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The cerebrovascular response to carbon dioxide in humans
Author(s) -
BattistiCharbonney A.,
Fisher J.,
Duffin J.
Publication year - 2011
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2011.206052
Subject(s) - middle cerebral artery , carbon dioxide , mean arterial pressure , anesthesia , cerebral blood flow , blood pressure , vasodilation , perfusion , hypoxia (environmental) , chemistry , cardiology , medicine , oxygen , heart rate , ischemia , organic chemistry
Non‐technical summary Two mechanisms control brain blood flow by changing blood vessel diameter: autoregulation maintains flow in the face of perfusion pressure changes, and brain metabolism adjusts flow to meet metabolic requirements. Brain blood vessel reactivity to CO 2 and O 2 is an important component of the latter. We used a specialised rebreathing technique to change CO 2 over a wide range at constant O 2 , estimating brain blood flow responses from measurements of middle cerebral artery flow velocity. We found that below a threshold CO 2 , blood pressure was unchanged, but blood flow increased in response to CO 2 . This response had a sigmoidal shape, centred at a CO 2 close to resting. Above the threshold, both blood flow and pressure increased with CO 2 . We concluded that this method measures the brain blood flow reactivity to CO 2 without the confounding influence of blood pressure changes. The results obtained contribute to our understanding of brain blood flow regulation.