Myocardial function during halothane and enflurane anesthesia in patients with coronary artery disease
Delaney, T.J.; Kistner, J.R.; Lake, C.L.; Miller, E.D.
Anesthesia and Analgesia 59(4): 240-244
1980
ISSN/ISBN: 0003-2999 PMID: 7189361 Document Number: 156758
Halothane and enflurane are known myocardial depressants in healthy individuals. Whether these 2 agents produce the same degree of myocardial depression in patients with coronary artery disease has not been studied. Informed consent was obtained from 16 adults with ischemic heart disease undergoing coronary artery bypass grafting. Patients with significant ventricular dysfunction were excluded from the study. Control measurements were made while the patient breathed 100% oxygen. The patients were divided into 2 groups, anesthetized with either halothane or enflurane, and repeat measurements made at 1/2 and 3/4 MAC was unchanged from control. Enflurane likewise resulted in a decrease in MAP from 99 .+-. 6 torr to 75 .+-. 4 torr at 1/2 MAC and 68 .+-. 5 torr at 3/4 MAC. PCWP did not increase. In contrast, cardiac index was unchanged from control value of 2.65 .+-. 0.16 L/min per m2 at both 1/2 and 3/4 MAC. Arterial PCO2 was unchanged from the awake control value. While halothane and enflurane decrease mean arterial blood pressure, the mechanisms responsible differ. The primary afterload-reducing effect of enflurane may be beneficial to some patients with ischemic heart disease whereas other patients may benefit from the greater myocardial depression seen with halothane.