[Evaluation of optimal dosage of heparin in hemodialysis patients by thromboelastograph]

To assess the blood coagulation function and investigate the appropriate dose of unfractionated heparin by thromboelastograph in maintenance hemodialysis (MHD) patients.

Thirty MHD patients were enrolled in this study and divided into two groups. The total dose of unfractionated heparin was below 80 u/kg in the low-dose group (LH, n=16), while it exceeded 80 u/kg in the high-dose group (HH, n=14). Blood routine tests and conventional coagulation examinations were measured before hemodialysis. TEG and activated partial thromboplastin time (APTT) were examined at the beginning and the end of hemodialysis at the arterial circuit, and the second hour (h 2) at the venous circuit.

The initial bolus dose of unfractionated heparin for LH and HH groups were (26.6±6.2) u/kg vs. (42.3±8.2) u/kg and the repeated maintenance dose for both the groups were (13.7±5.1) u/kg/h vs. (18.2±4.3) u/kg/h. No significant difference was noticed in results from blood routine tests and conventional coagulation parameters between the two groups. In LH group, the increase of APTT at h 2 of hemodialysis was significant compared with the baseline, while it recovered partly at the end of hemodialysis. R value prolonged at h 2 and the end of hemodialysis. CI value was more negative at the end of hemodialysis. In HH group, APTT obviously prolonged at h 2 and the end of hemodialysis. R value also obviously prolonged at h 2 of hemodialysis. At the end of hemodialysis, R and K values prolonged, MA value reduced, and CI value was more negative. APTT was significantly different between the two groups at h 2 of hemodialysis. At the end of hemodialysis, APTT was still extended in HH group, but there was no significant difference. R value at h 2, and R, K, MA, CI values at the end of hemodialysis were significantly different between the two groups. R values at the end of hemodialysis had a direct correlation with the dose of unfractionated heparin (r=0.403, P=0.041), but APTT had not. There was no significant difference in transmembrane pressure, venous pressure and filter clotting between the two groups.

Low-dose heparin is effective and safe as anticoagulant in hemodialysis. TEG shows that the blood coagulation function is more sensitive than conventional coagulation parameters and is useful to anticoagulant therapy in MHD patients.