Circulatory shock
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Previous studies of hypothermia and blood coagulation have focused on alterations in the levels of blood clotting elements using coagulation tests performed under normothermic conditions. However, because of the enzymatic nature of activated clotting factors, hypothermia should also be expected to affect clotting factor activities. Multiple determinations of activated partial thromboplastin times (APTT), prothrombin times (PT), and thrombin times (TT) were performed on commercially available normal human plasma at assay temperatures similar to those encountered clinically (25-37 degrees C). ⋯ Clotting time correlated significantly with assay temperature in a negative exponential fashion for all three tests (r = -0.97 for APTT, -0.93 for PT, -0.71 for TT, P less than 0.001 for all regressions). Clotting time prolongation appears proportional to the number of enzymatic steps involved. These data indicate that the coagulopathy observed during hypothermia is, in part, independent of clotting factor levels.
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The macro- and microcirculatory effect of small-volume resuscitation with hyperosmotic-hyperoncotic solutions was analyzed in 21 anesthetized beagles subjected to standardized traumatic-hemorrhagic hypotension (laparotomy and exteriorization of the intestine; MAP 40 mmHg for 75 min). Primary resuscitation consisted of bolus infusion of 10% of the blood loss (approx. 4 ml/kg) of either hyperosmotic (7.2%) saline -HSS-, hyperoncotic (10%) dextran 60 -HDS-, or hyperosomotic-hyperoncotic saline dextran (10% dextran 60 in 7.2% saline; HHS). Within 5 min CO was restored and systemic pressure significantly increased. ⋯ HHS). Despite the normalization of cardiac output by small volumes of hypertonic solutions, 7.2% saline alone failed to fully restore RBF after protracted traumatic hemorrhage. For the concept of small-volume resuscitation, the hyperosomotic-hyperoncotic solution of 10% dextran 60 in 7.2% saline appears to be most effective to improve organ perfusion during the prehospital period of trauma patients.