Hemofiltration During Cardiopulmonary Bypass

Comparison of the effects of red cell separation and ultrafiltration on heparin concentration during pediatric cardiac surgery

OBJECTIVE

To determine the effects of red cell separation and ultrafiltration on heparin concentration.

DESIGN

Prospective study.

SETTING

University-affiliated, pediatric medical center.

PARTICIPANTS

Thirty-one children undergoing cardiac surgery.

INTERVENTIONS

Blood sampled for heparin concentration and coagulation tests.

MEASUREMENTS AND MAIN RESULTS

Thirteen infants under-went modified veno-venous ultrafiltration (UF) after cardiopulmonary bypass (CPB). In addition, residual blood in the CPB circuit was hemoconcentrated by UF and reinfused (UF group). Heparin concentration increased from 2.0 +/- 0.6 to 2.5 +/- 0.8 U/mL, following modified UF; while activated coagulation time (ACT) decreased from 701 +/- 177 to 627 +/- 107 seconds. Heparin concentration of CPB circuit residual increased from 1.9 +/- 0.7 to 3.1 +/- 1.0 U/mL. In 18 children (older than 1 year old), the residual blood in the CPB circuit was hemoconcentrated by cell separation (CS) and reinfused (CS group). Heparin concentration of CPB circuit residual decreased from 2.6 +/- 0.6 to 0.3 +/- 0.2 U/mL. After reinfusion, patient heparin concentration remained unchanged at < 0.05 U/mL. Thrombin time increased from 28 +/- 6 to 48 +/- 29 seconds and did not correlate with H.

CONCLUSIONS

The plasma concentration of heparin increased after veno-venous modified UF of the patient. Heparin concentration also increased after UF of residual CPB circuit blood. In contrast, circuit blood hemoconcentrated by CS contained minimal heparin, and, when infused, did not increase patient's heparin concentration. ACT and thrombin time did not correlate with heparin concentration.