Prognosis of patients with acute renal failure in the intensive-care unit: a tale of two eras

Safety Summary of the Selective Cytopheretic Device: A Review of Safety Data Across Multiple Clinical Trials in ICU Patients With Acute Kidney Injury and Multiple Organ Failure

OBJECTIVES

Acute kidney injury (AKI) requiring continuous kidney replacement therapy is a significant complication in ICU patients with mortality rates exceeding 50%. A dysregulated immune response can lead to systemic inflammation caused by hyperactivity of pro-inflammatory neutrophils and monocytes leading to tissue damage. The selective cytopheretic device (SCD) is an investigational medical device in a new class of cell-directed extracorporeal therapies distinct from cytokine adsorbers or filters, as it targets activated leukocytes. These leukocytes are the cellular sources driving this hyperinflammatory process. The objective of this report is to summarize the safety experience from clinical studies of the SCD in ICU patients with AKI or acute respiratory distress syndrome (ARDS) and multiple organ dysfunction (MOD).

DATA SOURCES AND STUDY SELECTION

The studies included in this report represent all relevant trials of the SCD conducted in patients with AKI or ARDS and MOD. Adverse event data, clinical laboratory data and mortality rates were described and summarized in this report.

DATA EXTRACTION AND DATA SYNTHESIS

Five clinical studies were included in this report, including four adult studies of AKI and/or ARDS and one pediatric AKI study, which involved 151 patients treated with the SCD in an ICU setting. Over 800 SCD sessions were deployed with an estimated 19,000 exposure hours with no device-related infections or attributable serious adverse events. Furthermore, there were no safety signals of leukopenia, thrombocytopenia, or other indications of immunodepletion or immunosuppression.

CONCLUSIONS

The SCD has shown to be a promising extracorporeal therapy with promising clinical results and a favorable safety profile. These studies support that the SCD can be added as a therapeutic intervention in critically ill AKI patient populations with multiple organ failure without adding additional safety risks.

Rationale and Design of NEUTRALIZE-AKI: A Multicenter, Randomized, Controlled, Pivotal Study to Assess the Safety and Efficacy of a Selective Cytopheretic Device in Patients with Acute Kidney Injury Requiring Continuous Kidney Replacement Therapy

INTRODUCTION

NEUTRALIZE-AKI is a pivotal study to evaluate the safety and effectiveness of the selective cytopheretic device (SCD) in adult patients with acute kidney injury (AKI) requiring continuous kidney replacement therapy (CKRT).

METHODS/DESIGN

This is a two-arm, randomized, open-label, controlled multi-center pivotal US study which will enroll 200 adult patients (age 18-80 years) in the intensive care unit with acute kidney injury requiring CKRT and at least one additional organ failure across 30 clinical centers. Eligible patients will be randomized to CKRT plus SCD therapy versus CKRT alone. Therapy will be administered for up to 10 days, with the hypothesis that the CKRT plus SCD group will demonstrate a lower mortality rate or better rate of renal recovery than the CKRT alone group by day 90. The primary outcome is a composite of dialysis dependence or all-cause mortality at day 90.

CONCLUSION

The SCD is a cell-directed extracorporeal therapy that targets and deactivates pro-inflammatory neutrophils and monocytes, with evidence of efficacy across a variety of critically ill patient populations. Knowledge and experience from many of those studies and other AKI trials were incorporated into the design of this pivotal study, with the aim to investigate the role of effector cell immunomodulation in the intervention of AKI.

Predicting the Need for Renal Replacement Therapy Using a Vascular Occlusion Test and Tissue Oxygen Saturation in Patients in the Early Phase of Multiorgan Dysfunction Syndrome

Background: Acute kidney injury (AKI) is associated with an increased mortality in critically ill patients, especially in patients with multiorgan dysfunction syndrome (MODS). In daily clinical practice, the grading of AKI follows the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. In most cases, a relevant delay occurs frequently between the onset of AKI and detectable changes in creatinine levels as well as clinical symptoms. The aim of the present study was to examine whether a near infrared spectroscopy (NIRS)-based, non-invasive ischemia–reperfusion test (vascular occlusion test (VOT)) together with unprovoked (under resting conditions) tissue oxygen saturation (StO₂) measurements, contain prognostic information in the early stage of MODS regarding the developing need for renal replacement therapy (RRT). Methods: Within a period of 18 months, patients at the medical intensive care unit of a tertiary university hospital with newly developed MODS (≤24 h after diagnosis, APACHE II score ≥20) were included in our study. The VOT occlusion slope (OS) and recovery slope (RS) were recorded in addition to unprovoked StO₂. StO₂ was determined non-invasively in the area of the thenar muscles using a bedside NIRS device. The VOT was carried out by inflating a blood pressure cuff on the upper arm. AKI stages were determined by the changes in creatinine levels, urinary output, and/or the need for RRT according to KDIGO. Results: 56 patients with MODS were included in the study (aged 62.5 ± 14.4 years, 40 men and 16 women, APACHE II score 34.5 ± 6.4). Incidences of the different AKI stages were: no AKI, 16.1% (n = 9); AKI stage I, 19.6% (n = 11); AKI stage II, 25% (n = 14); AKI stage III, 39.3% (n = 22). Thus, 39.3% of the patients (n = 22) developed the need for renal replacement therapy (AKI stage III). These patients had a significantly higher mortality over 28 days (RRT, 72% (n = 16/22) vs. no RRT, 44% (n = 15/34); p = 0.03). The mean unprovoked StO₂ of all patients at baseline was 81.7 ± 11.1%, and did not differ between patients with or without the need for RRT. Patients with RRT showed significantly weaker negative values of the OS (−9.1 ± 3.7 vs. −11.7 ± 4.1%/min, p = 0.01) and lower values for the RS (1.7 ± 0.9 vs. 2.3 ± 1.6%/s, p = 0.02) compared to non-dialysis patients. Consistent with these results, weaker negative values of the OS were found in higher AKI stages (no AKI, −12.7 ± 4.1%/min; AKI stage I, −11.5 ± 3.0%/min; AKI stage II, −11.1 ± 3.3%/min; AKI stage III, −9.1 ± 3.7%/min; p = 0.021). Unprovoked StO₂ did not contain prognostic information regarding the AKI stages. Conclusions: The weaker negative values of the VOT parameter OS are associated with an increased risk of developing AKI and RRT, and increased mortality in the early phase of MODS, while unprovoked StO₂ does not contain prognostic information in that regard.

Acute kidney injury in dogs: Etiology, clinical and clinicopathologic findings, prognostic markers, and outcome

BACKGROUND

Acute kidney injury (AKI) is a common, potentially fatal condition.

OBJECTIVES

To characterize the etiologies, clinical and clinicopathologic findings, hospitalization period, and outcome of dogs with AKI and to identify markers of negative prognosis.

ANIMALS

Two hundred forty-nine client-own dogs diagnosed with AKI and hospitalized at a veterinary teaching hospital.

METHODS

Retrospective study. Search of medical records for dogs with AKI.

RESULTS

Common clinical signs included lethargy (225/249, 90%), anorexia (206/249, 83%), and vomiting (168/249, 68%). Etiologies included ischemic/inflammatory (144/249, 58%), infectious (19/249, 8%), nephrotoxicosis (14/249, 6%), or other (13/249, 5%). Hospital-acquired AKI was diagnosed in 9% (23/249) of the dogs. Median presentation and peak serum creatinine (sCr) concentrations were 4 mg/dL (range, 1.1-37.9) and 4.6 mg/dL (range, 1.1-43.1), respectively. Dogs were classified to AKI grades as follows: Grade I, 6 (2%), Grade II, 38 (15%), Grade III, 89 (36%), Grade IV, 77 (31%), and Grade V, 39 (16%). One hundred and sixty-four (66%) dogs survived. There was a positive association between death and AKI grade (P = .009). The case fatality rate was higher among dogs with anuria compared with dogs without anuria (50% vs 28%, respectively; odds ratio [95% confidence interval]: 2.5 [1.39-4.6]; P = .002). Forty-seven (18.8%) dogs underwent hemodialysis, of which 60% survived.

