SummaryWe have compared the effects of progressive in vitro haemodilution (30% and 60%) with potato starch derived hydroxyethyl starch and corn starch derived hydroxyethyl starch on blood coagulation in 80 patients using thrombelastography. Both solutions significantly compromised blood coagulation as evidenced by an increase in coagulation time and decreases in angle a, maximum amplitude and coagulation index (p < 0.05). Blood coagulation was more compromised during haemodilution with potato starch derived hydroxyethyl starch as compared with corn starch derived hydroxyethyl starch (p < 0.05). When taking the effect of haemodilution with 0.9% saline into account, haemodilution with both hydroxyethyl starch solutions also augmented clot lysis (p < 0.05), with potato starch derived hydroxyethyl starch having a greater effect than corn starch derived hydroxyethyl starch (p < 0.05). We conclude that potato starch derived hydroxyethyl starch compromises in vitro blood coagulation more than corn starch derived hydroxyethyl starch. Avoiding allogeneic blood transfusion has become an important issue in surgery and intensive care medicine with increasing awareness of the potential side-effects [1,2]. Besides transmission of infectious diseases, the increased incidence of postoperative infections with prolonged hospitalisation and increased costs [3] has recently created much interest. As a consequence, allogeneic blood transfusions are being withheld longer and volume replacement is performed using larger quantities of crystalloids and colloids. However, crystalloids and colloids affect blood coagulation, inducing hypercoagulable and hypocoagulable states [4][5][6][7]. Knowledge of the effects of different colloids on blood coagulation is therefore of clinical relevance.The present study was designed to investigate the effects on in vitro blood coagulation of a newly developed potato starch derived hydroxyethyl starch (HES) and to compare these effects with those of the traditional corn starch derived HES, as assessed by thrombelastography (TEG) [6,7]. Since it is important to differentiate between a haemodilutional effect per se and an intrinsic colloidal effect of different HES solutions, we simultaneously compared TEG parameters of native blood, blood diluted with 0.9% saline and blood diluted with potato starch derived HES and corn starch derived HES.
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