title: Pressures exerted by endobronchial devices.
abstract: BACKGROUND
  High endotracheal cuff pressures have been shown to cause high mucosal pressures and a reduction in mucosal blood flow, with the risk of mucosal ischemia. We aimed to directly measure the pressure exerted by the bronchial cuffs of double-lumen tubes (DLT) and by the cuffs of three new designs of endobronchial blocker (EBB).
  
  
  METHODS
  Using a validated in vitro model and a previously described technique, we measured the static pressures exerted by the cuff of DLTs and EBBs with 1 mL increments in cuff volume until maximum inflation was achieved. The study was repeated under dynamic conditions of simulated positive pressure ventilation.
  
  
  RESULTS
  The pressures exerted by the cuffs of DLTs ranged from 16-155 mm Hg. Pressures exerted by the EBB cuffs ranged from 39-194 mm Hg. At intra-cuff volumes required to create a seal to 25 cm H2O positive pressure, the pressures exerted by the cuffs of all the devices were <30 mm Hg.
  
  
  CONCLUSIONS
  A transmitted pressure <30 mm Hg has been recommended to avoid mucosal injury. Our study shows that at clinically relevant cuff volumes, the pressures exerted by the cuffs do not exceed the recommended safe limit.
authors.affiliation: Department of Anesthesia and Pain Management, Toronto General Hospital, Toronto, Ontario.
authors.forename: Andrew
authors.initials: A
authors.lastname: Roscoe
authors.forename: George W
authors.initials: GW
authors.lastname: Kanellakos
authors.forename: Karen
authors.initials: K
authors.lastname: McRae
authors.forename: Peter
authors.initials: P
authors.lastname: Slinger
mesh_terms: D001980:Bronchi / Q000473:pathology; D004867:Equipment Design; D004864:Equipment and Supplies; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation* / Q000379:methods; D008838:Microcomputers; D009092:Mucous Membrane / Q000473:pathology; D011312:Pressure; D012825:Silicon / Q000737:chemistry; D014132:Trachea / Q000473:pathology
chemical_list: D012825:Silicon