ABSTRACT : Low flow anaesthesia is becoming popular in Anaesthesia practice because of its advantages like reduction in cost & atmospheric pollution, conservation of heat & airway humidity. An airtight seal between the airway device and patient airway is essential to establish leak-free semi-closed circuit system in low flow anaesthesia. Aim of our study was to compare the safety and efficacy of two airway maintenance devices i.e. P-LMA and ETT while practicing low flow anaesthesia.

METHODS : : A prospective randomised single blind study was conducted in 60 ASA grade I/II patients, age group of 20-50 years , weighing 40-70 kg, undergoing planned surgery under general anaesthesia. They were divided into two groups- in Group L: P-LMA was used and in Group ET: ETT was used. Oropharyngeal leak pressure , Inspired and expired tidal volume, Peak and plateau pressure, Inspired Oxygen concentration (FiO2), Inspiratory & expiratory concentration of N2O, CO2, and Isoflurane, hemodynamic parameters and complications were observed and compared between two groups .Statistical analysis was done using student ‘t’ test.

RESULTS : The Demographic data were comparable between both groups. Expired N2O & Isoflurane concentration were significantly low in P-LMA than ETT group (P<0.0001). Leak pressure was 29.46±1.1 in P-LMA group and 31.3±0.5 in ETT group (P<0.0001).In our study Oropharyngeal leak Pressure was found higher in ETT group than P-LMA group which was similar in studies done by Molhoff et al & Honemann et al.

CONCLUSIONS : P-LMA can be effective alternative to ETT in maintaining airway seal during Low flow anaesthesia.