Lower fluid resuscitation volumes in the first 24 hours following a severe burn injury are independently associated with greater days alive and out of hospital: A retrospective cohort study.

Abstract

The optimal fluid resuscitation volume for severe burns is unknown. Clinical trials are challenged by the rarity of severe burns and the relatively low mortality rate resulting in the use of continuous surrogate outcomes to increase statistical power. Days alive and out of hospital (DAOH) at day 90 has been validated in the critically ill as a marker of long-term mortality and functional outcomes, although burns patients experience longer hospital admissions than the general critically ill population. We aimed to describe the association between fluid volume in the first 24 h post injury and DAOH at day 90 and day 180 (DAOH₉₀ and DAOH₁₈₀ respectively). Retrospective cohort study of all 124 patients admitted with > 20 % total body surface area (TBSA) burns to a major Australian burns referral centre ICU over a 5-year period. Median fluid volume in first 24 h was 4.8 (IQR 3.3-6.3) mL/kg/TBSA%. Using linear quantile regression modelling, after adjusting for age, TBSA%, injury severity, and inhalational injury, for every mL/kg/TBSA% increase in fluid in the first 24 h, there was a median decrease of 3.71 DAOH₉₀ (95 % CI 1.62-5.12, p = 0.002) and 4.41 DAOH₁₈₀ (95 % CI 2.21-7.22, p = 0.035). Restricted cubic spline modelling adjusted for the same covariates demonstrated a negative linear relationship between fluid volume in the first 24 h post injury and both DAOH₉₀ and DAOH₁₈₀ (p = 0.859 for DAOH₉₀ and p = 0.979 for DAOH₁₈₀). Adjusting for known confounders, there was a negative linear relationship between fluid volumes in the first 24 h and DAOH₉₀ and DAOH₁₈₀. Either could be used as a continuous, patient-centred outcome for future clinical trials of severe burn resuscitation.