Improved outcomes of renal injury following burn trauma

Acute kidney injury (AKI) is common in major burn injuries and associated with increased mortality. With advances in surgical and critical care it is unclear if mortality in this population remains this high. This study aims to describe incidence and outcomes of patients admitted to intensive care (ICU) with a burn injury who develop AKI. We additionally sought to determine risk factors for developing AKI.

A historical cohort study of patients admitted to ICU from 2010 to 2016 with major burn injury was conducted. Demographic, laboratory, and clinical information was collected. AKI was defined by Acute Kidney Injury Network (AKIN) classification. Multivariable logistic regression was used to model association between baseline risk factors and risk of AKI.

Of the 151 patients included, 64 people developed AKI (42%) defined by stages 1-3 of AKIN criteria. The median TBSA was 20% (IQR 9-41). Renal replacement therapy was required in 18/64 (28%) who developed AKI. Multivariable logistic regression demonstrated association between AKI and the following variables: APACHE II score (OR 1.2, 95%CI 1.1-1.3, P = 0.001), age (OR 1.8 per 10-year increase, 95%CI: 1.2-2.5, P = 0.002) and log(TBSA). Fractional polynomial regression analysis demonstrates that the best functional form of TBSA was in the natural logarithm (OR 2.7, 95%CI: 1.5-4.7, p = 0.001). Compared to those without AKI, patients with AKI had longer duration of mechanical ventilation, (median 11 [IQR 6-19] vs. 4 [IQR 2-9] days), ICU stay (15 [IQR 9-22] vs. 6 [IQR 3-10] days), and increased mortality (14 of 64(22%) vs. 4 of 87(5%).

AKI is common in patients with a major burn injury. However, mortality is lower than described in the literature, particularly for those who required renal replacement therapy.