Document Detail


Deep diving mammals: Dive behavior and circulatory adjustments contribute to bends avoidance.
MedLine Citation:
PMID:  16413835     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A mathematical model was created that predicted blood and tissue N(2) tension (P(N2)) during breath-hold diving. Measured muscle P(N2) from the bottlenose dolphin after diving repeatedly to 100 m (Tursiops truncatus [Ridgway and Howard, 1979, Science, 4423, 1182-1183]) was compared with predictions from the model. Lung collapse was modelled as a 100% pulmonary shunt which yielded tissue P(N2) similar to those reported for the dolphin. On the other hand, predicted muscle P(N2) for an animal with a dive response, reducing cardiac output by 66% from surface values (20.5 to 6.8l x min(-1)), also agreed well with observed values in the absence of lung collapse. In fact, modelling indicated that both cardiovascular adjustments and dive behaviour are important in reducing N2 uptake during diving and enhancing safe transfer of tissue and blood N2 back to the lung immediately before coming to the surface. In particular, diving bradycardia during the descent and bottom phase together with a reduced ascent rate and increase in heart rate reduced mixed venous P(N2) upon return to the surface by as much as 45%. This has important implications as small reductions in inert gas load (approximately 5%) can substantially reduce decompression sickness (DCS) risk by as much as 50% (Fahlman et al., 2001, J. Appl. Physiol. 91, 2720-2729).
Authors:
A Fahlman; A Olszowka; Brian Bostrom; David R Jones
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-01-18
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  153     ISSN:  1569-9048     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2006 Aug 
Date Detail:
Created Date:  2006-07-31     Completed Date:  2006-09-29     Revised Date:  2007-07-12    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  66-77     Citation Subset:  IM    
Affiliation:
Department of Zoology, The University of British Columbia, 6270 University Blvd., Vancouver, BC, Canada V6T 1Z4. andreas_fahlman@yahoo.com
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MeSH Terms
Descriptor/Qualifier:
Acclimatization / physiology*
Animals
Behavior, Animal
Blood Circulation / physiology*
Decompression Sickness / prevention & control*
Diving / physiology*
Mammals / physiology*
Models, Biological
Nitrogen / blood
Pulmonary Gas Exchange
Respiration*
Time Factors
Chemical
Reg. No./Substance:
7727-37-9/Nitrogen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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