Left paratracheal pressure versus cricoid pressure for successful laryngeal mask airway insertion in adult patients: a randomized, non-inferiority trial

BACKGROUND: Cricoid pressure (CP) is used to prevent pulmonary aspiration of regurgitated gastric contents and gastric insufflation during positive-pressure ventilation. However, CP impedes the successful insertion of laryngeal mask airway (LMA). Left paratracheal pressure (LPP), a maneuver of applying backward digital force at the lower left paratracheal level, was recently introduced as an alternative to CP. We assessed whether LPP is non-inferior to CP in successful LMA insertion on the first attempt in adult patients undergoing general anesthesia. METHODS: In this non-inferiority randomized controlled trial, 108 patients undergoing general anesthesia were randomly allocated to receive either LPP or CP during LMA insertion. The primary outcome was the success rate of LMA insertion on the first attempt. The margin of non-inferiority was defined as 15%. RESULTS: The success rate of LMA insertion on the first attempt was 68.5% (37/54) in the LPP group and 51.9% (28/54) in the CP group (P=0.077) with between-group difference of 16.7% (two-sided 95% CI, -1.9% to 35.2%). Time for successful device insertion was comparable in the two groups (P=0.355), whereas LMA insertion was easier in the LPP group than in the CP group (P=0.001). There was no significant difference between the two groups for change in antral cross-sectional area measured before and after mask ventilation (P=0.081). No serious complication was evident in any group. CONCLUSIONS: This randomized clinical trial demonstrated the non-inferiority of LPP over CP in the success rate of LMA insertion on the first attempt in adult patients undergoing general anesthesia.