Heparin level determination during extracorporeal circulation in open heart surgery
Binsack, T.; Hiller, E.; Pallast, M.; Welz, A.
Fortschritte der Medizin 101(46): 2138-2141
1983
ISSN/ISBN: 0015-8178 PMID: 6662465 Document Number: 211488
Because of the high dosages which have to be given during extracorporal circulation it is often impossible to measure the end point of coagulation for both thrombin time and aPTT. A correct determination of the heparin level has become possible with synthetic substrates with the help of the "Protopath proteolytic enzyme detection system" (AHS, Munich). With a fluorogenic synthetic substrate in a one-way cuvette and calibrated fluorometer the heparin and AT III levels can easily be measured. Very high levels of heparin which averaged 6,9 U/ml +/- 1,0 10 minutes after heparinization and 4,4 U/ml +/- 1,0 60 minutes later were found in ten patients with open heart surgery during extracorporal circulation. AT III decreased to less than 50% possibly due to dilutional effects. Ten minutes after protamine neutralization heparin levels were less than 0,1 U/ml. After two hours AT III levels returned to 70%. Measurement of heparin blood levels adds to the quality of anticoagulant control in situations where high dosages of heparin are given.