The role of molecular adsorbent recirculating system dialysis for extracorporeal liver support in children

Advances in medical management of acute liver failure in children: promoting native liver survival

Paediatric acute liver failure (PALF) is defined as a biochemical evidence of acute liver injury in a child with no previous history of chronic liver disease characterised by an international normalised ratio (INR) of 1·5 or more unresponsive to vitamin K with encephalopathy, or INR of 2·0 or more with or without encephalopathy. PALF can rapidly progress to multiorgan dysfunction or failure. Although the transplant era has substantially changed the outlook for these patients, transplantation itself is not without risks, including those associated with life-long immunosuppression. Consequently, there has been an increased focus on improving medical management to prioritise bridging of patients to native liver survival, which is possible due to improved understanding of the underlying pathophysiology of multiorgan involvement in PALF. In this Review, we discuss recent advances in the medical management of PALF with an aim of reducing the need for liver transplantation. The Review will focus on the non-specific immune-mediated inflammatory response, extracorporeal support devices, neuromonitoring and neuroprotection, and emerging cellular and novel future therapeutic options.

Pharmacokinetics of Commonly Used Medications in Children Receiving Continuous Renal Replacement Therapy: A Systematic Review of Current Literature

BACKGROUND AND OBJECTIVE

The use of continuous renal replacement therapy (CRRT) for renal support has increased substantially in critically ill children compared with intermittent modalities owing to its preferential effects on hemodynamic stability. With the expanding role of CRRT, the quantification of extracorporeal clearance and the effect on primary pharmacokinetic parameters is of the utmost importance. Within this review, we aimed to summarize the current state of the literature and compare published pharmacokinetic analyses of commonly used medications in children receiving CRRT to those who are not.

METHODS

A systematic search of the literature within electronic databases PubMed, EMBASE, Cochrane Library, and Web of Science was conducted. Published studies that were included contained relevant information on the use of commonly administered medications to children, from neonates to adolescents, receiving CRRT. Pharmacokinetic parameters that were analyzed included volume of distribution, total clearance, extracorporeal clearance, area under the curve, and elimination half-life. Information regarding CRRT circuit, flow rates, and membrane components was analyzed to investigate differences in pharmacokinetics between each modality.

RESULTS

Forty-five studies met the final inclusion criteria within this systematic review, totaling 833 pediatric patients, with 586 receiving CRRT. Antimicrobials were the most common pharmacological class represented within the literature, representing 81% (35/43) of studies analyzed. Children receiving CRRT largely had similar volume of distribution and total clearance to critically ill children not receiving CRRT, suggesting reno-protective dose adjustments may lead to subtherapeutic dosing regimens in these patients. Overall, there was a tendency for hydrophilic agents, with a low protein binding to undergo elevated total clearance in these children. However, results should be interpreted with caution because of the large variability amongst patient populations and heterogeneity with CRRT modalities, flow rates, and use of extracorporeal membrane oxygenation within studies. This review was able to identify that variation in solute removal, or CRRT modalities, properties (i.e., flow rates), and membrane composition, may have differing effects on the pharmacokinetics of commonly administered medications.

CONCLUSIONS

The current state of the literature regarding medications administered to children receiving CRRT largely focuses on antimicrobials. Significant gaps remain with other commonly used medications such as sedatives and analgesics. Overall reporting of patient clinical characteristics, CRRT settings, and circuit composition was poor, with only 10% of articles including all relevant information to assess the impact of CRRT on total clearance. Changes in pharmacokinetics because of CRRT often required higher than labeled doses, suggesting renally adjusted or reno-protective doses may lead to subtherapeutic dosing regimens. A thorough understanding of the interplay between patient, drug, and CRRT-circuit factors are required to ensure adequate delivery of dosing regimens to this vulnerable population.

Systemic causes of non-dermatologic chronic pruritus in the pediatric population and their management: An unexplored area

Chronic pruritus associated with systemic diseases in the pediatric population has been infrequently addressed in the literature. This review focuses on chronic pruritus presenting without cutaneous manifestations. Common systemic etiologies include diseases with hepatic, renal, and hematologic origins. This encompasses several congenital liver disorders, end-stage renal disease (ESRD), and lymphoproliferative disorders such as Hodgkin's lymphoma. In this paper, an expert panel describes the clinical characteristics, pathophysiology, and therapeutic treatment ladders for chronic pruritus associated with the aforementioned systemic etiologies. Novel therapies are also reviewed. Our aim is to shed light on this unexplored area of pediatric dermatology and instigate further research.

