Predictors of 15-Day Survival for the Intensive Care Unit Patient on Continuous Renal Replacement Therapy: A Retrospective Analysis

Abstract

Purpose In the intensive care unit (ICU), acute renal failure is mostly part of multiple organ dysfunction syndromes with mortality ranging from 28%-90%, continuous renal replacement therapy (CRRT) is the predominant mode of RRT used in ICU. The main objective of the study was to evaluate the outcomes in patients with acute kidney injury (AKI) on CRRT in the ICU. Methods A retrospective chart review was conducted for all ICU patients with acute renal failure on CRRT in a tertiary care teaching hospital. A subgroup analysis was conducted between 15 days in hospital survivors and non-survivors to look for predictors of survival for patients on CRRT. Results Two-hundred twenty-six patients underwent CRRT from January 2007 to December 2013. The overall in-hospital mortality was 84.1%. Fifty-six patients (24.77%) survived to the 15-day post-CRRT mark. Acute respiratory failure requiring mechanical ventilation was associated with significantly increased mortality; 89.2% vs. 97.6% (P=0.008), ICU length of stay was significantly longer in the survivor group than the nonsurvivor group. Median±IQR; {20±24 vs 6±7(P: <0.0001)} and so were the ventilator-associated days {16±24 vs 4±6.5 (P: <0.0001)} and duration of CRRT {4.5±5.5 vs 2±2.0(P: <0.0001)}. Patients who survived had a lower incidence of metabolic acidosis {44.6% vs 62.9% (P: 0. 016)} and uremic encephalopathy {12.5% vs 26.5%; (P: 0.031)} but a greater incidence of volume overload {28.6% vs 15.9% (P: 0.031)} as compared to the non-survivor. Acute Physiology And Chronic Health Evaluation II (APACHE II) scores were significantly higher in the non-survivor group (mean SD) 26.9±28.0 vs. 23.9±25.8 (P: 0.0136). Conclusions This observational study in patients undergoing CRRT in an ICU setting revealed that the overall mortality was 84.1%. Fluid overload as an indication of CRRT was associated with improved 15 days' survival whereas higher APACHE II scores and the use of mechanical ventilation were associated with reduced 15 days' survival.

Keywords: aki; continuous renal replacement therapy (crrt); cvvh; general nephrology dialysis and transplantation; medical icu; mortality; mortality rate in sepsis; renal failure.