CONCLUSION AND CLINICAL IMPORTANCE

Two-thirds of dogs with AKI survived. Hospital-acquired AKI was common. The severity of AKI, as reflected by presence of anuria, AKI grade, and other body organs involvement, was associated with the outcome.

Changing epidemiology and outcomes of acute kidney injury in Brazilian patients: a retrospective study from a teaching hospital

PURPOSE

While considerable information is available on acute kidney injury (AKI) in North America and Europe, large comprehensive epidemiologic studies on AKI from Latin America and Asia are still lacking. The present study aimed to evaluate the epidemiology and outcomes of AKI in patients evaluated by nephrologists in a Brazilian teaching hospital.

METHODS

We performed a large retrospective observational study that looked into the epidemiology of AKI and its effect on patient outcomes across time periods. For comparison purposes, patients were divided into two groups according to the year of follow up: 2011-2014 and 2015-2018.

RESULTS

We enrolled 7976 AKI patients and, after excluding patients with chronic kidney disease stages 4 and 5, kidney transplant recipients and those with incomplete data, 5428 AKI patients were included (68%). The maximum AKI stage was 3 (50.6%), and there was a mortality rate of 34.3% (1865 patients). Dialysis treatment was indicated in 928 patients (17.1%). Patient survival improved along the study periods, and patients treated in 2015-2018 had a relative risk death reduction of 0.89 (95% CI 0.81-0.98, p = 0.02). The independent risk factors for mortality were sepsis, > 65 years of age, admission to the intensive care unit, AKI-KDIGO 3, recurrent AKI, no metabolic and fluid demand to capacity imbalance (as a dialysis indication), and the period of treatment.

CONCLUSION

We observed an improvement in AKI patient survival over the years, even after correction for several confounders and using a competing risk approach. Identification of risk factors for mortality can help in decision-making for timely intervention, leading to better clinical outcomes.

LPS removal reduces CD80-mediated albuminuria in critically ill patients with Gram-negative sepsis

LPS-induced sepsis is a leading cause of acute kidney injury (AKI) in critically ill patients. LPS may induce CD80 expression in podocytes with subsequent onset of proteinuria, a risk factor for progressive chronic kidney disease (CKD) frequently observed after AKI. This study aimed to investigate the therapeutic efficacy of LPS removal in decreasing albuminuria through the reduction of podocyte CD80 expression. Between January 2015 and December 2017, 70 consecutive patients with Gram-negative sepsis-induced AKI were randomized to either have coupled plasma filtration and adsorption (CPFA) added to the standard care ( n = 35) or not ( n = 35). To elucidate the possible relationship between LPS-induced renal damage, proteinuria, and CD80 expression in Gram sepsis, a swine model of LPS-induced AKI was set up. Three hours after LPS infusion, animals were treated or not with CPFA for 6 h. Treatment with CPFA significantly reduced serum cytokines, C-reactive protein, procalcitonin, and endotoxin levels in patients with Gram-negative sepsis-induced AKI. CPFA significantly lowered also proteinuria and CD80 urinary excretion. In the swine model of LPS-induced AKI, CD80 glomerular expression, which was undetectable in control pigs, was markedly increased at the podocyte level in LPS-exposed animals. CPFA significantly reduced LPS-induced proteinuria and podocyte CD80 expression in septic pigs. Our data indicate that LPS induces albuminuria via podocyte expression of CD80 and suggest a possible role of timely LPS removal in preventing the maladaptive repair of the podocytes and the consequent increased risk of CKD in sepsis-induced AKI.

Epidemiology and Outcome in Renal Failure

Acute renal failure (ARF) in the ICU patient usually occurs as part of a wider multiple organ dysfunction, and is associated with mortality rates of around 50%. Differences in definitions make comparing study populations difficult and moves are being made to improve uniformity, and to recognize that ARF is not a single event but a continuous process from mild renal dysfunction through to complete organ failure requiring renal replacement therapy. In this review we will discuss the epidemiology of ARF within the limitations imposed by comparing studies that use different definitions and focus on different patient populations.

Selective Nanoparticle Targeting of the Renal Tubules

Direct targeting to the kidneys is a promising strategy to improve drug therapeutic index for the treatment of kidney diseases. We sought to investigate the renal selectivity and safety of kidney-targeted mesoscale nanoparticle technology. We found that direct intravenous administration of these particles resulted in 26-fold renal selectivity and localized negligibly in the liver or other organs. The nanoparticles targeted the renal proximal tubular epithelial cells, as evidenced by intravital microscopy and ex vivo imaging. Mice treated with the nanoparticles exhibited no negative systemic consequences, immune reaction, liver impairment, or renal impairment. The localization of material selectively to the renal tubules is uncommon, and this work portends the development of renal-targeted drugs for the treatment of kidney diseases.

Acute Renal Failure and the Critically Ill Patient

Acute renal failure (ARF) is a complication frequently observed in critically ill patients. This review provides details regarding the epidemiology and overall care of the ARF patient. ARF is defined and classified based on etiology. These classifications are prerenal azotemia, ischemic ARF, and postrenal azotemia. Examples of drug-induced nephrotoxicity are also outlined. Clinical presentation and diagnostic criteria of ARF are differentiated among the major ARF classes, and management strategies are outlined. These management strategies include preventive, supportive, pharmacologic, and nonpharmacologic interventions. Current standards of practice and investigational therapies are also discussed. Pharmacokinetic monitoring and dosing regimen adjustments in ARF patients with and without renal replacement therapy are reviewed. Finally, a prognostic evaluation of ARF in critically ill patients is provided based on current knowledge of the disease state and treatment options.

Validation of a Clinical Scoring System for Outcome Prediction in Dogs with Acute Kidney Injury Managed by Hemodialysis

Background

A scoring system for outcome prediction in dogs with acute kidney injury (AKI) recently has been developed but has not been validated.

Hypothesis

The scoring system previously developed for outcome prediction will accurately predict outcome in a validation cohort of dogs with AKI managed with hemodialysis.

Animals

One hundred fifteen client‐owned dogs with AKI.

Methods

Medical records of dogs with AKI treated by hemodialysis between 2011 and 2015 were reviewed. Dogs were included only if all variables required to calculate the final predictive score were available, and the 30‐day outcome was known. A predictive score for 3 models was calculated for each dog. Logistic regression was used to evaluate the association of the final predictive score with each model's outcome. Receiver operating curve (ROC) analyses were performed to determine sensitivity and specificity for each model based on previously established cut‐off values.

Results

Higher scores for each model were associated with decreased survival probability (P < .001). Based on previously established cut‐off values, 3 models (models A, B, C) were associated with sensitivities/specificities of 73/75%, 71/80%, and 75/86%, respectively, and correctly classified 74–80% of the dogs.

Conclusions and Clinical Relevance

All models were simple to apply and allowed outcome prediction that closely corresponded with actual outcome in an independent cohort. As expected, accuracies were slightly lower compared with those from the previously reported cohort used initially to develop the models.

A Multi-Center, Randomized, Controlled, Pivotal Study to Assess the Safety and Efficacy of a Selective Cytopheretic Device in Patients with Acute Kidney Injury

OBJECTIVE

Acute kidney injury (AKI) is a highly morbid condition in critically ill patients that is associated with high mortality. Previous clinical studies have demonstrated the safety and efficacy of the Selective Cytopheretic Device (SCD) in the treatment of AKI requiring continuous renal replacement therapy in the intensive care unit (ICU).

DESIGN, SETTING, PATIENTS

A randomized, controlled trial of 134 ICU patients with AKI, 69 received continuous renal replacement therapy (CRRT) alone and 65 received SCD therapy.

