The effect of laryngeal mask cuff pressure on postoperative sore throat incidence.

STUDY OBJECTIVE: To study the effect of laryngeal mask airway (LMA) cuff pressure on the incidence of postoperative sore throat.

DESIGN: Prospective, randomized, observational study.

SETTING: Operating room of a university hospital.

PATIENTS: 200 consecutive adult patients requiring anesthesia for gynecologic procedures.

INTERVENTIONS: Anesthesia was induced with thiopental 3-5 mg/kg, fentanyl 2 micrograms/kg, vecuronium bromide 0.05mg/kg, and enflurane 0.8% to 2% and maintained with nitrous oxide and oxygen (65%/35%) and enflurane.

MEASUREMENTS AND MAIN RESULTS: In Group 1, cuff pressure measurement was continuously performed until the end of the operation. In Group 2, 5 minutes after induction of anesthesia and 2 minutes after insertion of the LMA, cuff pressure was also continuously observed and reduced to the minimal pressure required for airtightness. In the recovery room, after the operation, patients were questioned for postoperative sore throat 4, 8, and 24 hours after the operation following a scoring protocol (score 0 = no complaints, score 1 = minimal sore throat, score 2 = moderate sore throat, score 3 = severe sore throat: "never a LMA again". Continuous monitoring of cuff pressure revealed a steady increase of pressure (during the first 60 minutes increases of 43 cm H2O) in Group 1. In Group 2, after release of air, cuff pressures were significantly lower through the entire operation when compared with Group 1. In Group 1, 8 patients claimed to have a sore throat (Score 1, n = 4; Score 2, n = 3; Score 3, n = 1). In Group 2, no patient complained of sore throat.

CONCLUSIONS: A significant increase in cuff pressure is seen during the first 60 minutes. Three minutes after insertion of the laryngeal mask, cuff pressure can significantly be reduced without any major gas leakage. Postoperative sore throat can be reduced when cuff pressure is continuously monitored and kept on low-pressure values.