Continuous renal replacement therapies in patients with acute neurological injury

Initial renal replacement therapy (RRT) modality associates with 90-day postdischarge RRT dependence in critically ill AKI survivors

PURPOSE

Real-world comparison of RRT modality on RRT dependence at 90 days postdischarge among ICU patients discharged alive after RRT for acute kidney injury (AKI).

METHODS

Using claims-linked to US hospital discharge data (Premier PINC AI Healthcare Database [PHD]), we compared continuous renal replacement therapy (CRRT) vs. intermittent hemodialysis (IHD) for AKI in adult ICU patients discharged alive from January 1, 2018 to June 30, 2021. RRT dependence at 90 days postdischarge was defined as ≥2 RRT treatments in the last 8 days. Between-group differences were balanced using inverse probability treatment weighting (IPTW).

RESULTS

Of 34,804 patients, 3804 patients (from 382 hospitals) had claims coverage for days 83-90 postdischarge. Compared to IHD-treated patients (n = 2740), CRRT-treated patients (n = 1064) were younger; had more admission to large teaching hospitals, surgery, sepsis, shock, mechanical ventilation, but lower prevalence of comorbidities (p < 0.05 for all). Compared to IHD-treated patients, CRRT-treated patients had lower RRT dependence at hospital discharge (26.5% vs. 29.8%, p = 0.04) and lower RRT dependence at 90 days postdischarge (4.9% vs. 7.4% p = 0.006) with weighted adjusted OR (95% CI): 0.68 (0.47-0.97), p = 0.03. Results persisted in sensitivity analyses including patients who died during days 1-90 postdischarge (n = 112) or excluding patients from hospitals with IHD patients only (n = 335), or when excluding patients who switched RRT modalities (n = 451).

CONCLUSIONS

Adjusted for potential confounders, the odds of RRT dependence at 90 days postdischarge among survivors of RRT for AKI was 30% lower for those treated first with CRRT vs. IHD, overall and in several sensitivity analyses.

SUMMARY

Critically ill patients in intensive care units (ICU) may develop acute kidney injury (AKI) that requires renal replacement therapy (RRT) to temporarily replace the injured kidney function of cleaning the blood. Two main types of RRT in the ICU are called continuous renal replacement therapy (CRRT), which is performed almost continuously, i.e., for >18 h per day, and intermittent hemodialysis (IHD), which is a more rapid RRT that is usually completed in a little bit over 6 h, several times per week. The slower CRRT may be gentler on the kidneys and is more likely to be used in the sickest patients, who may not be able to tolerate IHD. We conducted a data-analysis study to evaluate whether long-term effects on kidney function (assessed by ongoing need for RRT, i.e., RRT dependence) differ depending on use of CRRT vs. IHD. In a very large US linked hospital-discharge/claims database we found that among ICU patients discharge alive after RRT for AKI, fewer CRRT-treated patients had RRT dependence at hospital discharge (26.5% vs. 29.8%, p = 0.04) and at 90 days after discharge (4.9% vs. 7.4% p = 0.006). In adjusted models, RRT dependence at 90 days postdischarge was >30% lower for CRRT than IHD-treated patients. These results from a non-randomized study suggest that among survivors of RRT for AKI, CRRT may result in less RRT dependence 90 days after hospital discharge.

Crosstalk Between the Nervous System and Systemic Organs in Acute Brain Injury

Organ crosstalk is a complex biological communication between distal organs mediated via cellular, soluble, and neurohormonal actions, based on a two-way pathway. The communication between the central nervous system and peripheral organs involves nerves, endocrine, and immunity systems as well as the emotional and cognitive centers of the brain. Particularly, acute brain injury is complicated by neuroinflammation and neurodegeneration causing multiorgan inflammation, microbial dysbiosis, gastrointestinal dysfunction and dysmotility, liver dysfunction, acute kidney injury, and cardiac dysfunction. Organ crosstalk has become increasingly popular, although the information is still limited. The present narrative review provides an update on the crosstalk between the nervous system and systemic organs after acute brain injury. Future research might help to target this pathophysiological process, preventing the progression toward multiorgan dysfunction in critically ill patients with brain injury.

