Medium Molecular Hydroxyethyl Starch Research Articles

Microparticle-Containing Oncotic Solutions Augment In-vitro Clot Disruption by Ultrasound

Echocardiographic contrast agents enhance blood clot disruption by ultrasound. It has been suggested that the microbubbles add nuclei for the enhancement of cavitation by ultrasound. However, microbubbles are rapidly destroyed by the ultrasound energy. We assessed whether non-gas filled colloidal solutions (hyperoncotic medium molecular hydroxyethyl starch and degraded gelatin polypeptides) will facilitate clot disruption by ultrasound. In two separate experiments human blood clots, 200–400 mg in weight, were weighed and then immersed for 15 seconds in 10 ml normal saline solution containing 0%, 0.1%, 1%, 2%, and 5% of hyperoncotic medium molecular hydroxyethyl starch or 0%, 0.035%, 0.175%, 0.35%, and 0.7% degraded gelatin polypeptides. Clots were randomized to 10 seconds 20 kHz ultrasound or immersion without ultrasound. After treatment, the clots were re-weighed, and the percent difference in weight was calculated. Non-gas filled microparticle-containing solutions such as hyperoncotic medium molecular hydroxyethyl starch and degraded gelatin polypeptides significantly augmented blood clot disruption by ultrasound. The effect is dependent on the colloidal solution concentration with maximal effect achieved with 1% hyperoncotic medium molecular hydroxyethyl starch and 0.35% degraded gelatin polypeptides.

In Vitro Effects of Different Medium Molecular Hydroxyethyl Starch Solutions and Lactated Ringer’s Solution on Coagulation Using SONOCLOT

Hydroxyethyl starch (HES) solutions are widely used to replace intravascular volume. HES solutions differ from each other with regard to molecular weight and mode of hydroxyl substitution (degree of hydroxylation, C2:C6 hydroxyethyl ratio, concentration), factors which may have varying effects on coagulation. We studied, in vitro, three different HES preparations (molecular weight/degree of hydroxylation/concentration/C2:C6 ratio of substitution 70.000/0. 5/6%/3.2; Pharmacia & Upjohn Co., Erlangen, Germany; 130.000/0. 4/6%/11.2 and 200.000/0.5/6%/4.6; Fresenius Co., Bad Homburg, Germany) and, for comparison, lactated Ringer's solution (RL) at 33% and 66% dilution with whole blood. The influence of hemodilution was measured by using routine laboratory variables and SONOCLOT (Sonoclot II Coagulation and Platelet Function Analyzer, Sienco Co.) analysis, using a viscoelastic test, on the cellular as well as on the plasmatic hemostatic system. For statistical analysis of quantitative data, we used nonparametric analysis of variance and adequate post hoc tests. Qualitative data were analyzed by using the nonparametric Kruskal-Wallis test. A P value below 0.05 was considered significant. In contrast to the control group with RL, the liquid phase of coagulation (activated clotting time) was slightly affected by the 33% diluted HES solutions. HES 70.000, 130. 000, and 200.000 interfered significantly with the early stage of coagulation as expressed by the clot rate (gel/fibrin formation). Clot maturation and speed of maturation (time to peak) were strongly affected by HES 70.000 at all grades of dilution. HES 130.000 showed a faster clot formation process compared with the other HES solutions. HES 130.000 diluted 33% showed a better clot retraction as compared with the other HES solutions. In conclusion, in vitro hemodilution comparing different medium molecular weight HES solutions reveals that HES 130.000 seems preferable regarding some aspects of clot formation and retraction. RL affected clot formation only minimally, except for the early activation of clotting, which was measured by a shortened activated clotting time. We investigated the effect of different hydroxyethyl starch (HES) solutions (70.000, 130.000, 200.000) on coagulation. Regarding clot formation and retraction, HES 130.000 had some advantages over the other tested HES solutions. Lactated Ringer's solution affected coagulation only minimally, except for the early stage of clot formation.

