Background: Adverse events such as pharyngolaryngeal complications are indicators of quality patient care. Use of manometry to limit the laryngeal mask airway (LMA) intracuff pressure is not currently a routine practice. This double-blind randomized trial compared pharyngolaryngeal complications in patients managed with manometers to limit the LMA intracuff pressure (<44 mmHg) with patients under routine care.
Method: Two hundred consenting patients who underwent ambulatory surgery were randomly allocated to pressure-limiting and routine care groups. Anesthesia was induced with propofol and fentanyl, and maintained with desflurane in air-oxygen. An LMA was inserted, and the cuff was inflated as per usual practice. The patients breathed spontaneously. Research assistants measured the LMA intracuff pressure. In the pressure-limiting group, LMA intracuff pressure was adjusted to less than 44 mmHg. No intervention was performed in the routine care group. Sore throat, dysphonia, and dysphagia were assessed at 1, 2, and 24 h postoperatively. Composite pharyngolaryngeal complications were compared using chi-square test.
Results: Baseline demographic data were comparable between groups. Mean LMA intracuff pressure was less in the pressure-limiting group versus the routine care group (40 +/- 6 vs. 114 +/- 57 mmHg, P < 0.001). The incidence of composite pharyngolaryngeal complications was significantly lower in the pressure-limiting group versus the routine care group (13.4 vs. 45.6%, P < 0.001), with a relative risk reduction of 70.6%, and a number needed to treat of three (95% CI 2.2-7.5).
Conclusion: Reduction of LMA intracuff pressure to less than 44 mmHg lowers the incidence of postoperative pharyngolaryngeal complications. The LMA cuff pressures should be measured routinely using manometry, and deflating the intracuff pressure to less than 44 mmHg should be recommended as anesthetic best practice.