Comparison of the efficacy of Macintosh laryngoscope-guided insertion of I-gel^TM with the conventional blind insertion technique – A randomised study

Abstract

Background and Aims: This study was designed to compare the efficacy of Macintosh laryngoscope-guided insertion of I-gel™ with the conventional blind insertion technique. Methods: A total of 156 adult patients scheduled to undergo elective surgery under general anaesthesia were included. All participants were randomly divided into two groups; I-gel™ was inserted with conventional blind and Macintosh laryngoscopic-guided technique in group A and B respectively. The primary objective of the study was to determine the incidence of optimal positioning in both the groups based on fibreoptic bronchoscope score of the glottic view. Oropharyngeal leak pressure, haemodynamic parameters and insertion characteristics were also compared. Categorical data were presented as ratio or percentage, continuous data were presented as mean ± standard deviation or median (95% confidence interval). The strength of association between insertion technique and the anatomical fit of the device was calculated by relative risk ratio. Results: Fibreoptic scores were significantly better in laryngoscope-guided insertion group when compared to the blind insertion group ( P < 0.0001). The incidence of malposition was 3.85% in the laryngoscopic insertion group and 39.4% in the blind insertion ( P < 0.0001). Oropharyngeal leak pressure was higher in laryngoscope-guided insertion group than in blind insertion group (26.89 ± 3.37 cm H 2 O versus 24.42 ± 3.00 cm H 2 O; P < 0.0001). Other insertion characteristics except time taken to insert the device were comparable in both groups. Conclusion: When compared to the standard blind insertion technique, laryngoscope-guided insertion of I-gel™ results in better alignment with the laryngeal inlet providing a proper anatomical fit and better airway seal pressure.

Risk of bias in published randomised controlled trials

“…The demographic data of the 27 included articles are given in Table 1 . [ 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 ] Overall, 13 out of 27 were judged as having a low risk of bias. [ 5 6 9 10 12 15 16 20 21 22 23 24 27 ] In contrast, 6 out of 27 had a high risk of bias,[ 4 13 14 25 28 30 ] and 8 out of 27 had some concerns regarding biases.…”

“…[ 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 ] Overall, 13 out of 27 were judged as having a low risk of bias. [ 5 6 9 10 12 15 16 20 21 22 23 24 27 ] In contrast, 6 out of 27 had a high risk of bias,[ 4 13 14 25 28 30 ] and 8 out of 27 had some concerns regarding biases. [ 7 8 11 17 18 19 26 29 ] In domain 1, that is, bias arising from the randomisation process, 3 out of 27 had some concerns regarding biases.…”

Comparison of clinical performance of Ambu® AuraGain™ and BlockBuster® in anaesthetised preschool children-A randomised controlled trial

“…An ideal SGA device should have OSP higher than ventilating airway pressures or more than 20 cm H 2 O to ensure adequate ventilation. [ 8 ] The various first-generation SGA devices that have been used in the paediatric population like LMA Classic, LMA Flexible, LMA Unique, etc., have provided OSP values in the range of 16–20 cm H 2 O. [ 8 , 9 ] The second-generation devices—LMA BlockBuster ® , LMA Proseal, Air-Q®, LMA Supreme, AuraOnce™, AuraGain™ and i-gel®, are available in paediatric sizes as well.…”

“…[ 8 ] The various first-generation SGA devices that have been used in the paediatric population like LMA Classic, LMA Flexible, LMA Unique, etc., have provided OSP values in the range of 16–20 cm H 2 O. [ 8 , 9 ] The second-generation devices—LMA BlockBuster ® , LMA Proseal, Air-Q®, LMA Supreme, AuraOnce™, AuraGain™ and i-gel®, are available in paediatric sizes as well. [ 12 - 18 ] Due to changes in the structure and material of the cuff, and wide airway lumen, these devices provide higher seal pressures and can also be used as a conduit for intubation.…”

“…The OSP was determined by closing the expiratory valve of the circle system up to 30 cm H 2 O, at a fixed gas flow of 3 litres per minute and recording the airway pressure on the monitor at which equilibrium was reached and by detection of audible noise or by listening air leak through a stethoscope placed on the neck. [ 8 - 10 ] To ensure safety, maximum allowable OSP was set at 40 cm H 2 O, and adjustable pressure limiting valve pressure was released if there was no audible leak even at maximum allowable pressure.…”