title: Comparison of incidence of gastroesophageal reflux and regurgitation associated with timing of removal of the laryngeal mask airway: on appearance of signs of rejection versus after recovery of consciousness.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  Randomized clinical trial.
  
  
  METHODS
  Operating room and recovery room of a tertiary care referral hospital.
  
  
  METHODS
  63 ASA physical status I and II adult patients scheduled for elective orthopedic surgery.
  
  
  METHODS
  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).
  
  
  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 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 (SpO2 < 95%) and clinical evidence of aspiration of gastric contents did not occur in either group.
  
  
  CONCLUSIONS
  Maintenance of the LMA until the patient can open his or her mouth on command increases the incidence of gastroesophageal reflux.
authors.affiliation: Department of Anesthesiology, Wonkwang University School of Medicine, Iksan, Cheonbuk, South Korea. ypcheong@wonnms.wonkwang.ac.kr
authors.forename: Y P
authors.initials: YP
authors.lastname: Cheong
authors.forename: S K
authors.initials: SK
authors.lastname: Park
authors.forename: Y
authors.initials: Y
authors.lastname: Son
authors.forename: K C
authors.initials: KC
authors.lastname: Lee
authors.forename: Y K
authors.initials: YK
authors.lastname: Song
authors.forename: J S
authors.initials: JS
authors.lastname: Yoon
authors.forename: T Y
authors.initials: TY
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005764:Gastroesophageal Reflux / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D017214:Laryngeal Masks / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D013997:Time Factors