ACUTE KIDNEY INJURY CLASSIFICATION: COMPARISON OF AKIN AND RIFLE CRITERIA

Identification of Endothelial Cell Protein C Receptor by Urinary Proteomics as Novel Prognostic Marker in Non-Recovery Kidney Injury

Acute kidney injury is a common and complex complication that has high morality and the risk for chronic kidney disease among survivors. The accuracy of current AKI biomarkers can be affected by water retention and diuretics. Therefore, we aimed to identify a urinary non-recovery marker of acute kidney injury in patients with acute decompensated heart failure. We used the isobaric tag for relative and absolute quantification technology to find a relevant marker protein that could divide patients into control, acute kidney injury with recovery, and acute kidney injury without recovery groups. An enzyme-linked immunosorbent assay of the endothelial cell protein C receptor (EPCR) was used to verify the results. We found that the EPCR was a usable marker for non-recovery renal failure in our setting with the area under the receiver operating characteristics 0.776 ± 0.065; 95%CI: 0.648-0.905, (p < 0.001). Further validation is needed to explore this possibility in different situations.

Population pharmacokinetics of vancomycin in patients with diabetic foot infection: a comparison of five models

Purpose

This study aimed to compare individual pharmacokinetic (PK) parameters of vancomycin with predicted values from five population PK models in patients with diabetic foot infections (DFIs).

Methods

Patients with a diagnosis of DFI and an estimated glomerular filtration rate (eGFR) ≥ 30 mL/min were included in the study. Individual PK data was carried on by collecting three vancomycin serum concentrations in a steady-state condition. Five published population-based nomograms were assumed to predict PK parameters. Optimal vancomycin exposure was considered as a trough level of 15-20 mg/L or the area under the curve over 24 h/minimum inhibitory concentration (AUC24/MIC) ≥ 400.

Results

A total of 48 samples from 16 patients were analyzed. There was a statistically significant difference between the volume of distribution (Vd) obtained from population methods and the individual estimations (P ≤ 0.001 in Ambrose and Burton, P = 0.010 and 0.006 in Bauer and Burton revised models, respectively). AUC/MIC ≥ 400 was achieved in 68.7% of patients while 50% had a trough level of less than 15 mg/L.

Conclusions

Vancomycin PK parameters, particularly individualized Vd, may not be predictable by population nomograms in patients with DFI and stable renal function. Moreover, the weak correlation between AUC24 values and trough concentrations underlines the starting practice of vancomycin AUC24-based monitoring and dosing in the clinical setting.

Determination of Risk Factors for Postoperative Acute Kidney Injury in Patients With Gynecologic Malignancies

Background Postoperative acute kidney injury (AKI) is an important cause of mortality and morbidity among surgical patients. There is little information on the occurrence of AKI after operations for gynecologic malignancies. This study aimed to determine the incidence of AKI in patients who underwent surgery for gynecological malignancies and determine the risk factors in those who developed postoperative AKI. Methodology A total of 1,000 patients were enrolled retrospectively from January 2007 to March 2013. AKI was defined according to the Kidney Disease Improving Global Outcomes 2012 Clinical Practice Guideline for Acute Kidney Injury. Perioperative variables of patients were collected from medical charts. Results The incidence of postoperative AKI was 8.8%, with stage 1 occurring in 5.9%, stage 2 in 2.4%, and stage 3 in 0.5% of the patients. Patients who had AKI were significantly older, had higher body mass index (BMI) higher preoperative C-reactive protein (CRP) levels, and more frequently had a history of distant organ metastasis when compared with those who did not have AKI. When compared with patients who did not develop AKI postoperatively, longer operation times and intraoperative usage of higher amounts of erythrocyte suspension and fresh frozen plasma were seen in those who developed AKI. Conclusions Patients who had AKI were older, had higher BMI with higher preoperative CRP levels, more frequent distant organ metastasis, longer operation times, and higher amounts of blood transfused intraoperatively. Defining preoperative, intraoperative, and postoperative risk factors for postoperative AKI and taking necessary precautions are important for the early detection and intervention of AKI.

Effects of Mean Artery Pressure and Blood pH on Survival Rate of Patients with Acute Kidney Injury Combined with Acute Hypoxic Respiratory Failure: A Retrospective Study

Background and Objectives: In the intensive care unit (ICU), renal failure and respiratory failure are two of the most common organ failures in patients with systemic inflammatory response syndrome (SIRS). These clinical symptoms usually result from sepsis, trauma, hypermetabolism or shock. If this syndrome is caused by septic shock, the Surviving Sepsis Campaign Bundle suggests that vasopressin be given to maintain mean arterial pressure (MAP) > 65 mmHg if the patient is hypotensive after fluid resuscitation. Nevertheless, it is important to note that some studies found an effect of various mean arterial pressures on organ function; for example, a MAP of less than 75 mmHg was associated with the risk of acute kidney injury (AKI). However, no published study has evaluated the risk factors of mortality in the subgroup of acute kidney injury with respiratory failure, and little is known of the impact of general risk factors that may increase the mortality rate. Materials and Methods: The objective of this study was to determine the risk factors that might directly affect survival in critically ill patients with multiple organ failure in this subgroup. We retrospectively constructed a cohort study of patients who were admitted to the ICUs, including medical, surgical, and neurological, over 24 months (2015.1 to 2016.12) at Chiayi Chang Gung Memorial Hospital. We only considered patients who met the criteria of acute renal injury according to the Acute Kidney Injury Network (AKIN) and were undergoing mechanical ventilator support due to acute respiratory failure at admission. Results: Data showed that the overall ICU and hospital mortality rate was 63.5%. The most common cause of ICU admission in this cohort study was cardiovascular disease (31.7%) followed by respiratory disease (28.6%). Most patients (73%) suffered sepsis during their ICU admission and the mean length of hospital stay was 24.32 ± 25.73 days. In general, the factors independently associated with in-hospital mortality were lactate > 51.8 mg/dL, MAP ≤ 77.16 mmHg, and pH ≤ 7.22. The risk of in-patient mortality was analyzed using a multivariable Cox regression survival model. Adjusting for other covariates, MAP ≤ 77.16 mmHg was associated with higher probability of in-hospital death [OR = 3.06 (1.374–6.853), p = 0.006]. The other independent outcome predictor of mortality was pH ≤ 7.22 [OR = 2.40 (1.122–5.147), p = 0.024]. Kaplan-Meier survival curves were calculated and the log rank statistic was highly significant. Conclusions: Acute kidney injury combined with respiratory failure is associated with high mortality. High mean arterial pressure and normal blood pH might improve these outcomes. Therefore, the acid–base status and MAP should be considered when attempting to predict outcome. Moreover, the blood pressure targets for acute kidney injury in critical care should not be similar to those recommended for the general population and might prevent mortality.

Cl-Amidine Improves Survival and Attenuates Kidney Injury in a Rabbit Model of Endotoxic Shock

Objective: Sepsis causes millions of deaths on a global scale annually. Activation of peptidylarginine deiminase (PAD) enzymes in sepsis causes citrullination of histones, which results in neutrophil extracellular trap formation and sepsis progression. This study evaluates pan-PAD inhibitor, Cl-amidine, in a model of lipopolysaccharide (LPS)-induced endotoxic shock in rabbits. We hypothesized that Cl-amidine would improve survival and attenuate kidney injury. Methods: In the survival model, rabbits were injected injected intravenously with 1 mg/kg of LPS, and then randomly assigned either to receive dimethyl sulfoxide (DMSO; 1 mcL/g) or Cl-amidine (10 mg/kg diluted in 1 mcL/g DMSO). They were then monitored for 14 days to evaluate survival. In the non-survival experiment, the same insult and treatment were administered, however; the animals were euthanized 12 hours after LPS injection for kidney harvest. Acute kidney injury (AKI) scoring was performed by a histopathologist who was blinded to the group assignment. Serial blood samples were also collected and compared. Results: Rabbits that received Cl-amidine had a higher survival (72%) compared with the rabbits that received DMSO (14%; p < 0.05). Cl-amidine-treated rabbits had lower (p < 0.05) histopathologic AKI scores, as well as plasma creatinine and blood urea nitrogen (BUN) levels 12 hours after insult. Conclusions: Pan-PAD inhibitor Cl-amidine improves survival and attenuates kidney injury in LPS-induced endotoxic shock in rabbits.

