In vivo platelet function following cardiopulmonary bypass.
In order to test the in vivo hemostatic function of platelets exposed to cardiopulmonary bypass, template bleeding times (TBT) were performed prebypass, three hours postbypass and 18 to 20 hours postoperatively in 22 patients undergoing open-heart surgery. The Harker-Slichter formula was applied to platelet counts below 100,000/cu mm to determine the expected TBT if the platelets function normally but were associated with a prolonged bleeding time merely from thrombocytopenia. Half of the patients received only frozen erythrocyte transfusions. Twenty of the 22 patients (91%) had normal or shorter than the expected TBT. Eight of the ten patients with platelet counts under 100,000/cu mm had shorter than predicted TBTs. All of the patients receiving only frozen erythrocytes had normal or shorter than predicted TBTs. It is concluded that in vivo platelet hemostatic function is usually normal postbypass, that routine platelet transfusions are therefore not necessary, and that most open-heart surgical procedures can be performed using frozen erythrocyte transfusions exclusively.
D001772:Blood Cell Count; D001780:Blood Coagulation Tests; D001792:Blood Platelets / Q000502:physiology*; D001803:Blood Transfusion; D002315:Cardiopulmonary Bypass; D004912:Erythrocytes; D005112:Extracorporeal Circulation; D005615:Freezing; D006801:Humans; D013997:Time Factors