Effect of inspiratory pressure support on the arousal response to
co2 in sleeping dogs 1-2.
Kim, Woo Sung, Victoria L. Champagne, Stewart B. Gottfried, and R.
John Kimoff.
Respiratory Division, Royal Victoria Hospital, and Meakins-Christie
Laboratories, McGill University, Montreal, Quebec, Canada
APStracts 2:0280A, 1995.
The aim of the present study was to test the hypothesis that afferent
mechanoreceptor stimuli from the respiratory muscles contribute to
the arousal response to CO2 from both non-rapid-eye-movement (NREM)
and REM sleep. We studied 3 dogs implanted with EMG electrodes in the
costal diaphragm (EMGDi) and transversus abdominis muscles (EMGTA).
During sleep, the animals were exposed to supplemental CO2 in O2 to
maintain a constant level of end-tidal PCO2 (50 mm Hg for NREM, 56 mm
Hg for REM), and breathed either spontaneously (SB) or with
inspiratory pressure support (IPS). The arousal response was
quantified as the time from initiation of CO2 administration to
arousal. EMGDi on IPS was decreased to approximately 70%
(p<0.01) of that during SB trials for both NREM and REM, while
EMGTA activity did not differ between SB and IPS for either sleep
state. The mean time to arousal was increased during NREM from 128.3
+/- 24.7 s (SB) to 216.8 +/- 38.7 s (IPS) (p<0.025) and during
REM from 144.9 +/- 26.1 s (SB) to 219.0 +/- 23.8 s (IPS)
(p<0.001). In summary, in support of our hypothesis, we found
that suppression of inspiratory muscle activity, without augmented
expiratory muscle activity, delayed the arousal response to
hypercapnia during both NREM and REM sleep.
Received 8 August 1994; accepted in final form 12 June 1995.
APS Manuscript Number A826-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 11 July 1995.