Estimating the effect of lung collapse and pulmonary shunt on gas exchange during breath-hold diving: The Scholander and Kooyman legacy

We developed a mathematical model to investigate the effect of lung compression and collapse (pulmonary shunt) on the uptake and removal Of O-2, CO2 and N-2 in blood and tissue of breath-hold diving mammals. We investigated the consequences of pressure (diving depth) and respiratory Volume on pulmon...

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Bibliographic Details
Published in:Respiratory Physiology & Neurobiology
Main Authors: Fahlman, A., Hooker, Sascha Kate, Olszowka, A., Bostrom, B. L., Jones, D. R.
Format: Article in Journal/Newspaper
Language:English
Published: 2009
Subjects:
Mathematical modeling
Diving physiology
Decompression sickness
Marine mammal
Nitrogen
Oxygen
SEAL LEPTONYCHOTES-WEDDELLI
EUMETOPIAS-JUBATUS
NITROGEN TENSIONS
MARINE MAMMALS
SHALLOW DIVES
HARBOR SEALS
BLOOD
BEHAVIOR
LIONS
PERFORMANCE
Scholander
Weddell
Elephant Seals
Leptonychotes weddelli
Weddell Seals
Online Access:https://risweb.st-andrews.ac.uk/portal/en/researchoutput/estimating-the-effect-of-lung-collapse-and-pulmonary-shunt-on-gas-exchange-during-breathhold-diving-the-scholander-and-kooyman-legacy(4a4ceb3c-5c0a-449c-8902-e1f645d4e25c).html
https://doi.org/10.1016/j.resp.2008.09.013
http://www.scopus.com/inward/record.url?scp=57749084349&partnerID=8YFLogxK
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Summary:We developed a mathematical model to investigate the effect of lung compression and collapse (pulmonary shunt) on the uptake and removal Of O-2, CO2 and N-2 in blood and tissue of breath-hold diving mammals. We investigated the consequences of pressure (diving depth) and respiratory Volume on pulmonary shunt and gas exchange as pressure compressed the alveoli. The model showed good agreement with previous Studies of measured arterial O-2 tensions (Pa-O2) from freely diving Weddell seals and measured arterial and venous N-2 tensions from captive elephant seals compressed in a hyperbaric chamber. Pulmonary compression resulted in a rapid spike in Pa-O2 and arterial CO2 tension, followed by cyclical variation with a periodicity determined by Q(tot). The model showed that changes in diving lung volume are an efficient behavioural means to adjust the extent of gas exchange with depth. Differing models of lung compression and collapse depth caused major differences in blood and tissue N-2 estimates. Our integrated modelling approach contradicted predictions from simple models, and emphasised the complex nature of physiological interactions between circulation, lung compression and gas exchange. Overall, our work suggests the need for caution in interpretation of previous model results based on assumed collapse depths and all-or-nothing lung collapse models. (C) 2008 Elsevier B.V. All rights reserved.

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