Comparison of oropharyngeal leak pressure of LMA Protector and LMA ProSeal in anaesthetised paralysed patients – A randomised controlled trial

Abstract

Background and Aims: In the present study, we hypothesised that the laryngeal mask airway (LMA) Protector would provide higher oropharyngeal leak pressure (OLP) than LMA ProSeal. Thus, we planned this study to compare the clinical performance of LMA Protector and LMA ProSeal in terms of OLP as a primary objective and insertion characteristics as secondary objectives. Methods: Ninety patients of either gender, aged 18–70 years, were randomised into groups PS (LMA ProSeal) and P (LMA Protector). Following anaesthetic induction, the device was inserted as per group allocation. OLP of both devices was taken as a primary objective. Secondary objectives such as insertion time, ease of insertion, number of attempts required, fibre-optic view grading, amount of air (mL) required to get a cuff pressure (CP) of 60 cm H2O, and CP adjustment required and complications, if any, were also noted. Data were analysed using coGuide statistics software, Version 1 (BDSS Corp. Bangalore, Karnataka, India). Results: The median (interquartile range) OLP was significantly higher with LMA protector than with LMA ProSeal [33.00 (27.0, 36.0) versus [29.50 (26.0, 32.0) (P = 0.009)]. First-attempt success rate was 95.4% (42/44) in group PS and 93% (40/43) in group P. Insertion time, ease of insertion, and fibre-optic view grading were not different between the groups. Gastric tube placement failed in one patient in group PS and in three patients in group P (P = 0.606). The median amount of air (mL) required to get a CP of 60 cm H2O was 26.5 (20, 28) in group PS and 12 (8,13) in group P (95% confidence interval [CI] =10.808–14.575) (P < 0.001). At all time points, CP was significantly higher, and more CP adjustments were needed in group PS than in group P (P < 0.001). Incidence of blood staining and post-operative sore throat at 1 and 24 h were not different between the groups. Conclusion: LMA Protector provided a significantly higher OLP and less requirement of CP adjustments but comparable first-attempt success rate, mean insertion time, fibre-optic view, and gastric tube insertion as compared to LMA ProSeal.