Circulatory shock
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We examined the specific effects of 7.5% hypertonic saline (HTS) on myocardial performance and regional blood flow and compared the efficacies of HTS and lactated Ringer's solution (LR) for hypovolemic resuscitation. Studies were performed in anesthetized dogs subjected to rapid hemorrhage to decrease mean arterial pressure by 50% over 60 min. The animals were resuscitated with either HTS (n = 8) at 5 ml/kg or LR (n = 7) at a dose required for equivalent restoration of cardiac output. ⋯ Hemorrhage decreased blood flow to various organs by 50% to 70% of baseline. Except for better improvement in splenic and hepatic perfusion with HTS, similar restoration of blood flow to the heart, muscle, skin, kidney, and jejunum was observed at 10 min after resuscitation with either fluid. In this animal model of rapid and severe hemorrhagic shock, HTS given at approximately one-sixth the volume of LR was equally effective in providing temporary restoration of hemodynamic function.(ABSTRACT TRUNCATED AT 250 WORDS)
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Thirty dogs underwent hemorrhage over a 60 minute period to a predetermined O2 debt of 60-120 mL O2/kg, quantified real-time by a Beckman metabolic cart; they were then resuscitated with 120% of the shed volume. The [total amino acids], [lactate], and [alanine]/[glutamine] rose during hemorrhage and resuscitation. Blood pressure, VO2, cardiac index, circulating amino acid pool, and systemic amino acid transport decreased during hemorrhage, but rose during resuscitation. ⋯ The O2 debt during hemorrhage was substantially better related to [lactate] compared to shed volume or blood pressure. The changes in [total amino acids] and [alanine]/[glutamine] and their relationship to O2 debt suggest a hemorrhagic-induced alteration in tissue amino acid kinetics. These data further suggest that using a metabolic substrate parameter such as O2 utilization is useful to stratify other cellular alterations such as amino acid uptake and release and lactic acidosis.