Phospholipase A activation following extracorporeal circulation and its blockade by procaine.

The phospholipase A activity of human plasma was investigated in the course of operations with the aid of extracorporeal circulation. After an initial increase following heparin application, there is a continuous rise up to the end of perfusion and a decrease to normal values 30 minutes after the end of perfusion and the application of protamine. Procaine is suitable for the inhibition of the increased phospholipase A activity. In accordance with in vitro determinations of an effective dose of 1 mmol/ml, corresponding concentrations were attained with an infusion rate of 1.5-2 mg/kg/min. In a second series of investigations, a significantly smaller phospholipase A activation in the course of perfusion was detectable through the addition of procaine.