title: Activated clotting time (ACT) monitoring of intraoperative heparinization in peripheral vascular surgery.
abstract: We conclude that (1) the activated clotting time (ACT) is an accurate method of monitoring anti-coagulation during peripheral vascular surgery and can easily be performed by a technician in the operating room or at the bedside; (2) an initial heparinizing dose of 120 to 130 units/kg is adequate in 95 per cent of the patients; (3) the ACT should be maintained at greater than twice the control values (180 to 200 seconds), which required supplementation within 2 hours in 21 per cent; (4) the response to heparin is twofold: an initial sensitivity or resistance followed by an independent and variable rate of consumption; (5) the patient's heparin dose-response curve should be used to calculate the amount of supplemental heparin needed to maintain the ACT at a safe level; (6) protamine should be given if the ACT at the conclusion of the operation is greater than 150 seconds (50 per cent of our patients); and (7) a final ACT 15 to 30 minutes postoperatively should be obtained to ensure adequate reversal or to detect heparin rebound or depletion of clotting factors.
mesh_terms: D001158:Arteries / Q000601:surgery*; D001777:Blood Coagulation / Q000187:drug effects; D001780:Blood Coagulation Tests; D002339:Carotid Arteries / Q000601:surgery; D004305:Dose-Response Relationship, Drug; D005260:Female; D006493:Heparin / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D011479:Protamines / Q000627:therapeutic use; D014656:Vascular Surgical Procedures / Q000379:methods*; D014914:Whole Blood Coagulation Time
chemical_list: D011479:Protamines; D006493:Heparin