Enteral Nutrition in the Mechanically Ventilated Patient

Mechanically ventilated patients are unable to take food orally and therefore are dependent on enteral nutrition for provision of both energy and protein requirements. Enteral nutrition is supportive therapy and may impact patient outcomes in the intensive care unit. Early enteral nutrition has been shown to decrease complications and hospital length of stay and improve the prognosis at discharge. Nutrition support is unique for patients on mechanical ventilation and, as recently published literature shows, should be tailored to the individuals' underlying pathology. This review will discuss the most current literature and recommendations for enteral nutrition in patients receiving mechanical ventilation.

Validation of RIFLE, AKIN, and a modified AKIN definition ("backward classification") of acute kidney injury in a general ICU: Analysis of a 1-year period

The aim of this study was to validate Acute Kidney Injury Network (AKIN) and to develop a modified AKIN aimed at an improved classification of patients without baseline creatinine versus Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease (RIFLE) in general intensive care unit (ICU) patients.We retrospectively analyzed medical records of general ICU patients over a 1-year period. We compared the grading of severity as well as the prediction of mortality and renal replacement therapy by AKIN and RIFLE. Furthermore, a modified AKIN score was evaluated.A total of 321 patients were included. In 87% of cases, the 2 definitions classified patients in the concordant severity group. Higher scores of AKIN and RIFLE were associated with increased ICU- and 28-day mortality. Both definitions provided large receiver operating characteristics (ROC)-area under the curve (AUCs) for the prediction of mortality, which were comparable to the ROC-AUC of unclassified serum creatinine. Modification of the AKIN score with a "backward classification" of baseline creatinine based on its time course resulted in a higher AKIN score in 32 patients.RIFLE and AKIN definitions had a high concordance in staging the severity of acute kidney injury. There was a strong relationship between the stages and need for dialysis, ICU, and 28-day mortality. However, unclassified serum creatinine values were at least comparable. Standardized observation of the creatinine time course allows for "ex-post" AKIN-classification in a substantial number of patients with missing baseline creatinine values.

Challenges in Outcome Reporting

Although measuring outcomes is an integral part of medical quality improvement, large-scale outcome reporting efforts face several challenges. Among these are difficulties in establishing consensus definitions for outcome measurement; classifying gray outcomes, such as postoperative respiratory failure; and adequately adjusting for patient comorbidities and severity of illness. Unintended consequences of outcome reporting can also distort care in undesirable ways, and clinician reluctance to care for high-risk patients may occur with reporting programs. Ultimately, clinicians need not compare outcomes to improve and should recognize that even outcomes that cannot be precisely quantitated can still be improved.

Incidence, timing and outcome of AKI in critically ill patients varies with the definition used and the addition of urine output criteria

Background

Acute kidney injury (AKI) is a serious complication of critical illness with both attributed morbidity and mortality at short-term and long-term. The incidence of AKI reported in critically ill patients varies substantially with the population evaluated and the definitions used. We aimed to assess which of the AKI definitions (RIFLE, AKIN or KDIGO) with or without urine output criteria recognizes AKI most frequently and quickest. Additionally, we conducted a review on the comparison of incidence proportions of varying AKI definitions in populations of critically ill patients.

Methods

We included all patients with index admissions to our intensive care unit (ICU) from January 1^st, 2014 until June 11^th, 2014 to determine the incidence and onset of AKI by RIFLE, AKIN and KDIGO during the first 7 days of ICU admission. We conducted a sensitive search using PubMed evaluating the comparison of RIFLE, AKIN and KDIGO in critically ill patients

Results

AKI incidence proportions were 15, 21 and 20% respectively using serum creatinine criteria of RIFLE, AKIN and KDIGO. Adding urine output criteria increased AKI incidence proportions to 35, 38 and 38% using RIFLE, AKIN and KDIGO definitions. Urine output criteria detected AKI in patients without AKI at ICU admission in a median of 13 h (IQR 7–22 h; using RIFLE definition) after admission compared to a median of 24 h using serum creatinine criteria (IQR24-48 h). In the literature a large heterogeneity exists in patients included, AKI definition used, reference or baseline serum creatinine used, and whether urine output in the staging of AKI is used.

Conclusion

AKIN and KDIGO criteria detect more patients with AKI compared to RIFLE criteria. Addition of urine output criteria detect patients with AKI 11 h earlier than serum creatinine criteria and may double AKI incidences in critically ill patients. This could explain the large heterogeneity observed in literature.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0487-8) contains supplementary material, which is available to authorized users.

Preadmission Use of Calcium Channel Blockers and Outcomes After Hospitalization With Pneumonia: A Retrospective Propensity-Matched Cohort Study

In sepsis, an overwhelming immune response, as mediated by the release of various inflammatory mediators, can lead to shock, multiple organ damage, and even death. Pneumonia is the leading cause of sepsis. In animal septic models, sepsis could induce uncontrolled calcium (Ca) leaking, raising cytosolic Ca to a toxic level, causing irreversible cellular injuries and organ failure. All types of calcium channel blockers (CCBs), by inhibiting Ca influx, have been shown to decrease overall mortality in various septic animal models. However, to our best knowledge, no clinical study had been conducted to investigate the beneficial effect(s) of CCBs in sepsis. We conducted a retrospective propensity-matched cohort study after screening 2214 patients hospitalized for pneumonia from year 2012 to 2014 at our institution. We identified 387 preadmission CCB users and 387 nonusers by propensity score matching. Logistic regression analysis was then used to determine the association between preadmission CCB use and outcomes in pneumonia. Our study showed that the odds for development of severe sepsis was significantly lower in the CCB user group [odds ratio (OR), 0.466; 95% confidence interval (CI), 0.311-0.697; P = 0.002]. Preadmission CCB use was associated with a lower risk of contracting bacteremia (OR, 0.498; 95% CI, 0.262-0.99; P = 0.0327), lower risk of acute respiratory insufficiency (OR, 0.573; 95% CI, 0.412-0.798; P = 0.001), lower risk of intensive care unit admission (OR, 0.602; 95% CI, 0.432-0.840; P = 0.0028). In conclusion, our study suggested preadmission CCB use was associated with a reduction in the risks of development of respiratory insufficiency, bacteremia, and severe sepsis in patients admitted to the hospital with pneumonia.

Using acute kidney injury severity and scoring systems to predict outcome in patients with burn injury

BACKGROUND/PURPOSE

Acute kidney injury (AKI) is a frequent complication of severe burn injury and is associated with mortality. The definition of AKI was modified by the Kidney Disease Improving Global Outcomes Group in 2012. So far, no study has compared the outcome accuracy of the new AKI staging guidelines with that of the complex score system. Hence, we compared the accuracy of these approaches in predicting mortality.

METHODS

This was a post hoc analysis of prospectively collected data from an intensive care burn unit in a tertiary care university hospital. Patients admitted to this unit from July 2004 to December 2006 were enrolled. Demographic, clinical, and laboratory data and prognostic risk scores were used as predictors of mortality.

RESULTS

A total of 145 adult patients with a mean age of 41.9 years were studied. Thirty-five patients (24.1%) died during the hospital course. Among the prognostic risk models, the Acute Physiology and Chronic Health Evaluation III system exhibited the strongest discriminative power and the AKI staging system also predicted mortality well (areas under the receiver operating characteristic curve: 0.889 vs. 0.835). Multivariate logistic regression analysis identified total burn surface area, ventilator use, AKI, and toxic epidermal necrolysis as independent risk factors for mortality.

CONCLUSION

Our results revealed that AKI stage has considerable discriminative power for predicting mortality. Compared with other prognostic models, AKI stage is easier to use to assess outcome in patients with severe burn injury.