RESULTS

No significant difference in 60-day mortality was observed between the treated (27/69; 39%) and control patients (21/59; 36%, with six patients lost to follow up) in the intention to treat (ITT) analysis. Of the 19 SCD subjects (CRRT+SCD) and 31 control subjects (CRRT alone) who maintained a post-filter ionized calcium (iCa) level in the protocol's recommended range (≤ 0.4 mmol/L) for greater or equal to 90% of the therapy time, 60-day mortality was 16% (3/19) in the SCD group compared to 41% (11/27) in the CRRT alone group (p = 0.11). Dialysis dependency showed a borderline statistically significant difference between the SCD treated versus control CRRT alone patients maintained for ≥ 90% of the treatment in the protocol's recommended (r) iCa target range of ≤ 0.4 mmol/L with values of, 0% (0/16) and 25% (4/16), respectively (P = 0.10). When the riCa treated and control subgroups were compared for a composite index of 60 day mortality and dialysis dependency, the percentage of SCD treated subjects was 16% versus 58% in the control subjects (p<0.01). The incidence of serious adverse events did not differ between the treated (45/69; 65%) and control groups (40/65; 63%; p = 0·86).

CONCLUSION

SCD therapy may improve mortality and reduce dialysis dependency in a tightly controlled regional hypocalcaemic environment in the perfusion circuit.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01400893 http://clinicaltrials.gov/ct2/show/NCT01400893.

Predictors of outpatient kidney function recovery among patients who initiate hemodialysis in the hospital

BACKGROUND

Recent policy clarifications by the Centers for Medicare & Medicaid Services have changed access to outpatient dialysis care at end-stage renal disease (ESRD) facilities for individuals with acute kidney injury in the United States. Tools to predict "ESRD" and "acute" status in terms of kidney function recovery among patients who previously initiated dialysis therapy in the hospital could help inform patient management decisions.

STUDY DESIGN

Historical cohort study.

SETTING & PARTICIPANTS

Incident hemodialysis patients in the Mayo Clinic Health System who initiated in-hospital renal replacement therapy (RRT) and continued outpatient dialysis following hospital dismissal (2006 through 2009).

PREDICTOR

Baseline estimated glomerular filtration rate (eGFR), acute tubular necrosis from sepsis or surgery, heart failure, intensive care unit, and dialysis access.

OUTCOMES

Kidney function recovery defined as sufficient kidney function for outpatient hemodialysis therapy discontinuation.

RESULTS

Cohort consisted of 281 patients with a mean age of 64 years, 63% men, 45% with heart failure, and baseline eGFR≥30mL/min/1.73m(2) in 46%. During a median of 8 months, 52 (19%) recovered, most (94%) within 6 months. Higher baseline eGFR (HR per 10-mL/min/1.73m(2) increase eGFR, 1.27; 95% CI, 1.16-1.39; P<0.001), acute tubular necrosis from sepsis or surgery (HR, 3.34; 95% CI, 1.83-6.24; P<0.001), and heart failure (HR, 0.40; 95% CI, 0.19-0.78, P=0.007) were independent predictors of recovery within 6 months, whereas first RRT in the intensive care unit and catheter dialysis access were not. There was a positive interaction between absence of heart failure and eGFR≥30mL/min/1.73m(2) for predicting kidney function recovery (P<0.001).

LIMITATIONS

Sample size.

CONCLUSIONS

Kidney function recovery in the outpatient hemodialysis unit following in-hospital RRT initiation is not rare. As expected, higher baseline eGFR is an important determinant of recovery. However, patients with heart failure are less likely to recover even with a higher baseline eGFR. Consideration of these factors at hospital discharge informs decisions on ESRD status designation and long-term hemodialysis care.

Five-year risk of end-stage renal disease among intensive care patients surviving dialysis-requiring acute kidney injury: a nationwide cohort study

Introduction

Dialysis-requiring acute kidney injury (D-AKI) is common among intensive care unit (ICU) patients. However, follow-up data on the risk of end-stage renal disease (ESRD) among these patients remain sparse. We assessed the short-term and long-term risk of ESRD after D-AKI, compared it with the risk in other ICU patients, and examined the risk within subgroups of ICU patients.

Methods

We used population-based medical registries to identify all adult patients admitted to an ICU in Denmark from 2005 through 2010, who survived for 90 days after ICU admission. D-AKI was defined as needing acute dialysis at or after ICU admission. Subsequent ESRD was defined as a need for chronic dialysis for more than 90 days or a kidney transplant. We computed the cumulative ESRD risk for patients with D-AKI and for other ICU patients, taking into account death as a competing risk, and computed hazard ratios (HRs) using a Cox model adjusted for potential confounders.

Results

We identified 107,937 patients who survived for 90 days after ICU admission. Of these, 3,062 (2.8%) had an episode of D-AKI following ICU admission. The subsequent risk of ESRD up to 180 days after ICU admission was 8.5% for patients with D-AKI, compared with 0.1% for other ICU patients. This corresponds to an adjusted HR of 105.6 (95% confidence interval (CI): 78.1 to 142.9). Among patients who survived 180 days after ICU admission without developing ESRD (n = 103,996), the 181-day to 5-year ESRD risk was 3.8% for patients with D-AKI, compared with 0.3% for other ICU patients, corresponding to an adjusted HR of 6.2 (95% CI: 4.7 to 8.1). During the latter period, the impact of AKI was most pronounced in the youngest patients, aged 15 to 49 years (adjusted HR = 12.8, 95% CI: 6.5 to 25.4) and among patients without preexisting chronic kidney disease (adjusted HR = 11.9, 95% CI: 8.5 to 16.8).

Conclusion

D-AKI is an important risk factor for ESRD for up to five years after ICU admission.

Cysteinyl leukotriene receptor antagonism alleviates renal injury induced by ischemia-reperfusion in rats

BACKGROUND

Renal inflammation has an important role in the development of ischemia-reperfusion injury of the kidney. Cysteinyl leukotrienes have been implicated in many inflammatory conditions. The aim of this study was to investigate the ability of the cysteinyl leukotriene receptor blocker, zafirlukast, to alleviate renal dysfunction and injury in a rat model of renal ischemia-reperfusion injury.

METHODS

We induced renal ischemia for 45 min, followed by 24 h reperfusion. We gave zafirlukast at a dose of 20 mg/kg/d for 3 d before ischemia-reperfusion. At the end of the reperfusion (24 h), we collected blood samples to measure blood urea nitrogen, creatinine, tumor necrosis factor-α, intercellular adhesion molecule-1, and nitrite/nitrate. We took kidney samples for histological and immunohistochemical assessment, and to measure malondialdehyde, glutathione content, and myeloperoxidase activity.

RESULTS

Induction of renal ischemia-reperfusion resulted into renal dysfunction, as indicated by elevated levels of blood urea nitrogen and serum creatinine, serum nitrite and nitrate, serum tumor necrosis factor-α, and intercellular adhesion molecule-1. An oxidative stress marker, renal malondialdehyde concentration, was increased, whereas renal reduced glutathione content was decreased. Myeloperoxidase activity, suggestive of neutrophil infiltration, was elevated in renal tissues. Histological changes confirmed these biochemical changes, as did P-selectin overexpression in renal tissues subjected to ischemia-reperfusion. Administration of zafirlukast before ischemia-reperfusion improved renal functions and reduced serum levels of nitrite and nitrate, tumor necrosis factor-α, and intercellular adhesion molecule-1, renal concentration of myeloperoxidase activity, and malondialdehyde concentration, whereas increased renal reduced glutathione concentration. Moreover, zafirlukast reduced histopathological features of tubular injury and P-selectin overexpression in both cortex and medulla.

CONCLUSIONS

These results demonstrate that zafirlukast significantly reduces the severity of ischemic acute renal failure, probably via anti-inflammatory action, reduction of neutrophil infiltration into renal tissues, and oxidative stress subsequent to an attenuation of P-selectin expression.

Enabling innovative translational research in acute kidney injury

Acute kidney injury (AKI) is a common, heterogeneous, and detrimental clinical condition that has significant attributable morbidity and mortality. Despite major advances in understanding the epidemiology, pathogenesis, and outcomes of AKI, preventive measures remain inadequate and therapeutic approaches (except for renal replacement therapy) have largely proven futile so far. Critical to the process of designing rational therapies is translational research, which involves the transition between the basic research discoveries and everyday clinical applications to prevent, diagnose, and treat human diseases. Progress in innovative approaches has been hampered due in part to the reliance on functional markers (serum creatinine and blood urea nitrogen) that are neither sensitive nor specific to diagnose AKI. This limitation has created a great deal of interest and intense investigation to identify a "troponin-like marker" that would facilitate recognition of AKI and allow for timely implementation of the precise therapeutic agent. The other major obstacle in this field is the diverse and complex nature of AKI that involves multiple independent and overlapping pathways, making it difficult to cure AKI with a single approach. In this review, we will summarize the advances, ongoing studies, and future perspectives in the field of translational research of AKI.

