Hypercapnia is essential to reduce the cerebral oxidative metabolism during extreme apnea in humans

The cerebral metabolic rate of oxygen (CMRO2) is reduced during apnea that yields profound hypoxia and hypercapnia. In this study, to dissociate the impact of hypoxia and hypercapnia on the reduction in CMRO2, 11 breath-hold competitors completed three apneas under: (a) normal conditions (NM), yield...

Full description

Saved in:

Bibliographic Details
Published in:	Journal of cerebral blood flow and metabolism 2017-09, Vol.37 (9), p.3231-3242
Main Authors:	Bain, Anthony R, Ainslie, Philip N, Barak, Otto F, Hoiland, Ryan L, Drvis, Ivan, Mijacika, Tanja, Bailey, Damian M, Santoro, Antoinette, DeMasi, Daniel K, Dujic, Zeljko, MacLeod, David B
Format:	Article
Language:	eng
Subjects:	Adult Apnea - metabolism Apnea - physiopathology Blood Flow Velocity - physiology Breath Holding Cerebral Cortex - blood supply Cerebral Cortex - metabolism Cerebrovascular Circulation - physiology Female Humans Hypercapnia - metabolism Hypercapnia - physiopathology Hypoxia - metabolism Hypoxia - physiopathology Jugular Veins Lactic Acid - metabolism Male Original Oxidative Stress Oxygen - blood
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	The cerebral metabolic rate of oxygen (CMRO2) is reduced during apnea that yields profound hypoxia and hypercapnia. In this study, to dissociate the impact of hypoxia and hypercapnia on the reduction in CMRO2, 11 breath-hold competitors completed three apneas under: (a) normal conditions (NM), yielding severe hypercapnia and hypoxemia, (b) with prior hyperventilation (HV), yielding severe hypoxemia only, and (c) with prior 100% oxygen breathing (HX), yielding the greatest level of hypercapnia, but in the absence of hypoxemia. The CMRO2 was calculated from the product of cerebral blood flow (ultrasound) and the radial artery-jugular venous oxygen content difference (cannulation). Secondary measures included net-cerebral glucose/lactate exchange and nonoxidative metabolism. Reductions in CMRO2 were largest in the HX condition (−44 ± 15%, p
ISSN:	0271-678X 1559-7016