REASONS FOR PERFORMING STUDY : Clinical indications for hydroxyethyl starches (HES)
in horses include rapid plasma volume expansion and oncotic support during periods
of hypoproteinaemia. Side effects such as coagulopathies associated with HES
administration pose limitations to their use in veterinary medicine. In humans,
tetrastarch [hydroxyethyl starch (130/0.4)] has demonstrated less profound effects on
coagulation compared to 1st and 2nd generation HES.
OBJECTIVES : To evaluate the haemostatic and oncotic effects of tetrastarch (130/0.4)
administered at 10, 20 and 40 ml/kg bwt in healthy horses.
Study design: Randomised crossover study design.
METHODS : Tetrastarch (130/0.4) was administered to 6 healthy pony mares at 10, 20
and 40 ml/kg bwt with a 2-week washout period. Packed cell volume (PCV), total
solids (TS), plasma colloid oncotic pressure (pCOP), platelet count and
thromboelastography (TEG) was measured at baseline, immediately after infusion (0
h), 1, 6, 12, 24, 48, and 96 h after tetrastarch infusion.
RESULTS : All TEG variables remained within normal reference ranges in all 3
treatment groups. Administration of tetrastarch at 40 ml/kg bwt resulted in a
prolonged K-time (P=0.049) at 6 h post-infusion, and decreased maximum amplitude
at 0 (P<0.001), 1 (P=0.022), 6 (P=0.006), 24 (P<0.001) and 48 h (P=0.013) postinfusion
compared to baseline. Administration of tetrastarch increased mean pCOP
values above baseline in all 3 treatment groups, persisting to 24, 6 and 48 h for the 10,
20 and 40 ml/kg bwt dose respectively.
CONCLUSION : Although still within established reference ranges, compared to lower
dosages, the administration of 40 ml/kg bwt tetrastarch (130/0.4) is more likely to induce changes in coagu lation as measured by TEG. Tetrastarch increased pCOP at all
dosages evaluated in healthy horses.