Comparison of I-Gel and Laryngeal Mask Airwayblockbuster in the management of difficult airway in post burn contracture patients: A randomized controlled study

“Comparison of I-Gel and Laryngeal Mask Airwayblockbuster in the management of difficult airway in post burns contracturepatients: A randomized controlled trialâ€

BACKGROUND AND RATIONALE

Patients with postburn contracture (PBC) of the face and neck region usually have a difficultairway, and intubation failure is an important cause of morbidity and mortalityduring anesthesia in such patients.

Scarring orfibrosis after burns may result in decreased mouth opening and theoropharyngeal cavity, blocked nasal passages, restricted movement ofatlantooccipital joint and a flexed neck, trachea which may be deviated/pulledor compressed, and a noncompliant submandibular space. Alignment of the oral,pharyngeal, and the laryngeal axes is required for direct laryngoscopy (DL),hence the above features can make direct laryngoscopy difficult.1

Supraglotticdevices have been found useful to provide adequate airway management in postburn contracture patients. I-gel was found feasible for emergency airwaymanagement in difficult airway situation with reduced neck movement and limitedmouth opening in post burn neck contracture. 2

A newer LMA calledLMA BlockBuster invented in 2012 (Tuoren Medical Instrument co, Ltd, Changyuancity, China) has been gaining popularity to provide increased safety andquality of anesthesia.

 Figure 1a. LMA Blockbuster                                1b.i-gel

Singh J,  et al (2012)2 conducted a prospective, crossover, randomized controlled trial wasperformed amongst forty eight post burn neck contracture patients with limitedmouth opening and neck movement. i-gel and cLMA were placed in random order ineach patient. Success rate for the i-gel was 91.7% versus 79.2% for the cLMA.i-gel required shorter insertion time (19.3 seconds vs. 23.5 seconds, P=0.000).Airway leak pressure difference was statistically significant (i-gel 21.2 cmH20; cLMA 16.9 cm H20; P=0.00). Fiberoptic view throughthe i-gel showed there were less epiglottic downfolding and better fiberopticview of the glottis than cLMA. Overall agreement in insertion outcome for i-gelwas 22/24 (91.7%) successes and 2/24(8.3%) failure and for cLMA, 19/24 (79.16%)successes and 5/24 (16.7%) failure in the first attempt. The i-gel is cheap,effective airway device which is easier to insert and has better clinicalperformance in the difficult airway management of the airway in the post burncontracture of the neck. Our study shows that i-gel is feasible for emergencyairway management in difficult airway situation with reduced neck movement andlimited mouth opening in post burn neck.

Gupta S**(2017)5** conducted aprospective, randomized comparative study total 60 children, 30  each in i-gelâ„¢ and LMA-Supremeâ„¢ group.Oropharyngeal leak pressure (OPLP) for i-gelâ„¢ was found to be significantlyhigher in flexion (29.00± 1.95cmH2O, P <0.001)and lower in extension (21.07±2.08 cmH2O, P <0.001) as compared to neutral (24.67±2.08 cmH2O). Similar resultswere observed for LMA-Supremeâ„¢ which showed significantly higher OPLP inflexion (24.73±2.26, P < 0.001 respectively) and lower inextension (18.67 ± 1.42 cmH2O, P <0.001) ascompared to neutral (20.87 ± 1.80 cmH2O). Worsening of fiberopticview occurs for i-gelâ„¢ and LMA-Supremeâ„¢ in flexion (10/12/5/3/0 and11/14/2/2/1, P <0.05) as compared to neutral position(17/10/2/1/0 and 15/12/1/1/1), respectively. Significant change did not occurin extension. Ventilation worsening occurred in flexion as compared to neutralposition evidenced by significant decrease in exhaled tidal volume (92.90 ±11.42 and 94.13±7.75 ml, P <0.05) as compared to neutral(100.23± 12.31 and 101.50 ± 8.26 ml) for i-gelâ„¢ and LMA-Supremeâ„¢,respectively. Neck flexion caused a significant increase in leak pressurein both i-gelâ„¢ and LMA-Supremeâ„¢. With deterioration of fiberoptic view andventilation, both devices should be used cautiously in pediatric patients inextreme flexion.

