Measurement and Cerebral Blood Flow and Oxygen Consumption, and the Regulation of Cerebral Circulation
Measurements of cerebral blood blow (CBF) is based on the use of freely diffusible indicators, which reach the brain tissue by the arterial system and give rise to a fast and complete equilibration in concentration between blood and tissue. The principle of calculation of CBF is based on the measurement of mean transit time. The technique has been developed during the last 40 years and was originally introduced by Kety and Schmidt (1945) with the use of nitrous oxide as tracer. Later, the technique was elaborated to include diffusible indicators including Krypton-85 and Xenon-133. The Kety-Schmidt and the intraarterial 133-Xenon methods have been used in several animal experiments. By surgical removal of soft tissue over the calvaria and 133-Xenon injection in the lingual artery, it is possible to avoid extracerebral contamination in monkeys and rats (Harper and Jennett 1968, Hertz et al. 1977).
KeywordsCerebral Blood Flow Cerebral Autoregulation Severe Head Injury Acute Hypertension Diffusible Indicator
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