A randomised controlled study comparing the effects of laryngeal mask airway and endotracheal tube on early postoperative pulmonary functions

Sharma R, Dua CK, Saxena KN
Correspondence: Dr Rajeev Sharma, rajeevkrsharmaji@gmail.com

ABSTRACT
Introduction Classic laryngeal mask airway (LMA) has long been used for airway management. General anaesthesia has been associated with a significant decrease in pulmonary functions during the postoperative period. The decrease in pulmonary functions has been found to be greater with the use of a tracheal tube (TT). In this study, we compared the effects on pulmonary functions during the early postoperative period when the airway was managed using an LMA versus a TT.
Methods A total of 20 patients in each group received either LMA or TT for airway management. Postoperative pulmonary functions were recorded at 30 and 60 minutes after removal of the airway device in patients undergoing peripheral limb surgeries. Forced vital capacity (FVC), forced expiratory volume during the first second (FEV1), vital capacity, FEV1/FVC, peak expiratory flow rate and percentage saturation of oxygenated haemoglobin were compared. Postoperative coughing and hoarseness were also recorded.
Results Pulmonary functions were significantly decreased in both groups at 30 and 60 minutes postoperatively. The decrease in the TT group was significantly greater than that in the LMA group at both 30 and 60 minutes. The FEV1/FVC was not significantly changed, indicating a restrictive pattern. Patients in the TT group had a significantly higher incidence of coughing at both 30 and 60 minutes.
Conclusion The use of LMA instead of TT for airway management during peripheral limb surgeries causes less depression of pulmonary functions during the early postoperative period. The incidence of coughing is also significantly lower.

Keywords: classic laryngeal mask airway, early postoperative period, pulmonary functions, tracheal tube
Singapore Med J 2011; 52(12): 874-878