[Long-term outcomes of children treated with continuous renal replacement therapy]

Continuous Renal Replacement Therapy in Critically Ill Children in the Pediatric Intensive Care Unit: A Retrospective Analysis of Real-Life Prescriptions, Complications, and Outcomes

Introduction: Severe acute kidney injury is a common finding in the Pediatric Intensive Care Unit (PICU), however, Continuous Renal Replacement Therapy (CRRT) is rarely applied in this setting. This study aims to describe our experience in the rate of application of CRRT, patients' clinical characteristics at admission and CRRT initiation, CRRT prescription, predictors of circuit clotting, short- and long-term outcomes. Methods: A 6-year single center retrospective study in a tertiary PICU. Results: Twenty-eight critically ill patients aged 0 to 18 years received CRRT between January 2012 and December 2017 (1.4% of all patients admitted to PICU). Complete clinical and CRRT technical information were available for 23/28 patients for a total of 101 CRRT sessions. CRRT was started, on average, 40 h (20-160) after PICU admission, mostly because of fluid overload. Continuous veno-venous hemodiafiltration and systemic heparinization were applied in 83.2 and 71.3% of sessions, respectively. Fifty-nine sessions (58.4%) were complicated by circuit clotting. At multivariate Cox-regression analysis, vascular access caliber larger than 8 Fr [HR 0.37 (0.19-0.72), p = 0.004] and regional citrate anticoagulation strategy [HR 0.14 (0.03-0.60), p = 0.008] were independent protective factors for clotting. PICU mortality rate was 42.8%, and six survivors developed chronic kidney disease (CKD), within an average follow up of 3.5 years. Conclusions: CRRT is uncommonly applied in our PICU, mostly within 2 days after admission and because of fluid overload. Larger vascular access and citrate anticoagulation are independent protective factors for circuit clotting. Patients' PICU mortality rate is high and survival often complicated by CKD development.

Renal function in children assisted with extracorporeal membrane oxygenation

Acute kidney injury is a frequent complication in patients requiring extracorporeal membrane oxygenation. A single-center retrospective analysis from a prospective observational database assessing the incidence of acute kidney injury in children undergoing extracorporeal membrane oxygenation, the use of continuous renal replacement therapy and its association with outcomes was performed. One hundred children were studied. Creatinine was normal in 33.3% of children at the beginning of extracorporeal membrane oxygenation, between 1.5 and 2 times its baseline levels in 18.4% of children (stage I acute kidney injury), between 2 and 3 times baseline levels (stage II) in 20.7%, and over 3 times baseline levels or requiring continuous renal replacement therapy (stage III) in 27.6% of the patients. Eighteen patients were on continuous renal replacement therapy before the beginning of extracorporeal membrane oxygenation, 81 required continuous renal replacement therapy during extracorporeal membrane oxygenation, and 38 after weaning from extracorporeal membrane oxygenation, but none of them did at discharge from the pediatric intensive care unit. Fifty-one children survived to pediatric intensive care unit discharge. Mortality was lower in children with normal kidney function or with stage I acute kidney injury at the beginning of extracorporeal membrane oxygenation than in those with stage II or III acute kidney injury (33.3% vs 58.3%, p = 0.021). Mortality in children requiring continuous renal replacement therapy during extracorporeal membrane oxygenation was 54.3% and 21.1% in the rest of patients (p < 0.01). We conclude that kidney function is significantly impaired in a high percentage of children undergoing extracorporeal membrane oxygenation and many of them are treated with continuous renal replacement therapy. Patients treated with continuous renal replacement therapy have a higher mortality than those with normal kidney function or stage I acute kidney injury at the beginning of extracorporeal membrane oxygenation. Most patients surviving to pediatric intensive care unit discharge recover normal renal function after weaning from extracorporeal membrane oxygenation.

Biomarkers upon discontinuation of renal replacement therapy predict 60-day survival and renal recovery in critically ill patients with acute kidney injury

INTRODUCTION

There is no consensus on the specific indications for weaning critically ill patients with acute kidney injury (AKI) off renal replacement therapy (RRT). This study aimed to explore the prognostic value of several biomarkers measured upon discontinuation of RRT for their value in predicting 60-day survival and renal recovery in an effort to add knowledge to the decision-making process regarding RRT withdrawal.

METHODS

We prospectively enrolled 102 patients with AKI who required RRT from the intensive care unit. Serum osteopontin (sOPN), serum interleukin 6 (sIL-6), serum cystatin C (sCysC), sIL-18, serum neutrophil gelatinase-associated lipocalin and urinary IL-18 and urinary neutrophil gelatinase-associated lipocalin were measured upon discontinuation of RRT. Patients were followed up at 60 days for survival and renal recovery.

FINDINGS

Patients who survived showed lower levels of all serum and urinary biomarkers. Serum OPN (OR 1.029, 95% CI 1.013-1.047, P = 0.001), diabetes (OR 23.157, 95% CI 4.507-118.981, P < 0.001) and APACHE II score (OR 1.308, 95% CI 1.121-1.527, P = 0.001) were independent predictors of 60-day mortality. Patients whose sOPN values fell within the highest and middle tertiles showed 5.25- and 2.31-fold increased risks of mortality, respectively, compared with that of patients in the lowest tertile. The addition of sOPN to the clinical model resulted in significant net reclassification improvement of 0.453 (P = 0.026) and an integrated discriminative index of 0.155 (P = 0.032). Lower levels of sOPN and sIL-6 were associated with greater odds of 60-day survival (AUC 0.812 and 0.741). The AUC value for predicting survival reached its highest level when all biomarkers were combined with urine output (UO) and urinary and serum creatinine upon discontinuation of RRT (0.882). Lower sCysC performed as well as higher UO in predicting 60-day renal recovery with the greatest AUC of 0.743.

DISCUSSION

Upon discontinuation of RRT, serum and urinary biomarkers, particularly sOPN, may predict 60-day survival and renal recovery in critically ill patients with AKI. The serum levels of OPN, IL-6 and CysC may be useful when considering withdrawal of RRT on the basis of conventional indicators.

MnTBAP Therapy Attenuates Renal Fibrosis in Mice with 5/6 Nephrectomy

Renal fibrosis is a common pathological feature of all kinds of chronic kidney diseases (CKDs) with uncertain mechanisms. Accumulating evidence demonstrated an important role of oxidative stress in the pathogenesis of CKD. Here we hypothesized that MnTBAP (manganese (III) tetrakis (4-benzoic acid)porphyrin chloride), a cell-permeable mimic of superoxide dismutase (SOD), may protect against the fibrotic response in CKD by antagonizing oxidative stress. To verify this hypothesis, we performed experiments in tubular epithelial cells and mice with 5/6 nephrectomy (Nx). In mouse tubular epithelial cells, TGF-β1 induced a significant transition to fibrotic phenotype in line with a remarkable mitochondrial dysfunction, which was markedly improved by MnTBAP (1.14 μM) pretreatment. In remnant kidneys of 5/6 Nx mice, tubulointerstitial fibrosis occurred in parallel with mitochondrial abnormality in renal tubular cells. Administration of MnTBAP significantly attenuated the deposition of extracellular matrix as evidenced by the blocked expressions of fibronectin, collagen I, and collagen III. Masson staining also displayed an ameliorated accumulation of collagenous matrix in MnTBAP-treated mice. Moreover, MnTBAP also significantly improved the severity of proteinuria without altering CKD-related hypertension. Collectively, MnTBAP therapy served as a promising strategy in preventing renal fibrosis in CKDs possibly via antagonizing mitochondrial-derived oxidative stress and subsequent protection of mitochondrial function.