Technology Insight: treatment of renal failure in the intensive care unit with extended dialysis

Archetypal sustained low-efficiency daily diafiltration (SLEDD-f) for critically ill patients requiring kidney replacement therapy: towards an adequate therapy

Sustained low-efficiency dialysis is a hybrid form of kidney replacement therapy that has gained increasing popularity as an alternative to continuous forms of kidney replacement therapy in intensive care unit settings. During the COVID-19 pandemic, the shortage of continuous kidney replacement therapy equipment led to increasing usage of sustained low-efficiency dialysis as an alternative treatment for acute kidney injury. Sustained low-efficiency dialysis is an efficient method for treating hemodynamically unstable patients and is quite widely available, making it especially useful in resource-limited settings. In this review, we aim to discuss the various attributes of sustained low-efficiency dialysis and how it is comparable to continuous kidney replacement therapy in efficacy, in terms of solute kinetics and urea clearance, and the various formulae used to compare intermittent and continuous forms of kidney replacement therapy, along with hemodynamic stability. During the COVID-19 pandemic, there was increased clotting of continuous kidney replacement therapy circuits, which led to increased use of sustained low-efficiency dialysis alone or together with extra corporeal membrane oxygenation circuits. Although sustained low-efficiency dialysis can be delivered with continuous kidney replacement therapy machines, most centers use standard hemodialysis machines or batch dialysis systems. Even though antibiotic dosing differs between continuous kidney replacement therapy and sustained low-efficiency dialysis, reports of patient survival and renal recovery are similar for continuous kidney replacement therapy and sustained low-efficiency dialysis. Health care studies indicate that sustained low-efficiency dialysis has emerged as a cost-effective alternative to continuous kidney replacement therapy. Although there is considerable data to support sustained low-efficiency dialysis treatments for critically ill adult patients with acute kidney injury, there are fewer pediatric data, even so, currently available studies support the use of sustained low-efficiency dialysis for pediatric patients, particularly in resource-limited settings.

Daily Hemodialysis Helps Critical Nephritic Lupus Patient: A Case Report

Background: Nephritic lupus is the most common and serious complication of systemic lupus erythematosus (SLE) and is associated with a worse prognosis. Hemodialysis is effective in alleviating symptoms and renal involvement in a nephritic lupus patient. Method: A 33-year-old female was diagnosed with SLE in September 2017. She was also diagnosed with diffuse membranous proliferative glomerulonephritis, as confirmed with a kidney biopsy. She complained of gradual onset limb weakness and peripheral edema 3 months before admission. She was treated with 6 cycles of cyclophosphamide and continued with methylprednisolone 16 mg once daily, hydroxychloroquine 200 mg once daily, and myfortic 360 mg twice daily. A day before ICU admission, her creatinine level was increased to 4.6 mg/dl with an estimated GFR of 12 ml/min and her symptoms then worsened into seizures and lung edema. Daily hemodialysis with heparin-free SLEDD was performed. About 2L was extracted for the first 6 hours with Qb 150 ml and Qd 300 ml and was continued until the day after. For the next 4 days, 3L was extracted per day with Qb 200ml and Qd 500 ml. The patients’ hemodynamic status was within normal limits during dialysis period. The condition improved and the patient was transferred to the ward. Discussions: Hemodialysis is a way to solve kidney problems in in nephritic lupus and SLE patients in general. It should not only be employed for mainly kidney problems but could be beneficial in autoimmune patients with conditions such as nephritic lupus. Slowly extracted dialysis type would be a good and inexpensive option to resolve nephritic lupus in compromising lupus patients. Filtration is ensured and solute removal is achieved relatively equivalent to CRRT. Conclusion: Daily hemodialysis could increase renal salvation by providing less creatinine serum and removing accumulated fluids. The SLEDD type could be used for critical nephritic lupus patients with reduced hemodynamic perturbations, minimal anticoagulant, and lower cost.

Renal replacement therapy in cancer patients with acute kidney injury (Review)

Cancer patients are at high risk for developing acute kidney injury (AKI), which is associated with increased morbidity and mortality in these patients. Despite the progress made in understanding the pathogenic mechanisms and etiology of AKI in these patients, the main prevention consists of avoiding medication and nephrotoxic agents such as non-steroidal anti-inflammatory drugs, contrast agents used in medical imaging and modulation of chemotherapy regimens; when prophylactic measures are overcome and renal impairment becomes unresponsive to treatment, renal replacement therapy (RRT) is required. There are several methods of RRT that can be utilized for patients with malignancies and acute renal impairment; the choice of treatment being based on the patient characteristics. The aim of this article is to review the literature data regarding the epidemiology and management of AKI in cancer patients, the extracorporeal techniques used, choice of the appropriate therapy and the optimal time of initiation, and also the dose-prognosis relationship.

Elimination of fosfomycin during dialysis with the Genius system in septic patients

To assess fosfomycin (FOS) elimination in patients with sepsis and acute kidney injury (AKI) undergoing slow-extended daily dialysis (SLEDD) with the Genius system in a prospective observational study. After ethics committee approval ten patients with sepsis and AKI stage 3 underwent daily SLEDD sessions of eight hours. FOS was applied i.v. at doses of 3 × 5 g per day. FOS serum levels were measured pre- and post hemofilter before, during, and after SLEDD sessions, and instantaneous clearance was calculated. In five of the patients, we analyzed FOS levels after the first dose, in the other five patients serum levels were measured during ongoing therapy. FOS was eliminated rapidly via the hemofilter. FOS clearance decreased from 152 ± 10 mL/min (start of SLEED session) to 43 ± 38 mL/min (end of SLEDD session). In 3/5 first-dose patients after 4–6 h of SLEDD the FOS serum level fell below the EUCAST breakpoint of 32 mg/L for Enterobacterales and Staphylococcus species. In all patients with ongoing fosfomycin therapy serum levels were high and above the breakpoint at all times. FOS toxicity or adverse effects were not observed. FOS serum concentrations exhibit wide variability in critically ill patients with sepsis and AKI. FOS is eliminated rapidly during SLEDD. A loading dose of 5 g is not sufficient to achieve serum levels above the EUCAST breakpoint for common bacteria in all patients, considering that T > MIC > 70% of the dosing interval indicates sufficient plasma levels. We thus recommend a loading dose of 8 g followed by a maintenance dose of 5 g after a SLEDD session in anuric patients. We strongly recommend therapeutic drug monitoring of FOS levels in critically ill patients with AKI and dialysis therapy.

The need for disruptive innovation in acute kidney injury

Acute kidney injury (AKI) is a threatening medical condition associated with poor outcomes at different settings. The development of standardized diagnostic criteria and new biomarkers addressed significant clinical impacts of AKI and the need for an early AKI detection, respectively. There have been some breakthroughs in understanding the pathogenesis of AKI through basic research; however, treatments against AKI aside from renal replacement therapy (RRT) have not shown adequate successful results. Biomarkers that could identify good responders to certain treatment are expected to facilitate translation of basic research findings. Most patients with severe AKI treated with RRT died due to multiple-organ failure, not renal dysfunction. Hence, it is essential to identify other organ dysfunctions induced by AKI as organ crosstalk. Also, a multidisciplinary approach of critical care nephrology is needed to evaluate a complex organ crosstalk in AKI. For disruptive innovation for AKI, we further explore these new aspects of AKI, which previously were considered outside the scope of nephrology.

