EVALUATION OF THE TAS COAGULATION ANALYZER FOR MONITORING HEPARIN EFFECT IN CARDIAC SURGICAL PATIENTS

Objective: To assess the relationship between the Thrombolytic Assessm ent System (TAS); (Cardiovascular Diagnostics, Inc, Raleigh, NC) measu rements and heparin levels in cardiac surgical patients. Design: Equip ment evaluation in vitro and in vivo. Setting: A university teaching h ospital. Participants:Sixty adult patients undergoing elective cardiac surgery requiring cardiopulmonary bypass (CPB). Interventions: Part 1 : Simultaneous heparin management tests (HMTs) and activated coagulati on times (ACTs) were measured in 20 patients pre-CPB, during CPB, and post-CPB. In the same patients, the effect of heparin, 1 to 5 IU/mL, o n the HMT was assessed in vitro. The effect of aprotinin, 50 to 200 KI U/mL, on the HMT, was assessed in vitro in a further 10 patients. Part II: Simultaneous TAS and laboratory (LAB) activated partial thrombopl astin times (APTTs) were measured pre-CPB and post-CPB in 20 patients. In the same patients, the effect of heparin, 0.1 to 0.5 IU/mL, on the TAS APTT was assessed in vitro. The effect of aprotinin on the TAS AP TT was assessed in vitro in a further 10 patients. Main Results: Part 1: Heparin, 0, 1, 2, and 5 IU/mL in vitro resulted in HMTs of 164 +/- 12, 281 +/- 19, 338 +/- 16, and 436 +/- 33 seconds (mean +/- standard deviation [SD]), respectively. The HMT had less variability than the A CT in vivo. Part II: Heparin. 0, 0.1, 0.2, and 0.5 IU/mL in vitro, res ulted in TAS APTTs of 34.9 +/- 4.7, 61.2 +/- 2.5, 97.4 +/- 34.7, and 1 97.1 +/- 64.3 seconds, respectively. The correlation (r) between the T AS and LAB APTT was 0.726 pre-CPB and 0.794 post-CPB. Aprotinin increa sed both the HMT and TAS APTT in a dose-related manner. Conclusion: Th e TAS may be a useful monitor of heparin effect in cardiac surgical pa tients. Copyright (C) 1998 by W.B. Saunders Company.