• S C Nicholson, D M Keeling, M E Sinclair, and R D Evans.
• Nuffield Department of Anaesthetics, John Radcliffe Hospital, Headley Way, Oxford, UK.
• Br J Anaesth. 2001 Dec 1; 87 (6): 844-7.

AbstractHeparin infusion may cause heparin resistance and may affect monitoring by measurement of the activated coagulation time (ACT), making the assessment of anticoagulation difficult, with the risk of over- or undertreatment, especially during cardiac surgery. We studied two groups of patients undergoing cardiopulmonary bypass (CPB): patients on heparin infusions (group H) and heparin-naive controls (group C). All patients received heparin 300 IU kg(-1) before CPB and a further dose of 5000 IU if the ACT 5 min after commencing bypass was less than 400 s. Measurements of ACT, heparin concentration, antithrombin-3, thrombin-antithrombin complex, prothrombin fragment F(1+2) and D-dimers were made before and 5 and 20 min after start of CPB. A second dose of heparin was given to eight out of 18 patients in group C and 10 out of 24 in group H. Antithrombin-3 in group H was significantly less than in group C at 5 min [59 (14) vs 52 (9)%, P<0.05]. ACT was significantly lower in group H than group C at 20 min [387 (64) vs 431 (67) s, P<0.05]. Despite ACTs of less than 400 s in both groups, no coagulation was seen, suggesting that 300 IU kg(-1) heparin is a safe dose for anticoagulation in CPB even after heparin therapy.

21 keywords...

hide…