Renal function after severe burn trauma - effects of reducing resuscitation fluid volume and changing fluid tonicity.

Background: Severe burn trauma can significantly impair renal function with increased morbidity and mortality. To preserve renal function after burn trauma, fluid resuscitation should be adequate avoiding hypo- as well as hypervolemia. In 2018, the Dutch Burn Society revised its resuscitation guideline from 4 mL/kg/TBSA hypertonic solution to 3 mL/kg/TBSA isotonic solution. This study analyzes the effects of these changes in the fluid resuscitation protocol on renal function.

Methods: In this retrospective, single-center, cohort study, we included adult patients with a burn injury of at least 15 % of their total body surface area (≥ 15 % TBSA). The inclusion period lasted from 2.5 years before until 2.5 years after the modification of the fluid resuscitation protocol. We compared the effects of both protocols (4 mL/kg/TBSA hypertonic solution versus 3 mL/kg/TBSA isotonic solution) on renal function, as assessed by glomerular filtration rate, plasma creatinine concentration and urinary output, the incidence of AKI, and the need for renal replacement therapy.

Results: We included 108 patients with a median burned TBSA of 22 %, 52 patients receiving 4 mL/kg/TBSA hypertonic solution, and 56 patients receiving 3 mL/kg/TBSA isotonic solution. Baseline characteristics were similar between both groups (mean age 44 years). No significant differences were observed in renal function, need for renal replacement therapy, urinary output, incidence of acute kidney injury, or mortality.

Discussion: Determining the optimal fluid volume and composition for resuscitation of patients with severe burn trauma remains challenging. In our study, reducing the initial resuscitation volume from 4 to 3 mL/kg/TBSA and switching from a hypertonic to an isotonic solution showed no adverse effects on renal function after severe burn trauma. Future studies should investigate whether individualized strategies can help to reach the sweet spot of fluid resuscitation.