Principles of Drug Dosing in Sustained Low Efficiency Dialysis (SLED) and Review of Antimicrobial Dosing Literature

The use of sustained low-efficiency dialysis (SLED) as a renal replacement modality has increased in critically ill patients with both acute kidney injury (AKI) and hemodynamic instability. Unfortunately, there is a paucity of data regarding the appropriate dosing of medications for patients undergoing SLED. Dose adjustment in SLED often requires interpretation of pharmacodynamics and pharmacokinetic factors and extrapolation based on dosing recommendations from other modes of renal replacement therapy (RRT). This review summarizes published trials of antimicrobial dose adjustment in SLED and discusses pharmacokinetic considerations specific to medication dosing in SLED. Preliminary recommendation is provided on selection of appropriate dosing for medications where published literature is unavailable.

Evaluation on treatment of sustained low-efficiency hemodialysis against patients with multiple organ dysfunction syndrome following wasp stings

Background

To evaluate the treatment of sustained low-efficiency hemodialysis (SLED) against patients with multiple organ dysfunction syndrome (MODS) following wasp stings.

Methods

Clinical data of 35 patients with MODS following wasp stings were retrospectively analysed. These patients were divided into three groups according to the treatment strategy used: 1) hemodialysis (HD) group, 2) continuous veno-venous hemofiltration (CVVH)/HD group, and 3) SLED/HD group. The clinical parameters, treatment outcome, and safety findings were compared among the three groups.

Results

The recovery rate (76.92% vs 77.78% vs 91.67%, p = 0.621) and mortality rate (15.38% vs 11.11% vs 8.33%, p = 0.999) were similar among the three groups. When compared to the HD group, patients treated with CVVH/HD or SLED/HD required a shorter period of time to enter into polyuria stage [(24.7 ± 4.3) days vs (20.2 ± 4.7) days vs (18.2 ± 3.0) days, F = 9.11, p = 0.0007], and required a shorter time for serum creatinine to return to normal [(45.7 ± 13.4) days vs (33.1 ± 9.4) days vs (31.9 ± 9.8), F = 5.83, p = 0.0069]; while such parameters had no significant differences between SLED/HD group and CVVH/HD group. The adverse events of hypotension and arrhythmia were found in the HD group, while no adverse events were reported in the SLED/HD and CVVH/HD groups. There was no significant difference in the cost of blood purification treatment between the SLED/HD group and HD group.

Conclusion

The use of SLED, CVVH and HD provided a comparable recovery and survival rates in patients with MODS secondary to wasp stings. Compared to HD, the use of SLED is recommended as a treatment strategy because of the efficacy on recover of renal function, satisfactory safety outcome, as well as the reasonable treatment cost.

PPAR gamma agonist, pioglitazone, rescues liver damage induced by renal ischemia/reperfusion injury

Remote organ damage is the major cause of death in patients with acute kidney injury (AKI) due to renal ischemia reperfusion (IR). Liver is one of the vital organs which are profoundly affected by AKI. The present study aims to investigate the role of peroxisome proliferator activator receptor gamma (PPARγ) in liver damage induced by IR injury in rats. Renal IR was induced by right nephrectomy, occlusion of left renal pedicle for 45 min to induce ischemia, and then reperfusion for 6 or 24 h. The PPARγ agonist, pioglitazone, was given orally for 7 days before renal IR procedure. Animals receiving pioglitazone showed improvement in renal and hepatic functions when compared to IR groups. Renal IR increased renal, hepatic and serum levels of tumor necrosis factor-α (TNF-α) and induced apoptotic cell death in liver. These effects were diminished with pioglitazone. In addition, pioglitazone reduced renal IR-induced oxidative stress in liver. Pioglitazone reduced malondialdehyde (MDA) content and NADPH oxidase mRNA expression and induced further increase in nuclear factor erythroid 2-related factor 2 (Nrf2) expression when compared to IR groups. Furthermore, pioglitazone increased the expression of PPARγ target genes such as renal and hepatic PPARγ1 (Pparg1), hepatic hemoxygenase-1 (Hmox1), and hepatic thioredoxin (TRx). Histological profiles for kidney and liver were also ameliorated with pioglitazone. Hence, PPARγ is a potential target to protect liver in patients with renal IR injury.

Prolonged intermittent renal replacement therapy in children

Wide ranges of age and weight in pediatric patients makes renal replacement therapy (RRT) in acute kidney injury (AKI) challenging, particularly in the pediatric intensive care unit (PICU), wherein children are often hemodynamically unstable. Standard hemodialysis (HD) is difficult in this group of children and continuous veno-venous hemofiltration/dialysis (CVVH/D) has been the accepted modality in the developed world. Unfortunately, due to cost constraints, CVVH/D is often not available and peritoneal dialysis (PD) remains the common mode of RRT in resource-poor facilities. Acute PD has its drawbacks, and intermittent HD (IHD) done slowly over a prolonged period has been explored as an alternative. Various modes of slow sustained IHD have been described in the literature with the recently introduced term prolonged intermittent RRT (PIRRT) serving as an umbrella terminology for all of these modes. PIRRT has been widely accepted in adults with studies showing it to be as effective as CVVH/D but with an added advantage of being more cost-effective. Pediatric data, though scanty, has been promising. In this current review, we elaborate on the practical aspects of undertaking PIRRT in children as well as summarize its current status.

The Circular RNA ciRs-126 Predicts Survival in Critically Ill Patients With Acute Kidney Injury

Introduction

Circular RNAs (circRNAs) have recently been described as novel noncoding regulators of gene expression. They might have an impact on microRNA expression by their sponging activity. The detectability in blood of these RNA transcripts has been demonstrated in patients with cancer and cardiovascular disease. We tested the hypothesis that circulating circRNAs in blood of critically ill patients with acute kidney injury (AKI) at inception of renal replacement therapy may also be dysregulated and associated with patient survival.

Methods

We performed a global circRNA expression analysis using RNA isolated from blood of patients with AKI as well as controls. This global screen revealed several dysregulated circRNAs in patients with AKI. Most highly increased circRNA-array−based transcripts as well as expression of the circRNA target miR-126-5p were confirmed in blood of 109 patients with AKI, 30 age-matched healthy controls, 25 critically ill non-AKI patients, and 20 patients on maintenance hemodialysis by quantitative real-time polymerase chain reaction.

Results

Circulating concentrations of 3 novel circRNAs were amplified in blood of patients with AKI and in controls. Circular RNA sponge of miR-126 (or ciRs-126) was most highly altered compared to healthy controls and disease controls (fold change of 52.1). ciRs-126 was shown to bioinformatically sponge miR-126-5p, which was found to be highly suppressed in AKI patients and hypoxic endothelial cells. Cox regression and Kaplan−Meier curve analysis revealed ciRs-126 as an independent predictor of 28-day survival (P < 0.01).

Conclusion

Circulating concentrations of circRNAs in patients with AKI are detectable. ciRs-126 may potentially sponge miR-126-5p and acts as a predictor of mortality in this patient cohort.

A novel citrate-based protocol versus heparin anticoagulation for sustained low-efficiency dialysis in the ICU: safety, efficacy, and cost

BACKGROUND

The high cost, complexity of the available protocols, and metabolic complications are the major barriers that impede the clinical utilization of regional citrate anticoagulation (RCA) for sustained low efficiency dialysis (SLED) in critically ill patients. By comparing a novel protocol for SLED using 30% citrate solution with common protocol using unfractionated heparin, this study aimed to provide new insights for clinical applications of RCA.

METHODS

In this retrospective study, a total of 282 critically ill patients who underwent SLED with citrate and/or heparin anticoagulation in six adult ICUs were enrolled. These patients were divided into three groups based on the anticoagulation regimens they had received during the treatment in ICU: Group 1 (Citrate) had only received treatment with citrate anticoagulation (n=75); Group 2 (Heparin) only with heparin anticoagulation (n=79); and Group 3 (Both) with both citrate and heparin anticoagulation (n=128). We compared the mortality, metabolic complications as well as cost among these groups using different anticoagulation regimens.

