[The optimal resuscitation pressure of several resuscitation fluids in controlling hemorrhagic shock in rats].

OBJECTIVE: To investigate the optimal mean blood pressure of different resuscitation fluids in resuscitating hemorrhagic shock in rats. METHODS: One hundred and eighty Sprague-Dawley (SD) rats were used to reproduce hemorrhagic shock model by 35% and 45% depletion of blood volume, and they were randomly divided into Lactated Ringer solution (LR), 7.5% NaCl/6% Dextran 40 (HSD), and LR+hydroxyethyl starch (HES) groups. Mean arterial pressure (MAP) was maintained at 60, 80 and 100 mm Hg (1 mm Hg=0.133 kPa) respectively with these fluids. Left intraventricular systolic pressure (LVSP), the maximal change rate of left intraventricular pressure (+/-dp/dt max), blood gases and 12-hour survival rate were observed. RESULTS: In 35% hemorrhagic shock rats, LR and LR+HES could better maintain the MAP at the set level, but HSD could not maintain MAP at 100 mm Hg, reaching only 85 mm Hg. In 45% hemorrhagic shock rats, LR and HSD, also could not elevate MAP to 100 mm Hg, and LR infusion could restore MAP to about 85 mm Hg, HSD to 80 mm Hg and LR+HES to 60 mm Hg. Overall 12-hour survival rate was highest in group with LR+HES to maintain MAP at 60 mm Hg with satisfactory hemodynamic parameters and blood gases. HSD group ended up with a lowest survival rate. CONCLUSION: Different fluids to resuscitate hemorrhagic shock showed a different optimal MAP. LR between 85-100 mm Hg, HSD at 80 mm Hg and LR+HES at 60 mm Hg, may throw better effect on resuscitating moderate and severe hemorrhagic shock.