Resuscitation of severe thermal injury with hypertonic saline dextran: Effects on peripheral and visceral edema in sheep

Background: Edema of tissue not directly injured by heat is a common complication after resuscitation of burn shock. Hypertonic 7.5% NaCl 6% dextran (HSD) infusion reduces early fluid requirements in burn shock, but the effects of HSD on peripheral and visceral tissue edema are not well-defined. Methods: We measured the micro-circulatory absorptive pressures of burned and nonburned skin and tissue water content of skin and other tissues in anesthetized sheep after 70% to 85% total body surface area scald and resuscitation. Fluid infusion was initiated 30 minutes after injury using 10 mL/kg HSD (n = 11) or lactated Ringer's (LR) (n = 12), with infusion rates titrated to restore and maintain preburn oxygen delivery (Do₂). Thereafter, both groups received LR infusions as needed to maintain Do₂ until the study's end at 8 hours. Colloid osmotic pressure was measured in plasma, and combined interstitial colloid osmotic and hydrostatic pressures were measured in skin. Results: Both treatments successfully restored Do₂, but fluid requirements were less with the HSD group than with the LR group (43 ± 19 mL/kg vs. 194 ± 38 mL/ kg, respectively, p < 0.05). The peripheral and visceral tissue water contents at 8 hours postinjury until the end of the study in both burn groups were significantly higher than in nonburn controls. However, HSD-treated sheep had significantly less water content in the colon (↓ 28%), liver (↓ 9%), pancreas (↓ 55%), skeletal muscle (↓ 21%), and nonburned skin (12%) compared with LR-treated sheep (p < 0.05 for each). HSD-treated sheep maintained significantly higher (3 to 5 mm Hg) plasma colloid osmotic pressure than LR-treated sheep. Conclusion: There were no observed differences in edema in burn skin between the two treatment groups. The early volume-sparing effect of HSD and reduction in tissue edema are likely attributed to an increased extracellular osmolarity and a better maintenance of the plasma oncotic pressure.