Cerebral hypoxia historical perspective

Anika Zahoor M.D.[1]

The relationship between brain function and blood flow has been studied since the classical paper of Roy and Sherrington (61) at the end of the 19th century.

• Despite the absence of quantitative methods, early investigators were able to establish some of the basic principles of the cerebral circulation; among these was a recognition of the dominating influence of carbon dioxide and the reciprocal effect of oxygen (72).

• Interestingly, even the idea that local cerebral blood flow (CBF) was transiently augmented with increased neuronal activation, alluded to by Roy and Sherrington, had received additional qualitative experimental support.

• A listing of the qualitative methods in use at the time, including methods such as venous outflow, radium emanation, and thermocouple, can be found in the 1936 Wolff review (72).

• Nevertheless, despite more than 100 years of effort, there are still major areas concerning the control of the cerebral circulation that remain unknown.

• The observations that decreasing oxygen led to increased blood flow and that the increase was blunted perhaps by the accompanying hypoxia-induced hyperventilation and resultant decreased carbon dioxide remained wholly qualitative until a useful quantitative method, based on inert gases, was developed for measuring CBF and oxygen metabolism by Kety and Schmidt (33, 35).

1. https://journals.physiology.org/doi/full/10.1152/japplphysiol.00940.2005