Plasma substitutes.
Explore the source record for details and available documents.
SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
OBJECTIVE: To investigate the influence of colloidal plasma substitutes on human cytokine network, especially of tumor necrosis factor alpha (TNF-alpha), in vitro. DESIGN: Heparinized whole blood samples from 8 healthy volunteers were divided and set on various concentrations of artificial colloidal plasma substitutes (native = 0 mg/ml; 5 mg/ml; 15 mg/ml). As colloids were used hydroxyethyl starch 200/0.5 (HES), dextran 60 (DX), urea-linked gelatin (GEL) and human albumin solution (HA). After incubation (24 h; 5% CO2; 37 degrees C; with and without concomitant stimulation of blood cells with phytohemagglutinin [PHA]) measurement of TNF-alpha release was performed via ELISA by the method described by Gallati. For the statistical evaluation a repeated measures analysis of variance was used. RESULTS: Basic level of TNF-alpha was found between 226 and 273 pg/ml (0 mg of each colloid/ml), stimulation with PHA without any colloid increased the TNF-alpha level about fourfold (1,066-1,260 pg/ml; 0 mg of each colloid/ml). At 5 mg/ml and 15 mg/ml without PHA all 3 artificial colloids rose the level of TNF-alpha (up to 50%). Under concomitant stimulation each colloid induced additional TNF-alpha release in comparison to PHA alone. The changes elicited by DX and GEL were statistically significant (p < 0.001 and p = 0.005, respectively) in contrast to those induced by human albumin solution or HES. CONCLUSION: In relation to TNF-alpha plasma substitutes are not inert substances as perhaps suspected. The questions whether the observed effects exist in vivo how far other cytokines are influenced and the question about the clinical importance are subject of ongoing studies.
The present experiments compare the relative effectiveness of several plasma substitutes to reverse a standardized intestinal ischemic shock in dogs and rats. The colloids were given 3.5% solutions in a dose of 1.5 g/kg = 43 ml/kg for dogs and 2 g/kg = 57 ml/kg for rats.. Ringer's solution was given in a three times larger volume. Colloids of 3.5%, 6%, and 10% concentrations and Ringer's acetate were also given in increasing volumes for a test of the dose, concentration, and volume relationships. Ringer's solution was effective during rapid infusion and for about 30 minutes after the infusion. Gelatin and ACD-plasma was of corresponding effectiveness for 2 hours. Albumin and dextran solutions maintained plasma volume, oxygen consumption for at least 4 hours after the infusion. Colloids were more effective than Ringer's solution at corresponding volumes, and even when three times larger volumes of the latter was given. Colloids of 3.5 and 6% were more effective than a 10% colloid solution. These effects were related to the molecular weight distribution for colloids, the plasma volume expansion duration and their red blood cell aggregation properties. It is concluded that as single infusions albumin, dextran 40, and dextran 70 are superior to ACD plasma, gelatin, and Ringer's acetate in restoring hemodynamic and metabolic functions and in improving survival rate.
The best strategy for volume therapy has been the focus of debate and there are still no unique accepted guidelines. There is increasing evidence that some plasma substitutes possess additional effects on organ perfusion, microcirculation, tissue oxygenation, inflammation, endothelial activation, capillary leakage, and tissue edema that are beyond their volume replacing properties. Whether the different plasma substitutes differ with regard this additional effects was reviewed. The additional effects of plasma substitutes have mostly been studied experimentally or in animals, much less results are available in humans. The results are not uniform ranging from beneficial to even detrimental effects of a certain volume replacement strategy. Some important results from the literature are not reflected in the actual recommendations for treating volume deficits in the critically ill: although crystalloids have been shown to have considerable negative effects on microcirculation, organ perfusion, tissue oxygenation, and endothelial integrity, they are still often recommended as first choice volume replacement strategy. In several experimental studies hypertonic solutions have been shown to have various beneficial effects, they have not been, however, translated into humans. In future, the choice of the ideal volume replacement regimen should not only be focused on its volume restoring properties, but additional effects (e.g. on organ perfusion on, tissue oxygenation, inflammation, endothelial activation, capillary leakage) should also be taken into account when treating hypovolemia in the critically ill.
In a total of 152 cases of severe cerebral infarction intravascular infusion of plasma substitutes was a part of combined therapy. Hemostasis studies in these patients allowed us to detect various degrees of hypercoagulation as a response to hemodilution. In cases of most pronounced post-hemodilution++ hypercoagulation (77 patients) complications, including those of thrombohemorrhagic nature, were increased in rate (74%) with more severe course of cerebral infarction. Of these 77 patients 46 died (59.7%). In 75 cases with no substantial hypercoagulation, the disease had a more benign course with 2 casulties (2.7%). The hemodilution tests should precede the therapeutic use of plasma substitutes in cerebral infarct patients.
Explore the source record for details and available documents.
