title: Tracheal-innominate artery fistula caused by the endotracheal tube tip: case report and investigation of a fatal complication of prolonged intubation.
abstract: METHODS
  A patient with extensive burns was intubated with an 8.0 mm internal diameter endotracheal tube (ETT) equipped with a subglottic suction port (Mallinckrodt HiLo Evac). The ETT was secured to a left upper molar with wire sutures throughout the hospitalization course to ensure airway stability. On the 40th day of intubation, the patient exsanguinated and died from a tracheo-innominate artery fistula. Postmortem examination revealed a 1 cm lesion of the left anterior tracheal wall at the position of the ETT tip. The prolonged stationary position of the ETT was considered the primary factor responsible for the fistula. Yet tracheo-innominate artery fistula normally is associated with high cuff pressures rather than with the tube tip. The special ETT construction required for the subglottic suction feature was suspected to have increased tube rigidity and may have played a contributory role.
  
  
  METHODS
  The rigidity of the Mallinckrodt HiLo Evac was measured with a mechanical model and compared to 5 other commercially-available ETTs. Rigidity was expressed as the force generated by the ETT tip when the tube curvature was altered by 5 cm and 10 cm of flexion from its resting position.
  
  
  RESULTS
  The mean force exerted by the Mallinckrodt HiLo Evac was 10.1 +/- 2.8 g at 5 cm of flexion and 17.7 +/- 5.1 g at 10 cm of flexion. This was significantly greater than all other ETT brands tested (by one-way analysis of variance and Student-Newman-Kuels test, p < 0.05).
  
  
  CONCLUSIONS
  This case of fatal tracheo-innominate artery fistula formation associated with an ETT tip was unusual because of the extended duration of endotracheal intubation and the complexity of the patient's airway management problems. Our data suggest that the higher rigidity of the HiLo Evac ETT may have contributed to fistula development at the tube tip. However, we do not believe that the higher rigidity of the HiLo Evac ETT necessarily poses any greater risk than other ETTs under normal circumstances, in which the tube tip is not fixed in a stationary position for an extended period.
authors.affiliation: Respiratory Care Services, Department of Anesthesia, San Francisco General Hospital, University of California, San Francisco, California 94110, USA. msiobal@sfghsom.ucsf.edu
authors.forename: M
authors.initials: M
authors.lastname: Siobal
authors.forename: R H
authors.initials: RH
authors.lastname: Kallet
authors.forename: R
authors.initials: R
authors.lastname: Kraemer
authors.forename: E
authors.initials: E
authors.lastname: Jonson
authors.forename: D
authors.initials: D
authors.lastname: Lemons
authors.forename: D
authors.initials: D
authors.lastname: Young
authors.forename: A R
authors.initials: AR
authors.lastname: Campbell
authors.forename: W
authors.initials: W
authors.lastname: Schecter
authors.forename: J
authors.initials: J
authors.lastname: Tang
mesh_terms: D000328:Adult; D016122:Brachiocephalic Trunk / Q000293:injuries*; D002056:Burns / Q000628:therapy; D017809:Fatal Outcome; D005402:Fistula / Q000209:etiology*; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects*; D008297:Male; D014132:Trachea / Q000293:injuries*