Naslov
Regulation of Brain Blood Flow and Oxygen Delivery in Elite Breath-Hold Divers

Autori
Willie, CK ; Ainslie, PN ; Drviš, Ivan ; MacLeod, DB ; Bain, AR ; Madden, Dennis ; Zubin Maslov, Petra ; Dujić, Željko ;

Izvornik
Journal of cerebral blood flow and metabolism (0271-678X) 35 (2015), 1; 66-73

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
cerebral blood flow ; apnea diving

Sažetak
The roles of involuntary breathing movements (IBM) and cerebral oxygen delivery in the tolerance to extreme hypoxaemia displayed by elite breath-hold divers is unknown. Cerebral blood flow (CBF), arterial blood gases (ABG) 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 to ABG, end-tidal forcing (“clamp”) was then used to replicate an identical temporal pattern of decreasing arterial PO2 (PaO2) and increasing arterial PCO2 (PaCO2) whilst breathing. End-apnea PaO2 ranged from 23mmHg to 37mmHg (30 ± 7 mmHg). Elevation in mean arterial pressure was greater during apnea than during clamp reaching +54 ± 24% vs 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 40-50% reductions in arterial oxygen content, oxygen delivery was maintained by commensurately increased CBF.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

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