Banerjee G  et al (2018)6conducted a study that total 70 children wererandomly assigned to receive PLMA (n = 35) or I-Gelâ„¢ (n =35) for airway management. Oropharyngeal leak pressure in maximum flexion,maximum extension and the neutral position was taken as the primary outcome.Peak inspiratory pressures (PIPs), expired tidal volume, ventilation score andfibreoptic grading were also assessed.  No significant difference wasnoted in oropharyngeal leak pressures of PLMA and I-Gelâ„¢ during neutral (P =0.34), flexion (P = 0.46) or extension (P = 0.18). PIPsmean (standard deviation [SD]) were significantly higher (17.7 [4.03] vs. 14.6[2.4] cm H2O, P = 0.002) and expired tidal volumemean [SD] was significantly lower (5.5 [1.6] vs. 6.9 [2] ml/kg, P =0.0017) with I-Gelâ„¢ compared to PLMA. Fibreoptic grading and ventilation scorewere comparable in both the groups in all the three head-and-neckpositions.  PLMA and I-Gelâ„¢, both recorded similar oropharyngeal leakingpressures in all the three head-and-neck positions. However, higher peakpressures and lower expired tidal volume in maximum flexion of the neck whileventilating with I-Gel may warrant caution and future evaluation.

Endigeri A et al (****2019)7conducted a study that  Sixtypatients of age group 20-60 years undergoing general anaesthesia wererandomised in 2 groups, of 30 patients each, for tracheal intubation usingeither BlockBuster® LMA (Group B) or the Intubating LMAFastrach® (Group F). After induction of anaesthesia, LMAs wereinserted and on achieving adequate ventilation with the device, fibreopticscopy was performed to assess the glottis visualisation score. Blind intubationwas attempted through the supraglottic airway devices (SAD). The primaryobjective was first pass successful intubation and secondary outcomes wereease, time for LMA insertion, oropharyngeal seal pressure (OSP), LMA removaltime, fibreoptic scoring and complications. Data was analysed using SPSS V22software.  The first-attempt success rate of tracheal intubation was 90%in Group B and 66.6% in Group F (P = 0.028), while the overallsuccess rate of intubation was 96.6% in Group B and 89.9% in Group F (P =0.3). The OSP in Group B was 33.7 ± 1.8 and 22.7 ± 1.5 cm H2O inGroup F (P = 0.001). Complications such as sore throat and bloodstain were reduced with BlockBuster® LMA.  BlockBuster® LMAprovides higher first pass success rate of blind tracheal intubation with lesscomplications like sore throat and blood staining.

AIMS AND OBJECTIVES

·       To compare the clinical performance of airwaymanagement with i-gel and LMA blockbuster in patients with mild and moderatepost burn contractures of neck in adult patients undergoing general anesthesia.

Primary objective:

·       To assess the time taken for insertion of thedevices

Secondaryobjectives:

·       Ease of insertion,

·       Number of attempts (maximum 2),

·       Hemodynamic response and SpO2 duringdevice insertion and maintenance of General Anesthesia,

·       Airway leak pressures

·       Required attempts for gastric tube placements

·       Any complications

MATERIAL AND METHODS

Study settings:

This prospectiverandomized controlled study will be conducted in the operating rooms ofdepartment of plastic surgery in association with department of anesthesiaafter obtaining Institutional Ethical clearance and registration of the trialby Clinical Trial Registry of India  (CTRI).

Study type: Prospective Randomizedcontrolled study

Study duration : One year

Sample size: Weare planning a study to compare the insertion time of i-gel and LMA for airwaymanagement in patients with mild to moderate post-burn contractures. In aprevious study, Singh et al. (2012)2 reported the insertiontime for i-gel and LMA to be 19.4 and 23.5 seconds (Mean difference = 4.1seconds) respectively in post-burn neck contractures. In present study we willalso target a similar difference. The sample size was calculated using thefollowing formula suggested by Charan and Biswas (2013):

n= (r+1) *2(Zα/2+Zβ)2 SD2/d2

where, n: Sample size

r = ratio of study groups = 1:1 = 1; SD: Pooledstandard deviation = 5 seconds (Assumed); d: Difference in the means (effectsize) = 4.1 seconds

Zα/2 : critical value of z at 95% confidence =1.96; Zβ: critical value of z at 80% power = 10.84

n = (1+1) * 2*(1.96+0.84)2 * 52 /4.12

= 46.639 »47

Thus, the calculated sample size is only 47.After adding for a contingency provision of 20% and rounding off to the nearesttenth value we target a sample size of 60 divisible into two equal groups of 30cases each.