Hepatorenal syndrome in children: a review

Hepatorenal syndrome (HRS) occurs in patients with cirrhosis or fulminant hepatic failure and is a kind of pre-renal failure due to intense reduction of kidney perfusion induced by severe hepatic injury. While other causes of pre-renal acute kidney injury (AKI) respond to fluid infusion, HRS does not. HRS incidence is 5% in children with chronic liver conditions before liver transplantation. Type 1 HRS is an acute and rapidly progressive form that often develops after a precipitating factor, including gastrointestinal bleeding or spontaneous bacterial peritonitis, while type 2 is considered a slowly progressive form of kidney failure that often occurs spontaneously in chronic ascites settings. HRS pathogenesis is multifactorial. Cirrhosis causes portal hypertension; therefore, stasis and release of vasodilator substances occur in the hepatic vascular bed, leading to vasodilatation of splanchnic arteries and systemic hypotension. Many mechanisms seem to work together to cause this imbalance: splanchnic vasodilatation; vasoactive mediators; hyperdynamic circulation states and subsequent cardiac dysfunction; neuro-hormonal mechanisms; changes in sympathetic nervous system, renin-angiotensin system, and vasopressin. In patients with AKI and cirrhosis, fluid expansion therapy needs to be initiated as soon as possible and nephrotoxic drugs discontinued. Once HRS is diagnosed, pharmacological treatment with vasoconstrictors, mainly terlipressin plus albumin, should be initiated. If there is no response, other options can include surgical venous shunts and kidney replacement therapy. In this regard, extracorporeal liver support can be a bridge for liver transplantation, which remains as the ideal treatment. Further studies are necessary to investigate early biomarkers and alternative treatments for HRS.

Extracorporeal renal and liver support in pediatric acute liver failure

The liver is the only organ which can regenerate and, thus, potentially negate the need for transplantation in acute liver failure (ALF). Cerebral edema and sepsis are leading causes of mortality in ALF. Both water-soluble and protein-bound toxins have been implicated in pathogenesis of various ALF complications. Ammonia is a surrogate marker of water-soluble toxin accumulation in ALF and high levels are associated with higher grades of hepatic encephalopathy, raised intracranial pressure, and mortality. Therefore, extracorporeal therapies aim to lower ammonia and maintain fluid balance and cytokine homeostasis. The most common and easily available modality is continuous kidney replacement therapy (CKRT). Early initiation of high-volume CKRT utilizing an anticoagulation regimen minimizing treatment downtime and delivering the prescribed dose is highly desirable. Ideally, extracorporeal liver-assist devices (ECLAD) should perform both synthetic and detoxification functions of the liver. ECLAD may temporarily replace lost liver function and serve as a bridge, either to spontaneous recovery or liver transplantation. Various bioartificial and biologic liver-assist devices are described in specialty literature, including molecular adsorbent recirculating system (MARS), single pass albumin dialysis (SPAD), and total plasma exchange (TPE); however, clinicians commonly use modalities easily available in intensive care units. There is a lack of standardization of indications for ECLAD, availability of different extracorporeal devices with varied technical approaches, and, of note, the differences in doses of ECLAD provided in clinical practice. We review the practicalities and evidence regarding these four artificial liver support devices in pediatric ALF.

Molecular Adsorbent Recirculating System Therapy with Continuous Renal Replacement Therapy Enhanced Clearance of Piperacillin in a Pediatric Patient and Led to Failure to Attain Pharmacodynamic Targets

