['Many studies have shown that preconditioning with anesthetics can be used to simulate the myocardial protective effects of ischemic preconditioning. But it is still not certain whether they can protect the myocardium in hemorrhagic shock. This study was designed to examine the myocardial protective effects of propofol and fentanyl in acute hemorrhagic shock.', "Thirty-six white rabbits were randomly divided into a control group (group C), propofol preconditioning group (group P), and fentanyl preconditioning group (group F). The animal model of acute hemorrhagic shock was established according to Wigger's method. The same volumes of saline, propofol (5 mg/kg), or fentanyl (25 microg/kg) were administered 15 min before bleeding. Left ventricular function parameters were monitored continuously during 90 min of hemorrhagic shock. Serum cardiac troponin I (cTn-I) was detected by chemiluminescence before bleeding and 60 and 90 min after bleeding. Myocardial samples were taken for morphological studies.", 'Compared with group C, the hemodynamic indexes in group F and group P were higher at each time point of shock (P < 0.05). The cTn-I values in group P and group F were lower than in group C (P < 0.05). Electron microscopic examination of the myocardium indicated that the alterations of myocardial structure and mitochondria were less pronounced in both group F and group P.'] Does pretreatment with fentanyl and propofol attenuate myocardial injury in rabbits with acute hemorrhagic shock?