Partitioning of Arterial and Venous Volumes in the Brain under Hypoxic Conditions
Cerebral oxygen delivery is sustained in the face of, at least moderate, hypoxia.1 The measurements required to show this have, in the past, been especially invasive, with a requirement for jugular venous bulb sampling and carotid arterial administration of a marker to allow measurement of flow by dye dilution.2 With the advent of middle cerebral arterial blood velocity measurement (Doppler) and arterial oxygen saturation measurement (pulse oximetry) the procedure is greatly simplified, at least on a relative basis: SaO2 multiplied by middle cerebral artery velocity will, arguably, give individual changes in oxygen delivery for, at least, the distribution supplied by the middle cerebral artery. This will, for normal subjects, usually change in proportion to global changes.
KeywordsOxygen Delivery Cerebral Blood Volume Near Infrared Spectroscopy NIRS Data Blood Volume Fraction
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