Effects of the propofol combination anesthesia on the intrinsic blood-clotting system

Fat emulsions can cause changes in blood-clotting and fibrinolysis. The aim of this study was to examine the relation between the use of the short-acting hypnotic propofol and alteration of the blood clotting system. In a double-blind randomized study, 36 patients with an aortocoronary bypass operation were given either midazolam/fentanyl or propofol/alfentanil. Eleven blood samples were taken at fixed times pre-, intra- and postoperatively to determine changes caused by the anesthetic agents on the hemostaseologic parameters during the whole operation. Perioperative blood pressures of both groups were measured at seven fixed points. From the beginning of the extracorporeal circulation (ECC) to the end of the operation, the measured values of the factor XIIa- and kallikrein-like activity in the propofol group were significantly higher than those of the midazolam group. Also the values of the kallikrein inhibition capacity and the indicators of fibrinolysis (t-PA and D-dimers) suggest a stronger activation of the contact phase at the start of the recirculation and as a result of it a stronger fibrinolysis within the propofol group. Besides, the hypotensive side-effect in the propofol group was evident in contrast to the midazolam group. With this investigation, a correlation between the application of propofol/alfentanil, contact phase activation with activation of the kallikrein-kinin-bradykinin system and the observed hypotension can be set up.