[abstract] A MATHEMATICAL MODEL OF THE RESPIRATORY MECHANICS AND CALCULATIONS OF THE WORK OF BREATHING APPLIED TO THE DIVER.

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[abstract] A MATHEMATICAL MODEL OF THE RESPIRATORY MECHANICS AND CALCULATIONS OF THE WORK OF BREATHING APPLIED TO THE DIVER.

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Title: [abstract] A MATHEMATICAL MODEL OF THE RESPIRATORY MECHANICS AND CALCULATIONS OF THE WORK OF BREATHING APPLIED TO THE DIVER.
Author: Warkander, DE; Clarke, JR; Lundgren, CEG
Abstract: BACKGROUND: The work of breathing (WOB) may be performance and safety limiting in divers. The underwater environment imposes increased WOB on a diver by changing the characteristics of the diver's own respiratory organs in ways dependent on, for instance, ventilation, depth, lung volumes and inspired CO2 (PiCO2). We developed a model to quantify these effects especially with regard to WOB in the diving situation. METHODS: Published descriptions of airway resistance (VanLiew, 1987), lung volume (Bouhuys, Jonson, 1967), depth effects (square root of gas density) and PiCO2 were included. The WOB was calculated for the standard ventilations used in unmanned testing of UBAs (15, 22.5, 40, 62.5 and 75 L/min). The ventilation was changed the way a diver would breathe when exposed to different levels of PiCO2. RESULTS: The increased ventilation due to increased PiCO2 increases the WOB greatly. For diver breathing air at 40 L/min in the depth range 0 to 30 msw, the WOB increases by 11% if the PiCO2 is 0.5 kPa, by 24% at 1 kPa and by over 60% at a PIC02 of 2 kPa. Assuming an alveolar CO2 level of 6 kPa (45 mm Hg) with a ventilation of 40 L/min, the following situations are equivalent in terms of WOB: a PiCO2 of 0 kPa at 40 msw, a PiCO2 of 0.5 kPa at 26 msw, a PiCO2 of 1 kPa at 16 msw and a PiCO2 of 2 kPa at the surface. CONCLUSION: The present model allows calculations of internal WOB of divers exposed to different PiCO2 levels and diving depths. The level of PiCO2 has a great influence on the WOB.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org)
URI: http://archive.rubicon-foundation.org/6707
Date: 2000

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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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