Correlation of Preoperative Renal Insufficiency With Mortality and Morbidity After Aortic Valve Replacement: A Propensity Score Matching Analysis

Preoperative end-stage renal disease carries a high mortality and morbidity risk after aortic valve replacement (AVR), but the effect of renal insufficiency remains to be clarified. Through propensity score analysis, we compared the preoperative demographics, perioperative profiles, and outcomes between patients with and without renal insufficiency. From August 2005 to November 2014, 770 adult patients underwent AVR in a single institution. Patients were classified according to their estimated glomerular infiltration rate (eGFR) as renal insufficiency (eGFR: 30-89 mL/min/1.73 m) or normal (eGFR, ≥90 mL/min/1.73 m). Propensity scoring was performed with a 1:1 ratio, resulting in a matched cohort of 88 patients per group. Demographics, comorbidities, and surgical procedures were well balanced between the 2 groups, except for diabetes mellitus and eGFR. Patients with renal insufficiency had higher in-hospital mortality (19.3% versus 3.4%, P < 0.001), a greater need for postoperative hemodialysis (14.8% versus 3.1%, P = 0.009), and prolonged intubation times (>72 hour; 25% versus 9.1%, P = .008), intensive care unit stays (8.9 ± 9.9 versus 4.9 ± 7.5 days, P = .046), and hospital stays (35.3 ± 31.7 versus 24.1 ± 20.3 days, P = .008), compared with those with normal renal function. Multivariate analysis confirmed that preoperative renal insufficiency was an in-hospital mortality predictor (odds ratio, 2.33; 95% confidence interval, 1.343-4.043; P = .003), as were prolonged cardiopulmonary bypass time, intraaortic balloon pump support, and postoperative hemodialysis. The 1-year survival significantly differed between the 2 groups including (normal 87.5% versus renal insufficiency 67.9%, P < .001) or excluding in-hospital mortality (normal 90.7% versus renal insufficiency 82.1%, P = .05). Patients with preoperative renal insufficiency who underwent AVR had higher in-hospital mortality rates and increased morbidities, especially those associated with hemodynamic instabilities requiring intraaortic balloon pump support or hemodialysis. Earlier surgical intervention for severe aortic valve disease should be considered in patients who show deteriorating renal function during follow-up.

Predicting Acute Kidney Injury Following Mitral Valve Repair

BACKGROUND

Acute kidney injury (AKI) after cardiac surgery is associated with short-term and long-term adverse outcomes. Novel biomarkers have been identified for the early detection of AKI; however, examining these in every patient who undergoes cardiac surgery is prohibitively expensive. Society of Thoracic Surgeons (STS) and Age, Creatinine, and Ejection Fraction (ACEF) scores have been proven to predict mortality in bypass surgery. The aim of this study was to determine whether these scores can be used to predict AKI after mitral valve repair.

MATERIALS AND METHODS

Between January 2010 and December 2013, 196 patients who underwent mitral valve repair were enrolled. The clinical characteristics, outcomes, and scores of prognostic models were collected. The primary outcome was postoperative AKI, defined using the Kidney Disease Improving Global Outcome 2012 clinical practice guidelines for AKI.

RESULTS

A total of 76 patients (38.7%) developed postoperative AKI. The STS renal failure (AUROC: 0.797, P < .001) and ACEF scores (AUROC: 0.758, P < .001) are both satisfactory tools for predicting all AKI. The STS renal failure score exhibited superior accuracy compared with the ACEF score in predicting AKI stage 2 and 3. The overall accuracy of both scores was similar for all AKI and AKI stage 2 and 3 when the cut-off points of the STS renal failure and ACEF scores were 2.2 and 1.1, respectively.

CONCLUSION

In conclusion, the STS renal failure score can be used to accurately predict stage 2 and 3 AKI after mitral valve repair. The ACEF score is a simple tool with satisfactory power in screening patients at risk of all AKI stages. Additional studies can aim to determine the clinical implications of combining preoperative risk stratification and novel biomarkers.

The RIFLE versus AKIN classification for incidence and mortality of acute kidney injury in critical ill patients: A meta-analysis

The sensitivity and accuracy of the Risk/Injury/Failure/Loss/End-stage (RIFLE) versus acute kidney injury Network (AKIN) criteria for acute kidney injury (AKI) in critically ill patients remains uncertain. Therefore, we performed a systematic review and meta-analysis to investigate the incidence and prognostic value of the RIFLE versus AKIN criteria for AKI in critically ill patients. Literatures were identified by searching Medline, Embase, PubMed, and China National Knowledge Infrastructure (CNKI) database. Nineteen studies with 171,889 participants were included. The pooled estimates of relative risk (RR) were analyzed. We found that the RIFLE and AKIN criteria is different for the incidence of AKI in intensive care unit (ICU) patients (P = 0.02, RR = 0.88), while not for cardiac surgery patients (P = 0.30, RR = 0.93). For AKI-related hospital mortality, the AKIN criteria did not show a better ability in predicting hospital mortality in either ICU (P = 0.19, RR = 1.01) or cardiac surgery patients (P = 0.61, RR = 0.98) compared to RIFLE criteria. Our findings supported that the AKIN criteria can identify more patients in classifying AKI compared to RIFLE criteria, but not showing a better ability in predicting hospital mortality. Moreover, both RIFLE and AKIN criteria for AKI in cardiac surgery patients had better predictive ability compared with the ICU patients.

A comparison of RIFLE, AKIN, KDIGO, and Cys-C criteria for the definition of acute kidney injury in critically ill patients

PURPOSE

AKI is a major clinical problem and predictor of prognosis in critically ill patients. The aim of our study was to determine whether the new Cys-C criteria for identification and prognosis of AKI were superior to the RIFLE, AKIN, and KDIGO criteria.

METHODS

In the retrospective and multicenter study, the incidence of AKI was identified by the four criteria. Receiver operating characteristic (ROC) curve was applied to compare the predictive ability for 28-day mortality, and logistic regression analysis was used for the calculation of odds ratios and 95 % confidence intervals.

RESULTS

In the 1036 patients enrolled, the incidences of AKI were 26.4, 34.1, 37.8, and 36.1 %, respectively, under the four criteria. Patients with AKI had higher mortality and longer length of stay than those without in all definitions. Concordance in AKI diagnosis between Cys-C and KDIGO criteria was 95.9 %, higher than AKIN and RIFLE criteria (p < 0.0001). The area under ROC curves was 0.7023 for Cys-C criteria, which was a significantly greater discrimination (p < 0.05).

CONCLUSION

KDIGO criteria identified significantly more AKI and AKI patients had significantly higher 28-day mortality than patients without AKI. The Cys-C criteria were more predictive for short-term outcomes than other three criteria among critically ill patients.

Urinary Biomarkers Improve the Diagnosis of Intrinsic Acute Kidney Injury in Coronary Care Units

Acute kidney injury (AKI) is associated with increased morbidity and mortality and is frequently encountered in coronary care units (CCUs). Its clinical presentation differs considerably from that of prerenal or intrinsic AKI. We used the biomarkers calprotectin and neutrophil gelatinase-associated lipocalin (NGAL) and compared their utility in predicting and differentiating intrinsic AKI. This was a prospective observational study conducted in a CCU of a tertiary care university hospital. Patients who exhibited any comorbidity and a kidney stressor were enrolled. Urinary samples of the enrolled patients collected between September 2012 and August 2013 were tested for calprotectin and NGAL. The definition of AKI was based on Kidney Disease Improving Global Outcomes classification. All prospective demographic, clinical, and laboratory data were evaluated as predictors of AKI. A total of 147 adult patients with a mean age of 67 years were investigated. AKI was diagnosed in 71 (50.3%) patients, whereas intrinsic AKI was diagnosed in 43 (60.5%) of them. Multivariate logistic regression analysis revealed urinary calprotectin and serum albumin as independent risk factors for intrinsic AKI. For predicting intrinsic AKI, both urinary NGAL and calprotectin displayed excellent areas under the receiver operating characteristic curve (AUROC) (0.918 and 0.946, respectively). A combination of these markers revealed an AUROC of 0.946. Our result revealed that calprotectin and NGAL had considerable discriminative powers for predicting intrinsic AKI in CCU patients. Accordingly, careful inspection for medication, choice of therapy, and early intervention in patients exhibiting increased biomarker levels might improve the outcomes of kidney injury.