Validation:Projected time of insertion in I-gel group (n=30)= 19.4±5 seconds; Projectedtime of insertion in LMA group (n=30) = 23.5±5 seconds. Comparison of two using‘t’-test results in a ‘t’-value of 3.178 with a ‘p’ value 0.002, thus showingthat if results projected in index article are replicated then they will bestatistically significant too at the estimated sample size.

 Inclusioncriteria:

·       After obtaining informed consent, 100 ASAphysical status I or II patients, 18–60 years of age, having mild or moderatecontracture of the neck (Onah’s classification3 Type 1 and Type 2) ,with Mallampatti grade I or II and a mouth opening of at least 3 cm, plannedfor elective surgery under general anesthesia, will be included.

Exclusion Criteria:

·       Patients with any neck pathology other than thescar,

·       Body mass index (BMI) >30 kg/m2,

·       Reactive airway,

·       Gastroesophageal reflux disease,

·       Neck circumference >40 cm, and

·       Pregnant patients will be excluded.

Methodology:

Patients will berandomized using a computer-generated random number and the sealed envelopetechnique to two groups: group I and group B.

Group I **(****n=30):**– we will use i-gel

Group B**(**n=30) : we will use the blockbuster LMA.

A thorough pre anesthetic evaluation will be donea day before the procedure and all patients will be advised nil by mouth (NBM)for 8 hours prior to surgery. On the day of surgery, an intravenous access willbe established and slow infusion of crystalloids will be commenced. Noninvasivemonitors like electrocardiogram, Noninvasive blood pressure (BP), pulseoximetry will be instituted and baseline values of heart rate (HR), BP, oxygensaturation SpO2 will be recorded and IV cannula of 20G will beplaced.

While preoxygenating using 100% oxygen,intravenous injection glycopyrrolate 10 µg/kg, midazolam 0.03 mg/kg, fentanyl 1µg/kg will be administered. Anesthesia will be induced intravenously with 1%propafol (2 mg/kg). Once an adequate depth of anesthesia will be achieved (lossof eye lash reflex), LMA Blockbuster or i-gel will be inserted. The appropriatesize of LMA will be selected according to body weight and manufacturersrecommendations.

Adequate placement of the airway device will beassessed by squeezing the reservoir bag and observing the end-tidal CO2 waveform and movement of thechest wall.

If ventilation will be inadequate, the followingmanipulations will be done: gentle pushing or pulling the device, chin lift,jaw thrust, head extension, or neck flexion. The ease of LMA placement will beassessed using a subjective scale of 1-4 (1-no resistance, 2-mild resistance,3-moderate resistance, and 4-inability to place the device). 4 Timeof insertion will be measured from pickup of device till visible square wavecapnograph (with acceptable leak pressures).

The airway will be  manipulated after each attempt if a secureairway will not be achieved. Intervention required on the airway will be gradedas either minor [changing neck position/adjusting head (changing depth ofinspiration)] or major (requiring jaw thrust, re-insertion/change of device).

Anesthesia will be maintained with 1.5-2.5%Sevoflurane, along with injection Vecuronium intermittently.  Aftercompletion of surgery and resumption of adequate spontaneous breathing, thepatient would be reverted and the supraglottic device will be removed.  The timeof insertion will be measured from the pickup of supraglottic device tillvisible etCO2 graph and with adequate chest rise and acceptable leak pressure(proper ventilation). The oropharyngeal leak pressures will be measured andcompared.

Effective ventilation will bedefined as proper chest expansion or square wave capnograph trace, absence ofaudible leak and lack of gastric insufflations. The total time of placementfrom grasping of the device to observing a square wave capnograph trace (theinsertion time) and the numbers of attempts will be recorded. Airway leakpressure tests will be then performed. The oropharyngeal leak pressure will bemeasured by closing the expiratory valve of the circle system at a fixed gasflow of 3 litters per minute and noting the airway pressure (maximum allowed 40cm H2O). The position of the device will be assessed and graded bythe investigators using a fiberoptic bronchoscope (2.8 mm: Olympus, Tokyo,Japan) for the view of glottis. If both the devices failed then fiberopticbronchoscope will be kept as backup plan for intubation.

REFERENCES

1)    PrakashS, Mullick P. Airway management in patients with post burn contractures of theneck. Burns. 2015;41:1627–35.

2)    SinghJ, Yadav MK, Marahatta SB, Shrestha BL. Randomized crossover comparison of thelaryngeal mask airway classic with i-gel laryngeal mask airway in the managementof difficult airway in post burn neck contracture patients. Indian JAnaesth. 2012;56:348–52.

3)    OnahII. A classification system for post burn mentosternal contracture. ArchSurg. 2005;140:671–5.

