Sepsis: early interventions count but not RRT!

Acute kidney injury (AKI) frequently affects critically ill patients (1). While there are many measures to theoretically prevent the development of AKI or, at least, avoid worsening of AKI (2,3), ultimately, renal replacement therapy (RRT) is often required in the disease management of these patients. However, a continually vexing problem, which often arises when planning the initiation of RRT in critically ill patients, is finding the ideal time to instigate extracorporeal treatment. One can either decide to deliver rapid initiation of RRT or apply a delayed strategy waiting for “urgent” indications to occur (Table 1). The latter may provide the patient with additional time for possible renal recovery and negate the need for RRT. The importance of this is clear, when examining the results of the AKIKI trial (6). Here, 98% of patients in the early group received RRT, compared to 51% in the delayed group. It may therefore be argued that a considerable proportion of patients in the early group would have recovered renal function without ever needing RRT (7). However, the ELAIN trial (8), a single-center study including 231 mainly cardiac-surgical patients showed improved short term and even long-term survival if RRT was started at KDIGO stage 2 as compared to KDIGO stage 3. The majority of the patients included in this study had undergone cardiac surgery, they showed a high severity of disease often requiring mechanical ventilation as well as vasopressors. However, in the delayed group of ELAIN 91% of the patients received RRT, and there was only a 21 hours difference in starting RRT between the early and the delayed groups, giving little time for spontaneous recovery of renal function. As indicated by AKIKI, rapid initiation of RRT may lead to increased costs and staff requirements and may expose the patient to increased complications and side effects originating from the extracorporeal circuit. These include bleeding complications, catheter-related bloodstream infections (6) and leukocyte activation (9). Biomarkers are believed to aid in decision making in the future, however, the ideal biomarker for the initiation of RRT has yet to be determined (10)