title: Transcranial Doppler ultrasonography during cardiopulmonary bypass in patients with severe carotid stenosis or occlusion.
abstract: Blood flow velocity of the middle cerebral artery was monitored during cardiopulmonary bypass procedures by means of transcranial Doppler ultrasonography. Our investigation was carried out in a group of 16 patients with severe carotid stenosis or occlusion and in a control group of 42 patients with no or stenosis of less than 50% local diameter reduction. After onset of cardiopulmonary bypass, both groups showed a short unstable phase followed by increased blood flow velocity (10% increase ipsilateral to the obstruction, 27% increase in the control group). Just before rewarming, blood flow velocity was still comparable to (control group -3%) or higher than (ipsilateral to obstructions +14%) prebypass values. Analysis of three patients with postoperative diffuse encephalopathy did not reveal reduced blood flow during cardiopulmonary bypass as a relevant factor. Two of the three showed luxury perfusion. Reduced perfusion due to carotid obstruction was not observed during cardiopulmonary bypass and therefore cannot be considered a significant risk factor for the development of intraoperative stroke.
authors.affiliation: Department of Neurology, University of Freiburg, Federal Republic of Germany.
authors.forename: G M
authors.initials: GM
authors.lastname: von Reutern
authors.forename: A
authors.initials: A
authors.lastname: Hetzel
authors.forename: D
authors.initials: D
authors.lastname: Birnbaum
authors.forename: V
authors.initials: V
authors.lastname: Schlosser
mesh_terms: D000328:Adult; D000368:Aged; D001157:Arterial Occlusive Diseases / Q000503:physiopathology* / Q000601:surgery; D001783:Blood Flow Velocity; D002315:Cardiopulmonary Bypass; D002340:Carotid Artery Diseases / Q000503:physiopathology* / Q000601:surgery; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography