The effects of hydroxyethyl starch (HES) on hemostasis were investigated extensively. In order to simulate acute blood loss due to surgery or trauma, one unit (450 ml) of blood was drawn from normal healthy men. This was followed by a 1-liter infusion over 60 minutes of either 6 percent HES, 5 percent albumin, or 0.9 percent sodium chloride (NaCl) as replacement. Coagulation studies were performed before phlebotomy, before infusion and at 0, 4, 20, 27, and 92 hours following infusion. Following infusion of HES and albumin, plasma fibrinogen and antithrombin-III levels fell slightly due to plasma volume expansion and hemodilution. In subjects receiving HES, partial thromboplastin times (PTTs) were significantly (p less than .05) prolonged and factor VIII activities were significantly (p less than .05) decreased when compared to the albumin and NaCl groups. These findings could not be attributed solely to hemodilution. The effects of HES on PTT and factor VIII could not be correlated with plasma HES levels; neither could they be reproduced in vitro by mixing HES with normal plasma. Mean values of the following studies remained normal after infusion of all replacement fluids: prothrombin time, bleeding time, fibrin monomer, fibrin-fibrinogen degradation products, platelet adhesion, circulating platelet aggregates, and platelet count.(ABSTRACT TRUNCATED AT 250 WORDS)

Red cells preserved in extended-storage media are the standard product dispensed by many regional blood centers. When the red cells are intended for neonatal transfusion, concern exists about the safety of the relatively high quantities of additives present in these media. Definitive studies to address these concerns are not available. Therefore, to estimate the effects of additives and to delineate circumstances in which they might be harmful, the quantities transfused in defined clinical settings were calculated, and the following recommendations are offered for transfusing infants less than 4 months of age. First, red cells preserved in extended-storage media should present no substantive risks when used for small-volume (approximately 10 mL/kg) transfusions of premature infants and can be used without additional processing. Second, the risks of the most premature neonatal patients or those with severe renal and/or hepatic insufficiency cannot be defined clearly, and, because data are not available to ensure safety for these infants, removal of the additive medium and resuspension of the red cells in saline or albumin solution immediately before transfusion are recommended. Third, following a similar rationale, it seems prudent to avoid using entire units of red cells preserved in extended-storage media in massive transfusion settings (e.g., exchange transfusion, cardiac surgery, and extracorporeal membrane oxygenation). In these settings, the preservative medium should be removed and the red cells resuspended in the fluid that is most appropriate for the procedure that is planned. It must be emphasized that these recommendations are based on calculations and hypothetical settings, not actual data. Accordingly, they are tentative and should be altered as definitive information becomes available.

Studies of risk factors associated with reactions among autologous blood donors have been limited. Therefore, 2091 autologous and 4737 homologous donations were examined. Donors at greatest risk for reaction were autologous donors who had reactions at first donation; among 45 who made repeat donations for the same surgery, 17 (38%) had repeat reactions. The group least likely to experience reactions were the autologous donors greater than or equal to 66 years old; they experienced a 1.9 greater than or equal to percent (6/310) incidence of reactions. More reactions were seen in both autologous and homologous donors in the categories of first-time donor, female gender, decreasing age, and lower weight. Multiple logistic regression analysis showed that all of these variables were independent predictors of donor reaction, with first-time donation (odds ratio, 2.4) and female gender (odds ratio, 1.9) being the strongest predictors of reaction. Donor room personnel should be alerted that autologous donors who react at first donation are very likely to react at subsequent donations. Contrary to common concern, elderly autologous donors are least likely to have reactions.

The literature related to the effects of hydroxyethyl starch on blood coagulation was reviewed to determine whether or not recipients are placed at risk of hemorrhage or thrombosis. Effects on coagulation observed when blood and HES were mixed in vitro were trivial and seemed related simply to dilution. HES affected coagulation in vivo in a dose-related fashion. When infused in moderate amounts (as employed in leukapheresis), HES rarely, if ever, caused overt bleeding, and only minor changes of laboratory coagulation tests were detected. Following massive infusions, however, a wide variety of laboratory abnormalities were observed, and hemorrhage was documented in some reports. It must be emphasized that information is limited. Not all investigators employed a complete battery of modern techniques; data regarding massive infusions are derived almost exclusively from animal studies; and data are insufficient to determine the effects of HES on thrombosis. Additional studies are required to completely define the relationship between HES and coagulation in man.

We compared changes in muscle sympathetic nerve activity (SNA) during graded lower body negative pressure (LBNP) and 450 ml of hemorrhage in nine healthy volunteers. During LBNP, central venous pressure (CVP) decreased from 6.1 +/- 0.4 to 4.5 +/- 0.5 (LBNP -5 mmHg), 3.4 +/- 0.6 (LBNP -10 mmHg), and 2.3 +/- 0.6 mmHg (LBNP -15 mmHg), and there were progressive increases in SNA at each level of LBNP. The slope relating percent change in SNA to change in CVP during LBNP (mean +/- SE) was 27 +/- 11%/mmHg. Hemorrhage of 450 ml at a mean rate of 71 +/- 5 ml/min decreased CVP from 6.1 +/- 0.5 to 3.7 +/- 0.5 mmHg and increased SNA by 47 +/- 11%. The increase in SNA during hemorrhage was not significantly different from the increase in SNA predicted by the slope relating percent change in SNA to change in CVP during LBNP. These data show that nonhypotensive hemorrhage causes sympathoexcitation and that sympathetic responses to LBNP and nonhypotensive hemorrhage are similar in humans.