Comparison of the RIFLE, AKIN and KDIGO criteria to predict mortality in critically ill patients

Objective

Acute kidney injury is a common complication in critically ill patients, and the RIFLE, AKIN and KDIGO criteria are used to classify these patients. The present study's aim was to compare these criteria as predictors of mortality in critically ill patients.

Methods

Prospective cohort study using medical records as the source of data. All patients admitted to the intensive care unit were included. The exclusion criteria were hospitalization for less than 24 hours and death. Patients were followed until discharge or death. Student's t test, chi-squared analysis, a multivariate logistic regression and ROC curves were used for the data analysis.

Results

The mean patient age was 64 years old, and the majority of patients were women of African descent. According to RIFLE, the mortality rates were 17.74%, 22.58%, 24.19% and 35.48% for patients without acute kidney injury (AKI) in stages of Risk, Injury and Failure, respectively. For AKIN, the mortality rates were 17.74%, 29.03%, 12.90% and 40.32% for patients without AKI and at stage I, stage II and stage III, respectively. For KDIGO 2012, the mortality rates were 17.74%, 29.03%, 11.29% and 41.94% for patients without AKI and at stage I, stage II and stage III, respectively. All three classification systems showed similar ROC curves for mortality.

Conclusion

The RIFLE, AKIN and KDIGO criteria were good tools for predicting mortality in critically ill patients with no significant difference between them.

Septic versus non-septic acute kidney injury in critically ill patients: characteristics and clinical outcomes

OBJECTIVE

This study aimed to describe and compare the characteristics and clinical outcomes of patients with septic and non-septic acute kidney injury.

METHODS

This study evaluated an open cohort of 117 critically ill patients with acute kidney injury who were consecutively admitted to an intensive care unit, excluding patients with a history of advanced-stage chronic kidney disease, kidney transplantation, hospitalization or death in a period shorter than 24 hours. The presence of sepsis and in-hospital death were the exposure and primary variables in this study, respectively. A confounding analysis was performed using logistic regression.

RESULTS

No significant differences were found between the mean ages of the groups with septic and non-septic acute kidney injury [65.30±21.27 years versus 66.35±12.82 years, respectively; p=0.75]. In the septic and non-septic acute kidney injury groups, a predominance of females (57.4% versus 52.4%, respectively; p=0.49) and Afro-descendants (81.5% versus 76.2%, respectively; p=0.49) was observed. Compared with the non-septic patients, the patients with sepsis had a higher mean Acute Physiology and Chronic Health Evaluation II score [21.73±7.26 versus 15.75±5.98; p<0.001)] and a higher mean water balance (p=0.001). Arterial hypertension (p=0.01) and heart failure (p<0.001) were more common in the non-septic patients. Septic acute kidney injury was associated with a greater number of patients who required dialysis (p=0.001) and a greater number of deaths (p<0.001); however, renal function recovery was more common in this group (p=0.01). Sepsis (OR: 3.88; 95%CI: 1.51-10.00) and an Acute Physiology and Chronic Health Evaluation II score >18.5 (OR: 9.77; 95%CI: 3.73-25.58) were associated with death in the multivariate analysis.

CONCLUSION

Sepsis was an independent predictor of death. Significant differences were found between the characteristics and clinical outcomes of patients with septic versus non-septic acute kidney injury.

Vancomycin-associated renal dysfunction: where are we now?

Vancomycin has been in clinical use for over 60 years, during which time renal toxicity has been well documented. Multiple risk factors and outcomes are associated with vancomycin-related nephrotoxicity. Risk factors include vancomycin exposure (trough levels 15 mg/L or higher, larger area under the curve, duration of therapy), host susceptibility to vancomycin (increased body weight, preexisting renal dysfunction, critical illness), and concurrent nephrotoxin therapy. Nephrotoxicity is associated with prolonged hospital stays, mortality, and the need for renal replacement therapy. To what degree vancomycin-associated nephrotoxicity exacerbates these adverse clinical outcomes remains unclear. This article reviews the current evidence on vancomycin-associated nephrotoxicity and explores future research directions with potential implications for improved patient safety.

A comparison of different diagnostic criteria of acute kidney injury in critically ill patients

Introduction

Recently, the Kidney Disease: Improving Global Outcomes (KDIGO) proposed a new definition and classification of acute kidney injury (AKI) on the basis of the RIFLE (Risk, Injury, Failure, Loss of kidney function, and End-stage renal failure) and AKIN (Acute Kidney Injury Network) criteria, but comparisons of the three criteria in critically ill patients are rare.

Methods

We prospectively analyzed a clinical database of 3,107 adult patients who were consecutively admitted to one of 30 intensive care units of 28 tertiary hospitals in Beijing from 1 March to 31 August 2012. AKI was defined by the RIFLE, AKIN, and KDIGO criteria. Receiver operating curves were used to compare the predictive ability for mortality, and logistic regression analysis was used for the calculation of odds ratios and 95% confidence intervals.

Results

The rates of incidence of AKI using the RIFLE, AKIN, and KDIGO criteria were 46.9%, 38.4%, and 51%, respectively. KDIGO identified more patients than did RIFLE (51% versus 46.9%, P = 0.001) and AKIN (51% versus 38.4%, P <0.001). Compared with patients without AKI, in-hospital mortality was significantly higher for those diagnosed as AKI by using the RIFLE (27.8% versus 7%, P <0.001), AKIN (32.2% versus 7.1%, P <0.001), and KDIGO (27.4% versus 5.6%, P <0.001) criteria, respectively. There was no difference in AKI-related mortality between RIFLE and KDIGO (27.8% versus 27.4%, P = 0.815), but there was significant difference between AKIN and KDIGO (32.2% versus 27.4%, P = 0.006). The areas under the receiver operator characteristic curve for in-hospital mortality were 0.738 (P <0.001) for RIFLE, 0.746 (P <0.001) for AKIN, and 0.757 (P <0.001) for KDIGO. KDIGO was more predictive than RIFLE for in-hospital mortality (P <0.001), but there was no difference between KDIGO and AKIN (P = 0.12).

Conclusions

A higher incidence of AKI was diagnosed according to KDIGO criteria. Patients diagnosed as AKI had a significantly higher in-hospital mortality than non-AKI patients, no matter which criteria were used. Compared with the RIFLE criteria, KDIGO was more predictive for in-hospital mortality, but there was no significant difference between AKIN and KDIGO.

Acute kidney injury in adults receiving extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) has been utilized for critically ill patients such as patients with postcardiotomy cardiogenic shock or life-threatening respiratory failure. Acute kidney injury (AKI) that develops during ECMO is associated with a very poor outcome, possibly because of accumulated extravascular water causing interstitial overload, impaired oxygen transport through tissues, and increased extravascular lung water volume with impaired O(2) transport. Increased water is associated with subsequent organ dysfunction, particularly of the heart, lungs, and brain. Based on single-center studies, the incidence of AKI is 70-85% in ECMO patients. Therefore, renal replacement therapy is required in approximately 50% of these patients. This review summarizes three modalities that can be used to introduce renal replacement therapy to patients on ECMO, the pathophysiology of AKI in ECMO, and the impact of AKI on mortality. This review also identifies specific research-focused questions that need to be addressed to predict AKI early and to improve outcomes in this at-risk adult population.

Ketamine: synaptogenesis, immunomodulation and glycogen synthase kinase-3 as underlying mechanisms of its antidepressant properties

Major depressive disorder is an extremely debilitating condition affecting millions of people worldwide. Nevertheless, currently available antidepressant medications still have important limitations, such as a low response rate and a time lag for treatment response that represent a significant problem when dealing with individuals who are vulnerable and prone to self-harm. Recent clinical trials have shown that the N-methyl-D-aspartate receptor antagonist, ketamine, can induce an antidepressant response within hours, which lasts up to 2 weeks, and is effective even in treatment-resistant patients. Nonetheless, its use is limited due to its psychotomimetic and addictive properties. Understanding the molecular pathways through which ketamine exerts its antidepressant effects would help in the developing of novel antidepressant agents that do not evoke the same negative side effects of this drug. This review focuses specifically on the effects of ketamine on three molecular mechanisms that are relevant to depression: synaptogenesis, immunomodulation and regulation of glycogen synthase kinase-3 activity.

