BACKGROUND: 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. STUDY DESIGN: Uncontrolled hemorrhagic shock was produced in 40 rats by a preliminary bleed (3 ml per 100 g) followed by 75% tail amputation. Experimental design consisted of three phases: a pre-hospital phase (90 min of uncontrolled bleeding with or without treatment with lactated Ringer's [LR] solution), followed by a hospital phase (60 min, 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 mmHg with LR, and group 4 had prehospital resuscitation to MAP of 80 mmHg with LR. Groups 2, 3, and 4 received fluid and blood to MAP of 80 mmHg and hematocrit of 30% in the hospital phase. RESULTS: All rats in group 1 (untreated) died within 2.5 h. Five rats in group 2 (no prehospital FR) survived 90 min; however, only one survived three days. In group 3, all ten rats survived 2.5 h and six survived three days. In group 4, eight rats died within 90 min, 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). CONCLUSIONS: 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.