Evaluation of the TAS coagulation analyzer for monitoring heparin effect in cardiac surgical patients.
OBJECTIVE
To assess the relationship between the Thrombolytic Assessment System (TAS); (Cardiovascular Diagnostics, Inc, Raleigh, NC) measurements and heparin levels in cardiac surgical patients.


METHODS
Equipment evaluation in vitro and in vivo.


METHODS
A university teaching hospital.


METHODS
Sixty adult patients undergoing elective cardiac surgery requiring cardiopulmonary bypass (CPB).


METHODS
Part 1: Simultaneous heparin management tests (HMTs) and activated coagulation 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, on the HMT was assessed in vitro. The effect of aprotinin, 50 to 200 KIU/mL, on the HMT, was assessed in vitro in a further 10 patients. Part II: Simultaneous TAS and laboratory (LAB) activated partial thromboplastin 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 APTT was assessed in vitro in a further 10 patients.


RESULTS
Part I: 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 ACT in vivo. Part II: Heparin, 0, 0.1, 0.2, and 0.5 IU/mL in vitro, resulted in TAS APTTs of 34.9 +/- 4.7, 61.2 +/- 2.5, 97.4 +/- 34.7, and 197.1 +/- 64.3 seconds, respectively. The correlation (r) between the TAS and LAB APTT was 0.726 pre-CPB and 0.794 post-CPB. Aprotinin increased both the HMT and TAS APTT in a dose-related manner.


CONCLUSIONS
The TAS may be a useful monitor of heparin effect in cardiac surgical patients.
Gibbs
N M
NM
Department of Anaesthesia, Sir Charles Gairdner Hospital, Nedlands, Western Australia.
Weightman
W M
WM
Thackray
N M
NM
Michalopoulos
N
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000494:pharmacology*; D006348:Cardiac Surgical Procedures; D016903:Drug Monitoring; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D014914:Whole Blood Coagulation Time
D000925:Anticoagulants; D006493:Heparin