Urine Neutrophil Gelatinase-Associated Lipocalin and Interleukin-18 Predict Acute Kidney Injury after Cardiac Surgery

Background. About 30–50% patients develop acute kidney injury (AKI) after cardiac surgery, which is still diagnosed by serum creatinine on clinic. However, the increase of serum creatinine is insensitive and delayed. The aim of this study is to test the hypothesis that neutrophil gelatinase-associated lipocalin (NGAL) and interleukin-18 (IL-18) are early biomarkers for AKI in patients after cardiac surgery. Methods. Thirty-three cases undergoing cardiac surgery were classified into an AKI group and non-AKI group, according to the AKI definition (> 26.5 μmol/L increase of serum creatinine, more than or equal to 50% increase of serum creatinine within 48 h, or a reduction in urine output < 0.5 mL/Kg per hour for more than six hours). The concentrations of serum NGAL, urine NGAL, and urine IL-18 at different time-points were measured. Results. Nine cases (27.27%) developed postoperative AKI, but diagnosis with serum creatinine was 12–48 h postoperation. The concentrations of serum NGAL were not significantly increased postoperation. The concentrations of urine NGAL and IL-18 were significantly increased in the AKI group, which reached the peak at 2–4 h postoperation, and a more significant difference could be seen after correction for urine creatinine. The concentrations of urine NGAL and IL-18 2 h postoperation, either corrected for urine creatinine or not, showed good sensitivity and specificity. Increased levels of urine NGAL and IL-18 2 h postoperation were significantly correlated with increased level of serum creatinine 12 h postoperation. Logistic regression analysis showed that urine NGAL corrected for urine creatinine 2 h postoperation and urine IL-18 2 h postoperation emerged as powerful independent predictors of AKI after cardiac surgery. Conclusions. The concentrations of urine NGAL and IL-18 could be useful biomarkers for AKI in patients after cardiac surgery, especially after correction for urine creatinine.     

Timing of Initiation of Renal Replacement Therapy in Acute Kidney Injury: A Systematic Review and Meta-analysis

The indications for dialysis in patients with acute kidney injury (AKI), as well as the dose and timing of initiation, remain uncertain. Recent data have suggested that early initiation of renal replacement therapy (RRT) may be associated with decreased mortality but not with the recovery of kidney function. A blood urea nitrogen (BUN) level of 75 mg/dL is a useful indicator for dialysis in asymptomatic patients, but one that is based on studies with limitations. Different parameters, including absolute and relative indicators, are needed. Currently, nephrologists should consider the trajectory of disease, and the clinical condition and prognosis of the patient are more important than numerical values in the decision to initiate dialysis.     

Efficacy of N-Acetylcysteine in Preventing Acute Kidney Injury After Cardiac Surgery: A Meta-Analysis Study

Purpose: To evaluate whether perioperative N-acetylcysteine (NAC) administration reduces the risk of cardiac surgery associated acute kidney injury (CSA-AKI). Materials and Methods: A systematic literature review (Medline, PubMed, Cochrane, Biomedical central, Google Scholar) identified 10 studies (1391 patients; 695 NAC and 696 placebo) that compared the efficacy and adverse effects of perioperative NAC administration for CSA-AKI prevention in adults undergoing elective cardiac surgery. Meta-analysis was performed using Comprehensive Meta-Analysis statistical software. Results: Patients in the NAC-treated and placebo groups had similar rate of CSA-AKI occurrence, change in creatinine levels, as well as the in-hospital mortality rate (RR = 0.841, 95% CI = 0.691 to 1.023, p = 0.083; pooled difference in means = ?0.328, 95% CI = ?0.712 to 0.056, p = 0.094; RR = 0.741, 95% CI = 0.388 to 1.418, p = 0.366, respectively). Conclusions: Our study does not support perioperative NAC administration as a mean to reduce the risk of CSA-AKI.     

