Extreme, progressive isovolemic hemodilution with 5% human albumin, PentaLyte, or Hextend does not cause hepatic ischemia or histologic injury in rabbits.
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BACKGROUND: Physicians and their patients are greatly concerned about perioperative blood administration. Although isovolemic hemodilution is utilized to decrease the incidence of transfusion, it is unclear at what degree of hemodilution hepatoenteric ischemia and injury occurs. The authors hypothesized that hepatic ischemia, systemic ischemia, and tissue injury would occur during hemodilution in rabbits, and that the severity of ischemia and injury may be dependent on the fluid administered. METHODS: Rabbits anesthetized with isoflurane were assigned randomly to a sham-operated group (n = 8) or groups that underwent four isovolemic hemodilutions (25% of the blood volume removed at hourly intervals), with blood replaced with one of three solutions: balanced electrolyte solutions containing 6% pentastarch (n = 8), 6% hetastarch (n = 9), or 5% human albumin in normal saline (n = 8). Arterial ketone body ratio and plasma lactate, respectively, served as measures of hepatic and systemic ischemia. Gastric, duodenal, and hepatic histologic injury was assessed post mortem. RESULTS: Hemodilution from a baseline hematocrit of about 33% to about 8% (third hemodilution) with all three colloids did not result in a significant increase in plasma lactate concentration or decrease in arterial ketone body ratio. At a hematocrit of about 5% (fourth hemodilution), the hetastarch group had a significantly (P < 0.05) greater plasma lactate concentration than the sham-operated and 5% human albumin groups. There were no significant differences in arterial ketone body ratio or histologic injury between the groups. CONCLUSIONS: Isovolemic hemodilution (approximately 5% hematocrit) with albumin, pentastarch, or hetastarch solutions does not result in significant hepatic ischemia or injury assessed by histology. (+info)
Effect of intravenous saline, albumin, or hydroxyethylstarch on blood volume during combined ultrafiltration and hemodialysis.
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It is generally advocated to use saline or albumin infusions during symptomatic hypotension during dialysis. However, because of their side effects and/or costs, they are of limited use. Hydroxyethylstarch (HES), a synthetic colloid with a long-standing volume effect, is used in the management of hypovolemia. In this study, the efficacy of three fluids (isotonic saline [0.9%], albumin [20%], and HES [10%]) was assessed during three treatment sessions with combined ultrafiltration and hemodialysis, which differed in the type of fluid given intravenously. Changes in relative blood volume (BV), systolic BP (SBP), and vascular reactivity (venous tone [VT]) were compared. An intravenous infusion of 100 ml of fluid was given when the decrease in BV versus baseline was more than 10% as measured by a continuous optical reflection method. The ultrafiltration was continued. BV decreased significantly versus baseline independent of the intravenous fluid administration in all three treatment sessions. However, when we compared BV values at the end of the dialysis session with those at the time of infusion, BV continued to decrease significantly with saline (change in BV -4.56 +/- 2.75%; P < 0.05) and albumin (change in BV -2.13 +/- 2.51%; P < 0.05), but not with HES (change in BV -0.15 +/- 2.17%; NS). Between albumin and HES there were no significant differences in changes in BV (NS), whereas between HES and saline (P < 0.05) and between albumin and saline (P < 0.05) the differences in BV changes were significant. SBP remained unchanged within each session. Although SBP tended to decrease more with saline compared to albumin and HES, the difference was not significant. The higher decrease in BV and SBP with saline was counterbalanced by a significantly higher increase in VT, while VT remained unchanged in the other two sessions. It is concluded that HES is a promising fluid in preserving blood volume, comparable to albumin, but superior to saline. (+info)
Thrombelastogram reveals hypercoagulability after administration of gelatin solution.
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We have compared the effects of gelatin, low molecular weight hydroxyethyl starch (HES) or albumin on tests of haemostasis and on the thrombelastogram in 42 ASA I patients undergoing total hip or knee replacement. Patients were allocated randomly to receive one of the three blood substitutes to obtain moderate intraoperative haemodilution. Blood loss and packed red cell infusion was the same in each group. A greater amount of gelatin was given (1.5 times the measured blood loss) because of its shorter half-life. There was a statistically significant but clinically negligible decrease in platelets count, prothrombin time and fibrinogen, and an increase in bleeding time in all groups. Platelets were slightly but significantly lower after HES. Haemodilution was comparable between groups. TEG showed a state of hypercoagulability in the gelatin group with a significant decrease in r, r + k and an increase in alpha angle. (+info)
Hydroxyethyl starch does not impair immediate renal function in kidney transplant recipients: a retrospective, multicentre analysis.
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BACKGROUND: The effect of hydroxyethyl starch (HES) on early allograft function was examined retrospectively in a cohort of 119 renal transplantations realized by local organ exchange between four cooperating centres. METHODS: After exclusions, 109 transplant procedures were subdivided in three groups according to donor colloid loading: (i) HS-group (Haes steril 6%, mean volume (SD): 979 (946) ml, n = 20); (ii) PS-group [Plasmasteril, mean volume (SD): 769 (411) ml, n = 16]; and (iii) control group (gelatin albumin, n=73). RESULTS: Delayed graft function (DGF), defined as the need for dialysis during the first post-transplant week, occurred in 3/20 (15%) cases in the HS-group, in 5/16 (31%) cases in the PS-group and in 14/73 (19%) cases in the control group (P = 0.450). Uni- and multivariate analysis revealed older donor age (P = 0.001) and kidney preservation with histidine-tryptophan-ketoglutarate (HTK) (P = 0.001) as the only factors associated with a higher incidence of DGF. CONCLUSIONS: Renal function as measured by daily serum creatinine concentration and 24 h urinary output up to 14 days post-transplantation in the HS-group was comparable with that of controls. The higher serum creatinine observed during the first seven post-transplant days in the PS-group could be related to higher donor age and haemodynamic instability, and recipient male preponderance, rather than to HES itself. (+info)
Tissue deposits of hydroxyethyl starch (HES): dose-dependent and time-related.
