Journal of Applied Physiology, Vol 67, Issue 6 2351-2356, Copyright © 1989 by American Physiological Society

ARTICLES

Effects of acute hyperbaric oxygenation on respiratory control in cats

D. Torbati, A. Mokashi and S. Lahiri
Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia 19104-6085.

We studied ventilatory responsiveness to hypoxia and hypercapnia in anesthetized cats before and after exposure to 5 atmospheres absolute O2 for 90-135 min. The acute hyperbaric oxygenation (HBO) was terminated at the onset of slow labored breathing. Tracheal airflow, inspiratory (TI) and expiratory (TE) times, inspiratory tidal volume (VT), end-tidal PO2 and PCO2, and arterial blood pressure were recorded simultaneously before and after HBO. Steady-state ventilation (VI at three arterial PO2 (PaO2) levels of approximately 99, 67, and 47 Torr at a maintained arterial PCO2 (PaCO2, 28 Torr) was measured for the hypoxic response. Ventilation at three steady-state PaCO2 levels of approximately 27, 36, and 46 Torr during hyperoxia (PaO2 450 Torr) gave a hypercapnic response. Both chemical stimuli significantly stimulated VT, breathing frequency, and VI before and after HBO. VT, TI, and TE at a given stimulus were significantly greater after HBO without a significant change in VT/TI. The breathing pattern, however, was abnormal after HBO, often showing inspiratory apneusis. Bilateral vagotomy diminished apneusis and further prolonged TI and TE and increased VT. Thus a part of the respiratory effects of HBO is due to pulmonary mechanoreflex changes.

This article has been cited by other articles:

				B. Vulesevic, B. McNeill, and S. F. Perry Chemoreceptor plasticity and respiratory acclimation in the zebrafish Danio rerio J. Exp. Biol., April 1, 2006; 209(7): 1261 - 1273. [Abstract] [Full Text] [PDF]

				J. B. Dean, D. K. Mulkey, R. A. Henderson III, S. J. Potter, and R. W. Putnam Hyperoxia, reactive oxygen species, and hyperventilation: oxygen sensitivity of brain stem neurons J Appl Physiol, February 1, 2004; 96(2): 784 - 791. [Abstract] [Full Text] [PDF]

				J. B. Dean, D. K. Mulkey, A. J. Garcia III, R. W. Putnam, and R. A. Henderson III Neuronal sensitivity to hyperoxia, hypercapnia, and inert gases at hyperbaric pressures J Appl Physiol, September 1, 2003; 95(3): 883 - 909. [Abstract] [Full Text] [PDF]

				D. K. Mulkey, R. A. Henderson III, R. W. Putnam, and J. B. Dean Hyperbaric oxygen and chemical oxidants stimulate CO2/H+-sensitive neurons in rat brain stem slices J Appl Physiol, September 1, 2003; 95(3): 910 - 921. [Abstract] [Full Text] [PDF]

				D. K. Mulkey, R. A. Henderson III, J. E. Olson, R. W. Putnam, and J. B. Dean Oxygen measurements in brain stem slices exposed to normobaric hyperoxia and hyperbaric oxygen J Appl Physiol, May 1, 2001; 90(5): 1887 - 1899. [Abstract] [Full Text] [PDF]

				X. Ren, M. Fatemian, and P. A. Robbins Changes in respiratory control in humans induced by 8 h of hyperoxia J Appl Physiol, August 1, 2000; 89(2): 655 - 662. [Abstract] [Full Text] [PDF]

				J. B. Dean and D. K. Mulkey Continuous intracellular recording from mammalian neurons exposed to hyperbaric helium, oxygen, or air J Appl Physiol, August 1, 2000; 89(2): 807 - 822. [Abstract] [Full Text] [PDF]

				R. Gelfand, C. J. Lambertsen, J. M. Clark, and E. Hopkin Hypoxic ventilatory sensitivity in men is not reduced by prolonged hyperoxia (Predictive Studies V and VI) J Appl Physiol, January 1, 1998; 84(1): 292 - 302. [Abstract] [Full Text] [PDF]