Aviat Space Envir Md
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Hypobaric hypoxia during commercial air travel has the potential to cause or worsen hypoxemia in individuals with pre-existing cardiopulmonary compromise. Knowledge of cabin altitude pressures aboard contemporary flights is essential to counseling patients accurately about flying safety. The objective of the study was to measure peak cabin altitudes during U.S. domestic commercial flights on a variety of aircraft. ⋯ Peak cabin altitude on commercial aircraft flights has risen over time. Cabin altitude is lower with flights of shorter distance. Physicians should take these factors into account when determining an individual's need for supplemental oxygen during commercial air travel.
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The goal of this study was to investigate the contribution of splanchnic volume redistribution and lower limb vasoconstriction in the maintenance of blood pressure during progressive central hypovolemia induced by graded lower body negative pressure (LBNP). It was hypothesized that splanchnic blood volume loss during LBNP would buffer decreases in thoracic blood volume. ⋯ Our results suggest that splanchnic blood volume redistribution--rather than leg vasoconstriction--plays an important role in blood pressure regulation during central hypovolemia.