Hypotensive resuscitation has been advocated as a better means to perform field resuscitation of penetrating trauma. Our hypothesis is that hypotensive resuscitation using either crystalloid or colloid provides equivalent or improved metabolic function while reducing the overall fluid requirement for resuscitation of hemorrhage. We compared hypotensive and normotensive resuscitation of hemorrhage using lactated Ringer's (LR) with hypotensive resuscitation using Hextend (Hex), 6% hetastarch in isotonic buffered saline. Instrumented conscious sheep were hemorrhaged in three separate bleeds, 25 mL/kg at T0 and 5 mL/kg at both T50 and T70. Resuscitation was started at T30 and continued until T180. Hypotensive resuscitation to a mean arterial pressure (MAP) of 65 mmHg was performed with LR or Hex using a closed-loop resuscitation (CLR) system for a LR-65 and Hex-65 treatment protocol. A control treatment protocol was resuscitation with LR to a MAP target of 90 mmHg, LR-90. All treatment protocols were successfully resuscitated to near target levels. Two animals in the hypotensive treatment protocols died during the second and third bleedings, one in the LR-65 and one in the Hex-65 treatment protocol. Mean infused volumes were 61.4 +/- 11.3, 18.0 +/- 5.9, and 11.6 +/- 1.9 mL/kg in the LR-90, LR-65, and Hex-65 treatments, respectively (*P < 0.05 versus LR-90). Mean minimum base excess (BE) values were +1.9 +/- 1.4, -5.8 +/- 4.3, and -5.9 +/- 4.0 mEq/L in the LR-90, LR-65, and Hex-65 treatments, respectively. Hypotensive resuscitation with LR greatly reduced volume requirements as compared with normotensive resuscitation, and Hex achieved additional volume sparing. However, trends toward lower BE values and the occurrence of deaths only in the hypotensive treatment protocols suggest that resuscitation to a target MAP of 65 mmHg may be too low for optimal outcomes.

Volume sparing was apparent with HS, but no hemodynamic or metabolic advantage was apparent when used for either normotensive or hypotensive resuscitation. Trends toward lower base excess values and higher occurrences of deaths only in the hypotensive treatment protocols suggest that resuscitation to a target mean arterial pressure of 65 mm Hg may be too low.

Enteral resuscitation could provide a means to resuscitate burn shock when intravenous (IV) therapy is unavailable, such as in mass disasters. We evaluated the extent of intestinal absorption and resuscitative effects of World Health Organization Oral Rehydration Solution after a 40% TBSA burn in anesthetized swine compared with the IV infusion of lactated Ringer's infused by Parkland formula. Plasma volume (PV) was measured using indocyanine green dye dilution. Intestinal absorption was assessed using phenol red as a nonabsorbable marker. Changes in hematocrit, hemodynamics, and measured PV showed equivalent resuscitative effects of enteral and IV resuscitation. The duodenal fluid absorption rate started at 77 +/- 32 ml/hr per meter of intestine during the first hour and increased to 296 +/- 40 ml/hr during the fourth hour of resuscitation, with a total of 93 +/- 2% of World Health Organization Oral Rehydration Solution infused into the intestine being absorbed. Intestinal absorption rates after burn injury are sufficient to resuscitate a 40% TBSA burn.

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