Summary Background: Continuous veno‐venous haemofiltration is increasingly used to treat acute renal failure in critically ill patients, but a clear definition of an adequate treatment dose has not been established. We undertook a prospective randomised study of the impact of different ultrafiltration doses in continuous renal replacement therapy on survival. Methods: We enrolled 425 patients, with a mean age of 61 years, in intensive care who had acute renal failure. Patients were randomly assigned ultrafiltration at 20 ml/h−1/kg−1 (group 1, n = 146), 35 ml/h−1/kg−1 (group 2, n = 139), or 45 ml/h−1/kg−1 (group 3, n = 140). The primary endpoint was survival at 15 days after stopping haemofiltration. We also assessed recovery of renal function and frequency of complications during treatment. Analysis was by intention to treat. Results: Survival in group 1 was significantly lower than in groups 2 (p = 0.0007) and 3 (p = 0.0013). Survival in groups 2 and 3 did not differ significantly (p = 0.87). Adjustment for possible confounding factors did not change the pattern of differences among the groups. Survivors in all groups had lower concentrations of blood urea nitrogen before continuous haemofiltration was started than non‐survivors. 95%, 92% and 90% of survivors in groups 1, 2 and 3, respectively, had full recovery of renal function. The frequency of complications was similarly low in all groups. Interpretation: Mortality among these critically ill patients was high, but increase in the rate of ultrafiltration improved survival significantly. We recommend that ultrafiltration should be prescribed according to patient's bodyweight and should reach at least 35 ml/h−1/kg−1.

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PurposeNeutrophil gelatinase-associated lipocalin (NGAL) is a useful marker for acute kidney injury (AKI), particularly when the timing of renal insult is known. However, its performance in an adult critical care setting has not been well described. We performed this study to estimate the diagnostic accuracy of plasma NGAL for early detection of AKI and need for renal replacement therapy (RRT) in an adult intensive care unit (ICU).MethodsWe enrolled 307 consecutive adult patients admitted to a general medical-surgical ICU; 301 were included in the final analysis. Serial blood samples were analyzed for plasma NGAL using a standardized clinical platform. The primary outcome was AKI, defined as an increase in creatinine of at least 50% from baseline or a reduction in urine output to <0.5 ml/kg/h for >6 h.ResultsOf 301 patients, 133 (44%) had AKI during their ICU stay. Plasma NGAL was a good diagnostic marker for AKI development within the next 48 h (area under ROC 0.78, 95% CI 0.65–0.90), and for RRT use (area under ROC 0.82, 95% CI 0.70–0.95). Peak plasma NGAL concentrations increased with worsening AKI severity (R = 0.554, P < 0.001).ConclusionsPlasma NGAL is a useful early marker for AKI in a heterogeneous adult ICU population, in which the timing of renal insult is largely unknown. It allows the diagnosis of AKI up to 48 h prior to a clinical diagnosis based on AKI consensus definitions. Additionally, it predicts need for RRT and correlates with AKI severity. Early identification of high risk patients may allow potentially beneficial therapies to be initiated early in the disease process before irreversible injury occurs.Electronic supplementary materialThe online version of this article (doi:10.1007/s00134-009-1711-1) contains supplementary material, which is available to authorized users.

Acute kidney injury (AKI) in the intensive care unit (ICU) is associated with an enhanced mortality. The Acute Dialysis Quality Initiative group has proposed the RIFLE (Risk-Injury-Failure-Loss-ESRD) classification to standardize the approach to AKI. This study was performed to estimate the AKI incidence in ICU patients in northeastern Italy and describe clinical characteristics and outcomes of patients with AKI on the basis of their RIFLE class. A prospective multicenter observational study was performed of patients who fulfilled AKI criteria in 19 ICU in northeastern Italy. Data were analyzed using multivariate logistic regression and survival curve analysis. Of 2164 ICU patients who were admitted during the study period, 234 (10.8%; 95% confidence interval 9.5 to 12.1%) developed AKI; 19% were classified as risk (R), 35% as injury (I), and 46% as failure (F). Preexisting kidney disease was present in 36.8%. The most common causes of AKI were prerenal causes (38.9%) and sepsis (25.6%). At diagnosis of AKI, median serum creatinine and urine output were 2.0 mg/dl and 1100 ml/d, respectively. ICU mortality was 49.5% in class F, 29.3% in I, and 20% in R. Independent risk factors for mortality included RIFLE class, sepsis, and need for renal replacement therapy, whereas a postsurgical cause of AKI, exposure to nephrotoxins, higher serum creatinine, and urine output were associated with lower mortality risk. In this study, AKI incidence in the ICU was between 9 and 12%, with 3.3% of ICU patients requiring renal replacement therapy. Sepsis was a significant contributing factor. Overall mortality was between 30 and 42%, and was highest among those in RIFLE class F.