Reciprocal Risk of Acute Kidney Injury and Acute Respiratory Distress Syndrome in Critically Ill Burn Patients

Objective: To evaluate the association between acute respiratory distress syndrome and acute kidney injury with respect to their contributions to mortality in critically ill patients. Design: Retrospective analysis of consecutive adult burn patients requiring mechanical ventilation. Setting: A 16-bed burn ICU at tertiary military teaching hospital. Patients: Adult patients more than 18 years old requiring mechanical ventilation during their initial admission to our burn ICU from January 1, 2003, to December 31, 2011. Interventions: None. Measurements and Main Results: A total 830 patients were included, of whom 48.2% had acute kidney injury (n = 400). These patients had a 73% increased risk of developing acute respiratory distress syndrome after controlling for age, gender, total body surface area burned, and inhalation injury (hazard ratio, 1.73; 95% CI, 1.18-2.54; p = 0.005). In a reciprocal multivariate analysis, acute respiratory distress syndrome (n = 299; 36%) demonstrated a strong trend toward developing acute kidney injury (hazard ratio, 1.39; 95% CI, 0.99-1.95; p = 0.05). There was a 24% overall in-hospital mortality (n = 198). After adjusting for the aforementioned confounders, both acute kidney injury (hazard ratio, 3.73; 95% CI, 2.39-5.82; p < 0.001) and acute respiratory distress syndrome (hazard ratio, 2.16; 95% CI, 1.58-2.94; p < 0.001) significantly contributed to mortality. Age, total body surface area burned, and inhalation injury were also significantly associated with increased mortality. Conclusions: Acute kidney injury increases the risk of acute respiratory distress syndrome in mechanically ventilated burn patients, whereas acute respiratory distress syndrome similarly demonstrates a strong trend toward the development of acute kidney injury. Acute kidney injury and acute respiratory distress syndrome are both independent risks for subsequent death. Future research should look at this interplay for possible early interventions.