Withholding and withdrawing renal support in acute kidney injury

Management of critically ill patients with acute kidney injury (AKI) is mainly limited to supportive therapy, with dialysis as one of the main components. Whether or not to offer dialysis and when to withdraw dialysis is a one of the many choices physicians face in daily clinical practice. Withholding or withdrawing renal replacement therapy is a complex decision and depends on many interacting factors, which are unique for each patient and their families and for the care team. An evidence-based guideline with nine specific recommendations for managing patients has been available however is infrequently employed to help clinical decision making. In this review, we discuss the important issues affecting decisions to withhold or withdraw dialysis in AKI patients and provide an approach for making these decisions for patient management.

Acute kidney injury: what's the prognosis?

Acute kidney injury (AKI) is common (especially during critical illness), increasing in incidence, and is associated with considerable morbidity and mortality. The Risk, Injury, Failure, Loss, and End-stage renal disease (RIFLE) classification currently provides a standardized estimate of incidence and outcomes from AKI. Despite advances in the understanding of the pathogenesis of human AKI, our ability to assess kidney function is limited and functional impairment poorly correlates with structural injury to the kidneys. Emerging novel biomarkers are, however, likely to further enhance risk stratification, facilitate early diagnosis, enable early enrollment in therapeutic trials, and assess prognosis. Sepsis remains the leading cause of AKI among the critically ill and over the past few years insights into the pathogenesis of AKI in sepsis are beginning to shift attention from renal blood flow to inflammation-mediated organ injury. Emerging evidence suggests that survivors of AKI incur long-term risks for developing chronic kidney disease and end-stage renal disease compared with those without AKI. Despite decades of research, no specific therapy for AKI other than supportive care currently exists and further work is required to better understand the pathogenesis of AKI during critical illness and to develop novel treatments.

Regional citrate versus systemic heparin for anticoagulation in critically ill patients on continuous venovenous haemofiltration: a prospective randomized multicentre trial

BACKGROUND

Continuous venovenous haemofiltration (CVVH) in the intensive care setting requires anticoagulation to prevent clotting of the extracorporeal circuit. Several protocols avoiding heparin and using regional citrate anticoagulation have been developed to diminish bleeding risks. However, data from randomized trials comparing citrate anticoagulation with systemic heparinization are very limited.

METHODS

One hundred and seventy-four patients on mechanical ventilation, requiring renal replacement therapy for acute renal failure, were included in this prospective randomized multicentre trial comparing regional citrate with systemic heparin. The study was performed at nine different intensive care units at university or academic teaching hospitals. The participants were randomized to either CVVH using regional citrate anticoagulation or CVVH using systemic anticoagulation with unfractionated heparin. The primary outcome was to compare treatment efficacy represented by the patients' acid base status on Day 3 and on each consecutive day. Several parameters of safety and efficacy were analysed as secondary outcomes.

RESULTS

Comparison of standard bicarbonate from Day 3 to Day 11 revealed no difference between both treatment modalities. Use of citrate resulted in less systemic anticoagulation, a lower risk of bleeding and a longer haemofilter patency. Episodes of hypercalcaemia, hypocalcaemia and the need for additional bicarbonate infusions occurred more often under citrate. The patients' high mortality was not influenced by the mode of anticoagulation.

CONCLUSIONS

Citrate may be used as a regional anticoagulant and the only buffering agent in CVVH with adequate treatment efficacy and safety. However, neither citrate nor heparin anticoagulation should be regarded as a therapeutic standard, since there is no advantage of one of these substances with regard to patient mortality.

Effect of timing of dialysis on mortality in critically ill, septic patients with acute renal failure

Acute renal failure with concomitant sepsis in the intensive care unit is associated with significant mortality. The purpose of this study was to determine if the timing of initiation of renal replacement therapy (RRT) in septic patients had an effect on the 28-day mortality. Retrospective data on medical intensive care unit patients with sepsis and acute renal failure requiring RRT were included. Renal replacement therapy started with a blood urea nitrogen (BUN) of <100 mg/dL was defined as "early" initiation, and initiation with a BUN >or=100 mg/dL was defined as "late." Multivariate logistic regression analysis with the primary outcome of death at 14, 28, and 365 days following the initiation of RRT was performed. One hundred thirty patients were studied. The early dialysis (mean BUN 66 mg/dL) group had 85 patients; the late group (mean BUN 137 mg/dL) had 62 patients. The mean acute physiology and chronic health evaluation II score was 24.5 in both groups. The overall 14, 28, and 365-day survival rates were 58.1%, 41.9%, and 23.6%. Survival rates for the early group were 67%, 47.7%, and 30.7% at 14, 28, and 365 days. Survival rates for the late group were 46.7%, 31.7%, and 13.3% at 14, 28, and 365 days. Upon logistic regression analysis, initiating dialysis with a BUN >100 mg/dL predicted death at 14 days (odds ratio [OR] 3.6, 95% confidence interval [CI] 1.7-7.6, P=0.001), 28 days (OR 2.6, 95% CI 1.2-5.7, P=0.01), and 365 days (OR 3.5, 95% CI 1.2-10, P=0.02). Septic patients who started dialysis with a BUN <100 mg/dL had improved mortality rates up to 1 year after initiation of dialysis in this single-center, retrospective analysis.

Mechanisms of nephroprotective effect of mitochondria-targeted antioxidants under rhabdomyolysis and ischemia/reperfusion

Oxidative stress-related renal pathologies apparently include rhabdomyolysis and ischemia/reperfusion phenomenon. These two pathologies were chosen for study in order to develop a proper strategy for protection of the kidney. Mitochondria were found to be a key player in these pathologies, being both the source and the target for excessive production of reactive oxygen species (ROS). A mitochondria-targeted compound which is a conjugate of a positively charged rhodamine molecule with plastoquinone (SkQR1) was found to rescue the kidney from the deleterious effect of both pathologies. Intraperitoneal injection of SkQR1 before the onset of pathology not only normalized the level of ROS and lipid peroxidized products in kidney mitochondria but also decreased the level of cytochrome c in the blood, restored normal renal excretory function and significantly lowered mortality among animals having a single kidney exposed to ischemia/reperfusion. The SkQR1-derivative missing plastoquinone (C12R1) possessed some, although limited nephroprotective properties and enhanced animal survival after ischemia/reperfusion. SkQR1 was found to induce some elements of nephroprotective pathways providing ischemic tolerance such as an increase in erythropoietin levels and phosphorylation of glycogen synthase kinase 3β in the kidney. SkQR1 also normalized renal erythropoietin level lowered after kidney ischemia/reperfusion and injection of a well-known nephrotoxic agent gentamicin.

[Risk factors for renal dysfunction after total hip arthroplasty]

INTRODUCTION

Postoperative renal dysfunction (PRD) is well-documented after cardiovascular surgery but there are only limited available data concerning major orthopedic surgery, although patients may have several risk factors prone to impair renal function. We designed an epidemiologic prospective study to assess the incidence of PRD after total hip arthroplasty (THA) and to determine risk factors.

PATIENTS AND METHODS

Were included in the study 755 patients scheduled for THA in a single centre, over a 14 months period. Thirty-one demographic, clinical and biological parameters were collected for each patient. PRD was defined by a value of glomerular filtration, determined by the Cockroft and Gault formula<or=60 ml/min per 1.73 m2, on the seventh postoperative day. Risk factors were determined by univariate and then multivariate analyses using a linear regression model.

RESULTS

Pre- and postoperatively (POD7), respectively 22.4% and 31.4% of the patients, had a creatinine clearance less than 60 ml/min per 1.73 m2. Univariate analysis documented age, ASA score, diabetes mellitus, chronic hypertension, the use of diuretics and NSAID, anemia, and an increased value of plasma urea as risk factors. Risk factors documented by multivariate analysis were: preoperative creatinine clearance less than 60 ml/min per 1.73 m2, (OR: 5.8, 95% confidence interval: [1.6-8.1], p=0.0006), preoperative plasma urea greater than 7.49 mmol/l (2.1 [1.4-11.1], p=0.04), age above 70 years (1.8 [1.1-4.3], p=0.02), and duration of NSAID's treatment beyond 5 days (3.2 [1.4-7.1], p=0.02).