4)    JagannathanN, Sohn LE, Sawardekar A, Gordon J, Shah RD, Mukherji II et al. ARandomised trial comparing the Ambu Aura-i with air-qâ„¢ intubatingLMA as a conduit for tracheal intubation in children. Paediatr Anaesth 2012;22:156-60

5)   GuptaS, Dogra N, Chauhan K. Comparison of i-gelâ„¢ and Laryngeal Mask Airway Supremeâ„¢in different head and neck positions in spontaneously breathing pediatricpopulation. Anesth Essays Res 2017;11:647-50

6)    BanerjeeG, Jain D, Bala I, Gandhi K, Samujh R. Comparison of the ProSeal laryngeal maskairway with the I-Gelâ„¢ in the different head-and-neck positions inanaesthetised paralysed children: A randomised controlled trial. Indian JAnaesth 2018;62:103-8

7)    EndigeriA, Ganeshnavar A, Varaprasad B V, Shivanand Y H, Ayyangouda B. Comparison ofsuccess rate of BlockBuster® versus Fastrach® LMA as conduit for blindendotracheal intubation: A prospective randomised trial. Indian J Anaesth2019;63:988-94

   INFORMEDCONSENT

**Title of project:**Comparison of I-Gel andLaryngeal Mask Airway blockbuster in the management of difficult airway in postburns contracture patients: A randomized controlled trial

Investigators:

Dr Manish KumarTripathi, JR-1, Department of Anaesthesiology,KGMU, Lucknow.

Mob No. 9670986299; email ID:tripathi.manish81@gmail.com

Chief Supervisor: Dr. Tanmay Tiwari, Associate Professor,  Department of Anaesthesiology, KGMU, Lucknow

Co-supervisors: Dr. Divya Narain Upadhyay, AdditionalProfessor,  Department of PlasticSurgery, KGMU, Lucknow

Dr.Prem Raj Singh, Associate Professor,  Department of Anaesthesiology, KGMU, Lucknow

 Subject’sFull Name ________________________________________________

Date ofBirth/Age_________________________________________________

Address_________________________________________________________

Patient/Parent/GuardianConsent PART 1**Purpose of the study-**To compare the clinical performance of airway management withi-gel and LMA blockbuster in patients with mild and moderate post burncontractures of neck in adult patients undergoing general anesthesia.

**Study Procedure:**Prospective Randomized control study

Risk from thestudy-None

Benefits from the study-  This study to assess the timetaken for insertion of the devices; Ease of insertion, Number of attempts(maximum 2),  Hemodynamic response andSpO2 during device insertion and maintenance of General Anesthesia,Airway leak pressures, Required attempts for gastric tube placements and  Any complications.

**Complications–**None

Compensation-none

Confidentiality-all the information and clinical documents of subjects of the study will bekept strictly confidential and will be shown only to the investigator,supervisor and co- investigators of the study. The result of study will be usedfor clinical and academic purpose and the name of the subject would not bedisclosed.

Rights of theparticipants- Participation in the study isvoluntary. Refusal to participate will not influence the care of patient inthis hospital in any way.

Alternatives toparticipation in the study-None

PART2Consent 1       I confirm that I have read and understood the informationsheet dated ___________for the above study and have had the opportunity to askquestions.

OR

I have been explained the nature of the study by theInvestigator and had the opportunity to ask questions

2       I understand that my participation in the study is voluntaryand that I am free to withdraw at any time, without giving any reason andwithout my medical care or legal rights being affected.

3       I understand that the sponsor of the clinical trial/project,others working on the Sponsor’s behalf, the Ethics Committee and the regulatoryauthorities will not need my permission to look at my health records both inrespect of the current study and any further research that may be conducted inrelation to it, even if I withdraw from the trial. However, I understand thatmy Identity will not be revealed in any information released to third partiesor published.

4       I agree not to restrict the use of any data or results thatarise from this study provided such a use is only for scientific purpose(s)

5.  I agree to take part in the above study

Signature(or Thumb impression) of the Subject/Legally AcceptableRepresentative:___________________

Signatory’sName:______________________________

Date:_____________________________

Relationship withsubject:_______________________________

  Investigator’s statement:-

 I,the undersigned have explained to the parent/guardian in a language she/heunderstands the procedures to be followed in the study and risks and benefits.

 Signature of the Investigator:                                                       Date:

 Name of the Investigator:

 Signature of the Witness:                                                               Date:

Name of theWitness:

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