The impact of continuous renal replacement therapy on renal outcomes in dialysis-requiring acute kidney injury may be related to the baseline kidney function.

BACKGROUND: Many controversies exist regarding the management of dialysis-requiring acute kidney injury (D-AKI). No clear evidence has shown that the choice of dialysis modality can change the survival rate or kidney function recovery of critically ill patients with D-AKI. METHODS: We conducted a retrospective study investigating patients (≥16 years old) admitted to an intensive care unit with D-AKI from 1999 to 2012. We analyzed D-AKI incidence, and outcomes, as well as the most commonly used dialysis modality over time. Outcomes were based on hospital mortality, renal function recovery (estimated glomerular filtration rate-eGFR), and the need for dialysis treatment at hospital discharge. RESULTS: In 1,493 patients with D-AKI, sepsis was the main cause of kidney injury (56.2%). The comparison between the three study periods, (1999-2003, 2004-2008, and 2009-2012) showed an increased in incidence of D-AKI (from 2.56 to 5.17%; p = 0.001), in the APACHE II score (from 20 to 26; p < 0.001), and in the use of continuous renal replacement therapy (CRRT) as initial dialysis modality choice (from 64.2 to 72.2%; p < 0.001). The mortality rate (53.9%) and dialysis dependence at hospital discharge (12.3%) remained unchanged over time. Individuals who recovered renal function (33.8%) showed that those who had initially undergone CRRT had a higher eGFR than those in the intermittent hemodialysis group (54.0 × 46.0 ml/min/1.73 m2, respectively; p = 0.014). In multivariate analysis, type of patient, sepsis-associated AKI and APACHE II score were associated to death. For each additional unit of the APACHE II score, the odds of death increased by 52%. The odds ratio of death for medical patients with sepsis-associated AKI was estimated to be 2.93 (1.81-4.75; p < 0.001). CONCLUSION: Our study showed that the incidence of D-AKI increased with illness severity, and the use of CRRT also increased over time. The improvement in renal outcomes observed in the CRRT group may be related to the better baseline kidney function, especially in the dialysis dependence patients at hospital discharge.

Hypercitratemia is a mortality predictor among patients on continuous venovenous hemodiafiltration and regional citrate anticoagulation.

The use of regional citrate anticoagulation (RCA) in liver failure (LF) patients can lead to citrate accumulation. We aimed to evaluate serum levels of citrate and correlate them with liver function markers and with the Cat/Cai in patients under intensive care and undergoing continuous venovenous hemodiafiltration with regional citrate anticoagulation (CVVHDF-RCA). A prospective cohort study in an intensive care unit was conducted. We compared survival, clinical, laboratorial and dialysis data between patients with and without LF. Citrate was measured daily. We evaluated 200 patients, 62 (31%) with LF. Citrate was significantly higher in the LF group. Dialysis dose, filter lifespan, systemic ionized calcium and Cat/Cai were similar between groups. There were weak to moderate positive correlations between Citrate and indicators of liver function and Cat/Cai. The LF group had higher mortality (70.5% vs. 51.8%, p = 0.014). Citrate was an independent risk factor for death, OR 11.3 (95% CI 2.74-46.8). In conclusion, hypercitratemia was an independent risk factor for death in individuals undergoing CVVHDF-ARC. The increase in citrate was limited in the LF group, without clinical significance. The correlation between citrate and liver function indicators was weak to moderate.

How to choose the ideal renal replacement therapy in sepsis?

Sepsis is the main cause of acute kidney injury (AKI) among individuals hospitalized in intensive care units. Acute kidney injury is an independent risk factor for mortality, and its occurrence increases the complexity and cost of treatment. However, the pathophysiological mechanisms of AKI remain unclear. Hemodynamic, vascular, tubular, cellular, inflammatory, and oxidative processes are involved. Individuals with AKI generally have various comorbidities and are elderly and hypercatabolic and on vasopressors and mechanical ventilation. Dialysis is the main treatment for AKI. Although there is no clear benefit of any specific dialysis modality, these patients are initially instructed to use continuous dialysis methods, especially for the most severe cases with multiple organ system dysfunctions and for those who display signs of hemodynamic instability. Recent studies demonstrate that patients should receive a dialysis dose of at least 25 mL · kg · h.

The role of growth factors on renal tubular cells submitted to hypoxia and deprived of glucose.

BACKGROUND: In acute renal failure (ARF) renal tubular cell death and detachment can be induced by necrotic and apoptotic mechanisms. Several studies have demonstrated some benefits of the use of growth factors in experimental models of ARF. METHODS: MDCK cells were cultured in a glucose-free medium for 24h and were submitted to hypoxia (PO2 around 35 mmHg) for additional 24 h. To evaluate the possible protective role of growth factors, EGF, IGF-I or HGF were added to the medium (20 ng mL). LDH release, viability (acridine orange and ethidium bromide dyes) and quantification of apoptotic cells (Hoechst 33342 dye fluorescence) were determined. RESULTS: In the injury group, an increase on LDH release (60% vs. 3%) and on number of apoptotic cells (22% vs. 0.2%) which was associated with a reduced cell viability (61% vs. 94%) when compared with controls. Only HGF, not EGF or IGF-I, was able to protect cells from injury. HGF caused a significant reduction on LDH release (30%) and on number of apoptotic cells (5%), with an increase on viability cellular (79%). CONCLUSIONS: HGF decreases cell death on MDCK cells after hypoxic-induced injury, probably acting in both necrotic and apoptotic mechanisms.