RESULTS

The in-hospital mortality did not significantly differ among groups (p> 0.1). However, three patients in heparin group suffered from severe bleeding which led to death, while none in citrate group. Overall, 976 SLED sessions with heparin anticoagulation and 808 with citrate were analyzed. The incidence of extracorporeal circuit clotting was significantly less in citrate (5%), as compared to that in heparin (10%) (p< 0.001). Metabolic complications and hypotension which led to interruption of SLED occurred more frequently, though not significantly, in citrate (p= 0.06, p= 0.23). Furthermore, with 30% citrate solution, the cost of anticoagulant was reduced by 70% in comparison to previously reported protocol using Acid Citrate Dextrose solution A (ACD-A).

CONCLUSIONS

Our results indicated that anticoagulation regimens for SLED did not significantly affect the mortality of patients. Citrate anticoagulation was superior to heparin in preventing severe bleeding and circuit clotting. The protocol adopted in this study using 30% citrate solution was safe as well as efficacious. In the meantime, it was much more cost-efficient than other citrate-based protocol.

Daptomycin Pharmacokinetics and Pharmacodynamics in Septic and Critically Ill Patients

Infections, including sepsis, are associated with high mortality rates in critically ill patients in the intensive care unit (ICU). Appropriate antibiotic selection and adequate dosing are important for improving patient outcomes. Daptomycin is bactericidal in bloodstream infections caused by Staphylococcus aureus and other Gram-positive pathogens cultured in ICU patients. The drug has concentration-dependent activity, and the area under the curve/minimum inhibitory concentration ratio is the pharmacokinetic/pharmacodynamic (PK/PD) index that best correlates with daptomycin activity, whereas toxicity correlates well with daptomycin plasma trough concentrations (or minimum concentration [C min]). Adequate daptomycin exposure can be difficult to achieve in ICU patients; multiple PK alterations can result in highly variable plasma concentrations, which are difficult to predict. For this reason, therapeutic drug monitoring could help clinicians optimize daptomycin dosing, thus improving efficacy while decreasing the likelihood of serious adverse events. This paper reviews the literature on daptomycin in ICU patients with sepsis, focusing on dosing and PK and PD parameters.

Impact of acute kidney injury on distant organ function: recent findings and potential therapeutic targets

Acute kidney injury (AKI) is a common complication in critically ill patients and subsequently worsens outcomes. Although many drugs to prevent and treat AKI have shown benefits in preclinical models, no specific agent has been shown to benefit AKI in humans. Moreover, despite remarkable advances in dialysis techniques that enable management of AKI in hemodynamically unstable patients with shock, dialysis-requiring severe AKI is still associated with an unacceptably high mortality rate. Thus, focusing only on kidney damage and loss of renal function has not been sufficient to improve outcomes of patients with AKI. Recent data from basic and clinical research have begun to elucidate complex organ interactions in AKI between kidney and distant organs, including heart, lung, spleen, brain, liver, and gut. This review serves to update the topic of organ cross talk in AKI and focuses on potential therapeutic targets to improve patient outcomes during AKI-associated multiple organ failure.

Sustained low-efficiency extended dialysis (SLED) with single-pass batch system in critically-ill patients with acute kidney injury (AKI)

BACKGROUND

Single-pass batch dialysis (SBD) is a well-established system for treatment of end-stage renal disease. However, little evidence is available on sustained low-efficiency extended dialysis (SLED) performed with SBD in patients with acute kidney injury (AKI) in the intensive care unit (ICU).

METHODS

All SLED-SBD sessions conducted on AKI patients in nine ICUs between March and June 2010 were retrospectively analyzed regarding the achieved metabolic and fluid control. Logistic regression was performed to identify the risk factors associated with hypotension and clotting during the sessions.

RESULTS

Data from 106 patients and 421 sessions were analyzed. Patients were 54.2 ± 17.0 years old, 51 % males, and the main AKI cause was sepsis (68 %); 80 % of patients needed mechanical ventilation and 55 % vasoactive drugs. Hospital mortality was 62 %. The median session time was 360 min [interquartile range (IQR) 300-360] and prescribed ultrafiltration was 1500 ml (IQR 800-2000). In 272 sessions (65 %) no complications were recorded. No heparin was used in 269/421 procedures (64 %) and system clotting occurred in 63 sessions (15 %). Risk factors for clotting were sepsis [odds ratio (OR) 2.32 (1.31-4.11), p = 0.004], no anticoagulation [OR 2.94 (1.47-5.91), p = 0.002] and the prescribed time (hours) [OR 1.14 (1.05-1.24), p = 0.001]. Hypotension occurred in 25 % of procedures and no independent risk factors were identified by logistic regression. Adequate metabolic and fluid balance was achieved during SLED sessions. Median blood urea decreased from 107 to 63 mg/dl (p < 0.001), potassium from 4.1 to 3.9 mEq/l (p < 0.001), and increased bicarbonate (from 21.4 to 23.5 mEq/l, p < 0.001). Median fluid balance during session days ranged from +1300 to -20 ml/24 h (p < 0.001).

CONCLUSIONS

SLED-SBD was associated with a low incidence of clotting despite frequent use of saline flush, and achieved a satisfactory hemodynamic stability and reasonable metabolic and fluid control in critically-ill AKI patients.

Sustained low-efficiency dialysis with regional citrate anticoagulation in medical intensive care unit patients with liver failure: A prospective study

PURPOSE

Patients with liver failure requiring dialysis are at increased risk for citrate accumulation during sustained low-efficiency dialysis (SLED). The aim of this study was to evaluate the feasibilty of citrate SLED in critical ill patients with liver failure and investigate predictive parameters regarding citrate accumulation.

MATERIALS AND METHODS

This is a prospective study in 24 medical intensive care unit patients with liver failure and a total of 43 SLED runs (maximum of 3 runs per patient) using citrate anticoagulation. Liver function was characterized before SLED using not only laboratory parameters but also determination of the plasma disappearance rate of indocyanine green. In addition, blood gas parameters as well total calcium and citrate in serum were measured at baseline and defined time points during SLED.

RESULTS

Accumulation of citrate could be observed in all SLED runs, which were nearly normalized until the end of SLED and 24 hours after SLED, respectively. However, the critical threshold of total calcium/ionized calcium on ratio of greater than 2.5 was exceeded in only 1 patient. Equalization of initial metabolic acidosis was possible without major disturbances of acid base and electrolyte status. Liver function parameters showed poor predicitve capabilities regarding citrate accumulation.

CONCLUSIONS

Despite substantial accumulation of citrate in serum, SLED is save and feasible in patients with liver failure using a citrate anticoagulation. Careful monitoring of electrolytes and acid base status is mandatory to ensure patient safety.

