title: Heparin neutralising activity of whole blood in patients undergoing vascular surgery.
abstract: A test for measuring the heparin neutralizing activity in whole blood is described. This test was used in 13 patients having peripheral vascular surgery. The heparin neutralising activity (HNA) and fibrinogen concentration in the blood were measured on the day before operation. During operation, blood was withdrawn before and five minutes after administration of 10,000 units of heparin for the measurements of activated clotting time (ACT) and partial thromboplastin time (PTT). There was considerable variation in the ACT and the PTT values at five minutes after heparin administration which showed no correlation to the patients' weight. However, there was a significant linear correlation between the increase in ACT values and the HNA measured on the day before operation and a significant linear correlation between the HNA and the fibrinogen concentration. The results indicate that the ACT and PTT after giving heparin depended on HNA rather than the patients' weight, and are related to the fibrinogen concentration.
mesh_terms: D001777:Blood Coagulation / Q000187:drug effects*; D001780:Blood Coagulation Tests; D004334:Drug Administration Schedule; D005340:Fibrinogen / Q000032:analysis; D006493:Heparin / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology; D006801:Humans; D010314:Partial Thromboplastin Time; D014656:Vascular Surgical Procedures
chemical_list: D005340:Fibrinogen; D006493:Heparin