In Vitro Effects of Different Medium Molecular Hydroxyethyl Starch Solutions and Lactated Ringer’s Solution on Coagulation Using SONOCLOT

Hydroxyethyl starch (HES) solutions are widely used to replace intravascular volume. HES solutions differ from each other with regard to molecular weight and mode of hydroxyl substitution (degree of hydroxylation, C2:C6 hydroxyethyl ratio, concentration), factors which may have varying effects on coagulation. We studied, in vitro, three different HES preparations (molecular weight/degree of hydroxylation/concentration/C2:C6 ratio of substitution 70.000/0.5/6%/3.2; Pharmacia & Upjohn Co., Erlangen, Germany; 130.000/0.4/6%/11.2 and 200.000/0.5/6%/4.6; Fresenius Co., Bad Homburg, Germany) and, for comparison, lactated Ringer’s solution (RL) at 33% and 66% dilution with whole blood. The influence of hemodilution was measured by using routine laboratory variables and SONOCLOT (Sonoclot II Coagulation and Platelet Function Analyzer, Sienco Co.) analysis, using a viscoelastic test, on the cellular as well as on the plasmatic hemostatic system. For statistical analysis of quantitative data, we used nonparametric analysis of variance and adequate post hoc tests. Qualitative data were analyzed by using the nonparametric Kruskal-Wallis test. A P value below 0.05 was considered significant. In contrast to the control group with RL, the liquid phase of coagulation (activated clotting time) was slightly affected by the 33% diluted HES solutions. HES 70.000, 130.000, and 200.000 interfered significantly with the early stage of coagulation as expressed by the clot rate (gel/fibrin formation). Clot maturation and speed of maturation (time to peak) were strongly affected by HES 70.000 at all grades of dilution. HES 130.000 showed a faster clot formation process compared with the other HES solutions. HES 130.000 diluted 33% showed a better clot retraction as compared with the other HES solutions. In conclusion, in vitro hemodilution comparing different medium molecular weight HES solutions reveals that HES 130.000 seems preferable regarding some aspects of clot formation and retraction. RL affected clot formation only minimally, except for the early activation of clotting, which was measured by a shortened activated clotting time. Implications We investigated the effect of different hydroxyethyl starch (HES) solutions (70.000, 130.000, 200.000) on coagulation. Regarding clot formation and retraction, HES 130.000 had some advantages over the other tested HES solutions. Lactated Ringer’s solution affected coagulation only minimally, except for the early stage of clot formation.

Large-Dose Administration of 6% Hydroxyethyl Starch 200/0.5 for Total Hip Arthroplasty

Within a daily dose of 20 mL/kg, medium-molecular hydroxyethyl starch (HES) is a safe and effective colloid for intravascular blood volume replacement. The effect of large doses on coagulation and renal function is unknown. We prospectively studied 41 patients undergoing total hip arthroplasty during the perioperative period. Inevitable blood loss was replaced with HES (HES group) or albumin (ALB group) in combination with packed red blood cells (PRBC), fresh frozen plasma (FFP), and platelets. Hemodynamic, oncotic, coagulation, and renal functions were compared initially, at the end of surgery, during the postoperative period (1, 3, and 6 h), and also with respect to the volume of colloid solution administered (1500, 2000, and 3000 mL). Total intake and output balances, as well as the costs of blood replacement therapy, were registered at the end of the study. We found differences in oncotic variables even at 6 h after surgery (total serum proteins [TSP]: HES 36.4 +/- 7.9 g/L versus ALB 55.6 +/- 6.1 g/L, P < 0.01; serum albumin: HES 25.5 +/- 5.3 g/L versus ALB 42.0 +/- 5.6 g/L, P < 0.01). Colloid osmotic pressure (COP) and hemodynamic, coagulation, and renal functions were comparable, as was total blood loss (HES 4247 +/- 2090 mL versus ALB 4051 +/- 2830 mL). Total requirements for colloid solutions (HES 35.9 +/- 7.4 mL/kg versus ALB 33.9 +/- 10.5 mL/kg), PRBC, FFP, or platelets were comparable, whereas total cost of blood replacement therapy was 33% less in the HES group. With respect to efficacy and side effects on coagulation and renal function, medium molecular HES is an appropriate and economic alternative to albumin at daily doses of up to at least 36 mL/kg. (Anesth Analg 1996;83:262-8)