RESUMEN
Objective To compare the time course of distribution and elimination of gelatin and lactated Ringer's solution (LR) by volume kinetics and mass balance analysis during hemorrhagic shock in dogs, and try to design and optimize fluid therapy in a more scientific manner. Methods Twenty dogs were randomly divided into 4 groups: CL group, CG group, BL group, and BG group. Each animal was subjected to two randomly ordered experiments that separated for at least 1 week. In the first phase, plasma volume expansion was studied in the state of anesthesia, animals received 30 mL/kg of LR (CL group) or 10 mL/kg of gelatin (CG group) over 30 min. In the second phase, plasma volume expansion was studied in the state of hemorrhagic shock, animals received 30 mL/kg of LR (BL group) or 10 mL/kg of gelatin (BG group) over 30 min. Hb concentration and Hct were measured every 5 min during and after infusion for 90 min. Hemodynamic parameters were recorded at the same time. The distribution and elimination of infused fluid were studied by volume kinetics, based on serial analysis of hemoglobin dilution in arterial blood, and by mass balance that incorporated volume calculations derived from volume kinetic analysis and measurements of urinary volumes. Results When a one-volume kinetic model was fitted to the data, the value of V and Kr in CG, BL, and BG group were significantly smaller than those in CL group (P<0.05), which could be found from the computer-generated curves.When a two-volume kinetic model was fitted to the data, the value of V1, Kr, Kt in BL group were significantly smaller than those in CL group (P<0.05). The calculations based on mass balance corresponded to the predicted based on volume kinetics. The change of central volume (CCV) in BL, BG, and CG group was significantly greater than those in CL group (P<0.05). The VEE in BG and CG group was significantly higher than that in BL and CL group. The value of VEE in BL group was significantly higher than that in CL group (P<0.05). Conclusions Both of the efficacy of lactated Ringer's solution and gelatin increased significantly in the state of hemorrhagic shock, and the former increased more.