Dialysis complications in acute kidney injury patients treated with prolonged intermittent renal replacement therapy sessions lasting 10 versus 6 hours: results of a randomized clinical trial

Prolonged intermittent renal replacement therapy (PIRRT) has emerged as an alternative to continuous renal replacement therapy in the management of acute kidney injury (AKI) patients. This trial aimed to compare the dialysis complications occurring during different durations of PIRRT sessions in critically ill AKI patients. We included patients older than 18 years with AKI associated with sepsis admitted to the intensive care unit and using noradrenaline doses ranging from 0.3 to 0.7 µg/kg/min. Patients were divided into two groups randomly: in G1, 6-h sessions were performed, and in G2, 10-h sessions were performed. Seventy-five patients were treated with 195 PIRRT sessions for 18 consecutive months. The prevalence of hypotension, filter clotting, hypokalemia, and hypophosphatemia was 82.6, 25.3, 20, and 10.6%, respectively. G1 was composed of 38 patients treated with 100 sessions, whereas G2 consisted of 37 patients treated with 95 sessions. G1 and G2 were similar in male predominance (65.7 vs. 75.6%, P = 0.34), age (63.6 ± 14 vs. 59.9 ± 15.5 years, P = 0.28) and Sequential Organ Failure Assessment score (SOFA; 13.1 ± 2.4 vs. 14.2 ± 3.0, P = 0.2). There was no significant difference between the two groups in hypotension (81.5 vs. 83.7%, P = 0.8), filter clotting (23.6 vs. 27%, P = 0.73), hypokalemia (13.1 vs. 8.1%, P = 0.71), and hypophosphatemia (18.4 vs. 21.6%, P = 0.72). However, the group treated with sessions of 10 h were refractory to clinical measures for hypotension, and dialysis sessions were interrupted more often (9.5 vs. 30.1%, P = 0.03). Metabolic control and fluid balance were similar between G1 and G2 (blood urea nitrogen [BUN]: 81 ± 30 vs. 73 ± 33 mg/dL, P = 1.0; delivered Kt/V: 1.09 ± 0.24 vs. 1.26 ± 0.26, P = 0.09; actual ultrafiltration: 1731 ± 818 vs. 2332 ± 947 mL, P = 0.13) and fluid balance (-731 ± 125 vs. -652 ± 141 mL, respectively) . In conclusion, intradialysis hypotension was common in AKI patients treated with PIRRT. There was no difference in the prevalence of dialysis complications in patients undergoing different durations of PIRRT.

Extended Daily Dialysis Versus Continuous Renal Replacement Therapy for Acute Kidney Injury: A Meta-analysis

BACKGROUND

Extended daily dialysis (EDD) has been suggested as an effective renal replacement therapy for acute kidney injury. However, results from studies comparing EDD to continuous renal replacement therapy (CRRT) are inconclusive.

STUDY DESIGN

A systematic review and meta-analysis was performed by searching in MEDLINE, EMBASE, the Cochrane Library, Google Scholar, and a Chinese database (SinsoMed).

SETTING & POPULATION

Patients with acute kidney injury.

SELECTION CRITERIA FOR STUDIES

Randomized controlled trials (RCTs) and observational studies were included. EDD was defined as extended hemodialysis or hemodiafiltration for more than 6 but less than 24 hours per session using a conventional hemodialysis machine.

INTERVENTION

Renal replacement therapy comparing EDD with CRRT.

OUTCOMES

Mortality, kidney recovery, and fluid removal.

RESULTS

We included 17 studies from 2000 to 2014: 7 RCTs and 10 observational studies involving 533 and 675 patients, respectively. Meta-analysis of RCTs showed no difference in mortality rates between EDD and CRRT (relative risk, 0.90; 95% CI, 0.74-1.11; P=0.3). However, EDD was associated with lower mortality risk compared with CRRT in observational studies (relative risk, 0.86; 95% CI, 0.74-1.00; P=0.05). There was no evidence of heterogeneity in RCTs (I(2)=0%) or observational studies (I(2)=15%). In both RCTs and observational studies, there were no significant differences in recovery of kidney function, fluid removal, or days in the intensive care unit, and EDD showed similar biochemical efficacy to CRRT during treatment (serum urea, serum creatinine, and serum phosphate).

LIMITATIONS

The survival benefit of EDD is dependent on only observational studies and might have been affected by allocation or selection bias.

CONCLUSIONS

EDD is associated with similar outcomes to CRRT in RCTs. The finding that EDD is associated with a lower mortality rate relies on data from observational studies, which are potentially subject to allocation or selection bias, making further high-quality RCTs desirable.

Circulating long noncoding RNATapSaki is a predictor of mortality in critically ill patients with acute kidney injury

BACKGROUND

Long noncoding RNAs (lncRNAs) are novel intracellular noncoding ribonucleotides regulating gene expression. Intriguingly, these RNA transcripts are detectable and stable in the blood of patients with cancer and cardiovascular disease. We tested whether circulating lncRNAs in plasma of critically ill patients with acute kidney injury (AKI) at inception of renal replacement therapy were deregulated and might predict survival.

METHODS

We performed a global lncRNA expression analysis using RNA isolated from plasma of patients with AKI, healthy controls, and ischemic disease controls. This global screen revealed several deregulated lncRNAs in plasma samples of patients with AKI. lncRNA-array-based alterations were confirmed in kidney biopsies of patients as well as in plasma of 109 patients with AKI, 30 age-matched healthy controls, and 30 disease controls by quantitative real-time PCR.

RESULTS

Circulating concentrations of the novel intronic antisense lncRNA TrAnscript Predicting Survival in AKI (TapSAKI) (P < 0.0001) were detectable in kidney biopsies and upregulated in plasma of patients with AKI. Cox regression and Kaplan-Meier curve analysis revealed TapSAKI as an independent predictor of 28-day survival (P < 0.01). TapSAKI was enriched in tubular epithelial cells subjected to ATP depletion (P = 0.03).

CONCLUSIONS

The alteration of circulating concentrations of lncRNAs in patients with AKI supports TapSAKI as a predictor of mortality in this patient cohort.

Dialysis complications in AKI patients treated with extended daily dialysis: is the duration of therapy important?

This trial aimed to compare the dialysis complications occurring during different durations of extended daily dialysis (EDD) sessions in critically ill AKI patients. We included patients older than 18 years with AKI associated with sepsis admitted to the intensive care unit and using noradrenaline dose ranging from 0.3 to 0.7 μg/kg/min. Patients were divided into two groups randomly: in G1, 6 h sessions were performed and, in G2, 10 h sessions were performed. Seventy-five patients were treated with 195 EDD sessions for 18 consecutive months. The prevalence of hypotension, filter clotting, hypokalaemia, and hypophosphataemia was 82.6, 25.3, 20, and 10.6%, respectively. G1 and G2 were similar in male predominance and SOFA. There was no significant difference between the two groups in hypotension, filter clotting, hypokalaemia, and hypophosphataemia. However, the group treated with sessions of 10 hours showed higher refractory to clinical measures for hypotension and dialysis sessions were interrupted more often. Metabolic control and fluid balance were similar between G1 and G2. In conclusion, intradialysis hypotension was common in AKI patients treated with EDD. There was no difference in the prevalence of dialysis complications in patients undergoing different durations of EDD.

Regional citrate anticoagulation for RRTs in critically ill patients with AKI

Hemorrhagic complications have been reported in up to 30% of critically ill patients with AKI undergoing RRT with systemic anticoagulation. Because bleeding is associated with significantly increased mortality risk, strategies aimed at reducing hemorrhagic complications while maintaining extracorporeal circulation should be implemented. Among the alternatives to systemic anticoagulation, regional citrate anticoagulation has been shown to prolong circuit life while reducing the incidence of hemorrhagic complications and lowering transfusion needs. For these reasons, the recently published Kidney Disease Improving Global Outcomes Clinical Practice Guidelines for Acute Kidney Injury have recommended regional citrate anticoagulation as the preferred anticoagulation modality for continuous RRT in critically ill patients in whom it is not contraindicated. However, the use of regional citrate anticoagulation is still limited because of concerns related to the risk of metabolic complications, the complexity of the proposed protocols, and the need for customized solutions. The introduction of simplified anticoagulation protocols based on citrate and the development of dialysis monitors with integrated infusion systems and dedicated software could lead to the wider use of regional citrate anticoagulation in upcoming years.

