Influence of Different Intravascular Volume Therapies on Platelet Function in Patients Undergoing Cardiopulmonary Bypass

Abstract

The influence of four different kinds of intravascular volume replacement on platelet function was investigated in 60 patients undergoing elective aortocoronary bypass grafting using cardiopulmonary bypass (CPB). In a randomized sequence, high-molecular weight hydroxyethyl starch solution (HMW-HES, mean molecular weight [Mw] 450,000 d), low-molecular weight HES (LMW-HES, Mw 200,000 d), 3.5% gelatin or 5% albumin were infused preoperatively to double reduced filling pressure (pulmonary capillary wedge pressure [PCWP] < 5 mm Hg). Fifteen untreated patients served as a control. Platelet function was assessed by aggregometry using turbidometric technique (inductors: ADP, epinephrine, collagen). Maximum aggregation, maximum gradient of aggregation, and platelet volume were measured before, during, and after CPB until the first postoperative day. HMW-HES 840 +/- 90 mL, LMW 850 +/- 100 mL, gelatin 950 +/- 110 mL, and albumin 810 +/- 100 mL were given preoperatively. Maximum platelet aggregation (ranging from -23% to -44% relative from baseline value) and maximum gradient of platelet aggregation (ranging from -26% to -45% relative from baseline values) were reduced only in the HMW-HES patients. After CPB, aggregometry also was impaired most markedly in these patients. The other volume groups showed less reduction in platelet aggregation and were similar to the untreated control. On the first postoperative day, aggregation variables had returned almost to baseline in all patients. Platelet volume was the same among the groups within the investigation period. Postbypass blood loss was highest in the HMW-HES group (890 +/- 180 mL). There was significant (P < 0.04) correlation in this group between blood loss and change in platelet aggregation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Recombinant FVIIa in Hypothermic, Coagulopathic Pigs with Liver Injuries

“…For pigs there have been no studies formally comparing the above-noted three intravascular volume expanders. For humans one study compared albumin, HES with an average MW of 200,000, and HES with an average MW of 450,000 (Boldt et al, 1993). In this study with 75 cardiac surgery patients, use of the higher MW HES was associated with significantly higher blood losses during the first postoperative day when compared with controls and other treatments.…”

Post‐operative volume therapy in cardiac surgery: effects on hemostatic and circulatory variables

“…Large HES molecules interfere with fibrinogen, coagulation factor VIII, and von Willebrand factor, and their negligible effect on coagulation is more than can be expected as a result of hemodilution (Omar et al 1999). HES also promotes platelet dysfunction by disturbing platelet aggregation in vitro (Boldt et al 1993). In studies assessing viscoelastic properties of whole blood, HES has been consistently demonstrated to disturb fibrin formation and to reduce clot firmness Kuitunen 1998, Boldt et al 2007).…”

Crystalloids or Colloids for the Treatment of Hypovolemia?

“…The effects of hydroxyethyl starches on hemostasis have been studied by many authors 63,67,90,91 . Hydroxyethyl starches with a high in vivo Mw should be distinguished from other hydroxyethyl starches.…”