Clinical question: Does early renal replacement therapy (RRT) initiation affect clinical outcomes in patients with severe acute kidney injury (AKI) in the setting of septic shock or acute respiratory distress syndrome (ARDS)?
Background: Critically ill patients with AKI can benefit from RRT via improvement of electrolyte abnormalities, volume overload, and acid-base status. Potential harm from RRT includes complications of central venous access, intradialytic hypotension, and the bleeding risk of anticoagulation. The optimal timing of the elective initiation of RRT for AKI in septic shock or ARDS is unknown.
Study design: A post hoc subgroup study of a randomized, controlled trial.
Setting: Thirty-one ICUs in France.
Synopsis: Using data from the Artificial Kidney Initiation in Kidney Injury trial, the authors evaluated 619 patients with severe AKI and requirement for catecholamine infusion and/or invasive mechanical ventilation. Patients were randomly given RRT in an early or a delayed time frame. The early strategy involved RRT as soon as possible after randomization. In addition to the other parameters, the patients in the delayed group were given RRT for the following: anuria/oliguria 72 hours after randomization, blood urea nitrogen greater than 112 mg/dL, serum potassium greater than 6 mmol/L, metabolic acidosis with pH less than 7.15, or pulmonary edema from fluid overload causing severe hypoxia.
Early RRT did not show significant improvement in 60-day mortality, length of mechanical ventilation, or length of stay, compared with delayed RRT. The delayed RRT strategy was significantly associated with renal function recovery, with hazard ratios of 1.7 in ARDS (P = .009) and 1.9 in septic shock (P less than .001). Additionally, the likelihood of adequate urinary output was greater in the delayed RRT group.
Bottom line: A delayed RRT strategy in those with severe AKI and septic shock or ARDS may safely afford time for renal recovery in some patients.
Citation: Gaudry S et al. Timing of renal support and outcome of septic shock and acute respiratory distress syndrome. A post hoc analysis of the AKIKI randomized clinical trial..
Dr. James is a hospitalist at Emory University Hospital Midtown and an assistant professor at Emory University, both in Atlanta.