IN-VIVO AND IN-VITRO EFFECTS OF POLYVINYLPYRROLIDONE ON PLATELET ADHESIVENESS IN HUMAN BLOOD

Intravenous infusion of 500 ml. 6% polyvinylpyrrolidone (P.V.P. (Mw 40,000) in isotonic saline solution over a 2-hour period significantly diminished platelet adhesiveness in eight subjects from 27% before infusion to as low as 10% at the end of the infusion. 5 hours after the end of the infusion, platelet adhesiveness was still significantly reduced (16%). The addition of P.V.P. to citrated blood in vitro significantly decreased platelet adhesiveness. Both in vivo and in vitro, the platelet-count was not significantly altered by P.V.P. The in-vivo change in platelet adhesiveness is similar to that reported by others with dextran-a plasma expander that differs chemically from P.V.P.