Shock : molecular, cellular, and systemic pathobiological aspects and therapeutic approaches : the official journal the Shock Society, the European Shock Society, the Brazilian Shock Society, the International Federation of Shock Societies
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Comparative Study
The renal effects of 7.5% NaCl-6% dextran-70 versus lactated Ringer's resuscitation of hemorrhage in dehydrated sheep.
A small volume of 7.5% NaCl/6% Dextran-70 (HSD) can rapidly expand the plasma volume, but concerns exist regarding its adverse effects on renal function in the dehydrated state. Sheep were thirsted for 4 days (13% plasma volume contraction), and subjected to a fixed-pressure shock model (mean arterial pressure of 50 mmHg for 2 h), followed by resuscitation with either HSD (4 mL/kg) or lactated Ringer's solution (LR; 37 mL/kg). Mean arterial pressure was restored to 90%, cardiac output to 125% and 120%, and plasma volume to 78% and 72% of baseline in LR and HSD groups, respectively. ⋯ No significant urinary 70,000 molecular weight dextran was observed, suggesting an intact renal glomerular membrane. These data suggest that small volume HSD resuscitation is effective, even with pre-existing dehydration. In addition, renal function is not compromised by HSD resuscitation of hemorrhaged, dehydrated animals.
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The toxicity of D-lactate has been recognized for almost 30 years. This compound is found in the racemic mixture of lactated Ringer's solutions routinely used for peritoneal dialysis and the resuscitation of trauma victims. The current study was designed to investigate whether toxicity occurred at the D-lactate concentrations achieved during hemorrhage resuscitation with racemic lactated Ringer's solution. ⋯ Resuscitation with the racemic lactate mixture increased the D-lactate concentrations in the blood, but was not associated with overt changes in cardiac rhythm. The infusion of the different resuscitation fluids produced few significant differences in acid-base status of hemorrhaged rats. These findings indicate that although toxicity may be achieved with a Ringer's solution containing only D-lactate, resuscitation using the racemic mixture does not achieve D-lactate concentrations high enough to be detrimental to the animal.
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Clinical Trial Controlled Clinical Trial
Alterations in coagulation and fibrinolysis during sepsis.
Circulating levels of thrombin-antithrombin III complex (TAT) and plasmin-alpha 2 plasmin inhibitor complex (PIC) in 49 septic patients (23 patients with organ dysfunction (OD), 26 without OD) and 11 postgastrectomy patients were measured to determine the significance of the coagulation-fibrinolytic systems in the development of OD. Tissue plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), and thrombomodulin were also measured. The mean level of TAT on the day when OD occurred was significantly higher compared with the maximum level of TAT in septic patients without OD (P < .01) or postoperative patients (P < .01). ⋯ Septic patients with OD showed higher levels of PAI-1 (P < .001) but not of t-PA. Thrombomodulin levels were significantly higher in the septic patients with OD compared with the others (P < .001). We conclude that suppression of the fibrinolytic system contributes to the imbalance between coagulation and fibrinolysis, and that this hypercoagulable millieu on the endothelial surface leads to the onset of OD.
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The role of isolated blood transfusion as a means toward improving oxygen transport was evaluated in 19 critically ill patients having sepsis syndrome as defined by standard criteria. ICU therapies were unchanged during transfusion and hemodynamic profiles with serum lactate levels were obtained before and after packed red blood cells were given. ⋯ Oxygen uptake failed to increase with transfusion, corresponding to increased arterial and mixed venous oxygen content. In the presence of sepsis, patients having oxygen delivery and uptake above normal without evidence of ischemia (normal lactate) will not increase oxygen consumption by raising the hemoglobin.
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Porcine hypodynamic shock was induced by continuous infusion of 5 micrograms lipopolysaccharide/kg per hour. This resulted in a decrease of cardiac output from baseline values of 3.5 +/- .9 L/min to 1.5 +/- .8 L/min and a reduced left ventricular stroke work index in the endotoxin-group (n = 6 animals). Pretreatment with the H1-antagonist dimethindene (2 mg/kg) in a second group (n = 6) significantly prevented these effects. ⋯ This parameter as well as base excess values and lactate levels were significantly improved by dimethindene-pretreatment (p < .05). These results may indicate a beneficial effect of H1-antagonist-pretreatment on endotoxin-induced deterioration of the microcirculation. Furthermore our results clearly demonstrated that only pretreatment before endotoxemia with H1-antagonism is effective, since infusion of H1-antagonist in hypodynamic shock 45 min after addition of endotoxin (n = 6 animals) did not improve the cardiovascular system or the microcirculation.