title: Cerebral blood flow autoregulation is preserved during cardiopulmonary bypass in isoflurane-anesthetized patients.
abstract: In 21 patients undergoing elective coronary artery bypass surgery, cerebral blood flow (CBF) was measured during hypothermic nonpulsatile cardiopulmonary bypass to test the hypothesis that isoflurane abolished the mean arterial pressure-CBF relation (pressure-flow autoregulation). Cerebral blood flow was determined by 133Xe clearance. The patients were randomly divided into three groups according to anesthesia during cardiopulmonary bypass: group 1 received midazolam and fentanyl; group 2 received, in addition to midazolam and fentanyl, 0.6% isoflurane; and group 3 received, in addition to midazolam and fentanyl, 1.2% isoflurane. The groups were maintained at a constant temperature, PaO2, PaCO2, and pump flow during CBF measurements. Mean arterial pressure was increased by phenylephrine greater than or equal to 25% after the first CBF determination. Isoflurane decreased mean arterial pressure significantly (P less than 0.05) and was associated with lower CBF. Increasing the mean arterial pressure 29% in group 1, 25% in group 2, and 34% in group 3 had no effect on CBF. We conclude that, within the range studied, pressure-flow CBF autoregulation is preserved during isoflurane anesthesia administered for cardiopulmonary bypass.
authors.affiliation: Heart Center, Duke University Hospital, Durham, North Carolina.
authors.forename: L J
authors.initials: LJ
authors.lastname: Aladj
authors.forename: N
authors.initials: N
authors.lastname: Croughwell
authors.forename: L R
authors.initials: LR
authors.lastname: Smith
authors.forename: J G
authors.initials: JG
authors.lastname: Reves
mesh_terms: D000328:Adult; D000368:Aged; D002315:Cardiopulmonary Bypass; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006706:Homeostasis / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007530:Isoflurane; D008875:Middle Aged
chemical_list: D007530:Isoflurane