Lipoteichoic acid induces surfactant protein-A biosynthesis in human alveolar type II epithelial cells through activating the MEK1/2-ERK1/2-NF-κB pathway

BACKGROUND

Lipoteichoic acid (LTA), a gram-positive bacterial outer membrane component, can cause septic shock. Our previous studies showed that the gram-negative endotoxin, lipopolysaccharide (LPS), could induce surfactant protein-A (SP-A) production in human alveolar epithelial (A549) cells.

OBJECTIVES

In this study, we further evaluated the effect of LTA on SP-A biosynthesis and its possible signal-transducing mechanisms.

METHODS

A549 cells were exposed to LTA. Levels of SP-A, nuclear factor (NF)-κB, extracellular signal-regulated kinase 1/2 (ERK1/2), and mitogen-activated/extracellular signal-regulated kinase kinase (MEK)1 were determined.

RESULTS

Exposure of A549 cells to 10, 30, and 50 μg/ml LTA for 24 h did not affect cell viability. Meanwhile, when exposed to 30 μg/ml LTA for 1, 6, and 24 h, the biosynthesis of SP-A mRNA and protein in A549 cells significantly increased. As to the mechanism, LTA enhanced cytosolic and nuclear NF-κB levels in time-dependent manners. Pretreatment with BAY 11-7082, an inhibitor of NF-κB activation, significantly inhibited LTA-induced SP-A mRNA expression. Sequentially, LTA time-dependently augmented phosphorylation of ERK1/2. In addition, levels of phosphorylated MEK1 were augmented following treatment with LTA.

CONCLUSIONS

Therefore, this study showed that LTA can increase SP-A synthesis in human alveolar type II epithelial cells through sequentially activating the MEK1-ERK1/2-NF-κB-dependent pathway.

A critical appraisal of the accuracy of the RIFLE and AKIN classifications in defining "acute kidney insufficiency" in critically ill patients

PURPOSE

The lack of a consensus definition for acute kidney injury (AKI) has led to a great deal of discrepancies and confusion in the literature in this field. Thus, the RIFLE (Risk of renal dysfunction, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage renal disease) and Acute Kidney Injury Network (AKIN) classifications were developed by multidisciplinary collaborative groups and were validated by experts in an international consensus conference in 2007 under an umbrella "acute kidney insufficiency" definition.

METHODS

Search in the MEDLINE and PUBMED databases for relevant literature from January 2000 to June 2011 was performed to assess the accuracy of the novel consensus definitions for AKI.

CONCLUSIONS

Both systems are based on serum creatinine level and urine output criteria and are staged in 3 severity levels. A major difference between these 2 classifications is that smaller and more rapid changes in serum creatinine are considered in the AKIN stage 1. Each AKI classification has demonstrated its ability to stratify patients according to their AKI severity and to predict outcomes. No classification system has been shown to be superior over the others. Their application in clinical studies would benefit from standardization and the new Kidney Disease Improving Global Outcomes definition of AKI was recently proposed to achieve this aim. Because these classifications do not allow earlier AKI diagnosis and do not optimize the timing of RRT initiation, they remain of moderate utility from the patient's point of view.

Impact of acute kidney injury on one-year survival after surgery for aortic dissection

BACKGROUND

Surgical treatment is an option for both type A aortic dissection and complicated type B aortic dissection. Acute kidney injury (AKI) influences the disease course after surgery. Our hypothesis was that AKI should be an important prognostic factor for aortic dissection after surgical treatment.

METHODS

Between July 2005 and October 2010, 268 patients (mean age 53 ± 14 years; range, 16 to 88) underwent open surgery for aortic dissection. We reviewed the clinical presentations, surgical variables, and postoperative outcomes to identify the risk factors of death. The 256 patients were divided into groups, with and without AKI, within 24 hours after operation according to the RIFLE (acronym for risk, injury, failure, loss, end stage) criteria.

RESULTS

The in-hospital mortality rate was 17.9%, the 1-year mortality rate was 18.7%, and the major adverse cardiac events rate within 1 year was 29.9%. In multivariate analysis, patients more than 70 years of age (hazard ratio [HR] 2.390, p = 0.029), cardiogenic shock (HR 2.895, p = 0.005), preoperative ventilator use (HR 4.137, p = 0.018), operation at midnight (HR 2.295, p = 0.028), longer bypass time (HR 1.007, p < 0.001), and AKI (HR 2.552, p = 0.041) were clinical predictors of mortality. Kaplan-Meier analysis showed that the survival rate was strongly correlated with the severity of AKI by the RIFLE criteria. The independent predictors of AKI included hypertension (odds ratio 2.340, p = 0.027), sepsis (odds ratio 2.594, p = 0.043), and lower limb malperfusion (odds ratio 4.558, p = 0.022).

CONCLUSIONS

Our study provides outcomes of postoperative aortic dissection. We found that AKI was a predictor of 1-year mortality by using the RIFLE criteria. Factors associated with increased 1-year mortality and AKI should be taken into consideration for surgery and postoperative care.

Acute azotemia as a predictor of mortality in dogs and cats

BACKGROUND

Acute kidney injury (AKI) has been shown to be a predictor of mortality in human medicine. Published studies in the veterinary literature evaluating relative changes in serum creatinine concentration as a prognostic factor are limited.

OBJECTIVE

To evaluate an AKI grading system based on serum creatinine concentration to determine if it correlates with outcome prediction in dogs and cats.

ANIMALS

Six hundred forty-five dogs and 209 cats that had at least 2 serum creatinine concentration measurements measured within 7 days.

METHODS

Retrospective study. Dogs and cats with an initial serum creatinine concentrations of ≤ 1.6 mg/dL and that had more than 1 concentration measured within 2, 3, and 7 days were placed into levels (0-2) based on absolute changes. Mortality then was determined at 30 and 90 days.

RESULTS

Based on odds ratios calculated with a 95% confidence interval, dogs placed in level 1 within 2 days were approximately 3 times more likely to die within 90 days. Dogs placed in level 2 within 2, 3, or 7 days were approximately 3 times more likely to die within 30 or 90 days. Cats placed in level 2 within 3 or 7 days were approximately 3 times more likely to die at 30 days and 4 times more likely to die if placed in this level within 7 days. If placed in level 2 within 2 or 3 days, cats were approximately 3 times more likely to die within 90 days.

CONCLUSIONS AND CLINICAL IMPORTANCE

Detecting increasing severity of azotemia helps predict mortality in dogs and cats.

Early prediction of acute kidney injury in patients with acute myocardial injury

INTRODUCTION

Previous studies have revealed that acute myocardial infarction (AMI) with acute kidney injury (AKI), about 17%, is strongly related to long-term mortality and heart failure. The dynamic changes in renal function during AMI are strongly related to long-term mortality and heart failure.

OBJECTIVES

Our study used clinical parameters and AKI biomarkers including neutrophil gelatinase-associated lipocalin, interleukin (IL)-6, IL-18, and cystatin C to evaluate prognostic relevance of AKI in the setting of AMI.

METHODS

This prospective study was conducted from November 2009 to January 2011 and enrolled sequential 96 patients with catheter-proven AMI; it was approved by the institutional review board of Chang Gung Memorial Hospital, Taiwan (institutional review board no. 99-0140B) and conformed to the tenets of the Declaration of Helsinki. The definition of AKI is the elevation of serum creatinine of more than 0.3 mg/dL within 48 hours.