Acute Kidney Injury: Gaps and Opportunities for Knowledge and Growth

Acute kidney injury (AKI) occurs frequently in hospitalized patients, regardless of age or prior medical history. Increasing awareness of the epidemiologic problem of AKI has directly led to increased study of global recognition, diagnostic tools, both reactive and proactive management, and analysis of long-term sequelae. Many gaps remain, however, and in this article we highlight opportunities to add significantly to the increasing bodies of evidence surrounding AKI. Practical considerations related to initiation, prescription, anticoagulation, and monitoring are discussed. In addition, the importance of AKI follow-up evaluation, particularly for those surviving the receipt of renal replacement therapy, is highlighted as a push for global equity in the realm of critical care nephrology is broached. Addressing these gaps presents an opportunity to impact patient care directly and improve patient outcomes.

Debate: Intermittent Hemodialysis versus Continuous Kidney Replacement Therapy in the Critically Ill Patient: The Argument for CKRT

Continuous kidney replacement therapy (CKRT) is well entrenched as one of the dominant KRT modalities in modern critical care practice. Since its introduction four decades ago, there have been considerable innovations in CKRT machines that have improved precision, safety, and simplicity. CKRT is the preferred KRT modality for critically ill patients with hemodynamic instability. Early physical therapy and rehabilitation can be feasibly and safely provided to patients connected to CKRT, thus obviating concerns about immobility. Although randomized clinical trials have not shown a mortality difference when comparing CKRT and intermittent hemodialysis, CKRT allows precision delivery of solute and fluid removal that can be readily adjusted in the face of dynamic circumstances. Accumulated evidence from observational studies, although susceptible to bias, has shown that CKRT, when compared with intermittent hemodialysis, is associated with better short- and long-term kidney recovery and KRT independence. Critical care medicine encompasses a wide range of sick patients, and no single KRT modality is likely to ideally suit every patient in every context and for every condition. The provision of KRT represents a spectrum of modalities to which patients can flexibly transition in response to their evolving condition. As a vital tool for organ support in the intensive care unit, CKRT enables the personalization of KRT to meet the clinical demands of patients during the most severe phases of their illness.

Continuous KRT: A Contemporary Review

AKI is a common complication of critical illness and is associated with substantial morbidity and risk of death. Continuous KRT comprises a spectrum of dialysis modalities preferably used to provide kidney support to patients with AKI who are hemodynamically unstable and critically ill. The various continuous KRT modalities are distinguished by different mechanisms of solute transport and use of dialysate and/or replacement solutions. Considerable variation exists in the application of continuous KRT due to a lack of standardization in how the treatments are prescribed, delivered, and optimized to improve patient outcomes. In this manuscript, we present an overview of the therapy, recent clinical trials, and outcome studies. We review the indications for continuous KRT and the technical aspects of the treatment, including continuous KRT modality, vascular access, dosing of continuous KRT, anticoagulation, volume management, nutrition, and continuous KRT complications. Finally, we highlight the need for close collaboration of a multidisciplinary team and development of quality assurance programs for the provision of high-quality and effective continuous KRT.

Association of intermittent versus continuous hemodialysis modalities with mortality in the setting of acute stroke among patients with end-stage renal disease

Patients with end-stage renal disease (ESRD) are 8-10 times more likely to suffer from a stroke compared with the general public. Despite this risk, there are minimal data elucidating which hemodialysis modality is best for patients with ESRD following a stroke, and guidelines for their management are lacking. We retrospectively queried the US Renal Data System administrative database for all-cause mortality in ESRD stroke patients who received either intermittent hemodialysis (IHD) or continuous renal replacement therapy (CRRT). Acute ischemic stroke and hemorrhagic stroke were identified using the International Classification of Diseases 9th Revision (ICD-9)/ICD-10 codes, and hemodialysis modality was determined using Healthcare Common Procedure Coding System (HCPCS) codes. Time to death from the first stroke diagnosis was the outcome of interest. Cox proportional hazards modeling was used, and associations were expressed as adjusted HRs. From the inclusion cohort of 87,910 patients, 92.9% of patients received IHD while 7.1% of patients received CRRT. After controlling for age, race, sex, ethnicity, and common stroke risk factors such as hypertension, diabetes, tobacco use, atrial fibrillation, and hyperlipidemia, those who were placed on CRRT within 7 days of a stroke had an increased risk of death compared with those placed on IHD (HR=1.28, 95% CI 1.25 to 1.32). It is possible that ESRD stroke patients who received CRRT are more critically ill. However, even when the cohort was limited to only those patients in the intensive care unit and additional risk factors for mortality were controlled for, CRRT was still associated with an increased risk of death (HR=1.32, 95% CI 1.27 to 1.37). Therefore, further prospective clinical trials are warranted to address these findings.

