Effect of lactated Ringer’s solution on cardiac output and splanchnic blood flow during hemorrhagic shock in rabbits

Objective: To evaluate the effect of fluid resuscitation with lactated Ringer's solution on intestinal and systemic hemodynamic variables during hemorrhagic shock in rabbits. Methods: A controlled animal trial was conducted. Ten New Zealand rabbits underwent ear artery and femoral vein cannulation and thoraco-laparotomy in order to place flow transducers around the aortic root and superior mesenteric artery. Hemorrhage was induces up to 28 mL/kg, and then fluid resuscitation with lactated Ringer's solution was performed in a ratio 3:1 to blood loss. During hemorrhagic and resuscitation periods, mean arterial pressure, heart rate, cardiac output (cardiac index), splanchnic blood flow (splanchnic index) and intestinal to systemic flow ratio (TFIS) were measured. Results: Mean arterial pressure decreased during hemorrhage, with partial recovery during fluid resuscitation. Heart rate increased during hemorrhage and got stable during resuscitation not reaching baseline levels. On the other hand, cardiac index and splanchnic index decreased significantly during hemorrhage as well as during resuscitation. However, splanchnic index restoration with respect to baseline (66%) was significantly lower tan cardiac index restoration during fluid resuscitation, which is consistent with TFIS behavior. Conclusions: Fluid resuscitation with lactated Ringer's solution is less able to completely restore splanchnic flow as compared to systemic flow. It would be a useful recommendation to add different therapeutic strategies to fluid resuscitation to limit gut hypoperfusion during hemorrhagic shock.