CONCLUSION

PRD is common after THA and is prone to develop in aged patients with comorbidities. Duration of NSAID's administration should be limited in those patients.

Outcome among patients with acute renal failure needing continuous renal replacement therapy: A single center study

Outcome of acute renal failure (ARF) and use of continuous renal replacement therapy (CRRT) have shown a consistently high mortality. (1) Evaluate the short-term patient survival. (2) Evaluate dialysis-free survival. (3) Evaluate risk factors associated with overall survival and the continued need for intermittent dialysis. We identified adults (>/=18 years) needing CRRT, treated in the critical care units of Froedtert Medical and Lutheran Hospital from January 1, 2003 till December 31, 2005. Patients were divided into two major groups needing CRRT, end stage renal disease (ESRD) (chronic dialysis) and non-ESRD with ARF. Continuous renal replacement therapy was performed with an average of 2 L replacement fluid exchanges/h. Sigma stat software was used for analysis. Comparison was done for noncontinuous variables by chi-square and t test for categorical and continuous variables, respectively. A total of 110 (ESRD 24/non-ESRD 86) patients received CRRT during study period. Over all in-hospital mortality among non-ESRD patients was 63% vs. 46% for ESRD. Among non-ESRD patients who survived, 47% needed intermittent hemodialysis on intensive care unit discharge and 28% continued to need hemodialysis at last follow-up. Among non-ESRD patients alive at discharge, those who were dialysis dependent on last follow-up were older (64.5) than those who did not require dialysis on last follow-up (58.4) P=0.347. Non-ESRD patients who died were in the hospital for an average of 17.5 days compared with 29 days for those who were discharged from the hospital. Patients with ARF needing CRRT have high in-hospital mortality. A significant percentage of patients remained dialysis dependant on last follow-up.

Early Prognostic Factors in Patients with Acute Renal Failure Requiring Dialysis

PURPOSE

Despite improvements in renal therapy and technology, the mortality rate of patients with acute renal failure (ARF) remains high. Because ARF is a heterogeneous syndrome, occurring in patients with diverse etiologies and comorbid conditions, predicting its outcome is difficult. This study aims to identify early clinical and laboratory prognostic factors, including acute-phase reactants such as C-reactive protein (CRP), fibrinogen, and albumin, in ARF patients requiring dialysis.

MATERIAL AND METHODS

From June 2002 to March 2004, 61 patients with ARF requiring dialysis at Chang Gung Memorial Hospital, Chiayi, were prospectively analyzed. For each patient, the worst values of prognostic variables 24 hr before starting dialysis were prospectively assessed.

RESULTS

Oliguria, low plasma fibrinogen levels, hypotension, cardiac disease, and neoplastic disease were statistically significant in predicting hospital mortality. Using Youden's index, the best cut-off value for plasma fibrinogen in predicting mortality was 300 mg/dL with a sensitivity and specificity of 61% and 96%, respectively. Serum CRP and serum albumin were not predictive of hospital mortality.

CONCLUSION

Early prognostic factors in predicting mortality for patients with ARF requiring dialysis identified by multivariate logistic regression were oliguria, low plasma fibrinogen, hypotension, cardiac disease, and neoplastic disease. Serum CRP and albumin were not predictive of hospital mortality, whereas a plasma fibrinogen level < or =300 mg/dL had 61% sensitivity and 96% specificity in predicting mortality.

Causes and Prognosis of Nontraumatic Acute Renal Failure Requiring Dialysis in Adult Patients with and without Diabetes

Despite advanced techniques of renal replacement therapy the overall mortality of patients with ARF is still high. The majority of patients with ARF requiring dialysis are those with nontraumatic ARF. In a retrospective study we compared the causes of nontraumatic ARF, the risk factors for the development of renal failure and the mortality rates in patients with and without diabetes mellitus who received dialysis therapy in the years 1991-2000. A total of 232 patients were included in the study, 34 (14.6%) of them with and 198 patients (85.4%) without diabetes. The predominant causes of nontraumatic ARF like congestive heart failure (26.4 vs. 13.6, p < 0.05) and hypotension/hypovolemia (20.6 vs. 7.6%, p < 0.05) occurred more frequently in diabetic patients. The prevalence of sepsis (8.8 vs. 10.1%, NS), malignancy/ hypercalcemia (5.8 vs. 11.6%, NS) and other causes of nontraumatic ARF were similar in both groups. The prevalence of hepato-renal syndrome (5.8 vs. 13.6%, p < 0.05) and acute kidney graft failure (2.9 vs. 15.1%, p < 0.05) was higher in the nondiabetic individuals. Patients with diabetes showed more often chronic predictors for the onset of ARF like pre-existing hypertension (93.6 vs. 51.0%, p < 0.05), congestive heart failure (44.1 vs. 14.6%, p < 0.005), pre-existing renal insufficiency (76.4 vs. 46.9%, p < 0.05) and ACE-inhibitor therapy (32.3 vs. 9.6%, p < 0.005). Additionally, the prevalence of multiple organ failure (MOF) as prognostic factor was significantly higher in the diabetic patients (47.0 vs. 21.7%, p < 0.05). The mean number of dialyses therapy was 4.7 vs. 4.5 per patient. The overall mortality was 41.1 vs. 44.% (NS). In conclusion, the prevalence of the most common causes of nontraumatic ARF was different between the patients with and without diabetes. The diabetic individuals had more frequently predictors for the onset of ARF. The overall mortality was approximately the same in both groups.

Long-term risk of mortality and acute kidney injury during hospitalization after major surgery

OBJECTIVE

To determine the relationship between long-term mortality and acute kidney injury (AKI) during hospitalization after major surgery.

SUMMARY BACKGROUND DATA

AKI is associated with a risk of short-term mortality that is proportional to its severity; however the long-term survival of patients with AKI is poorly studied.

METHODS

This is a retrospective cohort study of 10,518 patients with no history of chronic kidney disease who were discharged after a major surgery between 1992 and 2002. AKI was defined by the RIFLE (Risk, Injury, Failure, Loss, and End-stage Kidney) classification, which requires at least a 50% increase in serum creatinine (sCr) and stratifies patients into 3 severity stages: risk, injury, and failure. Patient survival was determined through the National Social Security Death Index. Long-term survival was analyzed using a risk-adjusted Cox proportional hazards regression model.

RESULTS

In the risk-adjusted model, survival was worse among patients with AKI and was proportional to its severity with an adjusted hazard ratio of 1.18 (95% confidence interval [CI], 1.08-1.29) for the RIFLE-Risk class and 1.57 (95% CI, 1.40-1.75) for the RIFLE-Failure class, compared with patients without AKI (P < 0.001). Patients with complete renal recovery after AKI still had an increased adjusted hazard ratio for death of 1.20 (95% CI, 1.10-1.31) compared with patients without AKI (P < 0.001).

CONCLUSIONS

In a large single-center cohort of patients discharged after major surgery, AKI with even small changes in sCr level during hospitalization was associated with an independent long-term risk of death.

Long-term risk of mortality and other adverse outcomes after acute kidney injury: a systematic review and meta-analysis

BACKGROUND

Acute kidney injury (AKI) is common in hospitalized patients. The impact of AKI on long-term outcomes is controversial.

STUDY DESIGN

Systematic review and meta-analysis.

SETTING & PARTICIPANTS

Persons with AKI.

SELECTION CRITERIA FOR STUDIES

MEDLINE and EMBASE databases were searched from 1985 through October 2007. Original studies describing outcomes of AKI for patients who survived hospital discharge were included. Studies were excluded from review when participants were followed up for less than 6 months.

PREDICTOR

AKI, defined as acute changes in serum creatinine level or acute need for renal replacement therapy.

OUTCOMES

Chronic kidney disease (CKD), cardiovascular disease, and mortality.