Clinical and Neurologic Outcomes in Acetaminophen-Induced Acute Liver Failure: A 21-Year Multicenter Cohort Study

BACKGROUND & AIMS

Acetaminophen (APAP)-induced acute liver failure (ALF) is a rare disease associated with high mortality rates. This study aimed to evaluate changes in interventions, psychosocial profile, and clinical outcomes over a 21-year period using data from the ALF Study Group registry.

METHODS

A retrospective review of this prospective, multicenter cohort study of all APAP-ALF patients enrolled during the study period (1998-2018) was completed. Primary outcomes evaluated were the 21-day transplant-free survival (TFS) and neurologic complications. Covariates evaluated included enrollment cohort (early, 1998-2007; recent, 2008-2018), intentionality, psychiatric comorbidity, and use of organ support including continuous renal replacement therapy (CRRT).

RESULTS

Of 1190 APAP-ALF patients, recent cohort patients (n = 608) had significantly improved TFS (recent, 69.8% vs early, 61.7%; P = .005). Recent cohort patients were more likely to receive CRRT (22.2% vs 7.6%; P < .001), and less likely to develop intracranial hypertension (29.9% vs 51.5%; P < .001) or die by day 21 from cerebral edema (4.5% vs 11.6%; P < .001). Grouped by TFS status (non-TFS, n = 365 vs TFS, n = 704), there were no differences in psychiatric comorbidity (51.5% vs 55.0%; P = .28) or intentionality (intentional, 39.7% vs 41.6%; P = .58). On multivariable logistic regression adjusting for vasopressor support, development of grade 3/4 hepatic encephalopathy, King's College criteria, and MELD score, the use of CRRT (odds ratio, 1.62; P = .023) was associated with significantly increased TFS (c-statistic, 0.86). In a second model adjusting for the same covariates, recent enrollment was associated significantly with TFS (odds ratio, 1.42; P = .034; c-statistic, 0.86).

CONCLUSIONS

TFS in APAP-ALF has improved in recent years and rates of intracranial hypertension/cerebral edema have decreased, possibly related to increased CRRT use.

Choosing a CRRT machine and modality

Expanded use and steady improvements in continuous renal replacement techniques (CRRT) have enhanced the safety of the application of kidney replacement therapy (KRT) to hemodynamically unstable intensive care unit (ICU) patients. The longer duration of therapy and the personalized prescription provided by continuous therapies are associated with greater hemodynamic stability and a modestly higher likelihood of kidney recovery than standard intermittent hemodialysis (IHD). Studies designed to evaluate the effect on mortality over intermittent therapies lack evidence of benefit. A lack of standardization and considerable variation in how CRRT is performed leads to wide variation in how the technique is prescribed, delivered, and optimized. Technology has progressed in critical care nephrology, and more progress is coming. New CRRT machines are equipped with a friendly user interface that allows easy performance and monitoring, permitting outcome measurements and improved patient quality control. This review discusses the key concepts necessary to guide nephrologists to prescribe and deliver KRT to critically ill ICU patients.

