title: Changes in Pediatric-Sized Endotracheal Tube Cuff Pressure With Elevation Gain: Observations in Ex Vivo Simulations and In Vivo Air Medical Transport.
abstract: OBJECTIVE
  Prolonged excessive endotracheal cuff pressure greater than 30 cmH2O is thought to cause ischemic airway injury. Excessive cuff pressure with altitude gain during air medical transport has been previously described in adult patients. It is poorly understood how pediatric-sized endotracheal tube (ETT) cuffs behave with atmospheric pressure change during flight.
  
  
  METHODS
  In ex vivo models 4.0, 6.0, and 8.0, ETTs restricted within scaled syringe tubing were inflated to 20 cmH2O. Pressure was measured against 1500 ft elevation gain in ground and flight models. In an in vivo observation of pediatric patient transport, change in cuff pressure was measured between takeoff and helicopter peak flight altitudes.
  
  
  RESULTS
  In the ex vivo ground model, endotracheal cuff pressure increased linearly with altitude and exceeded 40 cmH2O in all tube sizes. Comparable pressure change was demonstrated in the flight model. No difference was demonstrated in the degree of pressure change between ETT sizes. In the in vivo observations during patient transport, pressure increase was consistent with that seen in the ex vivo models.
  
  
  CONCLUSIONS
  Children who are intubated with cuffed ETTs for air medical transport are subject to excessive endotracheal cuff pressure at even low flight altitudes. Endotracheal tube size did not affect the degree of cuff pressure change, contrary to previous study. These findings need to be validated and correlated to patient clinical outcomes. The implications of these data need to be considered clinically particularly for prolonged transport of intubated pediatric patients at elevation.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Long
authors.affiliation: UCSF Benioff Children's Hospital Oakland, Oakland, CA.
authors.forename: Natalie Z
authors.initials: NZ
authors.lastname: Cvijanovich
authors.affiliation: REACH Air Medical Services.
authors.forename: Gary P
authors.initials: GP
authors.lastname: McCalla
authors.affiliation: C.S. Mott Children's Hospital, University of Michigan, Ann Arbor, MI.
authors.forename: Heidi R
authors.initials: HR
authors.lastname: Flori
mesh_terms: D000293:Adolescent; D017732:Air Ambulances / Q000706:statistics & numerical data*; D000531:Altitude; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects / Q000295:instrumentation*; D008365:Manometry / Q000379:methods; D008962:Models, Theoretical; D011312:Pressure; D011446:Prospective Studies; D014132:Trachea / Q000503:physiopathology*