The influence of the plasma substitute oxyamal on shifts in the water and acid-base balance of the blood was studied in experiments on dogs with simulated severe hemorrhagic shock. Oxyamal therapy of the severe hemorrhagic shock led to a stable reduction of the volume of circulating plasma and blood, and to a rapid normalization of blood circulation. No disorders were observed in the fluid distribution in the body, acid-base balance rapidly recovered that has evidenced a full-value transcapillary water-ion exchange.
This study was designed to compare the influence of various plasma substitutes, administered for preoperative hemodilution, on blood rheology. We studied 40 patients, ASA grade I, who underwent elective facial reconstructive surgery and received 4% albumin (n = 10), 3.5% dextran 40 (n = 10), gelatin (n = 10), or hydroxyethyl starch (HES) (n = 10). Ten patients, undergoing the same surgical procedure without hemodilution, were chosen as controls. After hemodilution, hematocrit was decreased approximately 30%. Fibrinogen decreased in all tested groups except in the gelatin group. Plasma viscosity decreased with albumin (1.13 +/- 0.05 to 1.06 +/- 0.03 mPa.s; P < 0.01) and increased with HES (1.15 +/- 0.04 to 1.22 +/- 0.05 mPa.s; P < 0.01). At a high shear rate, the blood viscosity decreased in all groups. In contrast, at a low shear rate and at 40% corrected hematocrit, the blood viscosity decreased in the albumin (15.9 +/- 1.9 to 13.1 +/- 2.1 mPa.s; P < 0.01) and the dextran 40 (16.9 +/- 2.9 to 12.8 +/- 2.5 mPa.s; P < 0.01) groups and was unchanged in the gelatin and the HES groups. Erythrocyte aggregation (measured with primary aggregation time) was markedly decreased in the albumin (3.27 +/- 1.74 to 7.03 +/- 2.95 s; P < 0.01) and in the dextran 40 (2.72 +/- 0.58 to 6.24 +/- 2.55 s; P < 0.001) groups, unchanged with HES, and increased with gelatin (2.41 +/- 0.90 to 1.55 +/- 0.33 s). These findings suggest that albumin and dextran 40 may be the plasma substitutes of choice for preoperative hemodilution when this technique aims to improve rheologic conditions.
OBJECTIVE: To evaluate the effects on hemostasis of three different plasma substitutes with special reference to a newly developed hydroxyethyl starch used as priming solution in an extracorporeal circuit as well as peri- and postoperative infusion fluid, we studied 36 patients randomly assigned to one of three groups, undergoing coronary artery bypass grafting. METHODS: The compositions of the priming solutions were: 2.5% hydroxyethyl starch; 3% gelatin; and 4% human albumin. Platelet function tests and clotting assays were performed on blood samples collected during and after cardiopulmonary bypass. RESULTS: We found that plasma von Willebrand Factor remained higher in the human albumin group. Hydroxyethyl starch preserved platelet agglutination as well as human albumin, whereas platelet aggregation induced by adenosine 5'-di phosphate (ADP) proved to be similarly affected during cardiopulmonary bypass in the three study groups. Prolongation of the in vitro bleeding constant during the bypass period and subsequent partial recovery showed an affected platelet function in all groups during cardiopulmonary bypass. The clotting times, activated partial thromboplastin time and prothrombin time were similar in the three groups. Blood loss, peri- and postoperatively, showed also no differences. Hydroxyethyl starch appeared most cost-effective as priming solution in an extracorporeal circuit. CONCLUSIONS: We conclude that, with human albumin the golden standard, 2.5% hydroxyethyl starch is a suitable colloid plasma substitute to be used as priming solution in an extracorporeal circuit as well as peri- and postoperative infusion fluid, reasonably well maintaining hemostasis.
The objective was to investigate in vivo the rheological effects of plasma substitutes (fluid gelatin, dextran 40, dextran 60, hydroxyethylstarch). The study was performed during a hypervolemic hemodilution in 60 adult volunteers who underwent an odontological surgery. Two control groups were infused with Ringer-Lactate or 4% human albumin. Each patient was infused with 500 ml of plasma substitute or control fluid. Blood samples were obtained at four different times: prior to (t0) and immediately after (t1) the infusion, then 3 hours (t2) and 24 hours (t3) after the hemodilution. At t1 and t2, plasma viscosity did not present important variations, except for the group infused with dextran 60 where a significant increase in plasma viscosity was observed. Blood viscosity and erythrocyte aggregation measurements were performed at hematocrit 40% to determine the intrinsic properties of substitute and eliminate the effects of hemodilution. Blood viscosity at high shear rates underwent minor variations in all groups. In contrast, blood viscosity at low shear rate and aggregation parameters exhibited important variations which markedly depended on the used substitute. The infusion of Ringer-Lactate, albumin and dextran 40 induced a significant decrease in blood viscosity and in erythrocyte aggregation. With dextran 60 and gelatin, blood viscosity and erythrocyte aggregation increased. Finally, the infusion with hydroxyethylstarch did not present important differences as compared to the results recorded at t0. Twenty for hours after the infusion, it should be noted an increase in plasma fibrinogen, probably due to surgery, which caused an increase in erythrocyte aggregation in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Explore the source record for details and available documents.