Renal replacement therapy in critically ill patients with acute kidney injury: 2020 nephrologist's perspective

Renal replacement therapies (RRT) as support for acute kidney injury in critically ill patients have become a routine and essential practice in their management, resulting in the widespread use of various techniques among these patients, such as intermittent hemodialysis (IHD), extended hemodialysis and continuous RRT (CRRT). In this review we aim to summarize current evidence of indication, choice of modality, timing of initiation, dosing and technical aspects of RRT. We carried out a narrative review based on guidelines, consensus documents by main working groups and the latest relevant clinical trials on RRT in the critically ill. We did not find enough evidence of any RRT modality having superior benefits in terms of patient survival, length of intensive care unit/hospital stay or renal outcomes among critically ill patients, in spite of optimization of clinical indication, modality, timing of initiation and intensity of initial therapy. This is still a controverted matter, since only early start of high-flux CRRT has been proven beneficial over IHD among hemodynamically unstable postoperative patients. Our objective is to portrait current RRT practices in multidisciplinary management of critically ill patients by intensive care and nephrology professionals. Implication of a nephrologist in the assessment of hemodynamic status, coexisting medical conditions, renal outcome expectations and management of resources could potentially have benefits at the time of RRT selection and troubleshooting.

PCRRT Expert Committee ICONIC Position Paper on Prescribing Kidney Replacement Therapy in Critically Sick Children With Acute Liver Failure

Management of acute liver failure (ALF) and acute on chronic liver failure (ACLF) in the pediatric population can be challenging. Kidney manifestations of liver failure, such as hepatorenal syndrome (HRS) and acute kidney injury (AKI), are increasingly prevalent and may portend a poor prognosis. The overall incidence of AKI in children with ALF has not been well-established, partially due to the difficulty of precisely estimating kidney function in these patients. The true incidence of AKI in pediatric patients may still be underestimated due to decreased creatinine production in patients with advanced liver dysfunction and those with critical conditions including shock and cardiovascular compromise with poor kidney perfusion. Current treatment for kidney dysfunction secondary to liver failure include conservative management, intravenous fluids, and kidney replacement therapy (KRT). Despite the paucity of evidence-based recommendations concerning the application of KRT in children with kidney dysfunction in the setting of ALF, expert clinical opinions have been evaluated regarding the optimal modalities and timing of KRT, dialysis/replacement solutions, blood and dialysate flow rates and dialysis dose, and anticoagulation methods.

Intracranial pressure during hemodialysis in patients with acute brain injury

BACKGROUND

Because osmotic fluid shifts may occur over the blood-brain barrier, patients with acute brain injury are theoretically at risk of surges in intracranial pressure (ICP) during hemodialysis. However, this remains poorly investigated. We studied changes in ICP during hemodialysis in such patients.

METHODS

We performed a retrospective study of patients with acute brain injury admitted to Rigshospitalet (Copenhagen, Denmark) from 2012 to 2016 who received intermittent hemodialysis (IHD) or continuous renal replacement therapy (CRRT) while undergoing ICP monitoring. Data from each patient's first dialysis session were collected. Area under the curve divided by time (AUC/t) for ICP was calculated separately before and during dialysis.

RESULTS

Thirteen patients were included. During dialysis, ICP increased from a baseline of 11.9 mm Hg (median; interquartile range 6.3-14.7) to a maximum of 21 mm Hg (18-27) (P = 0.0024), and AUC/t for ICP was greater during dialysis (15.2 (13.4-18.8) vs 11.7 mm Hg (6.4-15.1), P = 0.042). The maximum ICP increase was independent of dialysis modality, but peak values were reached earlier in patients treated with IHD (N = 4) compared to CRRT (N = 9) (75 [30-90] vs 375 min [180-420] after start of treatment, P = 0.0095). The maximum ICP increase correlated positively to the baseline plasma urea concentration (Spearman's r = 0.69, P = 0.017).

CONCLUSION

Hemodialysis is associated with increased ICP in neurocritically ill patients, and the magnitude of the increase may be related to initial plasma urea levels.

The Effect of Continuous Renal Replacement Therapy with the AN69ST Membrane on Inflammatory Markers and the Level of Consciousness of Hemodialysis Patients with Stroke: Comparison with Hemodialysis with Low Blood Flow Rate

INTRODUCTION

Hemodialysis (HD) with low blood flow rate, continuous renal replacement therapy (CRRT), and peritoneal dialysis are recommended for patients with stroke complications to prevent intracranial hypertension because of the low diffusion capacity of the brain barrier. However, detailed guidelines are not currently available; thus, there is an urgent need to establish such guidelines.

