A comparison of postoperative sore throat after use of laryngeal mask airway and tracheal tube

Purpose We compared the degree of postoperative sore throat (PST) after use of a laryngeal mask airway (LMA; by two insertion techniques) and a tracheal tube (TT) in adult patients.Methods Eighty-six adult patients undergoing surgery of an extremity were randomized into three groups. The LMAs (size 4 for men, 3 for women) and TTs were lubricated with 2% lidocaine gel. After the induction of anesthesia, an LMA with the cuff deflated was inserted and then the cuff was inflated in group A, an LMA with the cuff inflated was inserted in group B, and the trachea was intubated using vecuronium in group C; staff anesthesiologists performed all these methods. LMA cuffs were inflated with the maximum recommended volume of air. TT cuffs were inflated with the minimum volume of air without gas leakage at 20cmH₂O pressure. The mode of ventilation depended on the individual anesthesiologists. Blood traces on the devices were examined after their removal. PST was rated immediately after anesthesia and on the first postoperative day, using a three-point score and a 100-mm visual analog scale, respectively.Results Most of the patients receiving an LMA breathed spontaneously and those receiving a TT underwent controlled ventilation. The ratio of positive blood traces on devices, as well as the degree of PST immediately after anesthesia, was similar in the three groups; however, on the first postoperative day, the severity of PST was greater in the LMA groups than in the TT group (P = 0.016). The severity of PST was similar with the two LMA insertion techniques.Conclusion In the conditions of our study, LMAs inserted with the cuff either fully inflated or deflated worsened PST compared with TTs.This work was presented in part at the 49th annual meeting of the Japanese Society of Anesthesiologists, Fukuoka, Japan, April 18–20, 2002