Regulation of brain blood flow and oxygen delivery in elite breath-hold divers.

Published

Journal Article

The roles of involuntary breathing movements (IBMs) and cerebral oxygen delivery in the tolerance to extreme hypoxemia displayed by elite breath-hold divers are unknown. Cerebral blood flow (CBF), arterial blood gases (ABGs), and cardiorespiratory metrics were measured during maximum dry apneas in elite breath-hold divers (n=17). To isolate the effects of apnea and IBM from the concurrent changes on ABG, end-tidal forcing ('clamp') was then used to replicate an identical temporal pattern of decreasing arterial PO2 (PaO2) and increasing arterial PCO2 (PaCO2) while breathing. End-apnea PaO2 ranged from 23 to 37 mm Hg (30 ± 7 mm Hg). Elevation in mean arterial pressure was greater during apnea than during clamp reaching +54 ± 24% versus 34 ± 26%, respectively; however, CBF increased similarly between apnea and clamp (93.6 ± 28% and 83.4 ± 38%, respectively). This latter observation indicates that during the overall apnea period IBM per se do not augment CBF and that the brain remains sufficiently protected against hypertension. Termination of apnea was not determined by reduced cerebral oxygen delivery; despite 40% to 50% reductions in arterial oxygen content, oxygen delivery was maintained by commensurately increased CBF.

Full Text

Duke Authors

Cited Authors

  • Willie, CK; Ainslie, PN; Drvis, I; MacLeod, DB; Bain, AR; Madden, D; Maslov, PZ; Dujic, Z

Published Date

  • January 2015

Published In

Volume / Issue

  • 35 / 1

Start / End Page

  • 66 - 73

PubMed ID

  • 25370857

Pubmed Central ID

  • 25370857

Electronic International Standard Serial Number (EISSN)

  • 1559-7016

Digital Object Identifier (DOI)

  • 10.1038/jcbfm.2014.170

Language

  • eng

Conference Location

  • United States