MATERIAL AND METHODS

We developed a novel protocol for performing CRRT with the AN69ST membrane, which has excellent adsorption capacity for various cytokines. The objective of this study was to compare the effect of the novel protocol with that of the current standard protocol, i.e. hemodialysis with low blood flow rate. To compare the effect of hemodialysis with low blood flow (HD group, n=27) and CRRT with AN69ST membrane (CRRT group, n=8), we measured the following consciousness and blood inflammatory parameters in patients with stroke complications at baseline and after 1 week of treatment: Glasgow Coma Scale (GCS) score, C-reactive protein (CRP) levels, and white blood cell (WBC) and platelet count.

RESULTS

After 1 week, the total GCS score did not improve in the HD group, but improved significantly in the CRRT group (HD group: 13.1±3.0 to 13.3±3.1, p=0.5508, CRRT group: 8.9±3.9 to 11.5±3.9, p=0.0313). Improvement in the CRRT group was significantly higher than in the HD group (p=0.0039). CRP levels did not change significantly in either the HD (3.8±5.5 to 5.3±4.3 n.s.) or CRRT groups (7.7±10.0 to 3.7±3.2 n.s.); however, they tended to increase in the HD group and decrease in the CRRT group. No significant changes were observed in WBC and platelet counts after 1 week of treatment in either group.

CONCLUSION

CRRT with the AN69ST membrane might have a beneficial effect on the consciousness level and inflammation of patients with stroke.

The Japanese clinical practice guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention is necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search.

Continuous Renal Replacement Therapy: Who, When, Why, and How

Continuous renal replacement therapy (CRRT) is commonly used to provide renal support for critically ill patients with acute kidney injury, particularly patients who are hemodynamically unstable. A variety of techniques that differ in their mode of solute clearance may be used, including continuous venovenous hemofiltration with predominantly convective solute clearance, continuous venovenous hemodialysis with predominantly diffusive solute clearance, and continuous venovenous hemodiafiltration, which combines both dialysis and hemofiltration. The present article compares CRRT with other modalities of renal support and reviews indications for initiation of renal replacement therapy, as well as dosing and technical aspects in the management of CRRT.

The Japanese Clinical Practice Guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention are necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search.

Renal replacement therapy in acute kidney injury from a Chinese cross-sectional study: patient, clinical, socioeconomic and health service predictors of treatment

Background

Renal replacement therapy (RRT) is important to support critically ill patients with acute kidney injury (AKI). This study, a part of a nation-wide survey for AKI conducted by the ISN AKF 0 by 25 China Consortium, aims to study the current RRT practical situation and problems in China.

Methods

The current study is a part of a nation-wide survey for AKI conducted by ISN AKF 0 by 25 China Consortium. The survey included 44 sites all over the country, including 22 academic hospitals in big cities and 22 local hospitals in smaller cities or rural areas. Of the 44 sites, all have access to PD and IHD, 93.5% are capable to perform CRRT. Of total 7604 AKI cases, 896 cases (11.8%) had indications for RRT and were included in the current abstract.

Results

of the 896 patients that had indications for RRT, only 59.3% received RRT. Patients who were older, male, from lower income areas, in local hospitals, or with severe comorbidities, were less likely to receive RRT. RRT treatment was associated with lower mortality (OR = 0.58, 95%CI 0.38–0.89). The RRT modalities were continuous renal replacement therapy (CRRT) in 53.9%, intermittent hemodialysis (IHD) in 38.0%, CRRT complemented by IHD in 6.2%, CRRT complemented by peritoneal dialysis (PD) in 0.8% and PD in 1.1%. Of the subgroup of patients receiving RRT who did not have an indication for modality of CRRT, 36.8% in fact received CRRT, and their medical cost and mortality rate was higher (7944[4248, 16,055] vs. 5100[2948, 9396] US dollars, p < 0.001 and 10.6% vs. 4.4%, p = 0.047, respectively) compared with those treated with other RRT modalities).

Conclusions

Extrapolated to the whole of China our results indicate that an estimated 139,000 patients with an indication of RRT are under treated without RRT over a year. Non-clinical factors influence RRT prescription for severe AKI patients. CRRT may be over-utilized in the treatment of severe AKI and the use of PD is extremely rare. These findings have implications for the effective application of medical resources in the treatment of severe AKI.