[Acute kidney injury in the perioperative setting]

BACKGROUND

Perioperative acute kidney injury (AKI) is common and is associated with adverse clinical outcomes, excess mortality, and an increased risk for chronic renal failure. Recommendations to prevent perioperative AKI include the early identification of patients at risk, the avoidance of nephrotoxic drugs, and early goal-directed haemodynamic stabilization. The major causes for perioperative AKI are severe sepsis and septic shock, hypovolemia, bleeding and cardiac failure.

POSSIBLE RENAL REPLACEMENT MODALITIES

The choice of modality, i.e. intermittent or continuous renal replacement (CRRT) therapy, can be made based on local resources. However, surgical patients frequently have impaired haemodynamics, a decreased pulmonary function and require removal of large amounts of fluid. In such cases, CRRT offers improved haemodynamic stability and volume control. Frequently, patients must be transferred to the operating theatre for redo procedures. Here, slow-extended daily dialysis treatments of 8-12 h can deliver a high dialysis dose with good haemodynamic stability at reduced costs. Surgical patients per se have an increased risk of bleeding. Regional citrate anticoagulation is a new and effective mode of anticoagulation which significantly reduces bleeding risk and transfusion requirements.

CONCLUSION

Data from a recent meta-analysis show that, in surgical patients, mortality is reduced when renal replacement therapy is started early. In certain surgical diseases, i.e. acute occlusive disease of the abdominal aorta (Leriche's syndrome) following surgical reperfusion, patients are at risk of severe metabolic acidosis and life-threatening hyperkalemia. In such cases, intraoperative dialysis using a mobile batch system can help to avoid these complications by delivering an effective dialysis therapy at the time of reperfusion.

Extended daily dialysis in acute kidney injury patients: metabolic and fluid control and risk factors for death

Intermittent hemodialysis (IHD) and continuous renal replacement therapies (CRRT) are used as Acute Kidney Injury (AKI) therapy and have certain advantages and disadvantages. Extended daily dialysis (EDD) has emerged as an alternative to CRRT in the management of hemodynamically unstable AKI patients, mainly in developed countries.

Objectives

We hypothesized that EDD is a safe option for AKI treatment and aimed to describe metabolic and fluid control of AKI patients undergoing EDD and identify complications and risk factors associated with death.

Study Selection

This is an observational and retrospective study describing introduction of EDD at our institution. A total of 231 hemodynamically unstable AKI patients (noradrenalin dose between 0.3 and 1.0 ucg/kg/min) were assigned to 1367 EDD session. EDD consisted of 6–8 h of HD 6 days a week, with blood flow of 200 ml/min, dialysate flows of 300 ml/min.

Data Synthesis

Mean age was 60.6±15.8 years, 97.4% of patients were in the intensive care unit, and sepsis was the main etiology of AKI (76.2). BUN and creatinine levels stabilized after four sessions at around 38 and 2.4 mg/dl, respectively. Fluid balance decreased progressively and stabilized around zero after five sessions. Weekly delivered Kt/V was 5.94±0.7. Hypotension and filter clotting occurred in 47.5 and 12.4% of treatment session, respectively. Regarding AKI outcome, 22.5% of patients presented renal function recovery, 5.6% of patients remained on dialysis after 30 days, and 71.9% of patients died. Age and focus abdominal sepsis were identified as risk factors for death. Urine output and negative fluid balance were identified as protective factors.

Conclusions

EDD is effective for AKI patients, allowing adequate metabolic and fluid control. Age, focus abdominal sepsis, and lower urine output as well as positive fluid balance after two EDD sessions were associated significantly with death.

Efficacy and safety of a citrate-based protocol for sustained low-efficiency dialysis in AKI using standard dialysis equipment

BACKGROUND AND OBJECTIVES

A simple anticoagulation protocol was developed for sustained low-efficiency dialysis (SLED) in patients with AKI, based on the use of anticoagulant citrate dextrose solution formulation A (ACD-A) and standard dialysis equipment. Patients' blood recalcification was obtained from calcium backtransport from dialysis fluid.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

All patients treated with SLED (8- to 12-hour sessions) for AKI in four intensive care units of a university hospital were studied over a 30-month period, from May 1, 2008 to September 30, 2010. SLED interruptions and their causes, hemorrhagic complications, as well as coagulation parameters, ionized calcium, and blood citrate levels were recorded.

RESULTS

This study examined 807 SLED sessions in 116 patients (mean age of 69.7 years [SD 12.1]; mean Acute Physiology and Chronic Health Evaluation II score of 23.8 [4.6]). Major bleeding was observed in six patients (5.2% or 0.4 episodes/100 person-days follow-up while patients were on SLED treatment). Citrate accumulation never occurred, even in patients with liver dysfunction. Intravenous calcium for ionized hypocalcemia (< 3.6 mg/dl or < 0.9 mmol/L) was needed in 28 sessions (3.4%); in 8 of these 28 sessions (28.6%), low ionized calcium was already present before SLED start. In 92.6% of treatments, SLED was completed within the scheduled time (median 8 hours). Interruptions of SLED by impending/irreversible clotting were recorded in 19 sessions (2.4%). Blood return was complete in 98% of the cases. In-hospital mortality was 45 of 116 patients (38.8%).

CONCLUSIONS

This study protocol affords efficacious and safe anticoagulation of the SLED circuit, avoiding citrate accumulation and, in most patients, systematic calcium supplementation; it can be implemented with commercial citrate solutions, standard dialysis equipment, on-line produced dialysis fluid, and minimal laboratory monitoring.

Cotrimoxazole plasma levels, dialyzer clearance and total removal by extended dialysis in a patient with acute kidney injury: risk of under-dosing using current dosing recommendations

BACKGROUND

Dosing of antibiotics in critically ill patients is challenging. It becomes even more difficult if renal or hepatic impairment ensue. Modern means of renal replacement therapy are capable of removing antibiotics to a higher rate than decades ago, leaving clinicians with a high degree of uncertainty concerning the dose of antibiotics in this patient population. Cotrimoxazole, a combination of trimethoprim (TMP) and sulfamethoxazole (SMX) is frequently used in the treatment of several infections including Pneumocystis jirovecii pneumonia (PCP).

CASE PRESENTATION

Here we describe a patient with acute kidney injury in which we investigated the TMP and SMX levels during the course of an ICU stay. Cotrimoxazole was administered every six hours i.v. in a dose of TMP/SMX 15/75 mg/kg/day. Extended dialysis was performed with a high-flux dialyzer. Blood samples, as well as pre- and postdialyzer samples and aliquots of the collected spent dialysate were collected.Observed peak concentrations (Cmax) were 7.51 mg/l for TMP and 80.80 mg/l for SMX. Decline of blood levels during extended dialysis (TMP 64%; SMX 84%) was mainly due to removal by the dialysis procedure, illustrated by the high dialyzer clearances (median of 4 extended dialysis sessions: TMP 94.0 / SMX 51.0 ml/min), as well as by the absolute amount of both substances in the collected spent dialysate (median of 6 extended dialysis sessions: TMP 556 mg / SMX 130 mg). Within the limitation of a case report our data from 4 consecutive extended dialysis sessions suggest that this procedure substantially removes both TMP and SMX.

CONCLUSIONS

Dose reduction, which is usually advocated in patients with acute kidney injury under renal replacement therapy, might lead to significant under-dosing. Pharmacokinetic studies for TMP/SMX dosing in this patient population are necessary to allow adequate dosing.

