Monitoring of intraoperative heparinization in vascular surgery

In 15 patients undergoing aortofemoral bypass, partial thromboplastin time (PTT) tests before and following intravenous administration of 75 U. per kilogram of heparin at zero, 30, 60, 90, and 120 minutes were determined for study of control of anticoagulant adequacy. The results demonstrate clearly that this amount provides excellent protection against thrombosis without bleeding complications. For intraoperative assay of heparin level effectiveness, the PTT test is advised. This test showed that a value of 250 percent of control still existed 75 minutes following the administration of heparin.