Pharmacodynamics of pentamorphone during coronary artery bypass grafting in humans.

Pentamorphone is a new, highly potent opioid reported to have minimal cardiovascular effects in humans and a high therapeutic index in animals. Pentamorphone was injected intravenously (IV) as the sole anesthetic in 10 patients with left ventricular ejection fractions greater than 0.35 who were undergoing elective coronary artery bypass grafting (CABG). After premedication with lorazepam, 40 micrograms/kg, and establishment of hemodynamic monitoring, pentamorphone was infused at a rate of 2 micrograms/kg/min until unconsciousness occurred (5.1 +/- 1.6 micrograms/kg). Anesthetic induction was accompanied by an average 30% decrease in systolic, diastolic, and mean arterial pressure (MAP), a 19% decrease in heart rate (HR), but no change in cardiac output (CO) or pulmonary artery occlusion pressure. Five patients had a MAP less than 60 mm Hg after induction. Following incision, blood pressure, pulmonary artery occlusion pressure, and CO were unchanged from baseline but HR remained significantly lower. Despite additional pentamorphone (total dose 9.6 +/- 1.8 micrograms/kg), 6 patients required thiopental and/or enflurane to control hypertension intraoperatively. When pentamorphone is used as the sole IV anesthetic in lorazepam-premedicated patients with normal or mildly impaired ventricular function, there is a high incidence of hypotension during induction, and poor control of hemodynamic responses to stimulation. Pentamorphone, 10 micrograms/kg, does not seem to offer any significant advantage over opioids currently used for anesthesia in patients undergoing CABG.

Effect of thiopental on neurologic outcome following coronary artery bypass grafting.

To determine if thiopental reduces the incidence of neurologic sequelae after coronary artery surgery, we prospectively studied 300 patients undergoing coronary artery bypass grafting. Patients who had no history of neurologic or psychiatric illness were randomly assigned to receive either a thiopental infusion or a saline placebo infusion beginning with the administration of heparin and ending just after aortic decannulation. The patients received an opioid-relaxant anesthetic administered by an anesthesiologist who was not involved in this investigation and who was blinded to the test infusion. One of the investigators infused either saline or thiopental to produce an isoelectric electroencephalogram with 30-45 s between bursts. Standardized neurologic examinations were performed preoperatively and on the 2nd and 5th postoperative days by one of the blinded investigators. The group of patients receiving thiopental required a longer time for awakening (6.4 +/- 3.9 vs. 4.0 +/- 2.4 h, mean +/- SD, P less than 0.05) and for tracheal extubation (22.4 +/- 18.4 vs. 17.4 +/- 9.6 h, P less than 0.05), and a greater number of these patients were lethargic on the 2nd postoperative day. More patients receiving thiopental required vasoconstrictors during the thiopental loading and cardiopulmonary bypass (CPB) periods, while a greater number of patients receiving placebo required vasodilators. A greater number of patients receiving thiopental required inotropic drugs during separation from CPB. Despite the above differences, only 2 of the 151 patients in the placebo group (1.3%) and 5 of the 149 patients in the thiopental group (3.3%) experienced strokes (P = 0.2535).(ABSTRACT TRUNCATED AT 250 WORDS)