title: Managing endotracheal tube cuff pressure at altitude: a comparison of four methods.
abstract: BACKGROUND
  Ascent to altitude results in the expansion of gases in closed spaces. The management of overinflation of the endotracheal tube (ETT) cuff at altitude is critical to prevent mucosal injury.
  
  
  METHODS
  We continuously measured ETT cuff pressures during a Critical Care Air Transport Team training flight to 8,000-ft cabin pressure using four methods of cuff pressure management. ETTs were placed in a tracheal model, and mechanical ventilation was performed. In the control ETT, the cuff was inflated to 20 mm Hg to 22 mm Hg and not manipulated. The manual method used a pressure manometer to adjust pressure at cruising altitude and after landing. A PressureEasy device was connected to the pilot balloon of the third tube and set to a pressure of 20 mm Hg to 22 mm Hg. The final method filled the balloon with 10 mL of saline. Both size 8.0-mm and 7.5-mm ETT were studied during three flights.
  
  
  RESULTS
  In the control tube, pressure exceeded 70 mm Hg at cruising altitude. Manual management corrected for pressure at altitude but resulted in low cuff pressures upon landing (<10 mm Hg). The PressureEasy reduced the pressure change to a maximum of 36 mm Hg, but on landing, cuff pressures were less than 15 mm Hg. Saline inflation ameliorated cuff pressure changes at altitude, but initial pressures were 40 mm Hg.
  
  
  CONCLUSIONS
  None of the three methods using air inflation managed to maintain cuff pressures below those associated with tracheal damage at altitude or above pressures associated with secretion aspiration during descent. Saline inflation minimizes altitude-related alteration in cuff pressure but creates excessive pressures at sea level. New techniques need to be developed.
authors.affiliation: From the CSTARS Cincinnati (T.B., J.E., D.R.); and University of Cincinnati (T.C.B., R.D.B.), Cincinnati; and 711th Human Performance Wing Wright-Patterson Air Force Base (H.O.), Dayton, Ohio.
authors.forename: Tyler
authors.initials: T
authors.lastname: Britton
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Blakeman
authors.forename: John
authors.initials: J
authors.lastname: Eggert
authors.forename: Dario
authors.initials: D
authors.lastname: Rodriquez
authors.forename: Heather
authors.initials: H
authors.lastname: Ortiz
authors.forename: Richard D
authors.initials: RD
authors.lastname: Branson
mesh_terms: D000399:Air Pressure; D000401:Aircraft; D000531:Altitude; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects / Q000379:methods*; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods; D014132:Trachea / Q000293:injuries