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Cerebral effects of anaesthesia and hypothermia
Author(s) -
STEPHAN H.,
SONNTAG H.,
LANGE H.,
RIEKE H.
Publication year - 1989
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1111/j.1365-2044.1989.tb11284.x
Subject(s) - midazolam , medicine , anesthesia , fentanyl , hypothermia , cardiopulmonary bypass , cerebral blood flow , etomidate , blood flow , venous blood , propofol , cardiology , sedation
Summary Cerebral blood flow, cerebral oxygen and glucose consumption, and cerebral lactate and pyruvate release were measured; spectral analysis of the EEG was recorded in 10 male patients who had coronary artery bypass surgery. The measurements were taken to evaluate the effects of fentanyl–midazolam anaesthesia during normothermia and during hypothermic nonpulsatile cardiopulmonary bypass at 26°C venous blood temperature, when a temperature‐corrected Paco 2 ‐value of 5.3 kPa was maintained. Anaesthesia with fentanyl 7 μg/kg and midazolam 200 μg/kg as induction doses, followed by infusions of fentanyl 0.15 μg/kg/minute and midazolam 3 μg/kg/minute, was characterised by a decrease in fast‐wave activity and an increase in high‐amplitude, slow‐wave activity in the EEG. There was also a decrease in cerebral blood flow (38%), oxygen consumption (22%) and glucose consumption (25%), while lactate and pyruvate production remained unchanged. Hypothermia of 26°C venous blood temperature suppressed EEG almost completely and decreased oxygen and glucose consumption by a further 61% and 54%, respectively, with no changes in lactate and pyruvate production while cerebral blood flow increased by 145%. These results show that the effects of fentanyl–midazolam anaesthesia on cerebral metabolism are enhanced during hypothermic cardiopulmonary bypass while the influence of anaesthesia on cerebral blood flow is overshadowed by the practice of a temperature‐corrected acid‐base management.