PROPOFOL-FENTANYL VERSUS ISOFLURANE-FENTANYL ANESTHESIA FOR CORONARY-ARTERY BYPASS-GRAFTING - EFFECT ON MYOCARDIAL-CONTRACTILITY AND PERIPHERAL HEMODYNAMICS

To avoid intraoperative awareness and postoperative respiratory depres sion from high-dose opioid anesthesia, propofol (P), or isoflurane (I) has been combined with moderate-dose opioid with varying results. How ever, the effects of both P and I on myocardial contractility and left ventricular afterload have not been completely quantified. The end-sy stolic pressure-diameter relationship (ESPDR) of the left ventricle (L V) is a reliable method to quantitatively assess LV contractility beca use it is relatively independent of changes in preload and incorporate s afterload changes. The purpose of this study was to quantify the car diodynamic effects of propofol-fentanyl (PF) anesthesia in comparison with isoflurane-fentanyl (IF) anesthesia in patients undergoing corona ry artery bypass grafting (CABG). Thirty patients with normal or moder ately impaired LV function (ejection fraction greater than or equal to 40% with LV end diastolic pressure less than or equal to 18 mmHg, no preoperative akinesia or dyskinesia) undergoing elective CABG were stu d led. After premedication with flunitrazepam, 2 mg orally, all patien ts were induced with thiopental, 1 mg/kg, fentanyl, 20 mu g/kg, and ve curonium, 0.1 mg/kg, and were ventilated with oxygen/air (F1O2 0.6) An esthesia was maintained throughout the procedure with a zero-order int ravenous (IV) continuous infusion of P, 3 mg/kg/h (PF group), or with isoflurane inhalation of 0.6% (IF group), supplemented by intermittent boluses (5 mu g/kg) of fentanyl (up to a total maintenance dose of 30 mu g/kg). After intubation, a cross-section of the LV was visualized by two dimensional transesophageal echocardiography and an m-mode echo cardiogram was obtained at the maximum anterior-posterior diameter. Th e radial artery pressure tracing and the ECG were simultaneously recor ded with the M mode. Slope of ESPDR (Ees) and fractional shortening (F S) were measured before (T-0) and during P or I administration (T-1). A contemporary full hemodynamic profile using a pulmonary artery cathe ter was obtained at T-0 and T-1. Statistical significance was tested w ith a t test for paired data. No patient experienced awareness of any intraoperative events. There were no significant differences between T -0 and T-1 hemodynamic parameters in both PF and IF groups. No signifi cant decrease of myocardial contractility, measured by Ees (15.3% with P vs. 11.1% with I), was seen at T-1, together with unchanged filling pressures (CVP and PCWP). Coronary perfusion pressure (CPP), as a myo cardial perfusion index, was unmodified after both anesthetic drugs. I n conclusion, low doses of P or I combined with moderate doses of fent anyl (up to 50 mu g/kg) give adequate levels of anesthesia and good he modynamic stability. Slightly depressed contractility together with an unchanged CPP suggest a good myocardial oxygen balance (MDO(2)/MVO(2) ) for both techniques. Copyright (C) 1995 by W.B. Saunders Company