RESULTS

48 studies that contained a total of 47,017 participants were reviewed; 15 studies reported long-term data for patients without AKI. The incidence rate of mortality was 8.9 deaths/100 person-years in survivors of AKI and 4.3 deaths/100 patient-years in survivors without AKI (rate ratio [RR], 2.59; 95% confidence interval, 1.97 to 3.42). AKI was associated independently with mortality risk in 6 of 6 studies that performed multivariate adjustment (adjusted RR, 1.6 to 3.9) and with myocardial infarction in 2 of 2 studies (RR, 2.05; 95% confidence interval, 1.61 to 2.61). The incidence rate of CKD after an episode of AKI was 7.8 events/100 patient-years, and the rate of end-stage renal disease was 4.9 events/100 patient-years.

LIMITATIONS

The relative risk for CKD and end-stage renal disease after AKI was unattainable because of lack of follow-up of appropriate controls without AKI.

CONCLUSIONS

The development of AKI, defined as acute changes in serum creatinine level, characterizes hospitalized patients at increased risk of long-term adverse outcomes.

Safety and performance of targeted renal therapy: the Be-RITe! Registry

PURPOSE

To evaluate the safety and patterns of use of targeted renal therapy (TRT) with the Benephit system. TRT, the delivery of therapeutic agents directly to the kidneys by renal arterial infusion, has the advantage of providing a higher local effective dose with potentially greater renal effects, while limiting systemic adverse effects due to renal first-pass elimination.

METHODS

The Benephit System Renal Infusion Therapy (Be-RITe!) Multicenter Registry was a post-market registry following patients treated using the Benephit systems for TRT. The registry enrolled 501 patients (332 men; mean age 72.2+/-9.5 years) at high risk for contrast-induced nephropathy (CIN) during coronary or peripheral angiography/intervention or cardiovascular surgery. The Mehran score was used to compare the actual to predicted incidence of CIN within 48 hours post procedure.

RESULTS

Bilateral renal artery cannulation was successful in 94.2%, with a mean cannulation time of 2.0 minutes. Either fenoldopam mesylate, sodium bicarbonate, alprostadil, or B-type natriuretic peptide (BNP) was infused for 184+/-212 minutes. Mean creatinine levels did not change significantly (baseline, 24, and 48 hours post procedure: 1.95, 1.99, and 1.98 mg/dL, respectively; p = NS). In 285 patients who received TRT with fenoldopam and were followed for at least 48 hours, the incidence of CIN was 71% lower than predicted (8.1% actual CIN versus 28.0% predicted; p<0.0001). Only 4 (1.4%) patients required dialysis (versus the 2.6% predicted rate, p = NS).

CONCLUSION

The Benephit system and TRT during coronary and endovascular procedures in patients at high risk for renal failure is simple to use and safe. With the infusion of intrarenal fenoldopam, the incidence of CIN was significantly lower than predicted by risk score calculations.

Validation of Liano score in acute renal failure: a prospective study in Indian patients

AIM

To validate Liano score as a prognostic scoring system in acute renal failure (ARF): a prospective study in Indian patients.

PATIENTS AND METHODS

Prospective study including 100 patients over a period of 1 year, from March 2006 to July 2007. Inclusion criteria were patients with no previous renal disease or any systemic disease known to affect the kidney and who presented with acute rise (hours to days) in serum creatinine. Exclusion criteria were patients with preexisting chronic renal failure, age younger than 12 years and ultrasound of the abdomen showing contracted kidneys.

RESULTS AND CONCLUSIONS

In this study there were 68 males and 32 females. Peak incidence by age was in the fifth decade. There was no increased mortality in any age group (p = 0.278). A total of 19 patients had pre-renal ARF, 74 patients had intrinsic ARF, of which 46 were acute tubular necrosis (ATN); 7 patients had obstructive ARF. A total of 21 patients had Liano score greater than 0.9, of which 18 patients died and 3 were discharged against medical advice in a critical condition (and died later at home). Calculated sensitivity was 62.1%, specificity was 100% and positive predictive value was 100%. Sensitivity and specificity when calculated separately for intrinsic renal ARF (after excluding post renal ARF) were 60.7% and 100%, respectively. There was statistically significant correlation between Liano score and mortality (p < 0.001).

Intensity of renal support in critically ill patients with acute kidney injury

BACKGROUND

The optimal intensity of renal-replacement therapy in critically ill patients with acute kidney injury is controversial.

METHODS

We randomly assigned critically ill patients with acute kidney injury and failure of at least one nonrenal organ or sepsis to receive intensive or less intensive renal-replacement therapy. The primary end point was death from any cause by day 60. In both study groups, hemodynamically stable patients underwent intermittent hemodialysis, and hemodynamically unstable patients underwent continuous venovenous hemodiafiltration or sustained low-efficiency dialysis. Patients receiving the intensive treatment strategy underwent intermittent hemodialysis and sustained low-efficiency dialysis six times per week and continuous venovenous hemodiafiltration at 35 ml per kilogram of body weight per hour; for patients receiving the less-intensive treatment strategy, the corresponding treatments were provided thrice weekly and at 20 ml per kilogram per hour.

RESULTS

Baseline characteristics of the 1124 patients in the two groups were similar. The rate of death from any cause by day 60 was 53.6% with intensive therapy and 51.5% with less-intensive therapy (odds ratio, 1.09; 95% confidence interval, 0.86 to 1.40; P=0.47). There was no significant difference between the two groups in the duration of renal-replacement therapy or the rate of recovery of kidney function or nonrenal organ failure. Hypotension during intermittent dialysis occurred in more patients randomly assigned to receive intensive therapy, although the frequency of hemodialysis sessions complicated by hypotension was similar in the two groups.

CONCLUSIONS

Intensive renal support in critically ill patients with acute kidney injury did not decrease mortality, improve recovery of kidney function, or reduce the rate of nonrenal organ failure as compared with less-intensive therapy involving a defined dose of intermittent hemodialysis three times per week and continuous renal-replacement therapy at 20 ml per kilogram per hour. (ClinicalTrials.gov number, NCT00076219.)

Long-term outcomes of acute kidney injury

Acute kidney injury (AKI) is common in the intensive care unit and is associated with significant morbidity and mortality. Based on the RIFLE criteria, AKI occurs in up to 67% of patients in the intensive care unit (ICU), with approximately 4% of critically ill patients requiring renal replacement therapy (RRT). It is well known that this subset of AKI patients who require RRT have an in-hospital mortality rate exceeding 50%. However, long-term outcomes of survivors of AKI requiring RRT remain poorly described. Long-term mortality is greater in those patients who survived AKI when compared with critically ill patients without AKI. Long-term morbidity, renal and extrarenal, is a frequent and underappreciated complication of AKI. Among survivors of AKI at long-term follow-up (1-10 years), approximately 12.5% are dialysis dependent (wide range of 1%-64%, depending on the patient population) and 19% to 31% have chronic kidney disease. According to the United States Renal Data System, "acute tubular necrosis without recovery" as a cause of end-stage kidney disease increased from 1.2% in 1994 to 1998 to 1.7% in 1999 to 2003. The incidence will likely continue to rise with the aging population, increase in comorbidities, and expansion of intensive care unit capabilities. AKI is an underrecognized cause of chronic kidney disease (CKD) and patients who survive should be followed closely for new CKD and/or progression of underlying CKD.

Ideal determinants for the initiation of renal replacement therapy: timing, metabolic threshold or fluid balance?

Patients with acute kidney injury (AKI) frequently require initiation of renal replacement therapy (RRT). Currently there is considerable variation worldwide on the indications for and timing of initiation and discontinuation of RRT for AKI. Numerous parameters for metabolic, solute and fluid control are generally utilized to guide the initiation and discontinuation of RRT. However, there are currently no standards in this field.

