RESUMEN
This work was performed on 20 patients [11 females and 9 males] with age ranged between 9 and 50 years with a mean value of 23.6 +/- 10.2 years underwent elective open heart surgery aiming to study the effect of cardiopulmonary bypass on some hemostatic parameters and to correlate these changes with post bypass bleeding. The results obtained showed that platelet count, mean platelet volume, platelet aggregation with ADP and bleeding time were significantly affected with CPB procedure and the degree of affection was correlated statistically with the time of bypass which had a mean value of 139.8 +/- 43.8 minutes. In addition, the postoperative blood loss was correlated with all post bypass platelet parameters. However, in the second postoperative day, all the hemostatic parameters tested showed statistically significant improvement