Impact of the intensity of intermittent renal replacement therapy in critically ill patients

Intermittent renal replacement therapy (IRRT) is prescribed across intensive care units (ICU) worldwide. While research regarding the prescribed dialysis dose has not yielded results concerning mortality, it is still unknown whether the same applies to the actual delivered dose.

We retrospectively analyzed two different cohorts of patients (562 IRRT sessions) who were admitted to the intensive care units at Hospital Clínic of Barcelona and required renal replacement therapy with IRRT. The first cohort included patients with acute kidney injury (AKI) (n = 42) and the second included patients already on chronic hemodialysis (CKD 5D) (n = 47). Only patients who had at least 3 recorded hemodialysis sessions in the ICU and with no previous continuous renal replacement therapy (CRRT) were included. The achieved dose was measured as Kt (L) by ionic dialysance and the primary endpoint was 90-day mortality.

Ninety-day mortality was 40.5% (n = 17) in the AKI cohort and 23.9% (n = 11) in the CKD 5D cohort with mean Kt of 43 ± 8.27 L and 47 ± 9.65 L respectively. Kt dose of IRRT was associated with 90-day mortality in the AKI cohort in a multivariate surveillance analysis adjusted for confounding factors (HR 0.935 [0.88-0.99], p = 0.02). Only the Kt dose and age remained statistically associated with the outcome in the AKI cohort.

Delivered dialysis dose as measured by ionic-dialysance Kt may be associated with survival in critically-ill patients with AKI, while it does not seem to affect outcomes in critically-ill CKD 5D patients. This exploratory analysis will need confirmation in larger prospective studies.