Ethics review: 'Living wills' and intensive care--an overview of the American experience

Withdrawal and limitation of life support in the intensive care unit is common, although how this decision is reached can be varied and arbitrary. Inevitably, the patient is unable to participate in this discussion because their capacity is limited by the nature of the illness and the effects of its treatment. Physicians often discuss these decisions with relatives in an attempt to respect the patient's wishes despite evidence suggesting that the relatives may not correctly reflect the patient's desires. Advance decisions, commonly known as 'living wills', have been proposed as a way of facilitating the maintenance of an individual's autonomy when they become incapacitated. Others have argued that legalising advance decisions is euthanasia by the back door. In October 2007 in England and Wales, advance decisions will become legally binding as part of the 2005 Mental Capacity Act. This has been the case in the USA for many years. The purpose of the present review is to examine the published literature regarding the effect of advance decisions in relation to the provision of adult critical care.

Withholding and withdrawing dialysis in the intensive care unit: benefits derived from consulting the renal physicians association/american society of nephrology clinical practice guideline, shared decision-making in the appropriate initiation of and withdrawal from dialysis

Despite advances in the technology of dialysis, mortality in patients who develop acute renal failure remains high. Scoring systems have been developed to improve the ability to define prognosis in seriously ill patients with acute renal failure but predicting outcomes for individual patients is uncertain. Decisions to withhold or withdraw dialysis in seriously ill patients are difficult for patients, families, and health care providers. The clinical practice guideline, Shared Decision-Making in the Appropriate Initiation of and Withdrawal from Dialysis, provides evidence-based recommendations to aid nephrologists in discussions and the process of medical decision-making about starting and stopping dialysis. Estimating prognosis and addressing the issues of advance directives and patient and family preferences through the process of shared decision-making can clarify appropriate strategies for clinical management and interventions. Time-limited trials of dialysis may be an invaluable tool in this process. Increasing nephrologists' awareness of the guideline may facilitate decision-making around the issues of withholding and withdrawing dialysis in part by clarifying patients and situations in which it may be appropriate to withhold or withdraw dialysis.

The local and systemic inflammatory transcriptome after acute kidney injury

Studies in humans and animal models have demonstrated that acute kidney injury (AKI) has a significant effect on the function of extrarenal organs. The combination of AKI and lung dysfunction is associated with 80% mortality; the lung, because of its extensive capillary network, is a prime target for AKI-induced effects. The study presented here tested the hypothesis that AKI leads to a vigorous inflammatory response and produces distinct genomic signatures in the kidney and lung. In a murine model of ischemic AKI, prominent global transcriptomic changes and histologic injury in both kidney and lung tissues were identified. These changes were evident at both early (6 h) and late (36 h) timepoints after 60-min bilateral kidney ischemia and were more prominent than similar timepoints after sham surgery or 30 min of ischemia. The inflammatory transcriptome (109 genes) of both organs changed with marked similarity, including the innate immunity genes Cd14, Socs3, Saa3, Lcn2, and Il1r2. Functional genomic analysis of these genes suggested that IL-10 and IL-6 signaling was involved in the distant effects of local inflammation, and this was supported by increased serum levels of IL-10 and IL-6 after ischemia-reperfusion. In summary, this is the first comprehensive analysis of concomitant inflammation-associated transcriptional changes in the kidney and a remote organ during AKI. Functional genomic analysis identified potential mediators that connect local and systemic inflammation, suggesting that this type of analysis may be a useful discovery tool for novel biomarkers and therapeutic drug development.

Evaluation of Outcome Scoring Systems for Patients on Extracorporeal Membrane Oxygenation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been used in critical conditions such as life-threatening respiratory failure or postcardiotomy cardiogenic shock. This investigation compares the predictive value of Acute Physiology, Age and Chronic Health Evaluation IV (APACHE IV), earlier APACHE models, Sequential Organ Failure Assessment (SOFA), and the risk of renal failure, injury to the kidney, failure of kidney function, loss of kidney function, and end-stage renal failure (RIFLE) classification obtained on the first day of ECMO support for hospital mortality in critically ill patients.

METHODS

We reviewed the medical records of 78 critically ill patients on ECMO support at the specialized intensive care unit in a tertiary care university hospital from March 2002 to October 2005. Demographic, clinical, and laboratory variables and five scoring systems were retrospectively gathered as predicators of survival on ECMO day 1.

RESULTS

The overall mortality rate was 60.3%. The most common condition requiring ECMO was cardiogenic shock. Goodness-of-fit was good for APACHE IV but not the APACHE III model. The APACHE IV and APACHE III scoring systems displayed excellent areas under the receiver operating characteristic curve (0.922 +/- 0.030 and 0.907 +/- 0.038, respectively). Furthermore, APACHE IV correlated significantly with APACHE III scores in individual patients (r2 = 0.902; p < 0.001). Finally, cumulative survival rates at 6-month follow-up after hospital discharge differed significantly (p < 0.001 for APACHE IV < or = 49% versus APACHE IV > 49%).

CONCLUSIONS

This study confirms the grave prognosis of critically ill patients receiving ECMO support. The APACHE IV proved to be a reproducible evaluation tool with excellent prognostic abilities in these patients.

Temporary worsening of renal function after aortic surgery is associated with higher long-term mortality

BACKGROUND

Little is known about acute changes in renal function in the postoperative period and the outcome of patients undergoing major vascular surgery. Specifically, data are scarce for patients in whom renal function temporarily decreases and returns to baseline at 3 days after surgery.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

1,324 patients who underwent elective open abdominal aortic aneurysm surgery in a single center.

PREDICTOR

Renal function (creatinine clearance was measured preoperatively and on days 1, 2, and 3 after surgery. Patients were divided into 3 groups: group 1, improved or unchanged (change in creatinine clearance, +/-10% of function compared with baseline); group 2, temporary worsening (worsening > 10% at day 1 or 2, then complete recovery within 10% of baseline at day 3); and group 3, persistent worsening (>10% decrease compared with baseline).

OUTCOMES & MEASUREMENTS

All-cause mortality.

RESULTS

30-day mortality rates were 1.3%, 5.0%, and 12.6% in groups 1 to 3, respectively. Adjusted for baseline characteristics and postoperative complications, 30-day mortality was the greatest in patients with persistent worsening of renal function (hazard ratio [HR], 7.3; 95% confidence interval [CI], 2.7 to 19.8), followed by those with temporary worsening (HR, 3.7; 95% CI, 1.4 to 9.9). During 6.0 +/- 3.4 years of follow-up, 348 patients (36.5%) died. Risk of late mortality was 1.7 (95% CI, 1.3 to 2.3) in the persistent-worsening group followed by those with temporary worsening (HR, 1.5; 95% CI, 1.2 to 1.4).

LIMITATIONS

No steady state was achieved to assess renal function.

CONCLUSION

Although renal function may recover completely after aortic surgery, temporary worsening of renal function was associated with greater long-term mortality.

Predictors of mortality in acute renal failure in a developing country: a prospective study

Acute renal failure (ARF) occurs in wide range of conditions, making the evaluation of its prognosis a difficult task. Data regarding prognostic factors in ARF in a general population in developing countries are scarce. The objective of the study was to describe predictors of mortality in ARF that are relevant in the developing world. This prospective study was carried out over a one-year period; all hospitalized adults with ARF were included in the study. Predictors of mortality studied included causes of ARF, pre-existing diseases, and severity as well as complications of ARF. Of 33,301 patients admitted during the study period, 294 (0.88%) were either admitted with or developed ARF after hospitalization. Mean age was 43.9 +/- 16.9 (18-86 yrs). Sepsis was the most common cause (63.26%). Pre-existing diseases like cardiovascular disease (CVSD), respiratory system disease (RSD), central nervous system disease (CNSD), hypertension, diabetes mellitus (DM), and malignancy were significantly higher in elderly as compared to younger patients. On univariate analysis sepsis, hypoperfusion as a cause of ARF and hospital-acquired ARF were associated with higher mortality. Pre-existing diseases viz. RSD, CVSD, CNSD, and DM had higher mortality. Among the severity and complications of ARF, oliguria, bleeding and infection during the course of ARF and critical illness were predictors of poor outcome. Age > 60 yrs was associated with significantly higher mortality. However, on multivariate analysis, only critical illness (odds ratio 37.3), age > 60 years (odds ratio of 5.6), and sepsis as cause of ARF (odds ratio of 2.6) were found to be independent predictors of mortality.