Vibration enhances clearance of solutes with varying molecular weights during in vitro hemodialysis

This proof of concept pilot study was performed to determine whether vibration can increase solute clearance when applied to an in vitro dialysis model. Urea, creatinine, gentamicin, and vancomycin transmembrane clearances were calculated at a blood flow rate of 200 ml/min, dialysate flow rates of 2 and 8 L/hr, and no concurrent ultrafiltration at various vibration intensities. Dialyzer integrity was determined by measuring transmembrane pressure, filter drop pressure, and albumin clearance, and by visually inspecting the dialysate. Comparing the highest vibration modality with no vibration, the median percentage increase in urea, creatinine, gentamicin, and vancomycin clearance was 18% (all p < 0.005). The transmembrane clearance of albumin was negligible for all experiments. When measuring transmembrane pressure and filter drop pressure, no significant differences were found between nonvibration and vibration dialysis. The addition of vibration during dialysis increased transmembrane clearance for solutes with molecular weights of 60-1450 Daltons.

Effect of isovolemic, isothermic hemodialysis on cerebral perfusion and vascular stiffness using contrast computed tomography and pulse wave velocity

Background

Patients undergoing hemodialysis treatment have a six-fold increased risk for stroke relative to the general population. However, the effect of hemodialysis on cerebral blood flow is poorly studied and confounding factors like blood pressure and ultrafiltration as well as temperature changes have rarely been accounted for. The aim of our study was to use state-of-the-art technology to evaluate the effect of a single dialysis session on cerebral perfusion as well as on vascular stiffness.

Methods

Chronic hemodialysis patients (7 male/3 female, mean age 58 years) were recruited. Cerebral blood flow and arterial pulse wave velocity were measured before and immediately after a hemodialysis session. To exclude effects of volume changes we kept ultrafiltration to a minimum, allowing no change in body weight. Isothermic conditions were maintained by using the GENIUS single-pass batch-dialysis system with a high-flux polysulfone dialyser. Cerebral blood flow was measured by contrast-enhanced computed tomography. Pulse wave velocity was measured using the SphygmoCor (AtCor Medical, USA) device by a single operator.

Results

This study shows for the first time that isovolemic, isothermic hemodialysis neither affected blood pressure or heart rate, nor total or regional cerebral perfusion. There was also no change in pulse wave velocity.

Conclusions

Mechanisms other than the dialysis procedure itself might be causative for the high incidence of ischemic strokes in this patient population. Moreover, the sole removal of uremic toxins does not lead to short-term effects on vascular stiffness, underlying the importance of volume control in this patient population.

New high-cutoff dialyzer allows improved middle molecule clearance without an increase in albumin loss: a clinical crossover comparison in extended dialysis

BACKGROUND

Accumulation of middle molecules is thought to have adverse effects in patients with acute kidney injury (AKI). Elimination of middle molecules by non-convective means, i.e. hemodialysis, remains difficult. The aim of the study was to investigate the removal characteristics of a new high permeability membrane in AKI patients undergoing extended dialysis (ED).

PATIENTS AND METHODS

We performed a prospective, crossover study comparing the EMiC2 dialyzer (1.8 m(2), FMC, Germany) and AV 1000S (1.8 m(2), FMC) in 11 critically ill patients with AKI. β2-Microglobulin, cystatin c, creatinine, and urea were measured before and after 0.5, 5.0 and 10 h of ED. Serum reduction ratios, dialyzer clearances, and mass in the total collected dialysate were determined.

RESULTS

Dialyzer clearance of β2-microglobulin (EMiC2: 52 ± 1.7 ml/min, AV 1000S: 41.7 ± 1.5 ml/min, p = 0.0002) and cystatin c (EMiC2: 47.2 ± 1.2 ml/min, AV 1000S: 34.2 ± 2.3 ml/min, p < 0.0001) was markedly different, as was the reduction of serum levels of β2-microglobulin (EMiC2: 54.3 ± 3.6%, AV 1000S: 39.1 ± 4.5%, p = 0.025) and cystatin c (EMiC2: 38.9 ± 2.6%, AV 1000S: 28.0 ± 3.9%, p = 0.043). Additionally, we observed a higher total amount of these substances in the collected dialysate. There was no significant difference in the total amount of albumin eliminated per treatment.

CONCLUSION

The new EMiC2 dialyzer enhances removal of middle molecules without an increase in albumin loss. The clinical relevance of this finding needs to be determined.

Renal function and survival in 200 patients undergoing ECMO therapy

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is increasingly used in the intensive care unit (ICU) setting to improve gas exchange in patients with acute respiratory distress syndrome as well as in patients pre- and post-heart and lung transplantation. In this clinical setting, acute kidney injury (AKI) is frequently observed. So far, it is unknown how AKI affects the survival of critically ill patients receiving ECMO support and whether veno-veno and veno-arterial ECMO have different effects on kidney function.

METHODS

This is a retrospective analysis of patients undergoing ECMO treatment in medical and surgical ICUs in a tertiary care centre. We evaluated all patients undergoing ECMO treatment at our centre between 1 January 2005 and 31 December 2010. Data from all 200 patients (83F/117M), median age 45 (17-83) years, were obtained by chart review. Follow-up data were obtained for up to 3 months.

RESULTS

Three-month survival of all patients was 31%. Of the 200 patients undergoing ECMO treatment, 60% (120/200) required renal replacement therapy (RRT) for AKI. While patients without RRT showed a 3-month survival of 53%, the survival of patients with AKI requiring RRT was 17% (P = 0.001). Longer duration of RRT was associated with a higher mortality.

CONCLUSIONS

AKI requiring RRT therapy in patients undergoing ECMO treatment increases mortality in ICU patients. Future studies have to clarify whether it is possible to identify patients who benefit from the combination of ECMO and RRT.

Circulating microRNAs are not eliminated by hemodialysis

Background

Circulating microRNAs are stably detectable in serum/plasma and other body fluids. In patients with acute kidney injury on dialysis therapy changes of miRNA patterns had been detected. It remains unclear if and how the dialysis procedure itself affects circulating microRNA level.

Methods

We quantified miR-21 and miR-210 by quantitative RT-PCR in plasma of patients with acute kidney injury requiring dialysis and measured pre- and post-dialyser miRNA levels as well as their amount in the collected spent dialysate. Single treatments using the following filters were studied: F60 S (1.3 m², Molecular Weight Cut Off (MWCO): 30 kDa, n = 8), AV 1000 S (1.8 m², MWCO: 30 kDa, n = 6) and EMiC 2 (1.8 m², MWCO: 40 kDa, n = 6).

Results

Circulating levels of miR-21 or -210 do not differ between pre- and post-dialyzer blood samples independently of the used filter surface and pore size: miR-21: F60S: p = 0.35, AV 1000 S p = 1.0, EMiC2 p = 1.0; miR-210: F60S: p = 0.91, AV 1000 S p = 0.09, EMiC2 p = 0.31. Correspondingly, only traces of both miRNAs could be found in the collected spent dialysate and ultrafiltrate.

Conclusions

In patients with acute kidney injury circulating microRNAs are not removed by dialysis. As only traces of miR-21 and -210 are detected in dialysate and ultrafiltrate, microRNAs in the circulation are likely to be transported by larger structures such as proteins and/or microvesicles. As miRNAs are not affected by dialysis they might be more robust biomarkers of acute kidney injury.

Preventing harm during treatment of acute kidney injury: what do we really know?

