Comparison of incidence of gastroesophageal reflux and regurgitation associated with timing of removal of the laryngeal mask airway: On appearance of signs of ejection versus after recovery of consciousness

Study Objectives: To compare the incidence of gastroesophageal reflux and regurgitation associated with laryngeal mask airway (LMA) removal when signs of rejecting the LMA, such as swallowing; struggling and restlessness, were observed and when the patient could open his or her mouth on command. Design: Randomized clinical trial. Setting: Operating room and recovery room of a tertiary care referral hospital. Patients: 63 ASA physical status I and II adult patients scheduled for elective orthopedic surgery. Interventions: Using a standardized general anesthetic technique, patients were allocated randomly to Group A (n = 34; LMA removed when signs of rejection, such as swallowing, struggling and restlessness, were observed) or Group B (n = 29; LMA removed when the patient could open his or her mouth on command). Measurements and Main Results: To detect gastroesophageal reflux throughout anesthesia, a pH monitoring probe was positioned in the lower esophagus on the day before surgery. To assess regurgitation during emergence, a gelatin capsule of methylene blue (50 mg) was swallowed prior to induction. At the end of anesthesia, episodes of reflux and regurgitation of gastric contents were analyzed/determined by pH below 4 and bluish staining of the pharynx and/or LMA, respectively. Physical events such as bucking, straining, and coughing during the arousal phase were recorded in both groups by an independent observer. The incidence of reflux (pH < 4) from the time of the the appearance of rejection signs to LMA removal and the total incidence of reflux in Group B were significantly higher than in Group A (p < 0.05). Staining of the LMA and the pharynx by methylene blue was not observed in patients from either experimental group. The number of physical events in Group B during the arousal phase was significantly increased compared to Group A (p < 0.05). Considering all patients in Group A and Group B, physical events were associated with the occurrence of reflux (p < 0.05). Desaturation (SpO(2) < 95%) and clinical evidence of aspiration of gastric contents did not occur in either group. Conclusion: Maintenance of LMA until the patient can open his or her mouth on command increases the incidence of gastroesophageal reflux. (C) 2000 by Elsevier Science Inc.