Increased Intracranial Pressure during Hemodialysis in a Patient with Anoxic Brain Injury

Dialysis disequilibrium syndrome (DDS) is a serious neurological complication of hemodialysis, and patients with acute brain injury are at increased risk. We report a case of DDS leading to intracranial hypertension in a patient with anoxic brain injury and discuss the subsequent dialysis strategy. A 13-year-old girl was admitted after prolonged resuscitation from cardiac arrest. Computed tomography (CT) revealed an inferior vena cava aneurysm and multiple pulmonary emboli as the likely cause. An intracranial pressure (ICP) monitor was inserted, and, on day 3, continuous renal replacement therapy (CRRT) was initiated due to acute kidney injury, during which the patient developed severe intracranial hypertension. CT of the brain showed diffuse cerebral edema. CRRT was discontinued, sedation was increased, and hypertonic saline was administered, upon which ICP normalized. Due to persistent hyperkalemia and overhydration, ultrafiltration and intermittent hemodialysis were performed separately on day 4 with a small dialyzer, low blood and dialysate flow, and high dialysate sodium content. During subsequent treatments, isolated ultrafiltration was well tolerated, whereas hemodialysis was associated with increased ICP necessitating frequent pauses or early cessation of dialysis. In patients at risk of DDS, hemodialysis should be performed with utmost care and continuous monitoring of ICP should be considered.

Continuous renal replacement therapy versus intermittent hemodialysis in intensive care patients: impact on mortality and renal recovery

PURPOSE

The best renal replacement therapy (RRT) modality remains controversial. We compared mortality and short- and long-term renal recovery between patients treated with continuous RRT and intermittent hemodialysis.

METHODS

Patients of the prospective observational multicenter cohort database OUTCOMEREA™ were included if they underwent at least one RRT session between 2004 and 2014. Differences in patients' baseline and daily characteristics between treatment groups were taken into account by using a marginal structural Cox model, allowing one to substantially reduce the bias resulting from confounding factors in observational longitudinal data analysis. The composite primary endpoint was 30-day mortality and dialysis dependency.

RESULTS

Among 1360 included patients with RRT, 544 (40.0 %) and 816 (60.0 %) were initially treated by continuous RRT and intermittent hemodialysis, respectively. At day 30, 39.6 % patients were dead. Among survivors, 23.8 % still required RRT. There was no difference between groups for the primary endpoint in global population (HR 1.00, 95 % CI 0.77-1.29; p = 0.97). In patients with higher weight gain at RRT initiation, mortality and dialysis dependency were significantly lower with continuous RRT (HR 0.54, 95 % CI 0.29-0.99; p = 0.05). Conversely, this technique appeared to be deleterious in patients without shock (HR 2.24, 95 % CI 1.24-4.04; p = 0.01). Six-month mortality and persistent renal dysfunction were not influenced by the RRT modality in patients with dialysis dependence at ICU discharge.

CONCLUSION

Continuous RRT did not appear to improve 30-day and 6-month patient outcomes. It seems beneficial for patients with fluid overload, but might be deleterious in the absence of hemodynamic failure.

High-volume hemofiltration and prone ventilation in subarachnoid hemorrhage complicated by severe acute respiratory distress syndrome and refractory septic shock

We report the successful treatment of two patients with aneurismal subarachnoid hemorrhage complicated by severe respiratory failure and refractory septic shock using simultaneous prone position ventilation and high-volume hemofiltration. These rescue therapies allowed the patients to overcome the critical situation without associated complications and with no detrimental effects on the intracranial and cerebral perfusion pressures. Prone position ventilation is now an accepted therapy for severe acute respiratory distress syndrome, and high-volume hemofiltration is a non-conventional hemodynamic support that has several potential mechanisms for improving septic shock. In this manuscript, we briefly review these therapies and the related evidence. When other conventional treatments are insufficient for providing safe limits of oxygenation and perfusion as part of basic neuroprotective care in subarachnoid hemorrhage patients, these rescue therapies should be considered on a case-by-case basis by an experienced critical care team.