Acute kidney injury (AKI) affects approximately 5% of all hospitalized patients, and its incidence continues to increase. The treatment of AKI involves tremendous financial costs, estimated to exceed $10 billion in the United States annually. Although our understanding of the pathophysiology of AKI has progressed at a tremendous pace, mortality remains high at 50% to 80%, with no improvement during the past several decades. More questions than answers currently exist regarding the optimal dialysis dose, optimal modality, and optimal timing of the initiation of renal replacement therapy in the setting of AKI, making it particularly difficult for the practicing clinician to both optimize treatment and practice cost-effective medicine. This article will review current evidence and concerns regarding these issues and identify areas of future research.

Pharmacokinetics of ampicillin/sulbactam in critically ill patients with acute kidney injury undergoing extended dialysis

BACKGROUND AND OBJECTIVES

The fixed antibacterial combination of ampicillin and sulbactam is frequently used for various infections. Intact kidneys eliminate approximately 71% of ampicillin and 78% of sulbactam. Patients on thrice-weekly low-flux hemodialysis exhibit an ampicillin t(1/2) of 2.3 hours on and 17.4 hours off dialysis. Despite its frequent use in intensive care units, there are no available dosing recommendations for patients with AKI undergoing renal replacement therapy. The aims of this study were to evaluate the pharmacokinetics of ampicillin/sulbactam in critically ill patients with AKI undergoing extended dialysis (ED) and to establish a dosing recommendation for this treatment method.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Twelve critically ill patients with anuric AKI being treated with ED were enrolled in a prospective, open-label, observational pharmacokinetic study. Pharmacokinetics after a single dose of ampicillin/sulbactam (2 g/1 g) was obtained in 12 patients. Multiple-dose pharmacokinetics after 4 days of twice-daily ampicillin/sulbactam (2 g/1 g) was obtained in three patients.

RESULTS

The mean dialyzer clearance for ampicillin/sulbactam was 80.1 ± 7.7/83.3 ± 12.1 ml/min. The t(1/2) of ampicillin and sulbactam in patients with AKI undergoing ED were 2.8 ± 0.8 hours and 3.5 ± 1.5 hours, respectively. There was no significant accumulation using a twice-daily dosage of 2 g/1 g ampicillin/sulbactam.

CONCLUSIONS

Our data suggest that in patients treated with ED using a high-flux dialyzer (polysulphone, 1.3 m(2); blood and dialysate flow, 160 ml/min; treatment time, 480 minutes), a twice-daily dosing schedule of at least 2 g/1 g ampicillin/sulbactam, with one dose given after ED, should be used to avoid underdosing.

Drug dosing consideration in patients with acute and chronic kidney disease-a clinical update from Kidney Disease: Improving Global Outcomes (KDIGO)

Drug dosage adjustment for patients with acute or chronic kidney disease is an accepted standard of practice. The challenge is how to accurately estimate a patient's kidney function in both acute and chronic kidney disease and determine the influence of renal replacement therapies on drug disposition. Kidney Disease: Improving Global Outcomes (KDIGO) held a conference to investigate these issues and propose recommendations for practitioners, researchers, and those involved in the drug development and regulatory arenas. The conference attendees discussed the major challenges facing drug dosage adjustment for patients with kidney disease. In particular, although glomerular filtration rate is the metric used to guide dose adjustment, kidney disease does affect nonrenal clearances, and this is not adequately considered in most pharmacokinetic studies. There are also inadequate studies in patients receiving all forms of renal replacement therapy and in the pediatric population. The conference generated 37 recommendations for clinical practice, 32 recommendations for future research directions, and 24 recommendations for regulatory agencies (US Food and Drug Administration and European Medicines Agency) to enhance the quality of pharmacokinetic and pharmacodynamic information available to clinicians. The KDIGO Conference highlighted the gaps and focused on crafting paths to the future that will stimulate research and improve the global outcomes of patients with acute and chronic kidney disease.

Sustained low-efficiency daily diafiltration with hemoperfusion as a therapy for severe star fruit intoxication: a report of two cases

Over the past decade, star fruit (Averrhoa carambola) intoxication decreased in the Taiwanese society due to improved public education on chronic kidney disease (CKD). Various complications including hiccups, altered levels of consciousness, coma, and seizures have been reported in individuals with renal failure who ingested fresh star fruit or star fruit juice. A high mortality rate (from 33 to 80%) was observed in patients with altered levels of consciousness, despite prompt dialysis and supportive care. According to previous case reports, the proposed treatment of choice for severe star fruit intoxication may be continuous renal replacement therapy with or without hemoperfusion. We report two cases of star fruit intoxication with stage V CKD (one case is predialysis) presenting with coma and generalized tonic-clonic seizures. The two patients were treated with sustained low-efficiency daily diafiltration (SLEDD-f) and charcoal hemoperfusion. Status epilepticus was controlled fairly quickly after treatment with SLEDD-f and hemoperfusion. However, the outcomes in this report are still poor (both remained comatose; one of two patients died). Currently, there are no data for the use of SLEDD-f with hemoperfusion for severe star fruit intoxication. SLEDD-f with charcoal hemoperfusion may play a role in managing refractory status epilepticus in patients with severe star fruit poisoning.

Circulating miR-210 predicts survival in critically ill patients with acute kidney injury

BACKGROUND AND OBJECTIVES

MicroRNAs (miRNAs) are small ribonucleotides regulating gene expression. MicroRNAs are present in the blood in a remarkably stable form. We tested whether circulating miRNAs in the plasma of critically ill patients with acute kidney injury (AKI) at the inception of renal replacement therapy are deregulated and may predict survival.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We profiled miRNAs using RNA isolated from the plasma of patients with AKI and healthy controls. The results were validated in 77 patients with acute kidney injury, 30 age-matched healthy controls, and 18 critically ill patients with acute myocardial infarction by quantitative real-time PCR.

RESULTS

Circulating levels of miR-16 and miR-320 were downregulated in the plasma of kidney injury AKI patients, whereas miR-210 was upregulated compared with healthy controls (all P < 0.0001) and disease controls (miR-210 and miR-16: P < 0.0001; miR-320: P = 0.03). Cox regression (P < 0.05) and Kaplan-Meier curve analysis (P = 0.03) revealed miR-210 as an independent and powerful predictor of 28-day survival.

CONCLUSIONS

Circulating miRNAs are altered in patients with kidney injury AKI. MiR-210 predicts mortality in this patient cohort and may serve as a novel biomarker AKI reflecting pathophysiological changes on a cellular level.

Effect of acute kidney injury requiring extended dialysis on 28 day and 1 year survival of patients undergoing interventional lung assist membrane ventilator treatment

Background

Extracorporeal lung assist devices are increasingly used in the intensive care unit setting to improve extracorporeal gas exchange mainly in patients with acute respiratory distress syndrome. ARDS is frequently accompanied by acute kidney injury; however it is so far unknown how the combination of these two conditions affects long term survival of critically ill patients.

Methods

In a retrospective analysis of a tertiary care hospital we evaluated all patients undergoing interventional lung assist (iLA) treatment between January 1^st 2005 and December 31^st 2009. Data from all 61 patients (31 F/30 M), median age 40 (28 to 52) years were obtained by chart review. Follow up data up to one year were obtained.

Results

Of the 61 patients undergoing iLA membrane ventilator treatment 21 patients had acute kidney injury network (AKIN) stage 3 and were treated by extended dialysis (ED). Twenty-eight day survival of all patients was 33%. While patients without ED showed a 28 day survival of 40%, the survival of patients with ED was only 19%. Patients on ED were not different in respect to age, weight, Horowitz index and underlying disease.

