DIFFERENTIAL-EFFECTS OF SERIAL HEMODILUTION WITH HYDROXYETHYL STARCH,ALBUMIN, AND 0.9-PERCENT SALINE ON WHOLE-BLOOD COAGULATION

Study Objectives: To determine by thrombelastography assessed coagulat ion, the effects of progressive hemodilution with three intravascular volume expanders. Design: Prospective, controlled, whole blood, volume tric ex vivo hemodilution study. Setting: University of Pennsylvania M edical Center Operating Rooms, Patients: 60 ASA physical status I and II patients; phlebotomy prior to administration of IV fluids or medica tions. Interventions: Analysis of whole blood clotting determined by s ix thrombelastographic channels for control and five volumetric hemodi lutions (11 %, 25 %, 33 %, 50 %, and 75%) with 0.9% saline, 5% albumin , and 6% hydroxyethyl starch (n = 20 for each diluent group). Measurem ents and Main Results: Thombelastographic parameters R (minutes), angl e alpha (degrees), MA (mm), and lysis (%) were measured and compared t o the sample control for each dilution of the same specimen. There was no significant difference between control groups in any thrombelastog raphic variable (R, angle alpha, MA, or lysis). No changes were seen i n any variable from any diluent at 11% hemodilution. Seventy-five perc ent hemodilution caused significantly hypocoagulable changes from cont rol for all thrombelastographic parameters for all three diluents. Thr ombelastographic indices differed significantly from controls at inter mediate hemodilutions. Both colloids caused decreases in measured angl e alpha and MA at lower hemodilution than did 0.9% saline. Albumin 5% caused significant hypocoagulable changes from control values at lower hemodilution than did either 0.9% saline or 6% hydroxyethyl starch fo r all thrombelastographic parameters. Saline 0.9% increased angle alph a significantly at 50% hemodilution. Abnormal lysis did not occur at a ny dilution. Differing ex vivo effects of three different intravascula r thrombelastography assessed coagulation are found. Conclusion: No di fferences were found after 11% hemodilution with any volume expanders. Hemodilution with up to 50 % saline maintained thrombelastographic in dices. Albumin produced early and profound hypocoagulable effects. Sig nificant hypocoagulability occurred for all three diluents at 75% hemo dilution. The study supports the use of albumin in patients at risk fo r thrombosis, and saline in patients with a need for normal hemostasis .