RESULTS

Our results show that the incidence of AKI after AMI is 17.7% (17 patients). The following could be statistically related to AKI after AMI: age (P = .012), cardiac functions (Killip stage and echocardiogram; P = .003 each), Thrombolysis in Myocardial Infarction (TIMI) flow grade (P < .001), stenting (P < .001), neutrophil gelatinase-associated lipocalin (P = .005), IL-6 (P = .01), IL-18 (P = .002), and cystatin C (P = .002) in serum. The TIMI flow grade and serum cystatin C were shown to be important predictors by using multivariate analysis. Both TIMI flow lower than grade 2 and serum cystatin C of more than 1364 mg/L could be used to predict AKI (both overall correctness, 0.78). Moreover, IL-6 in serum is also associated with the major cardiovascular events after AMI (P = .02), as demonstrated in our study.

CONCLUSION

In conclusion, the worse TIMI flow and high plasma cystatin C can be used to predict AKI after AMI. Moreover, IL-6 can also be used as a 30-day major cardiovascular event indicator after AMI. A larger prospective and longitudinal study should follow the relationship between AKI predictors after AMI.

Renal angina: an emerging paradigm to identify children at risk for acute kidney injury

Acute kidney injury (AKI) leads to high rates of morbidity and independently increases mortality risk. Therapy for AKI is likely limited by the inability to reliably diagnose AKI in its early stages, and, importantly, small changes in serum creatinine may be associated with poor outcomes and severe AKI. Whereas AKI biomarker research seeks to identify more sensitive and timely indices of kidney dysfunction, AKI lacks physical signs and symptoms to trigger biomarker assessment in at-risk patients, limiting biomarker efficacy. Accurate models of AKI prediction are unavailable. Severity of illness (SOI) scoring systems and organ dysfunction scores (OD), which stratify patients by prediction of mortality risk, are AKI reactive, not predictive. Kidney-specific severity scores do not account for AKI progression, and stratification models of AKI severity are not predictive of AKI. Thus, there is a need for a kidney scoring system that can help predict the development of AKI. This review highlights the concept of renal angina, a combination of patient risk factors and subtle AKI, as a methodology to predict AKI progression. Fulfillment of renal angina criteria will improve the efficiency of AKI prediction by biomarkers, in turn expediting early therapy and assisting in creation of AKI-predictive scoring systems.

Outcome scoring systems for short-term prognosis in critically ill cirrhotic patients

Cirrhotic patients admitted to intensive care units (ICUs) have high mortality rates. This study evaluated specific predictors and scoring systems for hospital and 6-month mortality in critically ill cirrhotic patients. This investigation is a prospective clinical study performed in a 10-bed specialized hepatogastroenterology ICU in a tertiary care university hospital in Taiwan. Two hundred two consecutive cirrhotic patients admitted to the ICU during a 2-year period were enrolled in this study. Demographic, clinical, and laboratory variables recorded on the first day of ICU admission and scoring systems applied were prospectively recorded for post hoc analysis for predicting survival. The overall hospital mortality was 59.9%, and the 6-month mortality rate was 70.8%. The main causes of cirrhosis were hepatitis B (29%), hepatitis C (22%), and alcoholism (20%). The major cause of ICU admission was upper gastrointestinal bleeding (36%). Multiple logistic regression analysis revealed that the Acute Kidney Injury Network (AKIN) score at the 48th hour of ICU admission and the Sequential Organ Failure Assessment (SOFA) as well as the Model for End-Stage Liver Disease scores on the first day of ICU admission were independent risk factors for hospital mortality. The SOFA score had the best discriminatory power (0.872 ± 0.036), whereas the AKIN had the best Youden index (0.57) and the highest correctness of prediction (79%). Cumulative survival rates at the 6-month follow-up after hospital discharge differed significantly (P < 0.05) for AKIN stage 0 vs. stages 1, 2, and 3, and for AKIN stage 1 vs. stage 3. The AKIN, SOFA, and Model for End-stage Liver Disease (MELD) scores showed well discriminative power in predicting hospital mortality in this group of patients. The AKIN scoring system proved to be a reproducible evaluation tool with excellent prognostic abilities for these patients.

Acute kidney injury classification: AKIN and RIFLE criteria in critical patients

Acute kidney injury (AKI) is a common and serious complication in critically ill patients. The mortality rate remains high despite improved renal replacement techniques. A possible cause of the high mortality rate is that intensive care unit patients tend to be older and more debilitated than before. Pathophysiological factors associated with AKI are also implicated in the failure of other organs, indicating that AKI is often part of a multiple organ failure syndrome. Until recently, there was a lack of consensus as to the best definition, characterization, and evaluation of acute renal failure. This lack of a standard definition has been a major impediment to progress in clinical and basic research. The introduction of the risk, injury, failure, loss, and end-stage kidney disease criteria and the modified version proposed by the Acute Kidney Injury Network have increased the conceptual understanding of AKI syndrome, and these criteria have been successfully tested in clinical studies. This article reviews current findings concerning the application of these criteria for assessing epidemiology and predicting outcome in specific homogeneous critically ill patient groups.

Induction of intestinal pro-inflammatory immune responses by lipoteichoic acid

Background

The cellular and molecular mechanisms of inflammatory bowel disease are not fully understood; however, data indicate that uncontrolled chronic inflammation induced by bacterial gene products, including lipoteichoic acid (LTA), may trigger colonic inflammation resulting in disease pathogenesis. LTA is a constituent glycolipid of Gram-positive bacteria that shares many inflammatory properties with lipopolysaccharide and plays a critical role in the pathogenesis of severe inflammatory responses via Toll-like receptor 2. Accordingly, we elucidate the role of LTA in immune stimulation and induced colitis in vivo.

Methods

To better understand the molecular mechanisms utilized by the intestinal microbiota and their gene products to induce or subvert inflammation, specifically the effect(s) of altered surface layer protein expression on the LTA-mediated pro-inflammatory response, the Lactobacillus acidophilus surface layer protein (Slp) genes encoding SlpB and SlpX were deleted resulting in a SlpB^- and SlpX^- mutant that continued to express SlpA (assigned as NCK2031).

Results

Our data show profound activation of dendritic cells by NCK2031, wild-type L. acidophilus (NCK56), and purified Staphylococcus aureus-LTA. In contrary to the LTA-deficient strain NCK2025, the LTA-expressing strains NCK2031 and NCK56, as well as S. aureus-LTA, induce pro-inflammatory innate and T cell immune responses in vivo. Additionally, neither NCK2031 nor S. aureus-LTA supplemented in drinking water protected mice from DSS-colitis, but instead, induced significant intestinal inflammation resulting in severe colitis and tissue destruction.

Conclusions

These findings suggest that directed alteration of two of the L. acidophilus NCFM-Slps did not ameliorate LTA-induced pro-inflammatory signals and subsequent colitis.

A systematic review of RIFLE criteria in children, and its application and association with measures of mortality and morbidity

The RIFLE criteria were developed to improve consistency in the assessment of acute kidney injury. The high face validity, collaborative development method, and validation against mortality have supported the widespread adoption of the RIFLE to evaluate adult patients; however, its inconsistent application in adult studies is associated with significant effects on the estimated incidence of acute kidney injury. As the RIFLE criteria are now being used to determine acute kidney injury in children, we conducted a systematic review to describe its application and assess associations between the RIFLE and measures of mortality and morbidity in pediatric patients. In 12 studies we found wide variation in the application of the RIFLE, including the range of assessed RIFLE categories, omission of urine output criteria, varying definitions of baseline renal function, and methods for handling missing baseline measurements. Limited and conflicting associations between the RIFLE and mortality, length of stay, illness severity, and measures of kidney function were found. Thus, although the RIFLE was developed to improve the consistency of defining acute kidney injury, there are still major discrepancies in its use in pediatric patients that may undermine its potential utility as a standardized measure of acute kidney injury in children.

Risk of poor outcomes with novel and traditional biomarkers at clinical AKI diagnosis

BACKGROUND AND OBJECTIVES

Studies have evaluated acute kidney injury (AKI) using biomarkers in various settings, but their prognostic utility within current practice is unclear. Thus, we sought to determine the prognostic utility of newer biomarkers or traditional markers (fractional excretion of sodium [FeNa] and urea [FeUrea] and microscopy) over clinical assessment alone.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a prospective cohort study of adults on the first day of meeting AKI criteria. We measured urine concentrations of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and IL-18 and determined FeNa, FeUrea, and microscopy score for casts and tubular cells. Primary outcome was worsened AKI stage from enrollment to peak serum creatinine or in-hospital death.

