EFFECTS OF THE PLATELET-ACTIVATING-FACTOR RECEPTOR ANTAGONIST BN-52021 ON HEMATOLOGIC VARIABLES AND BLOOD-LOSS DURING AND AFTER CARDIOPULMONARY BYPASS

Cardiopulmonary bypass (CPB)-induced thrombocytopenia and leukopenia i s augmented after heparin reversal of protamine. Platelet-activating f atter (PAF) might be implicated in these disorders. To evaluate the ef fects of PAF on the hematologic disorders and blood loss during and af ter CPB, patients were pretreated with BN 52021, a PAF receptor antago nist, or a placebo. BN 52021 (120 mg) (n = 13) or placebo (n = 15) wer e infused intravenously before vascular cannulation and before cross-c lamp release. Platelet and leukocyte counts were assessed in venous bl ood before and after the first dose of BN 52021 or placebo, 2 min afte r the beginning of CPB (at the entry of the oxygenator), at the end of CPB, 1, 15, and 30 min after protamine infusion, and 6 and 24 h after CPB. The decrease in platelet and leukocyte counts were the same betw een groups during and after CPB and after protamine infusion. Bleeding times were not modified by the pretreatment of patients with BN 52021 . During surgery, blood loss reached 1660 +/- 297 mL in the BN 52021 g roup and 1599 +/- 283 mL in the placebo group (P > 0.05). Forty-eight hours postoperatively, the chest tube outputs were not different betwe en groups (1460 +/- 418 mL vs 1640 +/- 362 mt in the BN 52021 and plac ebo groups, respectively). This study shows that BN 52021 infusion did not change the hematologic variables studied. Moreover, a PAF antagon ist pretreatment did not protect the patients against CPB- or protamin e-induced hematologic changes.