RESUMO
OBJECTIVE: Intravenous infusion of crystalloid solutions is a cornerstone of the treatment of hemorrhagic shock. However, crystalloid solutions can have variable metabolic acid-base effects, perpetuating or even aggravating shock-induced metabolic acidosis. The aim of this study was to compare, in a controlled volume-driven porcine model of hemorrhagic shock, the effects of three different crystalloid solutions on the hemodynamics and acid-base balance. METHODS: Controlled hemorrhagic shock (40 percent of the total blood volume was removed) was induced in 18 animals, which were then treated with normal saline (0.9 percent NaCl), Lactated Ringer's Solution or Plasma-Lyte pH 7.4, in a blinded fashion (n = 6 for each group). Using a predefined protocol, the animals received three times the volume of blood removed. RESULTS: The three different crystalloid infusions were equally capable of reversing the hemorrhage-induced low cardiac output and anuria. The Lactated Ringer's Solution and Plasma-Lyte pH 7.4 infusions resulted in an increased standard base excess and a decreased serum chloride level, whereas treatment with normal saline resulted in a decreased standard base excess and an increased serum chloride level. The Plasma-Lyte pH 7.4 infusions did not change the level of the unmeasured anions. CONCLUSION: Although the three tested crystalloid solutions were equally able to attenuate the hemodynamic and tissue perfusion disturbances, only the normal saline induced hyperchloremia and metabolic acidosis.