Physiologically and subjectively acceptable breathing resistance in divers' breathing gear

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Physiologically and subjectively acceptable breathing resistance in divers' breathing gear

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Title: Physiologically and subjectively acceptable breathing resistance in divers' breathing gear
Author: Warkander, DE; Norfleet, WT; Nagasawa, GK; Lundgren, CEG
Abstract: To determine acceptable levels of breathing resistance in divers' gear, 6 subjects were exposed to varying levels of breathing resistance under demanding and realistic conditions. The immersed air-breathing subjects exercised in the prone position at 60% of their maximum oxygen uptake for 25 min in a hyperbaric chamber at 1.45 and 6.8 atm abs (145 and 690 kPa, 4.5 and 57 msw, 15 and 190 fsw). The breathing resistance ranged from minimal to 8-12 cmH2O (0.8-1.2 kPa).liter-1.s at flow rates of 2-3 liter/s. The higher resistance levels interfered with the respiration in terms of end-tidal PCO2 and dyspnea scores. There were considerable individual differences, and changes in one parameter were typically not paralleled by changes in the other. None of maximal voluntary ventilation, forced expiratory volume, expiratory reserve volume, vital capacities, or oxygen uptake was influenced by resistance. We set the maximum allowable end-tidal PCO2 at 60 mmHg and maximum dyspnea score at 1.0 on a scale from 0 (none) to 3 (severe). Based on these criteria we concluded that the external work of breathing should not exceed 1.5-2.0 J/liter in the ventilation range 30 to 75 liter/min BTPS.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org )
URI: PMID: 1304670
http://archive.rubicon-foundation.org/2630
Date: 1992

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This item appears in the following Collection(s)

  • 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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