Fluid balance in the resorption stage correlates with outcomes of severe burn patients

The resorption stage is an important period involving early anti-shock treatment for severe burn patients. We aimed to investigate the quantitative variability in fluid balance during the resorption stage in severe burn patients, and to study its effect on patient outcomes. We conducted a single-centre retrospective study of 100 severe burn patients with involvement of > 50% total body surface area (TBSA). We extracted clinical data on demographics, clinical characteristics and outcomes; calculated the daily net fluid balance (difference between fluid intake and fluid output) and daily fluid intake/output within one week after injury; and analysed the association between fluid balance and functional outcomes and prognosis. The relative volume (ml/kg/TBSA) was used for the determination of daily fluid volume in this study. The daily net fluid balance (ml/kg/TBSA) of the deceased patients on the 4th, 5th, 6th, and 7th days after injury was higher than that of the surviving patients, but the opposite trend was found for the daily fluid output (ml/kg/TBSA). The partial correlation test showed that in the resorption stage of severe burn patients, fluid output was negatively correlated with the index levels of renal function and liver function, CRP level, blood lactic acid (LA) level, frequency of ventilator treatment, and capillary leakage index (CLI), but net fluid balance showed a completely opposite correlation. Moreover, fluid intake was negatively correlated with the index level of renal function and LA level, but positively correlated with the frequency of ventilator treatment. Furthermore, the logistic regression analysis showed that the net fluid balance and fluid output on Day 6 post-injury were independent risk factors for prognosis. This study suggested that greater fluid output in the resorption stage of severe burn patients was closely related to better outcomes, in addition, a gradually decreasing, lower positive net fluid balance may contribute to the improvement of functional outcomes, which will provide useful information for early fluid management and further prospective clinical study of severe burns.