[New KDIGO guidelines on acute kidney injury. Practical recommendations]

The incidence of acute kidney injury (AKI) in critically ill patients is very high and is associated with an increased morbidity and mortality. In 2012 the Kidney Disease: Improving Global Outcome (KDIGO) guidelines were published in which evidence-based practical recommendations are given for the evaluation and management of patients with AKI. The first section of the KDIGO guidelines deals with the unification of earlier consensus definitions and staging criteria for AKI. The subsequent sections of the guidelines cover the prevention and treatment of AKI as well as the management of renal replacement therapy (RRT) in patients with AKI. In each section the existing evidence is discussed and a specific treatment recommendation is given. The guidelines appreciates that there is insufficient evidence for many of the recommendations. As a specific pharmacological therapy is missing, an early diagnosis, aggressive hemodynamic optimization, tight volume control, and avoidance of nephrotoxic drugs are the only interventions to prevent AKI. If renal replacement therapy is required different modalities are available to provide an effective therapy with a low rate of adverse effects.

Brain-kidney crosstalk

Encephalopathy and altered higher mental functions are common clinical complications of acute kidney injury. Although sepsis is a major triggering factor, acute kidney injury predisposes to confusion by causing generalised inflammation, leading to increased permeability of the blood–brain barrier, exacerbated by hyperosmolarity and metabolic acidosis due to the retention of products of nitrogen metabolism potentially resulting in increased brain water content. Downregulation of cell membrane transporters predisposes to alterations in neurotransmitter secretion and uptake, coupled with drug accumulation increasing the risk of encephalopathy. On the other hand, acute brain injury can induce a variety of changes in renal function ranging from altered function and electrolyte imbalances to inflammatory changes in brain death kidney donors.

Molecular Absorbent Recirculating System therapy (MARS®) in pediatric acute liver failure: a single center experience

BACKGROUND

Supportive care as a bridge to transplant or recovery remains challenging in children suffering from acute liver failure (ALF). We report our experience in children using the Molecular Absorbent Recirculating System (MARS(®)).

METHODS

Retrospective data from children receiving therapy using MARS(®) from October 2009 to October 2012 were included in this single-center retrospective study. Patient characteristics, clinical presentation and complications of ALF, clinical and biological data before and after each MARS(®) session, technical modalities and adverse events were recorded.

RESULTS

A total of six children underwent 17 MARS(®) sessions during the study period. Two adolescents were treated with the adult filter MARSFLUX(®) and four infants were treated with the MiniMARS(®) filter. The mean PEdiatric Logistic Dysfunction (PELOD) score at admission was 19 (range 11-33). All patients were mechanically ventilated, and four had acute kidney injury. The neurological course improved in one case, judged as stable in two cases and worsened in one case; data were unavailable in two cases. Mean serum ammonia levels decreased significantly following treatment with MARS(®) from an initial 89 ± 29 to 58 ± 35 mcmol/L (p = 0.02). No other significant biological improvement was observed. Hemodynamic status improved/remained unchanged in the adolescent group, but in the infants four of the seven sessions were poorly tolerated and two sessions were aborted. Three patients died, two were successfully transplanted and one recovered without transplantation.

CONCLUSION

In our experience, treatment with MARS(®) is associated with encouraging results in adolescents, but it needs modification for very sick infants to improve tolerance.

Cerebrovascular autoregulation in critically ill patients during continuous hemodialysis

PURPOSE

In chronic renal failure, intermittent hemodialysis decreases cerebral blood flow velocity (CBFV); however, in critically ill patients with acute renal failure, the effect of continuous venovenous hemodialysis (CVVHD) on CBFV and cerebrovascular autoregulation (AR) is unknown. Therefore, a study was undertaken to investigate the potential effect of CVVHD on CBFV and AR in patients with acute renal failure.

METHODS

This cohort study investigated 20 patients with acute renal failure who required CVVHD. In these patients, the CBFV and index of AR (Mx) were measured using transcranial Doppler before and during CVVHD.

