Resuscitation using small volumes (3-5 mL/kg) of 7.5% hypertonic saline (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). Full thickness scald
burn (35% of total body surface area) was induced in
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 restoration of arterial blood pressure). Data from the HTS-or LR-resuscitated 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 with HTS and 105 +/- 5 mm Hg with LR at 30 min. In contrast to LR,
resuscitation using HTS was associated with
tachycardia. Blood flows to the skin and muscle of the normal or
burn regions did not change after fluid
resuscitation as compared to a nonresuscitated group. Fluid
resuscitation transiently increased intestinal perfusion. Similar improvements 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 x 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 pronounced improvements in blood flows to the heart (from 346 +/- 20 to 631 +/- 37 mL.min-1 x 100 g-1), liver (from 36 +/- 2 to 62 +/- 4 mL.min-1 x 100 g-1), and testis (from 29 +/- 2 to 43 +/- 2 mL.min-1 x 100g-1).
Resuscitation using HTS was associated with rapid improvement in organ tissue perfusion in anesthetized rats subjected to
burn 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 initial treatment of
burn shock.