title: Preoxygenation and intraoperative ventilation strategies in obese patients: a comprehensive review.
abstract: OBJECTIVE
  Obesity along with its pathophysiological changes increases risk of intraoperative and perioperative respiratory complications. The aim of this review is to highlight recent updates in preoxygenation techniques and intraoperative ventilation strategies in obese patients to optimize gas exchange and pulmonary mechanics and reduce pulmonary complications.
  
  
  RESULTS
  There is no gold standard in preoxygenation or intraoperative ventilatory management protocol for obese patients. Preoxygenation in head up or sitting position has been shown to be superior to supine position. Apneic oxygenation and use of continuous positive airway pressure increases safe apnea duration. Recent evidence encourages the intraoperative use of low tidal volume to improve oxygenation and lung compliance without adverse effects. Contrary to nonobese patients, some studies have reported the beneficial effect of recruitment maneuvers and positive end-expiratory pressure in obese patients. No difference has been observed between volume controlled and pressure controlled ventilation.
  
  
  CONCLUSIONS
  The ideal ventilatory plan for obese patients is indeterminate. A multimodal preoxygenation and intraoperative ventilation plan is helpful in obese patients to reduce perioperative respiratory complications. More studies are needed to identify the role of low tidal volume, positive end-expiratory pressure, and recruitment maneuvers in obese patients undergoing general anesthesia.
authors.affiliation: Department of Anaesthesia, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ushma
authors.initials: U
authors.lastname: Shah
authors.forename: Jean
authors.initials: J
authors.lastname: Wong
authors.forename: David T
authors.initials: DT
authors.lastname: Wong
authors.forename: Frances
authors.initials: F
authors.lastname: Chung
mesh_terms: D006801:Humans; D007430:Intraoperative Care / Q000379:methods*; D009765:Obesity / Q000150:complications / Q000601:surgery*; D010100:Oxygen / Q000008:administration & dosage*; D011175:Positive-Pressure Respiration / Q000379:methods; D011300:Preoperative Care / Q000379:methods*; D012121:Respiration, Artificial / Q000379:methods*
chemical_list: D010100:Oxygen