Molecular adsorbent recirculating system (MARS), an extracorporeal support device used in patients with liver failure, specifically removes albumin-bound molecules, including antibiotics. Case reports in adult patients showed that MARS enhances the clearance of piperacillin. However, for those patients, pharmacodynamic targets were achieved when piperacillin/tazobactam was administered as extended infusions over 3-4 hours. In contrast, piperacillin/tazobactam is typically given as short intermittent infusions in children. No reports describe the effect of MARS on piperacillin pharmacokinetics or pharmacodynamic target attainment in pediatric patients with liver failure. This case report describes the effects of MARS on piperacillin clearance and target attainment in a child with liver failure. It was noted that MARS, in conjunction with continuous renal replacement therapy (CRRT), enhanced the clearance of piperacillin when compared with CRRT alone (6.4-7.4 L/hr vs 3.0 L/hr). Pharmacodynamic targets were not attained during MARS-CRRT cycles with free piperacillin concentrations being above 64 µg/ml for < 50% of dosing intervals, the goal target. We performed simulation analysis to identify a dosing regimen to optimize target attainment. For this patient, doses 3 times what she received over 3-hour extended infusions and an additional dose within 5 hours of cycle initiation would have led to target attainment throughout the MARS-CRRT cycles.

Single Pass Albumin Dialysis and Plasma Exchange for Copper Toxicity in Acute Wilson Disease

Background: Wilson disease (WD) is a disorder of copper metabolism that results in accumulation of copper in tissues. In acute WD, patients present with fulminant hepatic failure, encephalopathy, and hemolytic anemia due to copper release from necrotic hepatocytes. Many will require life-saving liver transplantation. Extracorporeal liver support systems can provide a bridge to transplantation for critically ill patients. We report our experience with 2 patients for whom we used a combination of plasma exchange (PLEX) and single pass albumin dialysis (SPAD), or SPAD alone as a bridge to liver transplantation. Case Reports: A 17-year-old girl (patient 1) and a 12-year-old boy (patient 2) presented with fulminant hepatic failure, hemolytic anemia, and acute kidney injury. Patient 1 received SPAD on days 2 and 3 (total 32 h). Serum copper decreased from 22.3 to 15.9 µmol/L (28.7% decrease), measured after 28 h of continuous SPAD. She underwent successful liver transplantation on day 4 after presentation. Patient 2 was treated with PLEX on days 1, 3, 4, and 5 and with SPAD on days 3–6. Serum copper decreased from 48.7 to 25.8 µmol/L (47% decrease) after the first session of PLEX and from 35.5 to 21.5 µmol/L (39.4% decrease) after the second session. The serum copper level was 16.2 µmol/L after 4 sessions of PLEX (and ongoing SPAD), with an overall 66.7% reduction in copper levels over 5 days combining both therapies. He underwent successful liver transplantation on day 6. Conclusion: We conclude that SPAD, with or without PLEX, is effective in reducing serum copper levels as a bridge to liver transplantation in WD. PLEX may be more efficient at removing copper but is associated with a rebound increase in copper levels between sessions.

Acute kidney injury in children with chronic liver disease

Acute kidney injury (AKI) is a common accompaniment in patients with liver disease. The causes, risk factors, manifestations and management of AKI in these patients vary according to the liver disease in question (acute liver failure, acute-on-chronic liver failure, post-liver transplantation or metabolic liver disease). There are multiple causes of AKI in patients with liver disease-pre-renal, acute tubular necrosis, post-renal, drug-induced renal failure and hepatorenal syndrome (HRS). Definitions of AKI in liver failure are periodically revised and updated, but pediatric definitions have still to see the light of the day. As our understanding of the pathophysiology of liver disease and renal involvement improves, treatment modalities have become more advanced and rationalized. Treatment includes reversing precipitating factors, such as infections and gastrointestinal bleeding, volume expansion, paracentesis and vasoconstrictors. This approach is tried and tested in adults. A pediatric tailored approach is still lacking due to inadequate numbers of patients, differences in causes of AKI and paucity of literature. In this review, we attempt to explore the pathophysiological basis, treatment modalities and controversies in the diagnosis and treatment of AKI in pediatric patients with chronic liver disease and discuss our own personal practice. We recognize that, although it is not a very commonly encountered entity in pediatric population, HRS has specific diagnostic criteria and treatment modalities that differ from other causes of AKI in patients with chronic liver disease; hence among the etiologies of kidney injury in patients with chronic liver disease, we focus here on HRS.

