title: Cuff overinflation and endotracheal tube obstruction: case report and experimental study.
abstract: BACKGROUND
  Initiated by a clinical case of critical endotracheal tube (ETT) obstruction, we aimed to determine factors that potentially contribute to the development of endotracheal tube obstruction by its inflated cuff. Prehospital climate and storage conditions were simulated.
  
  
  METHODS
  Five different disposable ETTs (6.0, 7.0, and 8.0 mm inner diameter) were exposed to ambient outside temperature for 13 months. In addition, every second of these tubes was mechanically stressed by clamping its cuffed end between the covers of a metal emergency case for 10 min. Then, all tubes were heated up to normal body temperature, placed within the cock of a syringe, followed by stepwise inflation of their cuffs to pressures of 3 kPa and > or =12 kPa, respectively. The inner lumen of the ETT was checked with the naked eye for any obstruction caused by the external cuff pressure.
  
  
  RESULTS
  Neither in tubes that were exposed to ambient temperature (range: -12 degrees C to +44 degrees C) nor in those that were also clamped, visible obstruction by inflated cuffs was detected at any of the two cuff pressure levels.
  
  
  CONCLUSIONS
  We could not demonstrate a critical obstruction of an ETT by its inflated cuff, neither when the cuff was over-inflated to a pressure of 12 kPa or higher, nor in ETTs that had been exposed to unfavorable storage conditions and significant mechanical stress.
authors.affiliation: Clinic of Anesthesiology, Intensive Care Medicine, and Pain Therapy, J.W. Goethe-University Hospital Frankfurt, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Hofstetter
authors.forename: Bertram
authors.initials: B
authors.lastname: Scheller
authors.forename: Sandra
authors.initials: S
authors.lastname: Hoegl
authors.forename: Martin G
authors.initials: MG
authors.lastname: Mack
authors.forename: Bernhard
authors.initials: B
authors.lastname: Zwissler
authors.forename: Christian
authors.initials: C
authors.lastname: Byhahn
mesh_terms: D000399:Air Pressure; D000402:Airway Obstruction / Q000209:etiology*; D004868:Equipment Failure; D005858:Germany; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation*; D013696:Temperature