Levels of protein C and soluble thrombomodulin in critically ill patients with acute kidney injury: a multicenter prospective observational study.

Endothelial dysfunction contributes to the development of acute kidney injury (AKI) in animal models of ischemia reperfusion injury and sepsis. There are limited data on markers of endothelial dysfunction in human AKI. We hypothesized that Protein C (PC) and soluble thrombomodulin (sTM) levels could predict AKI. We conducted a multicenter prospective study in 80 patients to assess the relationship of PC and sTM levels to AKI, defined by the AKIN creatinine (AKI Scr) and urine output criteria (AKI UO). We measured marker levels for up to 10 days from intensive care unit admission. We used area under the curve (AUC) and time-dependent multivariable Cox proportional hazard model to predict AKI and logistic regression to predict mortality/non-renal recovery. Protein C and sTM were not different in patients with AKI UO only versus no AKI. On intensive care unit admission, as PC levels are usually lower with AKI Scr, the AUC to predict the absence of AKI was 0.63 (95%CI 0.44-0.78). The AUC using log10 sTM levels to predict AKI was 0.77 (95%CI 0.62-0.89), which predicted AKI Scr better than serum and urine neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C, urine kidney injury molecule-1 and liver-fatty acid-binding protein. In multivariable models, PC and urine NGAL levels independently predicted AKI (p=0.04 and 0.02) and PC levels independently predicted mortality/non-renal recovery (p=0.04). In our study, PC and sTM levels can predict AKI Scr but are not modified during AKI UO alone. PC levels could independently predict mortality/non-renal recovery. Additional larger studies are needed to define the relationship between markers of endothelial dysfunction and AKI.

Standard versus high-dose CVVHDF for ICU-related acute renal failure.

The effect of dosage of continuous venovenous hemodiafiltration (CVVHDF) on survival in patients with acute renal failure (ARF) is unknown. In this study, 200 critically ill patients with ARF were randomly assigned to receive CVVHDF with prefilter replacement fluid at an effluent rate of either 35 ml/kg per h (high dosage) or 20 ml/kg per h (standard dosage). The primary study outcome, survival to the earlier of either intensive care unit discharge or 30 d, was 49% in the high-dosage arm and 56% in the standard-dosage arm (odds ratio 0.75; 95% confidence interval 0.43 to 1.32; P = 0.32). Among hospital survivors, 69% of those in the high-dosage arm recovered renal function compared with 80% of those in the standard-dosage arm (P = 0.29); therefore, a difference in patient survival or renal recovery was not detected between patients receiving high-dosage or standard-dosage CVVHDF.

A practical citrate anticoagulation continuous venovenous hemodiafiltration protocol for metabolic control and high solute clearance.

Obstacles to the widespread use of continuous renal replacement therapy (CRRT) include the need for anticoagulation, customized solutions, and complex protocols that carry an attendant risk for error, raise cost, and increase pharmacy and nursing workload. However, high solute clearance using CRRT with an effluent rate of 35 ml/kg per h has also recently been associated with improved survival in critically ill patients with acute renal failure. No published CRRT protocols using dilute regional citrate anticoagulation have achieved adequate metabolic control, effective anticoagulation, and high solute clearance in a practical, user-friendly, and economical manner. The safety and the efficacy of continuous venovenous hemodiafiltration at effluent rates of 35 ml/kg per h in critically ill acute renal failure patients were evaluated prospectively using a standardized bicarbonate-based dialysate; a systemic calcium infusion; and two separate trisodium citrate replacement solutions, a 0.67% solution and a 0.5% solution. All patients achieved adequate metabolic control, the desired effluent rate of 35 ml/kg per h, and high solute clearance. Use of the 0.67% citrate replacement solution resulted in mild alkalosis, whereas the 0.5% solution maintained appropriate acid-base balance. There was no difference in dialyzer survival between the 0.67 and 0.5% citrate groups (80 versus 82%; P = 0.60, Kaplan-Meier analysis). Dilute regional citrate as part of a CRRT protocol with a standard 25-mmol/L bicarbonate dialysate provides adequate metabolic control, high diffusive and convective clearance, and excellent dialyzer patency in a practical and cost-effective manner.