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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Isolated third-order pulmonary arteries and veins from sheep were examined for the effects of septicemia on norepinephrine-induced contractions, nitric oxide (NO)-mediated dilation, and basal cyclic GMP levels. The groups studied were as follows: control sheep (n = 7); sheep given live Pseudomonas aeruginosa (Ps, n = 6) for 48 h; and sheep given NG-mono-methyl-L-arginine during the last 24 h of Ps infusion (Ps-L-NMMA, n = 4). The norepinephrine-induced contractions were significantly greater (p < .05) in arteries from septic (Ps and Ps-L-NMMA) sheep. ⋯ Removal of endothelium enhanced contractions and decreased cyclic GMP in arteries and veins only from control sheep. The results show that septicemia differently affects the pulmonary artery and vein. The enhanced vasoconstriction of the artery is due to decreased endothelium-dependent NO release; the attenuated vasoconstriction of the vein is associated with NO-mediated increased cyclic GMP levels.
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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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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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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.