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Publication AbstractsMonitoring acute whole-body fluid redistribution by changes in leg and neck volumesWatenpaugh DE, Breit GA, Ballard RE, Hargens ARAviat Space Environ Med 1997; 68:858-62 AbstractBackground: Acute fluid shifts initiate chronic cardiovascular acclimation to altered posture or gravity. Hypothesis: We hypothesized that neck volume increases with acute tilt from vertical to horizontal and head-down positions, and that neck volume correlates negatively with leg volume during tilting. Methods: Strain gauges measured changes in calf and neck volume in 9 subjects during the following tilt table protocol: 90° (upright control) 54°, 30°, 12°, 0° (horizontal supine), -6° (head-down tilt), -12°, -6°, 0°, 12°, 30°, 54° and 90°. Each position was held for 30 s. Results: Tilting from 90° upright to 0° supine increased neck volume 3.09 ± 0.37% (mean ± SE); neck volume increased further above upright control to 4.26 ±.39% at -12° head-down tilt. In the calf, tilting produced significant volume decrements of 1.66 ± 0.36% below 90° control at 0° supine, and 2.03 ± 0.50% below control at -12° tilt. Neck volume elevation consistently exceeded the absolute magnitude of calf volume reduction at a given tilt angle by a factor of about 1.5, and the two were linearly correlated (r2 = 0.60). Conclusions: Responses of body segment volumes to tilt were practically instantaneous, indicating that venous blood volume trans-location accounted for the changes. We conclude that leg and neck volume changes provide a convenient, non-invasive, and sensitive means of assessing acute regional fluid shifts in humans.
Information on subscribing, and on obtaining copies of an article or of an entire issue. Table of Contents for Volume 68, Number 9 of the ASEM journal.
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