The kidney in the critically ill

Acute kidney injury (AKI) is a common and serious complication in the intensive care setting. It seldom occurs in isolation, but is mostly part of a multiple organ dysfunction syndrome. The pathogenesis is frequently multifactorial, with sepsis contributing to 50% of the cases.The development of AKI in critically-ill patients is "bad news": patients with AKI have a high morbidity and mortality. In addition, AKI, even in its mildest from, is not only a marker of illness severity but appears to be independently associated with mortality. Prevention of AKI is therefore a major goal to improve outcome of critically-ill patients. Treatment of established AKI is largely supportive. The optimal modality for renal replacement therapy in critically-ill patients still remains a matter of debate). The majority of survivors recover renal function.

[Extracorporeal blood purification in the intensive care units]

Mortality remains high in intensive care patients with renal failure requiring extra corporeal blood purification. This article reviews the recent data that have led to the improvement of the care for such patients. We will discuss the criteria to determine the choice of the technique (intermittent or continuous), of the membrane, of the prescribing dose, and the type of anticoagulation and when to initiate such a treatment.

Long-term outcome of acute tubular necrosis: a contribution to its natural history

As long-term outcome studies of acute renal failure (ARF) are scarce and non-homogeneous, we studied 187 consecutive acute tubular necrosis (ATN) patients without previous nephropathies, discharged alive from our hospital between October 77 and December 92 and followed-up until December 99 (range 7-22 years; median 7.2). Variables were analyzed at the time of the acute episode and during follow-up. In 2000-2001 a clinical evaluation was made in 58 of the 82 patients still alive. Ten patients were lost to follow-up and 95 died. In 59% death was related with the disease present when the ATN developed. Kaplan-Meir survival curve showed 89, 67, 50, and 40% at 1, 5, 10, and 15 years, respectively, after discharge. Survival curves were significantly better (log-rank P<0.001) among the youngest, those surviving a polytrauma, those without comorbidity and surprisingly those treated in intensive care units. The proportional Cox model showed that age (hazard ratio (HR) 1.04 per year of age; P=0.000), presence of comorbid factors (HR 4.29; P=0.006), surgical admission (HR 0.45; P=0.000), and male sex (HR 1.72; P=0.020) were the variables associated with long-term follow-up. In the evaluated patients renal function was normal in 81%. Long-term outcome after ARF depends on absence of co-morbid factors, cause of initial admission and age. Although the late mortality rate is high and related with the original disease, renal function is adequate in most patients.

Brain dysfunction in critically ill patients--the intensive care unit and beyond

Critical care physicians often find themselves prognosticating for their patients, attempting to predict patient survival as well as disability. In the case of neurologic injury, this can be especially difficult. A frequent cause of coma in the intensive care unit is resuscitation following cardiac arrest, for which mortality and severe neurologic disability remain high. Recent studies of the clinical examination, of serum markers such as neuron-specific enolase, and of somatosensory evoked potentials allow accurate and specific prediction of which comatose patients are likely to suffer a poor outcome. Using these tools, practitioners can confidently educate the family for the majority of patients who will die or remain comatose at 1 month. Delirium is a less dramatic form of neurologic injury but, when sought, is strikingly prevalent. In addition, delirium in the intensive care unit is associated with increased mortality and poorer functional recovery, prompting investigation into preventative and therapeutic strategies to counter delirium. Finally, neurologic damage may persist long after the patient's recovery from critical illness, as is the case for cognitive dysfunction detected months and years after critical illness. Psychiatric impairment including depression or post-traumatic stress disorder may also arise. Mechanisms contributing to each of these entities are reviewed.

Emergency Department Hypotension is not an Independent Risk Factor for Post-Traumatic Acute Renal Dysfunction

BACKGROUND

Hypotension has been considered to be associated with renal dysfunction. The purpose of this study was to characterize the association of Emergency Department Hypotension (EDHypo) with post-traumatic renal insufficiency (RI) and renal failure (RF).

METHODS

A Level I center Intensive Care Unit database was analyzed. We reviewed all adult trauma patients surviving for more than 24 hours. EDHypo was defined as admission systolic blood pressure of less than 90 mm Hg, RI was defined as a peak serum creatine of > or = 2.0 mg/dL, RF was defined as requiring dialysis.

RESULTS

There were 2,574 admissions studied and RI occurred in 8.3% (213) of these patients whereas RF occurred in 1.1% (28). The mortality rate with RI was 41.0% (89) and 50.0% (14) with RF. There was no significant change in the incidence of RI, RF, or RI associated mortality during the study period. EDHypo was present in 7.9% (203) of patients and the incidence of RI was significantly higher than that of non-EDHypo patients (12.2% vs. 7.9%, p = 0.028). The incidence of RF was not different (1.0% vs. 1.1%). EDHypo was not independently associated with RI or RF but Injury Severity Score > 16, renal injury, age > 55, Body Mass Index > 30, male gender, and Intensive Care Unit (ICU) admission creatine kinase > or = 5,000 U/L had an independent association with RI. No risk factor in patients with RI could reliably predict RF.

CONCLUSIONS

EDhypo is not independently associated with post-traumatic RI or RF but severity of injury, renal injury, age, Body Mass Index, male gender, and elevated creatinine kinase are independently associated with RI. In critically ill trauma patients the incidence of RI and RF and the associated mortality rate has not changed significantly during a 6-year period despite, presumably, better understanding of resuscitative strategies.

Long-term quality of life and hospital mortality in patients treated with intermittent or continuous hemodialysis for acute renal and respiratory failure

OBJECTIVE

To describe long-term quality of life, intensive care, and hospital mortality in patients with acute renal and respiratory failure treated with one of two methods of renal replacement therapy (RRT).

DESIGN

Cross-sectional survey of long-term survivors from a prospective observational study of two methods of RRT.

SETTING

A combined surgical and medical intensive care unit in a university hospital.

PATIENTS AND PARTICIPANTS

One hundred and twenty-six patients with acute renal and respiratory failure who required treatment with RRT and mechanical ventilation. Interventions. (1) RRT for acute renal failure was with either continuous hemodialysis with ultrafiltration using biocompatible membranes and prostacyclin and heparin anticoagulation (CHDF) or intermittent hemodialysis using cuprophane membranes and heparin anticoagulation (IHD); (2) Health-related quality of life in long-term survivors was assessed with the SF-36 (HRQL) questionnaire.

MEASUREMENTS AND MAIN RESULTS

(1) There was no difference in ICU mortality (73.5% [39/53] IHD vs. 71.8% [46/64] CHDF, P = NS) or hospital mortality (83% [44/53] IHD vs. 76.5% [49/64] CHDF, P = NS) between the two RRT treatment groups. By 1999, there were 16 surviving patients; (2) Twelve of these survivors completed SF-36 forms (10 CHDF vs. 2 IHD). The overall physical health summary score and scores for seven of the health domains were significantly reduced. The mental health summary score and the domain mental health score did not differ from the general population.

CONCLUSIONS

(1) The method of RRT used in ICU patients with ARF had no influence on survival; (2) The long-term survivors of multi-organ failure have poor physical health.

Recent clinical advances in the management of critically ill patients with acute renal failure

BACKGROUND

Significant progress has been made in the field of renal replacement therapy for critically ill patients with acute renal failure (ARF) over the past few years. This review highlights these developments.

METHODS

Recent studies assessing the clinical utility of the RIFLE classification system for the diagnosis of ARF were reviewed. Clinical outcome studies evaluating the effect of continuous renal replacement therapy (CRRT) dose and timing of initiation were assessed. The final review topic was the effect of dialysis modality on the recovery of renal function in ARF patients.

CONCLUSIONS

Based on recent clinical studies, the increasing use of the RIFLE criteria is justified, as this approach appears to be a robust method for both the diagnosis of and prognostication in ARF. A large randomized trial involving convective CRRT supports the commonly used prescription of 35 ml/ kg/h in clinical practice. Moreover, numerous recent outcome studies, also largely involving convective CRRT, provide a clinical rationale for the increasingly common clinical practice of earlier initiation. Finally, several recent studies suggest CRRT, relative to conventional hemodialysis, results in a greater rate of renal recovery in ARF patients.