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Tissue deposits occur after administration of plasma substitutes. After hydroxyethyl starch (HES), deposits may last for months, causing pruritus and impairment of function. Because elimination of HES deposits has not been demonstrated in humans, we studied 26 patients, for up to 7 yr after HES administration, to assess HES storage. HES dose ranged from 0.34 to 15.00 g kg-1 body weight, and administration intervals from 1 day to 7 yr. Biopsies of the liver, muscle, spleen, intestine or skin were studied using light and electron microscopy and immunohistochemistry. HES storage was dose-dependent, decreased in all organs with time and was greater in patients suffering from pruritus. We conclude that tissue deposition of HES is transitory and dose-dependent, with differences between subjects in severity and duration. (+info)
Preparation and characterization of microencapsulated proteinase inhibitor aprotinin.
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Preparation of microcapsules through interfacial cross-linking of soluble starch/hydroxyethyl starch and bovine serum albumin (BSA) with terephthaloyl chloride is described. The proteinase inhibitor aprotinin, either native or active site protected, was microencapsulated, being incorporated in the aqueous phase. The influence of aqueous phase pH, BSA, and terephthaloyl chloride concentrations as well as stirring rate on microcapsule morphology and size was studied. The polycondensation pH was shown to be the determining factor for tough microcapsule production with a high encapsulation yield. The size of the microcapsules ranged between 10-30 and 50-100 microm at stirring speed 1500 and 500 rpm, respectively. Fourier transform infrared spectroscopic studies were performed on microcapsules prepared under various conditions. A correlation was established between spectral changes and microcapsule morphology and size. The optimal conditions for microcapsule degradation by alpha-amylase were found. Active site-protected aprotinin was shown to fully retain its activity after microencapsulation. (+info)
Effects of crystalloid and colloid preload on blood volume in the parturient undergoing spinal anesthesia for elective Cesarean section.
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BACKGROUND: The role of crystalloid preloading to prevent hypotension associated with spinal anesthesia in parturients during cesarean section has been challenged. Direct measurement of blood volume should provide insight regarding the volume-expanding effects. The aim of the current study was to clarify the effects of volume preload with either crystalloid or colloid solution on the changes in blood volume of parturients undergoing spinal anesthesia for cesarean section. METHODS: Thirty-six healthy parturients scheduled for elective cesarean section during spinal anesthesia were allocated randomly to one of three groups receiving 1.5 l lactated Ringer's solution (LR; n = 12), 0.5 l hydroxyethylstarch solution, 6% (0.5 l HES; n = 12), and 1.0 l hydroxyethylstarch solution, 6% (1.0 l HES; n = 12), respectively. Blood volume and cardiac output were measured before and after volume preloading with indocyanine green (ICG), and the indocyanine green blood concentrations were monitored by noninvasive pulse spectrophotometry. RESULTS: After volume preload, the blood volume significantly increased in all three groups (P < 0.01). The volume of infused solution remaining in the vascular space in the LR, 0.5-l HES, and 1.0-l HES groups were 0.43+/-0.20 l, 0.54+/-0.14 l, and 1.03+/-0.21 l, respectively, corresponding to 28% of lactated Ringer's solution and 100% of hydroxyethylstarch solution infused. Significant increases in cardiac output were observed in the 0.5-l and 1.0-l HES groups (P < 0.01). A significant correlation between the percentage increase in blood volume and that of cardiac output was observed by volume preloading (r2 = 0.838; P < 0.001). The incidence of hypotension was 75% for the LR group, 58% for the 0.5-l HES group, and 17% for the 1.0-l HES group, respectively. CONCLUSIONS: The incidence of hypotension developed in the 1.0-l HES group was significantly lower than that in the LR and 0.5-l HES groups, showing that greater volume expansion results in less hypotension. This result indicates that the augmentation of blood volume with preloading, regardless of the fluid used, must be large enough to result in a significant increase in cardiac output for effective prevention of hypotension. (+info)
Plant fructans stabilize phosphatidylcholine liposomes during freeze-drying.
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Fructans have been implicated as protective agents in the drought and freezing tolerance of many plant species. A direct proof of their ability to stabilize biological structures under stress conditions, however, is still lacking. Here we show that inulins (linear fructose polymers) isolated from chicory roots and dahlia tubers stabilize egg phosphatidylcholine large unilamellar vesicles during freeze-drying, while another polysaccharide, hydroxyethyl starch, was completely ineffective. Liposome stability was assessed after rehydration by measuring retention of the soluble fluorescent dye carboxyfluorescein and bilayer fusion. Inulin was an especially effective stabilizer in combination with glucose. Analysis by HPLC showed that the commercial inulin preparations used in our study contained no low molecular mass sugars that could be responsible for the observed stabilizing effect of the fructans. Fourier transform infrared spectroscopy showed a reduction of the gel to liquid-crystalline phase transition temperature of dry egg PtdCho by more than 20 degrees C in the presence of inulin. A direct interaction of inulin with the phospholipid in the dry state was also indicated by dramatic differences in the phosphate asymmetric stretch region of the infrared spectrum between samples with and without the polysaccharide. (+info)