title: [Pre-oxygenation in morbidly obese patients].
abstract: BACKGROUND
  Spontaneous respiration with 100% oxygen prior to induction of anaesthesia (preoxygenation) may enable safe management of an apnoeic phase. In the majority of patients, three minutes of inhalation of 100% of oxygen should result in almost complete (>90%) saturation of FRC. However, this may not be true in morbidly obese, because of their limited FRC and oxygen reserve.
  
  
  METHODS
  This was a prospective, non-randomised study in morbidly obese patients (BMI >40 kg m2). All patients were positioned in a 25 degrees head-up position, and were asked to breathe 100% O2 (flow rate 8 L min(-1)) via a tight face mask. We measured the time from the beginning of inhalation of 100% O2, to achievement of E(T)O2 >90%.
  
  
  RESULTS
  Forty-three patients with a mean BMI of 47 kg m(-2) were enrolled to the study. The mean time to E(T)O2 >90% was 295 sec, but in only 25% of patients was the time shorter than 3 min. Based on the results obtained, we estimated that the safe time for pre-oxygenation in 95% of morbidly obese patients should be 450 sec.There was no correlation between BMI, weight, age, and the time taken to achieve E(T)O2 > 90%.
  
  
  CONCLUSIONS
  We recommend pre-oxygenating morbidly obese patients for longer than those with standard body weight. Eight minutes of 100% oxygen inhalation should be effective in the majority of these patients.
authors.affiliation: Klinika Anestezjologii i Intensywnej Terapii, Uniwersytet Medyczny w Łodzi. tomgaszyn@poczta.onet.pl
authors.forename: Tomasz
authors.initials: T
authors.lastname: Gaszyński
mesh_terms: D000328:Adult; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D009767:Obesity, Morbid / Q000503:physiopathology*; D010100:Oxygen / Q000008:administration & dosage*; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D011229:Preanesthetic Medication; D011446:Prospective Studies
chemical_list: D010100:Oxygen