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beta-Adrenergic antagonism decreases the size of myocardial infarction and provides myocardial protection during hypothermic arrest for cardiac surgery. However, concern regarding the negative inotropic and chronotropic effects of beta-adrenergic antagonism persisting after cardiopulmonary bypass (CPB) has impeded the use of esmolol for this purpose during cardiac surgery. This is a randomized, double-blind prospective study of the effects of esmolol infused during CPB and the effects of hypothermic CPB on esmolol. Patients scheduled for CPB were randomized to receive intravenous esmolol (300.micrograms.kg-1.min-1 during CPB after a bolus of 2 mg/kg prior to CPB) or placebo. Infusion was stopped at 10 min after release of aortic cross-clamp. Hemodynamics were measured, as well as serum esmolol, catecholamines, lactate, and potassium. Postoperative variables measured included electrocardiographic changes, creatine kinase (CK)-MB fractions, post-CPB dysrhythmias and drugs, hospitalization time and cost, and mortality. Esmolol was administered to 16 patients and placebo to 14. Esmolol levels reached a high of 10.5 +/- 0.9 micrograms/mL during CPB, but decreased to 0.1 +/- 0.02 microgram/mL within 30 min after stopping infusion. Cardiac indices (cardiac index, stroke volume index, left cardiac work index, left ventricular stroke work index, right cardiac work index, and right ventricular stroke work index) were higher in the esmolol group for the first hour post-CPB (P < 0.05). Systemic arterial lactate and coronary sinus lactate were lower in the esmolol group after CPB (P < 0.05), but myocardial lactate extraction was not significantly different between groups. After CPB, hemoglobin was lower in the esmolol group (P < 0.05) due to longer CPB and aortic cross-clamp time (P < 0.05), but oxygen consumption was less than in the control group (P < 0.05). Post-CPB serum potassium was higher in the esmolol group (P < 0.05). Results are confounded by more chronically beta-adrenergically blocked patients randomized to the esmolol group (P < 0.05). Esmolol infused during CPB in this series of patients was associated with high concentrations during CPB but did not result in any adverse clinical effects after CPB.

Paired associates were presented to 25 surgical patients following the induction of anesthesia by thiopental, vecuronium, and isoflurane. Postoperative testing (immediately or after two weeks) showed no free recall for the list; nor was there significant cued recall or recognition, compared to a matched control list. However, a free-association task showed a significant priming effect on both immediate and delayed trials. At least under some conditions, adequate surgical anesthesia appears to abolish explicit, but not implicit, memory for intraoperative events.