Bypass flow, mean arterial pressure, and cerebral perfusion during cardiopulmonary bypass in dogs

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• 作者：Hulya Sungurtekin ; Umar S. Boston ; David J. Cook
• 刊名：Journal of Cardiothoracic and Vascular Anesthesia
• 出版年：2000
• 出版时间：February 2000
• 年：2000
• 卷：14
• 期：1
• 页码：25-28
• 全文大小：445 K

文摘

To determine if normal cardiopulmonary bypass (CPB) pump flows maintain cerebral perfusion in the context of reduced mean arterial pressure at 33°C.

A prospective investigation.

Animal CPB research laboratory.

Seven dogs that underwent CPB.

Seven dogs underwent CPB at 33°C using α-stat management and a halothane, fentanyl-midazolam anesthetic. Cerebral blood flow was measured using the sagittal sinus outflow technique. After control measurements at 70 mmHg, cerebral physiologic values were determined under four conditions in random order: (1) mean arterial pressure of 60 mmHg achieved by a reduction in pump flow, (2) mean arterial pressure of 60 mmHg determined by partial opening of a femoral arterial-to-venous reservoir shunt, (3) mean arterial pressure of 45 mmHg by reduced pump flow, and (4) mean arterial pressure of 45 mmHg by shunt. A 9F femoral arterial-to-venous reservoir shunt was controlled by a screw clamp.

Except for the controlled variables of mean arterial pressure and bypass flow, physiologic determinants of cerebral blood flow (temperature, PaCO₂ and hematocrit) did not differ under any of the CPB conditions. Pump flow per se was not a determinant of cerebral perfusion. Cerebral blood flow and cerebral oxygen delivery did not differ with changes in pump flow if mean arterial pressure did not differ. Cerebral blood flow depended on mean arterial pressure under all pump flow conditions, however.

Over the range of flows typical in adult CPB at 33°C, pump flow does not have an effect on cerebral perfusion independent of its effect on mean arterial pressure. A targeted pump flow per se is not sufficient to maintain cerebral perfusion if mean arterial blood pressure is reduced.