title: Cardiorespiratory effects of changing inspiratory to expiratory ratio during high-frequency oscillation in an animal model of respiratory failure.
abstract: To examine the effects of varying inspiratory/expiratory ratio (I/E) on cardiorespiratory function during high-frequency oscillation (HFO), 11 saline-lavaged rabbits were ventilated at I/E = 1:2, 1:1.5, 1.5:1, and 2:1 in a paired comparison to a baseline of I/E = 1:1. HFO was delivered by a SensorMedics model 3100 oscillator at a frequency of 10 Hz. Pressure amplitude and proximal mean airway pressure (PPaw) were held constant as I/E was varied from baseline to the experimental I/E. During each paired observation, PaO2, PaCO2, cardiac output, blood pressure, and distal mean airway pressure (DPaw) were measured. We found that as I/E was increased or decreased from 1:1, no significant changes in PaO2, PaCO2, blood pressure, or cardiac output occurred. We conclude that in this model, varying I/E has no significant effect on oxygenation, ventilation, or cardiovascular function.
authors.affiliation: Division of Newborn Medicine, Wright State University, Dayton, Ohio.
authors.forename: S E
authors.initials: SE
authors.lastname: Courtney
authors.forename: K R
authors.initials: KR
authors.lastname: Weber
authors.forename: W A
authors.initials: WA
authors.lastname: Spohn
authors.forename: C V
authors.initials: CV
authors.lastname: Bender
authors.forename: S W
authors.initials: SW
authors.lastname: Malin
authors.forename: R W
authors.initials: RW
authors.lastname: Gotshall
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001794:Blood Pressure; D002302:Cardiac Output; D006321:Heart / Q000503:physiopathology*; D006612:High-Frequency Ventilation; D008168:Lung / Q000503:physiopathology*; D008170:Lung Compliance; D011817:Rabbits; D012119:Respiration; D012131:Respiratory Insufficiency / Q000503:physiopathology / Q000628:therapy*