13.  
El-Ganzouri AR, McCarthy RJ, Tuman KJ, Tanck EN, Ivankovich AD. Preoperative 
airway assessment: predictive value of a multivariate risk index. Anesth Analg. 
1996;82(6):1197–204.  
14.  
Keller C, Brimacombe J, Puhringer F. A fibreoptic scoring system to assess the 
position of laryngeal mask airway devices. Interobserver variability and a comparison 
between the standard, flexible and intubating laryngeal mask airways. Anasthesiol 
Intensivmed Notfallmedizin Schmerztherapie. 2000;35(11):692–4.  
15.  
Zhang L, Seet E, Mehta V, Subramanyam R, Ankichetty SP, Wong DT, et al. 
Oropharyngeal leak pressure with the laryngeal mask airway Supreme at different 
intracuff pressures: a randomized controlled trial. Can J Anesth Can d’anesthésie 
[Internet]. 2011 Jul;58(7):624–9. Available from: https://doi.org/10.1007/s12630-011-
9514-6 
16.  
Dupont WD, Plummer WD. Power and sample size calculations for studies involving 
linear regression. Control Clin Trials. 1998;19(6):589–601.  
  
 
 
 
 

 
 
14
SIMPLIFIED AIRWAY RISK INDEX (SARI)  
(El-Ganzouri et. al., 1996) 
 
Assessment 
0 point 
1 point 
2 points 
Interincisor gap 
≥ 4cm 
< 4 cm 
 
Thyromental distance 
> 6.5 cm 
6-6.5 cm 
< 6 cm 
Modified Mallampati Score 
I-II 
III 
IV 
Neck Movement 
> 90 º 
80-90 º 
< 80 º 
Ability to prognath 
Yes 
No 
 
Weight 
< 90 kg 
90 - 110 kg 
> 110 kg 
History of difficult intubation 
None 
Questionable 
Definite 
 
 
Score: 
< 4: unlikely to be difficult 
≥ 4: likely will be difficult