title: A simple mechanical device reduces subglottic injury in ventilated animals.
abstract: OBJECTIVE
  To test whether a simple inexpensive device that dynamically minimizes endotracheal cuff pressure throughout the respiratory cycle reduces endotracheal cuff pressure-related subglottic injury.
  
  
  METHODS
  Hypoxic animal model with one control and one experimental group.
  
  
  METHODS
  Twelve S. scrofa domesticus piglets (14-16 kg) were intubated with standard endotracheal tubes and maintained in a hypoxic state to accelerate airway injury. Animals in the control group (n = 6) were ventilated with a constant pressure of 20 cm H₂O in the endotracheal tube cuff. Animals in the experimental group (n = 6) were ventilated using a custom-designed circuit that altered the pressure in the endotracheal tube cuff in synchrony with the ventilatory cycle. Larynges were harvested at the end of the experiment and examined histologically to determine the degree of airway injury induced by the endotracheal cuff.
  
  
  RESULTS
  Animals in the experimental group suffered significantly less airway damage than those in the control group. The differences were seen primarily in the subglottis (aggregate damage score 6.5 vs. 12, P <0.05), where the experimental endotracheal tube cuff exerted the least pressure. There was no difference in damage to the glottic or supraglottic structures.
  
  
  CONCLUSIONS
  A simple, reliable, and inexpensive means of modulating endotracheal tube cuff pressure with the ventilatory cycle led to a substantial decrease in airway injury in our animal model. Such reduction in cuff pressure may prove important for humans, particularly those in intensive care units who tend to have underlying conditions predisposing them to tracheal damage from the endotracheal tube cuff.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Osborn
authors.forename: Rose
authors.initials: R
authors.lastname: Chami
authors.forename: Evan J
authors.initials: EJ
authors.lastname: Propst
authors.forename: Igor
authors.initials: I
authors.lastname: Luginbuehl
authors.forename: Glenn
authors.initials: G
authors.lastname: Taylor
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Fisher
authors.forename: Vito
authors.initials: V
authors.lastname: Forte
mesh_terms: D000818:Animals; D004867:Equipment Design; D005931:Glottis / Q000293:injuries*; D007442:Intubation, Intratracheal / Q000009:adverse effects*; D012121:Respiration, Artificial / Q000295:instrumentation*; D013552:Swine; D014947:Wounds and Injuries / Q000517:prevention & control
keywords: Endotracheal tube; airway injury; cuff pressure modulation