ABSTRACT
STUDY OBJECTIVES: To determine whether the Laryngeal Mask Airway (LMA) triggers the pharyngo-esophago-gastric reflex during general anesthesia by comparing the esophageal motility of patients with the LMA and endotracheal tube (ETT) in place. DESIGN: Randomized clinical trial. SETTING: Operating room and recovery room of a tertiary-care referral hospital. PATIENTS: 50 adult ASA physical status I and II patients scheduled for elective orthopedic surgery. INTERVENTIONS: All patients received a standardized general anesthetic technique, then were allocated randomly to the LMA (n = 30) or ETT (n = 20) groups. MEASUREMENTS AND MAIN RESULTS: The esophageal manometric inputs were recorded continuously using an ambulatory esophageal manometric recorder and divided into five perioperative phases (preanesthesia, induction, surgery, LMA, or ETT rejection and arousal phase). The LMA or ETT was removed at the end of the surgery, when the patient was awake. An awake state was defined as the presence of the following clinical signs: swallowing, bucking, struggling, straining, and restlessness. The esophageal peristaltic wave percent and esophageal contraction frequency were significantly decreased during induction, surgery, and the LMA or ETT rejection and arousal phases compared with the preanesthetic phases in both the LMA and ETT groups. However, there were no significant group differences in any corresponding perioperative phases. CONCLUSION: During the general anesthetic period before the arousal phase in this study, a LMA does not provoke significantly different esophageal peristalsis compared with an ETT. Thus, the LMA is unlikely to stimulate the pharyngo-esophago-gastric reflex during that period.
