Department of Bio Medical Engineering seminar

Regulation of cerebral blood flow and metabolism

מרצה אורח

דר' מיכאל נ. דירינג'ר

Dr Michael N Diringer

The brain is a highly metabolic organ.  Oxidative metabolism of 2-carbon fragments in mitochondria is the primary source of energy using derived from oxygen and glucose.  The brain stores no substrates; glucose is actively transported by carrier-mediated facilitated diffusion, whereas oxygen passively diffuses down its concentration gradient.  While glucose supply is abundant, the brain utilizes 30-50% of delivered oxygen.  Cerebral oxygen delivery is the product of cerebral blood flow (CBF) and blood oxygen content (CaO2).

CBF is tightly coupled to metabolic demand. Regulatory factors include oxygen, potassium, adenosine, lactic acid.  CBF is also strongly influenced by CO2 and perfusion pressure.  It is the complex interplay all these factors that ultimately determines CBF.

The initial response to a fall in perfusion pressure is vasodilation in order to maintain stable CBF (pressure autoregulation).  If flow falls further brain oxygen extraction rises approaching 100%.

Dr. Michael N. Diringer is a Professor of Neurology, Neurological Surgery, Anesthesiology, and Occupational Therapy at Washington University School of Medicine, St. Louis, Missouri. He is also the Chair of the Board of Directors at Mid-American Transplant and the Editor-in-Chief of Neurocritical Care. Dr. Diringer is the author or 200 peer-reviewed papers and over 50 book chapters and invited publications.