title: The effect of ketamine on hypoventilation during deep sedation with midazolam and propofol: a randomised, double-blind, placebo-controlled trial.
abstract: BACKGROUND
  Hypoventilation is a major cause of morbidity and mortality in patients having procedures under sedation. Few clinical strategies have been evaluated to reduce intraoperative hypoventilation during surgical procedures under deep sedation.
  
  
  OBJECTIVE
  The primary objective of this investigation was to examine the effect of ketamine on hypoventilation in patients receiving deep sedation for surgery with midazolam and propofol.
  
  
  METHODS
  The study was a randomised, placebo-controlled, double-blind clinical trial.
  
  
  METHODS
  Intraoperative.
  
  
  METHODS
  Healthy women undergoing breast surgery.
  
  
  METHODS
  Randomised to receive ketamine (0.5 mg kg bolus, followed by an infusion of 1.5 μg kg min) or isotonic saline.
  
  
  METHODS
  Duration of hypercapnia measured continuously with a transcutaneous carbon dioxide (TCO2) monitor.
  
  
  RESULTS
  Fifty-four participants were recruited. Patient and surgical characteristics were similar between the study groups. The median percentage of the sedation time with TCO2 more than 6.7 kPa in participants in the ketamine group, 1.2% (95% confidence interval, CI, 0 to 83), was less than that in the isotonic saline group (65%, 95% CI, 0 to 88; P = 0.01). Severe hypoventilation (TCO2 >8.0 kPa) was also less in the ketamine group, median 0% (95% CI, 0 to 11.7) compared with 28% (95% CI, 0 to 79.3; P = 0.0002) for the isotonic saline group. The ketamine group required less airway manoeuvres (chin lift) to keep the SaO2 greater than 95% median (95% CI) [0 (0 to 3) compared with 3 (0 to 16) in the isotonic saline group] (P = 0.004).
  
  
  CONCLUSIONS
  Ketamine decreased the duration and severity of hypercapnia in patients undergoing deep sedation with propofol. The addition of ketamine may reduce hypoventilation and adverse effects in patients having procedures under sedation.
  
  
  BACKGROUND
  clinicaltrials.gov identifier: NCT01535976.
authors.affiliation: From the Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Gildasio S
authors.initials: GS
authors.lastname: De Oliveira
authors.forename: Paul C
authors.initials: PC
authors.lastname: Fitzgerald
authors.forename: Nora
authors.initials: N
authors.lastname: Hansen
authors.forename: Shireen
authors.initials: S
authors.lastname: Ahmad
authors.forename: Robert J
authors.initials: RJ
authors.lastname: McCarthy
mesh_terms: D000328:Adult; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000009:adverse effects*; D007040:Hypoventilation / Q000139:chemically induced* / Q000175:diagnosis / Q000517:prevention & control*; D007649:Ketamine / Q000627:therapeutic use*; D008874:Midazolam / Q000009:adverse effects*; D008875:Middle Aged; D010865:Pilot Projects; D015742:Propofol / Q000009:adverse effects*; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: D006993:Hypnotics and Sedatives; D007649:Ketamine; D008874:Midazolam; D015742:Propofol