SMALL-VOLUME RESUSCITATION USING HYPERTONIC SALINE IMPROVES ORGAN PERFUSION IN BURNED RATS

Resuscitation using small volumes (3-5 mL/kg) of 7.5% hypertonic salin e (HTS) is effective for hemorrhagic shock. Whether HTS is beneficial for the initial resuscitation of burn injury is not clear. We compared the hemodynamic effects of HTS versus lactated Ringer's solution (LR) and examined organ tissue perfusion during burn resuscitation (R). Fu ll thickness scald burn (35% of total body surface area) was induced i n pentobarbital-anesthetized rats. Regional blood flows were measured using radioactive microspheres before and 30 min after burn, and after R with either HTS (4 mL/kg) or LR (at a dose required for equivalent restora tion of arterial blood pressure). Data from the HTS- or LR-res uscitated groups were compared to those from a nonresuscitated group ( n = 10 in each group). Mean arterial pressure decreased 30% after burn (from 120 +/- 4 to 84 +/- 5 mm Hg, mean +/- SEM) and returned toward baseline (112 +/- 7 mm Hg) at 10 min after R with HTS (4 mL/kg) or LR (22.6 +/- 0.7 mL/kg), but subsequently decreased to 100 +/- 7 mm Hg wi th HTS and 105 +/- 5 mm Hg with LR at 30 min. In contrast to LR, resus citation using HTS was associated with tachycardia. Blood flows to the skin and muscle of the normal or burn regions did not change after fl uid resuscitation as compared to a nonresuscitated group. Fluid resusc itation transiently increased intestinal perfusion. Similar improvemen ts in blood flow to the spleen were observed with HTS and LR at 10 min after R (from 128 +/- 10 to 156 +/- 15 and from 113 +/- 10 to 145 +/- 26 mL . min(-1). 100 g(-1), respectively). However, at 30 min after R , splenic perfusion in the LR group was not different from that in the nonresuscitated group. Blood flows to the brain and kidney increased 39% and 42%, respectively, with HTS. HTS was also associated with pron ounced improvements in blood flows to the heart (from 346 +/- 20 to 63 1 +/- 37 mt min(-1). 100 g(-1)), liver (from 36 +/- 2 to 62 +/- 4 mL . min(-1). 100 g(-1)), and testis (from 29 +/- 2 to 43 +/- 2 mL . min(- 1). 100 g(-1)) Resuscitation using HTS was associated with rapid impro vement in organ tissue perfusion in anesthetized rats subjected to bur n injury. In comparison to LR, greater increases in blood flows to the heart, kidney, liver, and testis were observed with HTS. The results suggest that significant improvement in blood flow distribution can be achieved using HTS at less than one fifth the volume of LR for the in itial treatment of burn shock.