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Publication AbstractsEffect of G-Suit Protection on Carotid-Cardiac Baroreflex FunctionVictor A. Convertino, Ph.D., and Craig A. Reister, M.S.Aviat Space Environ Med 2000; 71:31-6 AbstractIntroduction: To test the hypothesis that G-suit inflation could increase cardiac chronotropic responses to baroreceptor stimulation and enhance baroreflex buffering of BP, the carotid-cardiac baroreflex response of 12 subjects was measured across two levels of lower body negative pressure (LBNP = 0 and 50 mmHg) and two levels of G-suit inflation (0 and 50 mmHg) in random order. Methods: Carotid-cardiac baroreflex stimulation was delivered via a silastic neck pressure cuff and responsiveness quantified by determination of the maximum slope of the stimulus-response function between R-R intervals (ms) and their respective carotid distending pressures (mmHg). Results: Mean ± SE baseline control baroreflex responsiveness was 3.8 ± 0.4 ms · mmHg-1. LBNP reduced the baroreflex response to 2.7 ± 0.4 ms · mmHg-1, but G-suit inflation with LBNP restored the baroreflex response to 4.3 ± 0.6 ms · mmHg-1. Conclusions: These results suggest that, in addition to increased venous return and elevated peripheral resistance, G-suit inflation may provide protection against the debilitating effects of blood distribution to the lower extremities during orthostatic challenges such as standing or high +Gz acceleration by increasing cardiovascular responsiveness to carotid baroreceptor stimulation.Keywords: autonomic function, G-suits, LBNP, orthostatism. Information on subscribing, and on obtaining copies of an article or of an entire issue. Table of Contents for Volume 71, Number 1 of the ASME journal.
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