Low-dose enflurane as adjunct to high-dose fentanyl in patients undergoing coronary artery surgery: stable hemodynamics and maintained myocardial oxygen balance.
The effects of enflurane (end-tidal concentration 0.7%) on central and coronary hemodynamics and myocardial oxygenation were studied during steady state, high-dose fentanyl anesthesia in ten patients undergoing coronary artery bypass grafting operations. Compared with the response in ten patients receiving the same fentanyl anesthesia (100 micrograms/kg) without enflurane supplementation, enflurane caused a moderate reduction in mean arterial pressure, systemic vascular resistance, and left ventricular stroke work index. No patient showed signs of myocardial ischemia, and mean coronary sinus flow and calculated coronary resistance remained unchanged. Surgical stimulation induced no central or coronary hemodynamic responses in the enflurane-fentanyl group. No coronary hemodynamic changes occurred in the fentanyl group, but a marked increase in arterial pressure and systemic vascular resistance was seen. Myocardial oxygen extraction decreased in the enflurane supplemented group although it increased in the fentanyl group after surgical stimulation. Three fentanyl group patients and one enflurane-fentanyl group patient had a low myocardial lactate extraction as a sign of myocardial ischemia during surgery. We conclude that a 0.7% enflurane supplementation of 100 micrograms/kg fentanyl anesthesia does not endanger myocardial oxygenation and effectively prevents central and coronary hemodynamic responses to skin incision and sternotomy in patients undergoing coronary artery surgery.
D000768:Anesthesia, General / Q000379:methods*; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000378:metabolism; D004737:Enflurane / Q000008:administration & dosage*; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage*; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects*
D007773:Lactates; D019344:Lactic Acid; D004737:Enflurane; D005283:Fentanyl