RESULTS

In 249 recipients, 57% were ≥65 years old, 48% were from intensive care, and mean baseline GFR was 69 ± 30 ml/min per 1.73 m(2). AKI was considered prerenal in 164 (66%), acute tubular necrosis (ATN) in 51 (20%), and "other" in 34 (14%). All mean protein biomarker concentrations, FeNa, FeUrea, and microscopy scores were statistically different between prerenal and ATN. Seventy-two patients (29%) developed the primary outcome. There was an approximate three-fold increase in adjusted risk for the outcome for upper versus lower values of NGAL, KIM-1, IL-18, and microscopy score (P values <0.05). Net reclassification improved after adding these to baseline clinical assessment. FeNa and FeUrea were not useful.

CONCLUSIONS

On the first day of AKI, urine protein biomarkers and microscopy significantly improve upon clinical determination of prognosis, indicating their potential utility in current practice.

Management of hematological malignancies in patients affected by renal failure

The management of hematological malignancies (HM) in renally impaired patients may be a difficult task. Indeed, the kidney represents a major elimination pathway for many chemotherapeutic agents and their metabolites, whose serum levels are not usually measured in daily clinical practice. In addition, many antineoplastic drugs have a narrow therapeutic index for which they require dose adjustment when administered to patients with renal failure. Only limited data regarding the use of chemotherapy in patients with renal impairment and in those on dialysis are available. Indeed, renal patients with HM are often excluded from most clinical trials. Thus far, in order to provide recommendations, we have reviewed the pertinent literature, gathering information from published guidelines regarding chemotherapy in patients with kidney dysfunction and from articles describing the use of individual agents in renal patients with HM.

Ketamine depresses toll-like receptor 3 signaling in spinal microglia in a rat model of neuropathic pain

Reports suggest that microglia play a key role in spinal nerve ligation (SNL)-induced neuropathic pain, and toll-like receptor 3 (TLR3) has a substantial role in the activation of spinal microglia and the development of tactile allodynia after nerve injury. In addition, ketamine application could suppress microglial activation in vitro, and ketamine could inhibit proinflammatory gene expression possibly by suppressing TLR-mediated signal transduction. Therefore, the present study was designed to disclose whether intrathecal ketamine could suppress SNL-induced spinal microglial activation and exert some antiallodynic effects on neuropathic pain by suppressing TLR3 activation. Behavioral results showed that intrathecal ketamine attenuated SNL-induced mechanical allodynia, as well as spinal microglial activation, in a dose-dependent manner. Furthermore, Western blot analysis displayed that ketamine application downregulated SNL-induced phosphorylated-p38 (p-p38) expression, which was specifically expressed in spinal microglia but not in astrocytes or neurons. Besides, ketamine could reverse TLR3 agonist (polyinosine-polycytidylic acid)-induced mechanical allodynia and spinal microglia activation. It was concluded that intrathecal ketamine depresses TLR3-induced spinal microglial p-p38 mitogen-activated protein kinase pathway activation after SNL, probably contributing to the antiallodynic effect of ketamine on SNL-induced neuropathic pain.

Prognosis of patients on extracorporeal membrane oxygenation: the impact of acute kidney injury on mortality

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been utilized for patients in critical condition, such as those with life-threatening respiratory failure or postcardiotomy cardiogenic shock. This study analyzed the outcomes of patients treated with ECMO and identified the relationship between prognosis and the Acute Kidney Injury Network (AKIN) scores obtained at pre-ECMO support (AKIN0-hour); and at post-ECMO support 24 hours (AKIN24-hour) and 48 hours (AKIN48-hour).

METHODS

This study reviewed the medical records of 102 critically ill patients on ECMO support at a specialized intensive care unit at a tertiary care university hospital between March 2002 and January 2008. Demographic, clinical, and laboratory variables were retrospectively collected as survival predicators.

RESULTS

The overall mortality rate was 57.8%. The most common condition requiring ECMO support was cardiogenic shock. Goodness-of-fit was good for AKIN0-hour, AKIN24-hour, and AKIN48-hour criteria. The AKIN0-hour, AKIN24-hour, and AKIN48-hour scoring systems also had excellent areas under the receiver operating characteristic curve (0.804±0.046, 0.811±0.045, and 0.858±0.040, respectively). Furthermore, multiple logistic regression analysis indicated that AKIN48-hour, age, and Glasgow Coma Scale score on the first day of intensive care unit admission were independent risk factors for hospital mortality. Finally, cumulative survival rates at 6-month follow-up after hospital discharge differed significantly (p<0.05) for AKIN48-hour stage 0 versus AKIN48-hour stages 1, 2, and 3; and AKIN48-hour stage 1 and 2 versus AKIN48-hour stage 3.

CONCLUSIONS

During ECMO support, the AKIN48-hour scoring system proved to be a reproducible evaluation tool with excellent prognostic abilities for these patients.

Inhibition of spinal astrocytic c-Jun N-terminal kinase (JNK) activation correlates with the analgesic effects of ketamine in neuropathic pain

Background

We have previously reported that inhibition of astrocytic activation contributes to the analgesic effects of intrathecal ketamine on spinal nerve ligation (SNL)-induced neuropathic pain. However, the underlying mechanisms are still unclear. c-Jun N-terminal kinase (JNK), a member of mitogen-activated protein kinase (MAPK) family, has been reported to be critical for spinal astrocytic activation and neuropathic pain development after SNL. Ketamine can decrease lipopolysaccharide (LPS)-induced phosphorylated JNK (pJNK) expression and could thus exert its anti-inflammatory effect. We hypothesized that inhibition of astrocytic JNK activation might be involved in the suppressive effect of ketamine on SNL-induced spinal astrocytic activation.

Methods

Immunofluorescence histochemical staining was used to detect SNL-induced spinal pJNK expression and localization. The effects of ketamine on SNL-induced mechanical allodynia were confirmed by behavioral testing. Immunofluorescence histochemistry and Western blot were used to quantify the SNL-induced spinal pJNK expression after ketamine administration.

Results

The present study showed that SNL induced ipsilateral pJNK up-regulation in astrocytes but not microglia or neurons within the spinal dorsal horn. Intrathecal ketamine relieved SNL-induced mechanical allodynia without interfering with motor performance. Additionally, intrathecal administration of ketamine attenuated SNL-induced spinal astrocytic JNK activation in a dose-dependent manner, but not JNK protein expression.

Conclusions

The present results suggest that inhibition of JNK activation may be involved in the suppressive effects of ketamine on SNL-induced spinal astrocyte activation. Therefore, inhibition of spinal JNK activation may be involved in the analgesic effects of ketamine on SNL-induced neuropathic pain.

Clinical accuracy of RIFLE and Acute Kidney Injury Network (AKIN) criteria for acute kidney injury in patients undergoing cardiac surgery

Introduction

The RIFLE (risk, injury, failure, loss of kidney function, and end-stage renal failure) classification for acute kidney injury (AKI) was recently modified by the Acute Kidney Injury Network (AKIN). The two definition systems differ in several aspects, and it is not clearly determined which has the better clinical accuracy.

Methods

In a retrospective observational study we investigated 4,836 consecutive patients undergoing cardiac surgery with cardiopulmonary bypass from 2005 to 2007 at Mayo Clinic, Rochester, MN, USA. AKI was defined by RIFLE and AKIN criteria.