RESULTS

The median Mx values at baseline were 0.33 [interquartile range (IQR): 0.02-0.55], and during CVVHD, they were 0.20 [0.07-0.40]. The differences in Mx (CVVHD--baseline) was (median [IQR]) -0.015 [-0.19-0.05], 95% confidence interval (CI) -0.16 to 0.05. The Mx was > 0.3 in 11/20 patients at baseline measurement. Six of these patients recovered to Mx < 0.3 during CVVHD. The CBFV was (median [IQR]) 47 [36-59] cm · sec(-1) at baseline and 49 [36-66] cm · sec(-1) during CVVHD. The difference of CBFV was 0.0 [-4 - 2.7], 95% CI -2.5 to 4.2.

CONCLUSION

Compared with patients with intermittent hemodialysis, CVVHD did not influence CBFV and AR in critically ill patients with acute renal failure, possibly due to lower extracorporeal blood flow, slower change of plasma osmolarity, and a lower fluid extraction rate. In a subgroup of patients with sepsis, the AR was impaired at baseline in more than half of the patients, and this was reversed during CVVHD. The trial was registered at ClinicalTrials.gov ID: NCT01376531.

Contrast-induced acute kidney injury and renal support for acute kidney injury: a KDIGO summary (Part 2)

Acute kidney injury (AKI) is a common and serious problem affecting millions and causing death and disability for many. In 2012, Kidney Disease: Improving Global Outcomes completed the first ever international multidisciplinary clinical practice guideline for AKI. The guideline is based on evidence review and appraisal, and covers AKI definition, risk assessment, evaluation, prevention, and treatment. Two topics, contrast-induced AKI and management of renal replacement therapy, deserve special attention because of the frequency in which they are encountered and the availability of evidence. Recommendations are based on systematic reviews of relevant trials. Appraisal of the quality of the evidence and the strength of recommendations followed the Grading of Recommendations Assessment, Development and Evaluation approach. Limitations of the evidence are discussed and a detailed rationale for each recommendation is provided. This review is an abridged version of the guideline and provides additional rationale and commentary for those recommendation statements that most directly impact the practice of critical care.

An update on neurocritical care for the patient with kidney disease

Patients with kidney disease have increased rates of neurologic illness such as intracerebral hemorrhage and ischemic stroke. The acute care of patients with critical neurologic illness and concomitant kidney disease requires unique management considerations including attention to hyponatremia, renal replacement modalities in the setting of high intracranial pressure, reversal of coagulopathy, and seizure management to achieve good neurologic outcomes.

Renal replacement therapy in acute kidney injury

Although the use of renal replacement therapy (RRT) to support critically ill patients with acute kidney injury (AKI) has become routine, many of the fundamental questions regarding optimal management of RRT remain. This review summarizes current evidence regarding the timing of initiation of RRT, the selection of the specific modality of RRT, and prescription of the intensity of therapy. Although absolute indications for initiating RRT-such as hyperkalemia and overt uremic symptoms-are well recognized, the optimal timing of therapy in patients without these indications continues to be a subject of debate. There does not appear to be a difference in either mortality or recovery of kidney function associated with the various modalities of RRT. Finally, providing higher doses of RRT is not associated with improved clinical outcomes.

Renal replacement therapy in special situations: heart failure and neurological injury

The cardiorenal syndrome is a complicated and increasingly prevalent entity requiring a multidisciplinary approach. Renal replacement therapy (RRT) in the form of slow ultrafiltration (UF) demonstrates promise for the treatment of acutely decompensated heart failure. Despite the lack of evidence for decreased mortality, there is considerable short-term benefit in decreased rehospitalizations and a restoration of diuretic responsiveness. Given the potential for improvement in quality of life and cost if hospitalizations are minimized, slow UF should be considered in patients with repeated hospitalization for decompensated heart failure. Acute neurologic injury is a highly unstable state requiring strict adherence to evidence-based guidelines to achieve the best possible functional outcomes. With improved short-term survival, a greater burden of non-neurologic injury may hinder long-term functional recovery. Acute kidney injury is among such important considerations that can lead to worsened neurological injury. Careful application of continuous modalities of therapy, probably early in the course of illness to avoid intradialytic osmolar shifts and provide hemodynamic stability, will allow for unimpeded neurologic recovery. Newer evidence on dose and RRT modality on patients with acute and chronic brain injury will certainly add important knowledge to this field.