Effect of an equal volume replacement with 500 mL 6% hydroxyethyl starch on the blood and plasma volume of healthy volunteers.

The effect of an equal volume replacement with 6% low molecular weight (200,000) hydroxyethyl starch (substitution ratio 0.60-0.66) (Elohaes) on the blood volume and plasma volume of eight healthy volunteers was investigated with special attention to volume overshooting. After replacement of 500 mL whole blood, blood volume was measured repeatedly for 8 1/2 h using chromium-51 labelled erythrocytes. Red cell volume and plasma volume were calculated from standard formulae. After replacement, blood and plasma volumes were unchanged from control (4754 +/- 630 mL and 2900 +/- 450 mL, respectively). The haematocrit decreased from 43.7 +/- 2.5% to 39.0 +/- 1.4% (1 h after starch infusion) and 41.1 +/- 1.9% (7.5 h after starch infusion). There were no significant changes in haemodynamic variables (systolic and diastolic blood pressure; heart rate), liver function (bilirubin; transaminases), renal function (serum creatinine; serum sodium) or coagulation (activated partial thromboplastin time). Alpha-amylase was significantly increased, which is a well known effect of starches. The replacement of 500 mL whole blood by hydroxyethyl starch maintains isovolaemia for at least 8 h in normal volunteers without any significant volume overshooting; this is not what was seen in earlier studies. This should increase safety in patients with cardiac disease.