Results

Significantly more patients were diagnosed as AKI by AKIN (26.3%) than by RIFLE (18.9%) criteria (P < 0.0001). Both definitions showed excellent association to outcome variables with worse outcome by increased severity of AKI (P < 0.001, all variables). Mortality was increased with an odds ratio (OR) of 4.5 (95% CI 3.6 to 5.6) for one class increase by RIFLE and an OR of 5.3 (95% CI 4.3 to 6.6) for one stage increase by AKIN. The multivariate model showed lower predictive ability of RIFLE for mortality. Patients classified as AKI in one but not in the other definition set were predominantly staged in the lowest AKI severity class (9.6% of patients in AKIN stage 1, 2.3% of patients in RIFLE class R). Potential misclassification of AKI is higher in AKIN, which is related to moving the 48-hour diagnostic window applied in AKIN criteria only. The greatest disagreement between both definition sets could be detected in patients with initial postoperative decrease of serum creatinine.

Conclusions

Modification of RIFLE by staging of all patients with acute renal replacement therapy (RRT) in the failure class F may improve predictive value. AKIN applied in patients undergoing cardiac surgery without correction of serum creatinine for fluid balance may lead to over-diagnosis of AKI (poor positive predictive value). Balancing limitations of both definition sets of AKI, we suggest application of the RIFLE criteria in patients undergoing cardiac surgery.

Outcome scoring systems for acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is commonly diagnosed in intensive care units (ICUs), often in association with acute kidney injury. In this study, we compared the predictive value of outcome scoring systems: Acute Physiology and Chronic Health Evaluation IV (APACHE IV), earlier APACHE models, Sequential Organ Failure Assessment (SOFA), the Risk of renal failure, Injury to the kidney, Failure of kidney function, Loss of kidney function, and End-stage renal failure (RIFLE) classification, and Acute Lung Injury score in critically ill patients with ARDS. We retrospectively abstracted data from the medical records of 135 critically ill ARDS patients in two medical ICUs of a tertiary care hospital from December 1999 to June 2006. Overall mortality rate was 65% (88/135). Forward conditional logistic regression identified APACHE IV, alveolar-arterial O2 tension difference, age, sepsis, and maximum RIFLE (RIFLEmax) score on ICU days 1 and 3 to be independent predictors of hospital mortality. The area under the receiver operating characteristic curve for the APACHE IV score revealed good fit (Hosmer and Lemeshow goodness-of-fit test results) and discriminative power (area under the receiver operating characteristic curve, 0.792 ± 0.038; P < 0.001). The cumulative survival rates at 6-month follow-up after hospital discharge were significantly (P < 0.001) different among ARDS patients with APACHE IV mortality rate 35% or less and APACHE IV mortality rate higher than 35%. The APACHE IV score and RIFLEmax score are predictors of hospital mortality in ARDS patients, with APACHE IV demonstrating desirable properties of prognostic accuracy.

Acute kidney injury in patients with hemorrhagic fever with renal syndrome caused by Hantaan virus: comparative evaluation by RIFLE and AKIN criteria

Acute kidney injury (AKI) is one of the most prominent characteristics of hemorrhagic fever with renal syndrome (HFRS) caused by Hantaan virus. The present study evaluated the incidence and severity of AKI classified by both the RIFLE and AKIN criteria in 120 HFRS patients at 48  h and 1 week of the patient admission. The agreements between RIFLE and AKIN and RIFLE and AKIN defined by serum creatinine (AKINc and RIFLEc) were examined by Kappa statistics. AKI occurred in 79.2% and 82.5% at 48  h and in 84.2% and 89.2% at 1 week of admission by RIFLE and AKIN criteria, respectively. RIFLE and AKIN showed very good agreement in classifying AKI at 48  h and 1 week of admission (κ > 0.900). RIFLE and RIFLEc and AKIN and AKINc at 48  h and 1 week of admission had almost perfect agreement (κ > 0.900). The classifications of RIFLE and RIFLEc and AKIN and AKINc at 48  h and 1 week were in good agreement (κ > 0.650). AKI classifications by RIFLE and AKIN were associated with mortality, occurrence of complications, and length of hospital stay. We conclude that AKI occurs in nearly 90% of HFRS patients during the disease course. RIFLE and AKIN classify AKI in HFRS with similar sensitivity. RIFLEc and AKINc may be used as alternatives of standard RIFLE and AKIN in the settings of general wards. The AKI classifications defined at 48  h of admission have predictive value for HFRS disease progression and severity.

Acute kidney injury: can we improve prognosis?

The incidence of pediatric acute kidney injury (AKI) is increasing. AKI has been found to be independently associated with increased mortality, and current management options are limited in that they are mainly supportive. The use of various definitions of AKI can still be found in the literature, making it difficult to discern the epidemiology behind pediatric AKI. The use of a more uniform definition is a necessary first step to clarify AKI epidemiology and direct our research efforts, and it will ultimately improve prognosis. There is evidence that neonates and infants may be at higher risk for AKI than adults. However, the least amount of research is found for this youngest age group, and more focused efforts on this population are necessary. This paper reviews existing data on and definitions for pediatric AKI, general preventive and treatment strategies, as well as ongoing research efforts on AKI. We are hopeful that the prognosis of AKI will improve with collaboration on a multicenter, multinational scale in the form of prospective, long-term studies on pediatric AKI.

Early and small changes in serum creatinine concentrations are associated with mortality in mechanically ventilated patients

Emerging evidence suggests that minor changes in serum creatinine concentrations are associated with increased hospital mortality rates. However, whether serum creatinine concentration (SCr) on admission and its change are associated with an increased mortality rate in mechanically ventilated patients is not known. We have conducted an international, prospective, observational cohort study enrolling adult intensive care unit patients under mechanical ventilation (MV). Recursive partitioning was used to determine the values of SCr at the start of MV (SCr0) and the change in SCr ([DeltaSCr] defined as the maximal difference between the value at start of MV [day 0] and the value on MV day 2 at 8:00 am) that best discriminate mortality. In-hospital mortality, adjusted by a proportional hazards model, was the primary outcome variable. A total of 2,807 patients were included; median age was 59 years and median Simplified Acute Physiology Score II was 44. All-cause in-hospital mortality was 44%. The variable that best discriminated outcome was a SCr0 greater than 1.40 mg/dL (mortality, 57% vs. 36% for patients with SCr0 <or=1.40 mg/dL, P < 0.001). Among patients with SCr0 less than or equal to 1.40 mg/dL, DeltaSCr greater than 0.31 discriminated mortality (56% vs. 34%, P < 0.001). In multivariate analysis, geographic area, advanced age, severity of illness, reason for MV, and cardiovascular and hepatic failure were also associated with mortality. Our study suggests that SCr0 greater than 1.40 mg/dL and, in patients with low baseline SCr, a DeltaSCr greater than 0.31 are predictors of in-hospital mortality in mechanically ventilated patients.

Acute kidney injury in non-critically ill children treated with aminoglycoside antibiotics in a tertiary healthcare centre: a retrospective cohort study

BACKGROUND

Aminoglycosides (AG) cause acute kidney injury (AKI), but the incidence and severity distribution are unclear, particularly in non-critically ill children. We determined the incidence, severity and risk factors of AG-associated AKI and assessed for associations with longer hospitalization and higher costs.

METHODS

At Texas Children's Hospital, we conducted a retrospective cohort study of children treated with AG for ≥ 5 days in 2005, excluding children with admission primary renal diagnoses. AKI was defined by the paediatric Risk, Injury, Failure, Loss, End Stage Kidney Disease (pRIFLE) and Acute Kidney Injury Network (AKIN) definitions. Multiple logistic and linear regression analyses were used to assess independence of associations with outcomes.

RESULTS

Five hundred and fifty-seven children [mean ± SD age = 8.0 ± 5.9 years, 286 (51%) male, 489 (88%) gentamicin] were studied. The AKI rate was 33% and 20% by pRIFLE and AKIN definitions, respectively. Longer treatment, higher baseline estimated glomerular filtration rate, being on a medicine (versus surgical) treatment service and prior AG treatment were independent risk factors for AKI development. AKI by pRIFLE or AKIN was independently associated with longer hospital stay and higher total hospital costs. The pRIFLE definition was more sensitive for AKI detection, but the AKIN definition was more strongly related to outcomes.

CONCLUSIONS

AKI is common and associated with poorer outcomes in non-critically ill children treated with AG. Future research should attempt to understand how to best define AKI in the non-critical illness paediatric setting.