The Journal of Thoracic and Cardiovascular Surgery, Vol 72, 735-741, Copyright © 1976 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
The contribution of anticoagulants to platelet dysfunction with extracorporeal circulation
HW Wallace, H Brooks, TP Stein and NJ Zimmerman
This investigations evaluates the effects of anticoagulants on platelet
function. Fresh human blood from 40 nonmedicated volunteers was
anticoagulated with 4.3 units per milliliter heparin and/or acid-
citrate-dextrose (ACD) solution 1:9. Retention of platelets from whole
blood on glass beads was performed by the method of Bowie. Platelet
retention of heparinized blood averaged 88.1 +/- S.E. 1.5 per cent; ACD
platelets averaged 24.6 +/- S.E. 2.8 per cent. Platelet retention with
citrate-phosphate-dextrose (CPD) and ethylenediaminetetraacetic acid (EDTA)
yielded 26.0 +/- S.E. 3.9 per cent and 19.1 +/- S.E. 7.5 respectively. The
addition of ACD to heparinized blood decreased platelet retention (19.7 +/-
S.E. 3.1 per cent). The addition of heparin to ACD or CPD blood did not
alter the original decreased retention. Calcium added, even in excess, to
blood containing heparin and ACD did not reverse the depressed retention
(29.3 +/- S.E. 4.6 per cent). The substitution of CPD gave similar results.
With mixtures of separately collected ACD and heparininzed blood,
depression of platelet retention was directly proportional to the amount of
ACD blood present. Altering the pH of the ACD blood did not affect its
depressed retention of platelets. Neutralizing heparinized blood 50 per
cent with protamine or Polybrene also significantly depressed platelet
retention 34.6 +/- S.E. 5.8 per cent and 35.5 +/- S.E. 4.0 per cent,
respectively. Neither protamine nor Polybrene had any effect upon ACD
blood. These data indicate that anticoagulants may play a significant role
in the depressed platelt function observed during and following
extracorporeal circulation.
