Pharmacodynamics and tolerability of acetyl starch as a new plasma volume expander in patients undergoing elective surgery.

Objective: Acetyl starch (ACS) is a new synthetic colloid solution for plasma volume expansion and is now undergoing phase II clinical trials. We compared the pharmacodynamics and tolerability of ACS with those ofhydroxyethyl starch (HES) in 32 patients (American Society of Anesthesiologists physical status I and II) undergoing elective surgery. Subjects, material and methods: In this prospective, randomized, double-blind trial patients received either 15 ml/kg ACS 6% (average molecular weight (Mw) 200,000/ molar substitution (MS) 0.5) or HES 6% (Mw 200,000/ MS 0.5) i.v. up to a maximum dose of 1000 ml. Hemodynamic parameters, rheologic parameters, volume effect, acid-base status as well as effects on hemostasis were studied. Results: After infusion of ACS and HES there was a similar increase in central venous pressure and mean arterial pressure in both groups. Acid-base status was not significantly altered after the end of the colloid infusions. After ACS infusion, plasma acetate concentration increased from 0.13 ± 0.16 mg/dl to 2.87 ± 1.13 mg/dl, however, after 24 h there was no significant difference in plasma acetate concentration compared to HES. The volume effect ranged from 104 - 116% (ACS) and from 88 - 118% (HES) of the colloid dose administered. These differences were not statistically significant. Partial thromboplastin time (aPTT) was only slightly increased after ACS infusion (from 38.6 ± 5.7 sec to 41.4 ± 5. I sec), but was significantly increased after HES infusion (from 38.7 ± 5.7 sec to 46.1 ± 7.0 sec). Conclusions ACS and HES are equally effective plasma volume expanders; ACS might be a new, alternative colloid solution with fewer coagulation side-effects than HES.