Hybrid Extracorporeal Therapies as a Bridge to Pediatric Liver Transplantation

OBJECTIVES

Standard intensive care treatment is inadequate to keep children with liver failure alive without catastrophic complications to ensure successful transplant, as accumulation of endogenous protein-bound toxins often lead to hepatic encephalopathy, hepatorenal syndrome, cardiovascular instability, and multiple organ failure. Given paucity of proven treatment modalities for liver failure, blood purification using different extracorporeal treatments as a bridge to transplantation is used, but studies evaluating the safety and efficacy of combination of these therapies, especially in pediatric liver failure, are lacking. We describe our experience at a major tertiary children's hospital, where a unique hybrid extracorporeal treatment protocol has been instituted and followed for acute liver failure or acute-on-chronic liver failure as a bridge to transplantation. This protocol combines high-flux continuous renal replacement therapy for hyperammonemia, therapeutic plasma exchange for coagulopathy, and albumin-assisted dialysis (molecular adsorbent recirculating system) for hepatic encephalopathy.

DESIGN

Retrospective observational study.

SETTING

Freestanding tertiary children's hospital and liver transplant referral center.

PATIENTS

All patients with acute liver failure/acute-on-chronic liver failure receiving hybrid extracorporeal therapy over 24 months.

INTERVENTION

Hybdrid extracorporeal therapy.

MEASUREMENTS AND MAIN RESULTS

Fifteen children (age 3 yr [0.7-9 yr]; 73% male) with acute liver failure/acute-on-chronic liver failure who were either listed or actively considered for listing and met our protocol criteria were treated with hybrid extracorporeal therapy; 93% were ventilated, and 80% were on vasoactive support. Of these, two patients recovered spontaneously, four died prior to transplant, and nine were successfully transplanted; 90-day survival post orthotopic liver transplant was 100%. Overall survival to hospital discharge was 73%.

CONCLUSIONS

Hybrid extracorporeal therapies can be effectively implemented in pediatric liver failure as a bridge to transplantation. Overall complexity and heavy resource utilization need to be carefully considered in instituting these therapies in suitable candidates.

Acute Liver Failure: Outcome and Value of Pediatric End-Stage Liver Disease Score in Pediatric Cases

PURPOSE

The aims of this study were to analyze the characteristics of patients with acute liver failure (ALF) in our center and evaluate the prognostic value of the Pediatric End-Stage Liver Disease (PELD) score calculated at admission.

METHODS

A retrospective analysis of patients with ALF younger than 15 years between 2005 and 2013 was performed. Information collected included age, sex, etiology of ALF, laboratory tests, PELD score, stage of encephalopathy, and need for liver support devices such as MARS and/or liver transplant (LT) and survival. A poor prognosis was defined as the need for LT or death.

RESULTS

Twenty patients (10 male patients, 50%) with a median age of 2.6 years (3 days-14.5 y old) were included. Acute liver failure was of indeterminate cause in 5 cases (25%). Within the recognized causes, the most frequent were viral hepatitis (herpes simplex virus, adenovirus, influenza B, Epstein-Barr virus), autoimmune hepatitis, and metabolopathies. Sixty percent presented with encephalopathy at diagnosis. Four patients were aided by a MARS liver support device. Six patients received a total of 7 transplants, all from deceased donors. The rate of spontaneous recovery was 45%. Currently 13 patients (65%) are living, 4 of them with an LT. Six patients died because of ALF. The mean PELD score of patients with spontaneous recovery was 15.31 (5.3-27.6) compared with a mean of 29.5 (17.2-39.4) in LT patients and 31.55 (15.8-52.4) for nonsurvivors (P = 0.013).

CONCLUSIONS

High PELD scores at diagnosis were accurate predictors of a poor prognosis in our patients with ALF. This model may help in the clinical management of this entity, although prospective validation is needed.

