CONSEQUENCES OF ELECTROENCEPHALOGRAPHIC-SUPPRESSIVE DOSES OF PROPOFOLIN CONJUNCTION WITH DEEP HYPOTHERMIC CIRCULATORY ARREST

Background: Some patients who undergo cerebral aneurysm surgery requir e cardiopulmonary bypass and deep hypothermic circulatory arrest. Duri ng bypass, these patients often are given large doses of a supplementa l anesthetic agent in the hope that additional cerebral protection wil l be provided. Pharmacologic brain protection, however, has been assoc iated with undesirable side effects. These side effects were evaluated in patients who received large doses of propofol. Methods: Thirteen n eurosurgical patients underwent cardiopulmonary bypass and deep hypoth ermic circulatory arrest to facilitate clip application to a giant or otherwise high-risk cerebral aneurysm. Electroencephalographic burst s uppression was established before bypass with an infusion of propofol and the infusion was continued until the end of surgery. Hemodynamic a nd echocardiographic measurements were made before and during the preb ypass propofol infusion and again after bypass. Emergence time also wa s determined. Results: Prebypass propofol at 243 +/- 57 mu g . kg(-1) . min(-1) decreased vascular resistance from 34 +/- 8 to 27 +/- 8 unit s without changing heart rate, arterial or filling pressures, cardiac index, stroke volume, or ejection fraction. Propofol blood concentrati on was 8 +/- 2 mu g/ml. Myocardial wall motion appeared hyperdynamic a t the end of cardiopulmonary bypass, and all patients were weaned ther efrom without inotropic support. After bypass, vascular resistance dec reased further, and cardiovascular performance was improved compared t o baseline values. Nine of the 13 patients emerged from anesthesia and were able to follow commands at 3.1 +/- 1.4 h. Three others had strok es and a fourth had cerebral swelling. Conclusions: Propofol infused a t a rate sufficient to suppress the electroencephalogram does not depr ess the heart or excessively prolong emergence from anesthesia after c ardiopulmonary bypass and deep hypothermic circulatory arrest.