title: Use of manometry for laryngeal mask airway reduces postoperative pharyngolaryngeal adverse events: a prospective, randomized trial.
abstract: BACKGROUND
  Adverse events such as pharyngolaryngeal complications are indicators of quality patient care. Use of manometry to limit the laryngeal mask airway (LMA) intracuff pressure is not currently a routine practice. This double-blind randomized trial compared pharyngolaryngeal complications in patients managed with manometers to limit the LMA intracuff pressure (<44 mmHg) with patients under routine care.
  
  
  METHODS
  Two hundred consenting patients who underwent ambulatory surgery were randomly allocated to pressure-limiting and routine care groups. Anesthesia was induced with propofol and fentanyl, and maintained with desflurane in air-oxygen. An LMA was inserted, and the cuff was inflated as per usual practice. The patients breathed spontaneously. Research assistants measured the LMA intracuff pressure. In the pressure-limiting group, LMA intracuff pressure was adjusted to less than 44 mmHg. No intervention was performed in the routine care group. Sore throat, dysphonia, and dysphagia were assessed at 1, 2, and 24 h postoperatively. Composite pharyngolaryngeal complications were compared using chi-square test.
  
  
  RESULTS
  Baseline demographic data were comparable between groups. Mean LMA intracuff pressure was less in the pressure-limiting group versus the routine care group (40 +/- 6 vs. 114 +/- 57 mmHg, P < 0.001). The incidence of composite pharyngolaryngeal complications was significantly lower in the pressure-limiting group versus the routine care group (13.4 vs. 45.6%, P < 0.001), with a relative risk reduction of 70.6%, and a number needed to treat of three (95% CI 2.2-7.5).
  
  
  CONCLUSIONS
  Reduction of LMA intracuff pressure to less than 44 mmHg lowers the incidence of postoperative pharyngolaryngeal complications. The LMA cuff pressures should be measured routinely using manometry, and deflating the intracuff pressure to less than 44 mmHg should be recommended as anesthetic best practice.
authors.affiliation: Department of Anesthesia, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Edwin
authors.initials: E
authors.lastname: Seet
authors.forename: Farhanah
authors.initials: F
authors.lastname: Yousaf
authors.forename: Smita
authors.initials: S
authors.lastname: Gupta
authors.forename: Rajeev
authors.initials: R
authors.lastname: Subramanyam
authors.forename: David T
authors.initials: DT
authors.lastname: Wong
authors.forename: Frances
authors.initials: F
authors.lastname: Chung
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000556:Ambulatory Surgical Procedures; D000769:Anesthesia, Inhalation; D000771:Anesthesia, Intravenous; D003680:Deglutition Disorders / Q000209:etiology / Q000517:prevention & control; D055154:Dysphonia / Q000209:etiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects* / Q000379:methods*; D017214:Laryngeal Masks; D007830:Larynx / Q000293:injuries*; D008297:Male; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010612:Pharyngitis / Q000209:etiology / Q000517:prevention & control; D010614:Pharynx / Q000293:injuries*; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control*; D011446:Prospective Studies; D012121:Respiration, Artificial; D011795:Surveys and Questionnaires; D055815:Young Adult