A COMPARISON OF THE EFFECTS OF FENTANYL AND PROPOFOL ON LEFT-VENTRICULAR CONTRACTILITY DURING MYOCARDIAL STUNNING

Background: The intravenous anaesthetic propofol has been shown to pos sess free radical scavenging activity and calcium channel blocking eff ects in a number of in vitro models. We decided to compare the effects of propofol with those of fentanyl on myocardial contractility during and after ischaemia to determine whether propofol could protect the h eart and improve recovery of ventricular contractile function in open- chested dogs. Methods: Twenty adult beagles were acutely instrumented, under halothane anaesthesia, to measure ECG; aortic, left ventricular pressures; cardiac output; coronary flow; and segmental lengths in th e regions perfused by the left anterior and left circumflex coronary a rteries. After surgery and a stabilisation period halothane anaesthesi a was terminated and fentanyl (100 mu g . kg(-1) bolus followed by 2 m u g . kg(-1) . min(-1) infusion; n=10) or propofol (5 mg . kg(-1) bolu s followed by 0.3 mg . kg(-1) . min(-1) infusion; n=10) anaesthesia co mmenced. After a stabilisation period the LAD coronary artery was occl uded for 10 min and then reperfused for 3 h. Measurements were taken t hroughout the protocol. Results: We found no significant difference in recovery of contractile function between propofol and fentanyl as ass essed by normalised preload recruitable work area (50+/-10 vs 47+/-16% ), normalised systolic shortening (36+/-12 vs 48+/-14%) and peak left ventricular dP/dt (1665+/-276 vs 1846+/-151 mmHg . s(-1)) at the end o f reperfusion. Conclusion: We conclude that at the concentration used in this study propofol shows no improvement in contractility during '' stunning'' when compared to fentanyl. (C) Acta Anaesthesiologica Scand inavica 42 (1998).