Conclusions

AKI requiring ED therapy in patients undergoing iLA treatment increases mortality in ICU patients. Patients in whom iLA was placed as a bridge to lung transplantation and that were successfully transplanted showed the best outcome. Future studies have to clarify whether it is possible to identify patients that truly benefit from the combination of these two extracorporeal treatment methods.

Dialysate and blood temperature during hemodialysis: comparing isothermic dialysis with a single-pass batch system

The Genius is a convenient single-pass batch hemodialysis system. Dialysate is heated during the preparation phase. Once the container is filled at one of the three available starting temperatures, dialysate cools spontaneously. As dialysate temperature plays an important role in hemodynamic stability, knowledge of the instantaneous dialysate temperature is important. We documented the evolution of dialysate temperature during Genius dialysis with dialysate prepared at two different temperatures (low and medium) as well as its effect on blood temperature and hemodynamic stability. Genius dialysis was compared to isothermic dialysis obtained by a module programmed to obtain a constant blood temperature. With Genius, dialysate temperature progressively decreased from 36.3 (low) and 37.6°C (medium) in the beginning to 34.4 and 35.3°C at the end of the session, both following first-order kinetics. During isothermic dialysis, dialysate cooled from 37.3 to 35.4°C, being warmer than with Genius low. Blood temperature decreased during dialysis with Genius low, from 36.4 to 36.2°C, whereas with medium temperature, blood temperature initially rose from 36.4°C at 15 min to 36.5 and 36.6°C at 30 and 60 min, respectively, followed by a decrease from 180 min onward, to 36.4°C at the end. During isothermic dialysis, blood temperature remained stable, as expected. Blood pressure decreased during all three schedules, with the highest value at 15 min during isothermic dialysis, and at the end of the session, the lowest value with isothermic dialysis.

High permeability dialysis membrane allows effective removal of myoglobin in acute kidney injury resulting from rhabdomyolysis

OBJECTIVE

The objective of this study was to test the ability of myoglobin removal of a novel, high-permeability polysulphone dialyzer in acute kidney injury as a result of rhabdomyolysis.

SETTING

Intensive care unit of a tertiary care hospital.

PATIENTS

Six patients (one female; aged 24, 36, 41, 55, 63, and 65 yrs) with oligoanuric acute kidney injury resulting from rhabdomyolysis.

INTERVENTIONS

Extended dialysis was performed using a single-pass batch dialysis system and a novel polysulphone high-flux dialyzer (effective surface area 1.8 m; inner lumen 220 μm; wall thickness 35 μm; allowing elimination of substances with a molecular weight of up to 30 kDa).

MEASUREMENTS AND MAIN RESULTS

Samples were collected at prefilter and postfilter sites as well as from the collected spent dialysate. The dialyzer clearance was calculated from concentrations before and directly after the dialysis membrane, the blood flow, and the ultrafiltration rate. The total amount of the myoglobin removed was measured directly as the whole dialysate was preserved. A median myoglobin clearance of 90.5 mL/min (range, 52.4-126.3 mL/min) was achieved, resulting in a median myoglobin removal per treatment hour of 0.54 g (range, 0.15-2.21 g).

CONCLUSIONS

Extended dialysis with a high-flux, high-permeability membrane allowed effective elimination of myoglobin with a clearance of myoglobin that surpassed all previously reported dialysis techniques. This membrane may be advantageous in preventing acute kidney injury or avoiding complete loss of kidney function in patients with rhabdomyolysis. Further studies are needed to determine whether improving renal recovery or mortality in patients with acute kidney injury resulting from rhabdomyolysis is possible.

Pharmacokinetics of sulfobutylether-beta-cyclodextrin and voriconazole in patients with end-stage renal failure during treatment with two hemodialysis systems and hemodiafiltration

Sulfobutylether-beta-cyclodextrin (SBECD), a large cyclic oligosaccharide that is used to solubilize voriconazole (VRC) for intravenous administration, is eliminated mainly by renal excretion. The pharmacokinetics of SBECD and voriconazole in patients undergoing extracorporeal renal replacement therapies are not well defined. We performed a three-period randomized crossover study of 15 patients with end-stage renal failure during 6-hour treatment with Genius dialysis, standard hemodialysis, or hemodiafiltration using a high-flux polysulfone membrane. At the start of renal replacement therapy, the patients received a single 2-h infusion of voriconazole (4 mg per kg of body weight) solubilized with SBECD. SBECD, voriconazole, and voriconazole-N-oxide concentrations were quantified in plasma and dialysate samples by high-performance liquid chromatography (HPLC) and by HPLC coupled to tandem mass spectrometry (LC-MS-MS) and analyzed by noncompartmental methods. Nonparametric repeated-measures analysis of variance (ANOVA) was used to analyze differences between treatment phases. SBECD and voriconazole recoveries in dialysate samples were 67% and 10% of the administered doses. SBECD concentrations declined with a half-life ranging from 2.6 +/- 0.6 h (Genius dialysis) to 2.4 +/- 0.9 h (hemodialysis) and 2.0 +/- 0.6 h (hemodiafiltration) (P < 0.01 for Genius dialysis versus hemodiafiltration). Prediction of steady-state conditions indicated that even with daily hemodialysis, SBECD will still exceed SBECD exposure of patients with normal renal function by a factor of 6.2. SBECD was effectively eliminated during 6 h of renal replacement therapy by all methods, using high-flux polysulfone membranes, whereas elimination of voriconazole was quantitatively insignificant. The SBECD half-life during renal replacement therapy was nearly normalized, but the average SBECD exposure during repeated administration is expected to be still increased.

Dosing of daptomycin in intensive care unit patients with acute kidney injury undergoing extended dialysis--a pharmacokinetic study

BACKGROUND

Daptomycin is a new intravenous cyclic lipopeptide antibiotic, licensed for the treatment of complicated skin and soft tissue infections caused by Gram-positive organisms including both susceptible and resistant strains of Staphylococcus aureus and for the treatment of various infections due to susceptible organisms, including serious and life-threatening Gram-positive infections, vancomycin-resistant enterococcal infections and right-sided endocarditis with associated bacteremia. Currently, no dosing recommendations exist for this drug for patients with acute kidney injury (AKI) undergoing renal replacement therapy. The aim of this study was to evaluate pharmacokinetics of daptomycin in critically ill patients with AKI undergoing extended dialysis (ED), a frequently used mean of renal replacement therapies in intensive care units (ICUs) around the world. Patients and methods. A prospective, single-dose pharmacokinetic study was performed in the medical and surgical ICUs of a tertiary care center. The aim was to investigate critically ill patients with anuric AKI being treated with ED and receiving daptomycin (n = 10). Daptomycin (6 mg/kg) was administered 8 h before ED was started.

RESULTS

Key pharmacokinetic parameters like half-life in critically ill patients treated with ED were comparable to healthy controls. The dialyser clearance for daptomycin was 63 +/- 9 ml/min. Based on the amount of the drug recovered from the collected spent dialysate, the mean fraction of the drug removed by one dialysis treatment was 23.3%.

CONCLUSION

Our data suggest that patients treated with ED using a high-flux dialyzer (polysulphone, 1.3 m(2); blood and dialysate flow, 160 ml/min; ED time, 480 min) and employing current dosing regimen, 6 mg/kg daptomycin every 48 h, run the risk of becoming significantly under dosed if one adheres to a twice daily dosing schedule that is recommended for patients on maintenance haemodialysis. Our data suggest that a daily dose of 6 mg/kg daptomycin is necessary in this special patient population to avoid under dosing, which may have detrimental effects in critically ill patients suffering from life-threatening infections.