Sustained Cerebral Hypoxia Increases Cerebral O2 Metabolism

Erin Krizay¹, John S. Hunt Jr. ¹, Ethan Li¹, Billy C. Hsu¹, David D. Shin¹, Zachary Smith¹, Richard B. Buxton¹, Miriam Scadeng¹, David J. Dubowitz¹

Hypoxia results in decreased arterial oxygenation to the brain and increased cerebral blood flow. Previous studies suggest moderate global hypoxia does not influence resting cerebral oxygen metabolism (CMRO2), yet basal metabolic rate increases with sustained hypoxia. We examined the effects of 2 and 7 days of sustained global hypoxia on CMRO2 from measurements of venous T2 (using TRUST MRI), resting CBF (using ASL MRI), and SaO2 and Hb. Following 2 days hypoxia, CMRO2 increased by 59% to 2.5 mmol/g/min (+/- 0.9, p<0.01). Following 7 days hypoxia, CMRO2 increased 36% relative to normoxia, to 2.2 mmol/g/min (+/- 0.8, p<0.05).