Changes in the intracuff pressure in disposable classic LMA filled with either air, saline or 2% lignocaine while using nitrous oxide anaesthesia: A prospective, randomised, double-blinded study

Abstract

Introduction: Increase in cuff pressure is seen during nitrous oxide anaesthesia if air is used to inflate the cuff of LMA. This can lead to post-operative complications like sore throat, hoarseness and dysphagia. The aim of this study was to compare changes in the intracuff pressure in disposable LMA filled with Air, Saline or 2% Lignocaine in the cuff while using nitrous oxide anaesthesia and to assess postoperative pharyngolaryngeal complications. Methods: This was a prospective, randomized comparative study conducted in a tertiary care hospital in Karnataka. 120 patients were randomized into three groups containing 40 patients each using computer
generated random numbers and sealed envelope method. For subjects in Group A, air was injected into disposable LMA. For the subjects in Group S, Saline was injected, and for subjects in Group L, 2% Lignocaine was injected.
Results: The groups were comparable for demographic data, type of surgery, size of LMA, duration of anaesthesia, cuff volume and seal pressure. The mean cuff pressures at 30, 60, 90 and 120 minutes and at the end of surgery were significantly higher in group A and S as compared to group L (p<0.05).The cuff pressure increased from 70.42±8.3 cm H2O to 98.31±4.66 cm H2 O at 120 minutes in group A,whereas there was no significant increase in cuff pressure from baseline in group S and group L.
Conclusion: Intracuff pressure increases significantly within 15 minutes of nitrous oxide anaesthesia when air is used to inflate the cuff than saline or 2% Lignocaine. Pharyngeal complications like sore throat, dysphagia were seen only in air and saline group when compared to Lignocaine group.