[abstract] FACTORS ASSOCIATED WITH EXERTIONAL DYSPNEA AT HIGH AMBIENT PRESSURES.

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[abstract] FACTORS ASSOCIATED WITH EXERTIONAL DYSPNEA AT HIGH AMBIENT PRESSURES.

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Title: [abstract] FACTORS ASSOCIATED WITH EXERTIONAL DYSPNEA AT HIGH AMBIENT PRESSURES.
Author: Clark, JM; Gelfand, R; Puglia, CD; Lambertsen, CJ
Abstract: Exertional dyspnea that is disproportionate to the inspired gas density has been experienced by men during exposure to heliox at high ambient pressures. Measurement of ventilatory responses (VE) to light exercise (450 Kpm/min on a bicycle ergometer) during and after rapid compression to pressures equivalent to 800, 1200 and 1600 fsw in Predictive Studies IV provided opportunity for further study of this phenomenon. Divers I and VI were "exercise" subjects during exposure to 800-1200-800 fsw, while divers I and III performed exercise during subsequent exposure to 800-1200-1600-1200 fsw. Exertional dyspnea was reported by only diver I and only during his second exposure, at 800-1200-1600 fsw. During his first exposure repeated periods of exercise without dyspnea were characterized by a VE of 32-35 L/min in response to a stable VO2 of 1.1-1.3 L/min. Reports of dyspnea during his second exposure were associated with VE levels of 40-65 L/min in response to higher workloads (VO2 1.5-2.0 L/min) that were self-induced by increased pedaling rates. Relationships of VE to the total swing in divers I and III. Diver III, who denied dyspnea with VE levels of 30-44 L/min, had a progressive increase in Pexp-Pinsp for a given level of VE at 800, 1200 and 1600 fsw, whereas relationships of VE to Pexp-Pinsp in diver I were widely scattered and did not show a consistent shift at higher ambient pressures. It is possible that transient increases in work of breathing during the self-induced workload increments may have been exacerbated by distortions of the chest wall and diaphragm associated with erratic changes in breathing pattern. These data are consistent with a mechanical basis for the exertional dyspnea in diver I at high ambient pressures.
Description: Abstract of the Undersea and Hyperbaric Medical Society, Inc. Annual Scientific Meeting held April 28-May 1, 1978. Washington Plaza Hotel, Seattle, Washington (http://www.uhms.org)
URI: http://archive.rubicon-foundation.org/4078
Date: 1978

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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