Hana Kai II: a 17-day dry saturation dive at 18.6 ATA. IV. Cardiopulmonary functions

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Hana Kai II: a 17-day dry saturation dive at 18.6 ATA. IV. Cardiopulmonary functions

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Title: Hana Kai II: a 17-day dry saturation dive at 18.6 ATA. IV. Cardiopulmonary functions
Author: Smith, RM; Hong, SK; Dressendorfer, RH; Dwyer, HJ; Hayashi, E; Yelverton, C
Abstract: Impedance plethysmography was used to measure resting cardiac stroke volume (SV) and thoracic conductive volume (TCV) in four divers at intervals during a prolonged dry saturation dive (17 days at 18.6 ATA and 7 days' decompression). Resting heart rate (HR), blood pressure (BP), and pulmonary minute ventilation (VE) were measured 4 times per day for the duration of the 30-day experiment. The vital capacity (VC) and its subdivisions IC and ERV were measured by spirometry every 3 days. In nonsmokers, VC fell significantly with time (r = 0.64), while VC in smokers increased nearly 400 ml during the first week at pressure before tending to fall with time. Compared to predive, the mean ERV was increased 629 ml at pressure, while VE and respiratory rate were not changed. The increased ERV did not persist postdive and was probably the result of the increased work of breathing a dense gas (4.1 g/liters). Residual volume (RV) measured by nitrogen dilution before and after the dive increased 38percent and remained significantly increased (22percent) even after one year in 4 divers. It is suggested that hyperoxia (0.3 ATA PO2) combined with increased gas flow resistance caused the VC to fall and RV to increase. The major cardiovascular findings were a transient bradycardia associated with increased stroke volume leading to a significant increase in resting cardiac output associated with an increased rate of rapid ventricular filling, TCV, and BP at depth. Lowering the ambient temperature for 3 days did not re-establish the bradycardia, suggesting that hyperbaric bradycardia is not due to a subtle cold stress. Adult Atmosphere Exposure Chambers Cardiac Output Cold *Diving Heart Rate *Hemodynamic Processes Human Male Plethysmography, Impedance *Respiration Respiratory Function Tests Smoking Support, U.S. Gov't, Non-P.H.S.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org )
URI: PMID: 910317
http://archive.rubicon-foundation.org/2796
Date: 1977

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  • Undersea Biomedical Research Journal
    The Undersea Baromedical Research journal was published by the Undersea Medical Society, Inc. (now the Undersea and Hyperbaric Medical Society) quarterly from 1974 to 1992 when the name changed to the Undersea and Hyperbaric Medicine Journal.

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