Coagulation effects of in vitro serial haemodilution with a balanced electrolyte hetastarch solution compared with a saline‐based hetastarch solution and lactated Ringer's solution*

Abstract

SummaryThe hydroxyethyl starches are a group of compounds that has been associated with impairment of coagulation when large volumes are administered. The thrombelastographÒ is commonly used to assess point-of-care whole blood coagulation. Little is known about the dose-response relationships of haemodilution, and it is reasonable to assume that a linear association exists. This may not be the case with altered electrolyte compositions of the fluids used for haemodilution. We have therefore conducted an in vitro study of haemodilution of human whole blood using lactated Ringer's solution and two high molecular weight hetastarches, one in a balanced salt solution, the other in a 0.9% saline solution. The thrombelastographÒ, commonly used for the assessment of the coagulation effects of synthetic colloids, was used as the coagulation assessment device. Serial haemodilution with hetastarch in a balanced salt solution demonstrated a biphasic response (of r-times and k-times, as well as alpha angles), with haemodilution in the 20-40% range causing enhanced coagulation, and higher degrees of dilution causing a decrease in overall coagulation performance. A similar picture was observed with lactated Ringer's solution, but only significantly so in alpha angles. Hetastarch in saline did not display this initial increased coagulability at mild to moderate dilutions. This biphasic response of lactated Ringer's solution and hetastarch in a balanced salt solution reflects the complex interaction of fluids and the coagulation system, and that these effects cannot be attributed to simple haemodilution. On the other hand, there was a linear decrease in maximum amplitude with haemodilution. Maximum amplitude was particularly affected by both starches, which is an expected finding in view of the known interaction between the hydroxyethyl starches and von Willebrand's factor.

The Colloid Crystalloid Debate: Are We Asking the Right Question?

“…[102][103][104][105] This TEG pattern is compatible with hemodilutional coagulopathy and platelet dysfunction. 106 Recently, a comparison of the in vivo effect of high, middle and low-MW HES solutions on TEG variables showed prolongation of reaction time with HES 450/0.7/4.6 and deterioration of platelet function with HES 450/0.7/4.6 and HES 70/0.5/4.…”

Coagulation and biochemical effects of balanced salt‐based high molecular weight vs saline‐based low molecular weight hydroxyethyl starch solutions during the anhepatic period of liver transplantation

“…Interestingly, this type of biphasic coagulation activity is rarely observed in in vivo studies even at mild haemodilution with HES solutions [22]. Less deterioration of thromboelastography in the high MW group might be due to balanced-salt medium containing Ca 2+ [23]. High MW and high DS HES molecules require more time to be hydrolysed by amylase into smaller molecules.…”

“…Martin et al [14] reported that a bhHES is not associated with any significant changes in the coagulation profile compared with its saline-based counterpart, which showed hypocoagulation. Moreover, Roche et al [23] asserted that the bhHES enhanced coagulation at 20-40% haemodilution, whereas the saline-based counterpart did not show this initial increase of coagulability. It can therefore be deduced that the lesser deterioration of thromboelastography in the high MW group might be ascribed to the balanced salt-medium, although they compared the same high MW and high DS HES solutions with or without balanced-salt medium.…”

The effect of serial in vitro haemodilution with maternal cerebrospinal fluid and crystalloid on thromboelastographic (TEG®) blood coagulation parameters, and the implications for epidural blood patching

“…When considering the effect of CSF on whole blood, we only concentrated on a dilution of up to 30%. From previous work by Roche et al, with lactated Ringer's solution, a procoagulant effect was seen with up to 40% dilution, yet further dilution resulted in a reduction in coagulation [28]. This may suggest that as large a volume of blood as possible (20 ml) should be injected, as even if the CSF leak is small (up to 10 ml), this may represent up to a maximum of 30% haemodilution, allowing for uniform distribution of CSF.…”