Effect of Muscle Relaxants on the Postoperative Sore Throat Associated With LMA Protector Mask: A Prospective Randomized, Double-Blind Clinical Study.

Objectives: To observe the performance of the LMA Protector mask during short anesthesia procedures in gynecology with or without muscle relaxants.

Methods: A total of 100 patients (aged 18-65 years old, BMI <35 kg/m2) with American Society of Anesthesiologists (ASA) physical status I to III, scheduled to undergo elective gynecologic surgery, with an expected operative time <1 hour, were randomly divided into 2 groups, that is, the muscle relaxant group and the control group. The patients were given 0.06 mg/kg cisatracurium or the same amount of normal saline. The primary outcome was postoperative sore throat, and the secondary outcomes were the postoperative adverse effects, recovery time, oropharyngeal leak pressure (OLP), and the ease score of placements.

Results: There were no significant differences in postoperative sore throat, the amount of blood stained on the laryngeal mask, and other postoperative adverse effects in both groups. The OLP of LMA Protector in the muscle relaxant group was 32 cm H2O, which was significantly higher than the 28 cm H2O in the control group (P=0.0017). The ease of mask placement score was significantly lower in the muscle relaxant group at 2 (0-4) than in the control group at 3 (0-6) (P=0.042). The eye-opening time, laryngeal mask removal time, and leaving time in the muscle relaxant group were significantly longer than in the control group (all P<0.001).

Conclusions: The use of muscle relaxants does not affect postoperative sore throat associated with the LMA Protector mask, but facilitates the placement and also helped to improve OLP, thus improving mask tightness and enhancing the safety of the laryngeal mask.