尿生物标志物在儿童急性肾损伤早期诊断中的作用研究

目的：评价尿NGAL,KIM-1和β2-MG在儿童不同基础疾病导致的AKI早期诊断中的价值。方法：我们做的是前瞻性临床研究,检测在我院儿科门急诊不同疾病患儿尿中性粒细胞明胶酶相关的脂质运载蛋白（NGAL）,肾脏损伤因子-1（KIM-1）和-β2微球蛋白（β2-MG）的水平,以AKIpRIFLE为分期标准将入选患儿分组,比较尿NGAL,KIM-1和β2-MG在儿童急性肾损伤诊断中的敏感性,特异性,阳性似然比,阴性似然比,分析比较这3个指标在急性肾损伤早期诊断中的作用。结果：入选262例患儿中,23例患儿可诊断为AKI,15例患儿为AKI-R期,8例患儿为AKI-I期,入选患儿中没有AKI-F期,23例患儿中只有5例临床有AKI的诊断。尿NGAL,KIM-1和β2-MG的水平在血肌酐没有明显升高之前已经升高,随着肾损伤的加重升高的更明显,不同组间差异有统计学意义。尿NGAL和β2-MG在预测儿童AKI的早期诊断方面好于尿KIM-1（AUC〉0.8）。结论：尿NGAL,KIM-1和β2-MG均可以在Scr没有升高之前预测儿童AKI的发生,是儿童AKI的早期生物标志物。尿NGAL在早期预测不同基础疾病可能发生AKI方面好于其他两项指标。     

A Multi-Center Evaluation of Early Acute Kidney Injury in Critically Ill Trauma Patients

Rationale. Few studies have evaluated the epidemiology of acute kidney injury (AKI) in trauma. Objective. To evaluate the incidence, risk factors, and outcomes associated with early AKI (evident within 24 hours of admission) in critically ill trauma patients. Methods. A retrospective interrogation of prospectively collected data from the Australian New Zealand Intensive Care Society Adult Patient Database. A total of 9,449 trauma patients were admitted for ≥24 hours to 57 intensive care units across Australia from January 1^st, 2000, to December 31^st, 2005. Main Findings. The crude incidence of AKI was 18.1% (n = 1,711). Older age, female sex (OR 1.60, 95% CI, 1.43–1.78, p < 0.0001), and the presence of co-morbid illness (OR 2.70, 95% CI 2.3–3.2, p < 0.0001) were associated with higher odds of AKI. Those with trauma not associated with brain injury (OR 2.40, 95% CI, 2.1–2.7, p < 0.0001) and a higher illness severity (OR 1.12, 95% CI, 1.11–1.12, p < 0.001) also had higher likelihood of AKI. Overall, AKI was associated with a higher crude mortality (16.7% vs. 7.8%, OR 2.36, 95% CI, 2.0–2.7, p < 0.001). Each RIFLE category of AKI was independently associated with hospital mortality in multi-variable analysis (risk: OR 1.69; injury OR 1.88; failure 2.29). Conclusions. Trauma admissions to ICU are frequently complicated by early AKI. Those at high risk for AKI appear to be older, female, with co-morbid illnesses, and present with greater illness severity. Early AKI in trauma is also independently associated with higher mortality. These data indicate a higher burden of AKI than previously described.     

Analyzing Chinese Patients with Post-Operative Acute Kidney Injury

Abstract

Background: To investigate clinical characteristics and risk factors of Chinese patients with post-operative acute kidney injury (PO-AKI). Methods: Patients with PO-AKI in Ruijin Hospital from December 1997 to December 2005 were retrospectively studied. Results: Patients’ mean age was 62.2 ± 18.1 years. There were 111 males and 57 females. The mean serum creatinine at diagnosis was 370.41 ± 320.92 μmol/L and the mean estimated glomerular filtration rate was 33.56 ± 24.24 mL/min. For the outcome of the patients, 38 died and the mortality rate was 22.6%. There were 17 patients (10.1%) with Acute Dialysis Quality Initiative-RIFLE (risk-injury-failure-loss-end classification) phase R, 21 (12.5%) with phase I, and 130 (77.4%) with phase F. There was no significant difference in mortality regarding patients who underwent different types of surgeries. For the risk factors related to PO-AKI, acute tubular necrosis (ATN) increased relative risk of mortality PO-AKI (odds ratio = 7.089, 95% confidence interval = 2.069–24.288, p < 0.001). Multivariate regression models showed that ATN had a positive correlation with mortality of PO-AKI. Conclusions: PO-AKI is one of the most common causes of AKI in patients who underwent operations. Special attention should be paid to risk factors related to PO-AKI in order to improve prognosis.