Improved outcome with fluid restriction in treatment of uncontrolled hemorrhagic shock

Recent studies have challenged current guidelines for prehospital fluid resuscitation. However, long-term studies evaluating the consequences of fluid restriction in uncontrolled hemorrhagic shock are lacking. This study was done to examine the long-term effects of deliberate hypotension in the treatment of uncontrolled hemorrhage.

Uncontrolled hemorrhagic shock was produced in 40 rats by a preliminary bleed (3 mL per 100 g) followed by 75 percent tail amputation. Experimental design consisted of three phases: a "prehospital phase" (90 minutes of uncontrolled bleeding with or without treatment with lactated Ringer's [LR] solution), followed by a "hospital phase" (60 minutes, including control of hemorrhage and fluid resuscitation including blood), and a three day observation phase. Forty rats were studied in four treatment groups (ten rats per group). Group 1 consisted of untreated controls (no resuscitation). Group 2 had no fluid during the prehospital phase. Group 3 had prehospital resuscitation to a mean arterial pressure (MAP) of 40 mm Hg with LR, and group 4 had prehospital resuscitation to MAP of 80 mm Hg with LR. Groups 2, 3, and 4 received fluid and blood to MAP of 80 mm Hg and hematocrit of 30 percent in the hospital phase.

All rats in group 1 (untreated) died within 2.5 hours. Five rats in group 2 (no prehospital FR) survived 90 minutes; however, only one survived three days. In group 3, all ten rats survived 2.5 hours and six survived three days. In group 4, eight rats died within 90 minutes, but none survived long-term. Blood loss (mL per 100 g) for each group was 3.75 0.6 for group 1, 3.35 0.1 for group 2, 4.15 0.8 for group 3, and 8.45 0.6 for group 4, (p < 0.05, group 4 compared with groups 1, 2, and 3).

Attempts to achieve normal MAP during uncontrolled bleeding increased blood loss, hemodilution and mortality. Hypotensive resuscitation resulted in less acidemia and improved long-term survival.