A comparison between continuous infusion versus standard bolus administration of heparin based on monitoring in cardiac surgery.

This study was designed to determine prospectively if stable heparin concentrations can be maintained during extracorporeal circulation by using a continuous infusion technique, compared with a bolus regimen based on whole blood heparin concentration monitoring. Forty patients were assigned randomly to either an infusion or a monitoring group. The reference heparin concentration was defined as the whole blood heparin concentration associated with a kaolin activated clotting time (ACT) of approximately 480 s prior to institution of cardiopulmonary bypass (CPB) for both cohorts.

Antithrombin III during cardiac surgery: effect on response of activated clotting time to heparin and relationship to markers of hemostatic activation.

Unlabelled: This study was designed to determine if, and to what extent, antithrombin III (AT) levels affect the response of the activated clotting time (ACT) to heparin in concentrations used during cardiac surgery, and to characterize the relationship between AT levels and markers of activation of coagulation during cardiopulmonary bypass (CPB). After informed consent, blood specimens obtained from eight normal volunteers (Phase I) were used to measure the response of the kaolin and celite ACT to heparin after in vitro addition of AT (200 U/dL) and after dilution with AT-deficient plasma to yield AT concentrations of 20, 40, 60, 80, and 100 U/dL. In Phase II, blood specimens collected before the administration of heparin and prior to discontinuation of CPB, were used to measure the response of the kaolin ACT to heparin (preheparin only), AT concentration, and a battery of coagulation assays in 31 patients undergoing repeat or combined cardiac surgical procedures.

Effects of platelets and white blood cells and antiplatelet agent C7E3 (Reopro) on a new test of PAF procoagulant activity of whole blood.

This study was designed to evaluate the effects of varying concentrations of platelets, white blood cells (WBC) and Fab fragments of a monoclonal antibody (c7E3, Reopro) directed at the platelet GpIIb-IIIa receptor complex on ACT-based clot ratio values (hemoSTATUS assay) in healthy volunteers. These measurements were made in heparinized whole blood from 10 normal volunteers in which either platelet or WBC concentrations had been varied by differential centrifugation. In addition, blood collected in either heparin or argatroban was incubated with varying concentrations of c7E3 (Reopro).

Hemofiltration during cardiopulmonary bypass: the effect on anti-Xa and anti-IIa heparin activity.

Previous studies have demonstrated that heparin concentrations during cardiopulmonary bypass (CPB) may vary considerably, which may be related to variability in redistribution, cellular and plasma protein binding, and clearance of heparin. The purpose of this study was to determine whether hemofiltration removes lower molecular weight fractions of heparin from plasma and thus contributes to variability of blood levels of heparin. Twenty patients undergoing cardiac surgery with CPB were enrolled in this study after informed consent was obtained.