Extracorporeal Liver Support Systems in Paediatric Liver Failure

Extracorporeal liver support systems (ELSS), encompassing artificial and bioartificial devices, have been used for decades, with the aim of supporting patients with acute liver failure and acute-on chronic liver failure, as a bridge to recovery (acute liver failure only) or liver transplantation, in an era of organ donation shortage. Although biochemical efficacy has been consistently demonstrated by these devices, translation into clinical and survival benefits has been unclear, due to study limitations and lack of reliable prognostic scoring in liver failure. Consequently, extracorporeal devices are not widely accepted as routine therapy in adult liver failure. Recent large multicentre trials using artificial liver systems have not revealed beneficial outcomes associated with albumin dialysis but plasma exchange practices have shown some potential. In paediatric liver failure, data on extracorporeal systems is scarce, comprising few reports on albumin dialysis (namely, Molecular Adsorbent Recirculating System; MARS) and plasma exchange. When extrapolating data from adult studies differences in disease presentation, aetiology, prognosis and the suitability, and safety of such devices in children must be considered. The aim of this review is to critically appraise current practices of extracorporeal liver support systems to help determine efficacy in paediatric liver failure.

Hemadsorption with Adult CytoSorb® in a Low Weight Pediatric Case

Cytokine adsorber (CytoSorb) has been used successfully as adjunctive treatment for adult patients with elevated cytokine levels in the setting with severe sepsis and septic shock and to reduce blood myoglobin, unconjugated bilirubin, and conjugated bilirubin. In this article we present the case of a nine-month-old male infant who was admitted to the NICU due to sepsis after cardiac surgery, Fallot tetralogy, and multisystem organ failure (MSOF) including liver failure and renal failure which was successfully treated by a combination of continuous hemodiafiltration (HDF) and hemadsorption with CytoSorb. HDF was safe and effective from the first day for urea removal, but the patient's bilirubin levels kept increasing gradually, culminating on the 9th day with a maximum value of 54 mg/dL of total bilirubin and 31.67 mg/dL of direct bilirubin when we performed hemadsorption with CytoSorb. Over the 49-hour period of hemadsorption, the total bilirubin value decreased from 54 to 14 mg/dL, and the patient's general status improved considerably accompanied by a rapid drop of aminotransferases. Hemodynamic status has been improved as well and inotropes dropped rapidly. The patient's ventilation settings improved during CytoSorb treatment permitting weaning the patient from mechanical ventilation after five days of hemadsorption. The patient was discharged home after 34 days of hospitalization, in a good general status.

COMBINATION OF MOLECULAR ADSORBENT RECIRCULATING SYSTEM AND RADIOIODINE FOR THE TREATMENT OF CONCURRENT HYPERTHYROIDISM AND SEVERE LIVER DYSFUNCTION: A RETROSPECTIVE COHORT STUDY

OBJECTIVE

The treatment of hyperthyroidism associated with severe liver dysfunction (LD) is a clinical challenge, and there has been no unified examination of this problem. The objective of this study was to assess the efficacy and safety of radioiodine (¹³¹I) in combination with a molecular adsorbent recirculating system (MARS) for the treatment of hyperthyroidism complicated by severe liver LD.

METHODS

A total of 116 hyperthyroidism patients with concomitant LD who received MARS treatment were studied retrospectively. The patients were grouped according to whether or not they also received ¹³¹I treatment: Group 1 (59 patients) received ¹³¹I following MARS treatment, while Group 2 (57 cases) received only MARS. Clinical outcomes, including thyroid hormone levels, liver function parameters, and therapeutic efficacy were calculated.

RESULTS

The overall response rate was significantly greater in Group 1 than in Group 2 (P<.01). The clinical indicators improved significantly in both groups 3 months after treatment compared with before treatment (P<.05), but Group 1 showed a greater improvement. Compared with Group 1, patients in Group 2 had a longer stay in hospital (P<.05), and received more frequent MARS treatments (P<.05).

CONCLUSION

The combination of MARS and ¹³¹I for the treatment of hyperthyroidism complicated by severe LD was effective and safe. The use of this system could rapidly improve liver function and metabolism, allowing ¹³¹I therapy to be applied as early as possible with a shortened recovery time of liver function.

ABBREVIATIONS

ALSS = artificial liver support system ALT = alanine transaminase AST = aspartate transaminase ATD = antithyroid drugs DBil = direct bilirubin FT3 = free tri-iodothyronine FT4 = free thyroxine ¹³¹I = radioiodine INR = international normalized ratio LD = liver dysfunction MARS = molecular adsorbent recirculating system MELD = model for end-stage liver disease PT = prothrombin time TBil = total bilirubin TSH = thyroid-stimulating hormone.

