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https://hdl.handle.net/2440/5895
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Type: | Journal article |
Title: | Cerebrovascular carbon dioxide reactivity in sheep: Effect of propofol or isoflurane anaesthesia |
Author: | Myburgh, J. Upton, R. Ludbrook, G. Martinez, A. Grant, C. |
Citation: | Anaesthesia and Intensive Care, 2002; 30(4):413-421 |
Publisher: | Australian Soc Anaesthetists |
Issue Date: | 2002 |
ISSN: | 0310-057X 1448-0271 |
Statement of Responsibility: | J. A. Myburgh, R. N. Upton, G. L. Ludbrook, A. Martinez, C. Grant |
Abstract: | Propofol and isoflurane are commonly used in neuroanaesthesia. Some published data suggest that the use of these agents is associated with impaired cerebral blood flow/carbon dioxide (CO₂) reactivity. Cerebrovascular CO₂ reactivity was therefore measured in three cohorts of adult merino sheep: awake (n=6), anaesthetized with steady-state propofol (15 mg/min; n=6) and anaesthetized with 2% isoflurane (n=6). Changes in cerebral blood flow were measured continuously from changes in velocities of blood in the sagittal sinus via a Doppler probe. Alterations in the partial pressure of carbon dioxide in arterial blood (PaCO₂) over the range 18-63 mmHg were achieved by altering either the inspired CO₂ concentration or the rate of mechanical ventilation. Cerebral blood flow/CO₂ relationships were determined by linear regression analysis, with changes in cerebral blood flow expressed as a percentage of the value for a PaCO₂ of 35 mmHg. Propofol decreased cerebral blood flow by 55% relative to pre-anaesthesia values (P=0.0001), while isoflurane did not significantly alter cerebral blood flow (88.45% of baseline, P=0.39). Significant linear relationships between cerebral blood flow and CO₂ tension were determined in all individual studies (r2 ranged from 0.72 to 0.99). The slopes of the lines were highly variable between individuals for the awake cohort (mean 4.73, 1.42-7.12, 95% CI). The slopes for the propofol (mean 2.67, 2.06-3.28, 95% CI) and isoflurane (mean 2.82, 2.19-3.45, 95% CI) cohorts were more predictable. However, there was no significant difference between these anaesthetic agents with respect to the CO₂ reactivity of cerebral blood flow. |
Keywords: | Animals Sheep Carbon Dioxide Isoflurane Propofol Anesthetics, Inhalation Anesthetics, Intravenous Ultrasonography, Doppler Blood Flow Velocity Linear Models Blood Pressure Cerebrovascular Circulation Intracranial Pressure Hydrogen-Ion Concentration Female |
Description: | Publisher's copy made available with the permission of the publisher © Australian Society of Anaesthetists |
DOI: | 10.1177/0310057x0203000402 |
Description (link): | http://www.aaic.net.au/Article.asp?D=2001371 |
Published version: | http://dx.doi.org/10.1177/0310057x0203000402 |
Appears in Collections: | Anaesthesia and Intensive Care publications Aurora harvest |
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