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https://hdl.handle.net/2440/5897
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Type: | Journal article |
Title: | The cerebrovascular effects of adrenaline, noradrenaline and dopamine infusions under propofol and isoflurane anaesthesia in sheep |
Author: | Myburgh, J. Upton, R. Grant, C. Martinez, A. |
Citation: | Anaesthesia and Intensive Care, 2002; 30(6):725-733 |
Publisher: | Australian Soc Anaesthetists |
Issue Date: | 2002 |
ISSN: | 0310-057X 1448-0271 |
Abstract: | Infusions of catecholamines are frequently administered to patients receiving propofol or isoflurane anaesthesia. Interactions between these drugs may affect regional circulations, such as the brain. The aim of this animal (sheep) study was to determine the effects of ramped infusions of adrenaline, noradrenaline (10, 20, 40 µg/min) and dopamine (10, 20, 40 µg/kg/min) on cerebral blood flow (CBF), intracranial pressure (ICP), cerebrovascular resistance (CVR) and cerebral metabolic rate for oxygen (CMRO₂). These measurements were made under awake physiological conditions, and during continuous propofol (15 mg/min) or 2% isoflurane anaesthesia. All three catecholamines significantly and equivalently increased mean arterial pressure from baseline in a dose-dependent manner in the three cohorts (P<0.001). In the awake cohort (n=8), dopamine (P<0.01) significantly increased CBF from baseline whilst adrenaline and noradrenaline did not (P>0.05). Under propofol (n=6) and isoflurane (n=6), all three catecholamines significantly increased CBF (P<0.001). Dopamine caused the greatest increase in CBF, and was associated with significant increases in ICP (awake: P<0.001; propofol P<0.05; isoflurane P<0.001) and CVR (isoflurane P<0.05). No significant changes in CMRO₂ were demonstrated. Under propofol and isoflurane anaesthesia, the cerebrovascular effects of catecholamines were significantly different from the awake, physiological state, with dopamine demonstrating the most pronounced effects, particularly under propofol. Dopamine-induced hyperaemia was associated with other cerebrovascular changes. In the presence of an equivalent effect on mean arterial pressure, the exaggerated cerebrovascular effects under anaesthesia appear to be centrally mediated, possibly induced by propofol- or isoflurane-dependent changes in blood-brain barrier permeability, thereby causing a direct influence on the cerebral vasculature. |
Keywords: | Brain Animals Sheep Epinephrine Norepinephrine Catecholamines Dopamine Isoflurane Propofol Anesthetics, Inhalation Anesthetics, Intravenous Anesthesia Infusions, Intravenous Oxygen Consumption Blood Pressure Cerebrovascular Circulation Intracranial Pressure Dose-Response Relationship, Drug Female |
Description: | Publisher's copy made available with the permission of the publisher © Australian Society of Anaesthetists |
DOI: | 10.1177/0310057x0203000602 |
Description (link): | http://www.aaic.net.au/Article.asp?D=2002057 |
Published version: | http://dx.doi.org/10.1177/0310057x0203000602 |
Appears in Collections: | Anaesthesia and Intensive Care publications Aurora harvest 5 |
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