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

Publication ,  Journal Article
Bain, AR; Ainslie, PN; Barak, OF; Hoiland, RL; Drvis, I; Mijacika, T; Bailey, DM; Santoro, A; DeMasi, DK; Dujic, Z; MacLeod, DB
Published in: J Cereb Blood Flow Metab
September 2017

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 < 0.05), with the most severe hypercapnia (PaCO2 = 58 ± 5 mmHg) but maintained oxygen saturation. The CMRO2 was reduced by 24 ± 27% in NM ( p = 0.05), but unchanged in the HV apnea where hypercapnia was absent. A net-cerebral lactate release was observed at the end of apnea in the HV and NM condition, but not in the HX apnea (main effect p < 0.05). These novel data support hypercapnia/pH as a key mechanism mediating reductions in CMRO2 during apnea, and show that severe hypoxemia stimulates lactate release from the brain.

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Published In

J Cereb Blood Flow Metab

DOI

EISSN

1559-7016

Publication Date

September 2017

Volume

37

Issue

9

Start / End Page

3231 / 3242

Location

United States

Related Subject Headings

  • Oxygen
  • Oxidative Stress
  • Neurology & Neurosurgery
  • Male
  • Lactic Acid
  • Jugular Veins
  • Hypoxia
  • Hypercapnia
  • Humans
  • Female
 

Citation

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Bain, A. R., Ainslie, P. N., Barak, O. F., Hoiland, R. L., Drvis, I., Mijacika, T., … MacLeod, D. B. (2017). Hypercapnia is essential to reduce the cerebral oxidative metabolism during extreme apnea in humans. J Cereb Blood Flow Metab, 37(9), 3231–3242. https://doi.org/10.1177/0271678X16686093
Bain, Anthony R., Philip N. Ainslie, Otto F. Barak, Ryan L. Hoiland, Ivan Drvis, Tanja Mijacika, Damian M. Bailey, et al. “Hypercapnia is essential to reduce the cerebral oxidative metabolism during extreme apnea in humans.J Cereb Blood Flow Metab 37, no. 9 (September 2017): 3231–42. https://doi.org/10.1177/0271678X16686093.
Bain AR, Ainslie PN, Barak OF, Hoiland RL, Drvis I, Mijacika T, et al. Hypercapnia is essential to reduce the cerebral oxidative metabolism during extreme apnea in humans. J Cereb Blood Flow Metab. 2017 Sep;37(9):3231–42.
Bain, Anthony R., et al. “Hypercapnia is essential to reduce the cerebral oxidative metabolism during extreme apnea in humans.J Cereb Blood Flow Metab, vol. 37, no. 9, Sept. 2017, pp. 3231–42. Pubmed, doi:10.1177/0271678X16686093.
Bain AR, Ainslie PN, Barak OF, Hoiland RL, Drvis I, Mijacika T, Bailey DM, Santoro A, DeMasi DK, Dujic Z, MacLeod DB. Hypercapnia is essential to reduce the cerebral oxidative metabolism during extreme apnea in humans. J Cereb Blood Flow Metab. 2017 Sep;37(9):3231–3242.
Journal cover image

Published In

J Cereb Blood Flow Metab

DOI

EISSN

1559-7016

Publication Date

September 2017

Volume

37

Issue

9

Start / End Page

3231 / 3242

Location

United States

Related Subject Headings

  • Oxygen
  • Oxidative Stress
  • Neurology & Neurosurgery
  • Male
  • Lactic Acid
  • Jugular Veins
  • Hypoxia
  • Hypercapnia
  • Humans
  • Female