The study of high frequency ventilation (HFV) and its use as a clinical tool has centered primarily on gas exchange and respiratory mechanics. The effects of high frequency ventilation on the control of breathing has received much less attention. HFV produces a slowing of breathing and apnea in patients, normal adult and neonatal humans and experimental animals. The apnea during HFV in experimental animals has been shown to be vagally mediated. However, the role of particular vagal afferents and respiratory muscle afferents remains in question. A systematic study of the ventilatory parameters most likely involved in the reflex apnea during HFV (stroke volume, frequency, CO2 and resting lung volume) has not been done. The experiments proposed herein will investigate the interaction of these four parameters in the respiratory reflex response to HFV. This will be done by independently varying each of the parameters to test for their effect on the apneic threshold. Once an apneic threshold has been defined, the relative contribution of vagal and muscle afferents to the response to HFV will be assessed. The results of these experiments will provide information that will be predictive in choosing a HFV ventilator setting that will elicite or avoid apnea in patients depending on the therapeutic regimen. A better understanding of the role of vagal and muscle afferents in the control of respiration will also result from these experiments.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Unknown (R23)
Project #
5R23HL030905-02
Application #
3448538
Study Section
Respiratory and Applied Physiology Study Section (RAP)
Project Start
1984-04-01
Project End
1987-03-31
Budget Start
1985-04-01
Budget End
1986-03-31
Support Year
2
Fiscal Year
1985
Total Cost
Indirect Cost
Name
University of Florida
Department
Type
Schools of Veterinary Medicine
DUNS #
073130411
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Davenport, P W; Shannon, R; Mercak, A et al. (1993) Cerebral cortical evoked potentials elicited by cat intercostal muscle mechanoreceptors. J Appl Physiol 74:799-804
Davenport, P W; Dalziel, D J (1989) High-frequency ventilation-induced apnea: interaction of frequency, volume, FRC, and CO2. J Appl Physiol 66:2462-7
Wozniak, J A; Davenport, P W; Kosch, P C (1988) Responses of pulmonary vagal mechanoreceptors to high-frequency oscillatory ventilation. J Appl Physiol 65:633-9
Davenport, P W; Friedman, W A; Thompson, F J et al. (1986) Respiratory-related cortical potentials evoked by inspiratory occlusion in humans. J Appl Physiol 60:1843-8