Preservation of Human Platelets with Prostaglandin Ei during in Vitro Simulation of Cardiopulmonary Bypass

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SUMMARYPlatelet abnormalities that occur during cardiopulmonary bypass may be produced in vitro by recirculating 500 ml of human blood at 37°C in a silicone rubber circuit (0.9 m1) containing a spiral coil membrane oxygenator. Platelet counts fall to 20% of initial levels, plasma levels of low affinity platelet factor 4 (LA-PF4) rise from 0 to 66% of that in control platelet rich plasma, and sensitivity to aggregating agents diminishes. Inhibition of platelet function with prostaglandin Ei (PGE1) prevents these alterations. In 14 trials (PGE1 - o.l to 10 μM), the thrombocyte count achieved a stable value of 88% within 1 hour. Plasma LA-PF4 (PGE1 £ 0.3 μM) rose to only 10% after 6 hours. Electron microscopy revealed intact platelet granules in recirculated platelets. Platelets incubated and recirculated with PGEi remained equally sensitive to epinephrine and ADP for 3 hours. At 6 hours, recirculated platelets in plasma (PGEi £ 0.1 p.u) and gel-filtered platelets (PGE1 < 0.3 MM) became significantly less sensitive to epinephrine. At PGE1 £ 0.3 μM, however, gel-filtered recirculated platelets responded normally to epinephrine even after 6 hours of recirculation. PGEi preserves platelet numbers, prevents contact-initiated release, and preserves platelet sensitivity to aggregating agents during in vitro extracorporeal bypass. cire Res 44: 350-357, 1979

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