Ventilatory dynamics during transient arousal from nrem sleep:
implications for respiratory control stability.
Khoo, Michael C. K., Steve S. W. Koh, John J. W. Shin, Philip R.
Westbrook, and Richard B. Berry.
Biomedical Engineering Dept., University of Southern California,
Los Angeles, CA; Dept. of Medicine, University of California at
Irvine and V.A. Medical Center, Long Beach, CA; and Pacific Sleep
Medicine, Redlands, CA
APStracts 2:0549A, 1995.
The polysomnographic and ventilatory patterns of 9 normal adults were
measured during NREM Stage 2 sleep before and after repeated
administrations of a tone (40-72 dB) lasting 5 s. The ventilatory
response to arousal (VRA) was determined in data sections showing
electrocortical arousal following the start of the tone. Mean
inspiratory flow and tidal volume increased significantly above
control levels in the first 7 breaths following the start of arousal,
with peak increases (64.2% > control) occurring on the second
breath. Breath-to-breath P100 showed significant increases only on
the second and third post-arousal breaths, while upper airway
resistance declined immediately and remained below control for >
7 consecutive breaths. These results suggest that the first breath
and latter portion of the VRA are determined more by upper airway
dynamics than by changes in the neural drive to breathe. Computer
model simulations comparing different VRA time-courses show that
sustained periodic apnea is more likely to occur when the fall in the
post-arousal increase in ventilation is more abrupt.
Received 13 September 1995; accepted in final form 5 December
1995.
APS Manuscript Number A1003-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95