One important issue regarding the classical model of cerebral autoregulation

I just read a very interesting, and provocative, review on cerebral autoregulation written by Shieak Tzeng and Phil Ainslie. These authors challenged existing paradigms regarding how brain perfusion pressure and brain blood flow are related. I definitely encourage you to read it (open access paper !).

In the first section of the review, they are presenting the original description of cerebral autoregulation from Lassen’s work, that has dominated cerebrovascular physiologists’ thinking on the association between blood pressure and brain perfusion:

CBF* is maintained at a constant level across a wide range of mean arterial blood pressure (60-150 mmHg)

In two previous posts (here and here), I’ve provided some information regarding static and dynamic cerebral autoregulation, skipping one important issue. As highlighted by Tzeng and Ainslie in this review:

Although Lassen’s diagram is widely cited as the “autoregulation curve” describing the pressure-flow relations within an individual, it must be acknowledged that each data point on the curve derives from independent subjects, and therefore represents inter- (not intra-) individual relationships.

Indeed,

In a review paper, Lassen constructed a plot of average pressure and flow from 7 studies involving 11 different patient groups with varying drug and pathology induced blood pressure levels.

So, one need to remember that piece of information from the original review paper when discussing their results related to static cerebral autoregulation !

________________________

* CBF: Cerebral blood flow

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