The advantages of the LMA over the tracheal tube or facemask: a meta-analysis.

A meta-analysis was performed on randomised prospective trials comparing the laryngeal mask airway (LMA) with other forms of airway management to determine if the LMA offered any advantages over the tracheal tube (TT) or facemask (FM). Of the 858 LMA publications identified to December 1994, 52 met the criteria for the analysis. Thirty-two different issues were tested using Fisher's method for combining the P values. The LMA has 13 advantages over the TT and four over the FM. The LMA had two disadvantages over the TT and one over the FM. There were 12 issues where neither device had an advantage. Advantages over the TT included: increased speed and ease of placement by inexperienced personnel; increased speed of placement by anaesthetists; improved haemodynamic stability at induction and during emergence; minimal increase in intraocular pressure following insertion; reduced anaesthetic requirements for airway tolerance; lower frequency of coughing during emergence; improved oxygen saturation during emergence; and lower incidence of sore throat in adults. Advantages over the FM included: easier placement by inexperienced personnel; improved oxygen saturation; less hand fatigue; and improved operating conditions during minor paediatric otological surgery. Disadvantages over the TT were lower seal pressures and a higher frequency of gastric insufflation. The only disadvantage compared with the FM was that oesophageal reflux was more likely. The importance of these findings in terms of patient outcome could not be determined from the published data.