Blood, 1959, Vol. 14, No. 11, pp. 1230-1236.
© 1959 American Society of Hematology, Inc.
Use of the Plasma Thrombin Time to Assess the Adequacy
of in Vivo Neutralization of Heparin: Comparative
Studies Following Operations Employing
Extracorporeal Circulation
JAMES C. PEDEN JR. 1 and
JAMES A. MCFARLAND 1
1 Department of Clinical Pathology, Clinical Center, and the Clinic of Surgery,
National Heart Institute, National Institutes of Health, Bethesda, Md.
1. The dosage of protamine necessary for the postoperative neutralization
of heparin, used as anticoagulant during extracorporeal circulation, was
studied in 25 patients by means of both the protamine titration test and
the plasma thrombin time.
2. The plasma thrombin time was found to be far more sensitive in the
detection of small quantities of residual heparin than was the protamine
titration test, which failed to demonstrate significant quantities of circulating
heparin.
3. Adequate neutralization of circulating heparin was achieved when an
initial postoperative protamine dose of 1.5 times the calculated residual
heparin was given and followed by additional protamine when indicated
by the result of the plasma thrombin time.
4. No toxic effects of protamine were noted on such a dosage schedule.
Submitted on October 9, 1958
Accepted on December 21, 1958