Comparison of two different modes of molecular adsorbent recycling systems for liver dialysis

BACKGROUND

In children acute liver failure is a rare but life-threatening condition from which two-thirds do not recover with supportive therapy. Treatment is limited by the availability of liver transplants. Molecular adsorbent recirculating system (MARS) dialysis is a bridge to transplantation that enhances the chances of survival during the waiting period for a transplant, although it cannot improve survival. Open albumin dialysis (OPAL) is a new mode of albumin dialysis developed to further improve dialysis efficiency.

CASE DIAGNOSIS/TREATMENT

We report a paediatric case of acute-on-chronic liver failure and compare the two modes of albumin dialysis, namely, the MARS and OPAL, used to treat this patient's cholestatic pruritus. Removal of total and direct bilirubin, ammonia and bile acids were measured by serial blood tests. There was an increased removal of bile acids with the OPAL mode, whereas the removal of total and direct bilirubin and ammonia was similar in both modes. The patient reported better improvement in pruritus following OPAL compared to dialysis with the MARS.

CONCLUSION

OPAL may offer a better solution than the MARS in the treatment of refractory pruritus in liver failure.

[Methods of Molecular Transfusion in Intensive Care of Critical States in Pediatric Postoperative Cardiac Surgery Patients]

Molecular techniques in transfusion medicine have become popular in the clinical practice of pediatric intensive care units when the patient needs blood purification, more recently, in children in critical condition. Considering the anatomical and physiological characteristics of the child’s body, pronounced severity, and rapid progression of multiple organ disorders, the key problems defining the treatment results are instrument reading, choice and timely initiation of extracorporeal therapy. Today, along with the methods of renal replacement therapy in children albumin dialysis therapy and high-volume plasmapheresis are successfully applied in the treatment of acute liver dysfunction; extracorporeal membrane oxygenation — in the treatment of biventricular cardiac and/or respiratory failure. Selective endotoxin sorption methods (LPS-adsorption) are implemented in the treatment of severe gram-negative sepsis.

Dialysis-dependent acute kidney injury in children with end-stage liver disease: prevalence, dialysis modalities and outcome

BACKGROUND

Acute kidney injury (AKI) is a major complication in children with hepatic failure which leads to increased morbidity and mortality. The aim of this study was to provide paediatric data on the prevalence of dialysis-dependent AKI (dAKI), the feasibility and efficacy of dialysis methods and outcome.

METHODS

We conducted a retrospective analysis of 367 children listed for orthotopic liver transplantation (OLT) in our centre during the past decade.

RESULTS

Data on 30 children (15 boys, 15 girls) were compiled for retrospective analysis, and data on dialysis feasibility and efficacy were available for 26 of these. Median age was 3.5 (range 0.4-17.7) years. Median MELD (Model For End-Stage Liver Disease) score was 33. dAKI was caused by hepato-renal syndrome in 16 of the 30 children. Twenty-one patients were treated with continuous veno-venous haemofiltration (CVVH), and nine patients received peritoneal dialysis (PD). Overall mortality was 77%. Mortality within the PD-group was 100 % versus 67% in the CVVH-group (p = 0.039). Urea reduction rate within the first 24 h of treatment was 12.9% in the PD group and 23.5% in the CVVH group (p = 0.019).

CONCLUSIONS

Children with end-stage liver disease have a high risk for dAKI associated with high mortality. CVVH is associated with better efficacy and less mortality than PD.

Continuous Veno-Venous Hemodiafiltration and Plasma Exchange in Infantile Acute Liver Failure

OBJECTIVES

The purpose of the current study was to assess our multidisciplinary approach consisting of early application of neurology-oriented intensive care, aggressive artificial liver support and liver transplantation at the appropriate time for infants with acute liver failure.

DESIGN

Retrospective cohort study.

SETTING

A tertiary pediatric medical center in Japan.

PATIENTS

Seventeen infants younger than 12 months with acute liver failure who subsequently underwent liver transplantation between February 2006 and June 2011.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The patients varied from 1 to 11 months, with a median of 6 months. The median body weight was 8.0 kg (range, 2.7-10 kg). With respect to the encephalopathy grading before liver transplantation, four cases were categorized as grade II, seven cases were categorized as grade III, and five cases were categorized as grade IV. Continuous veno-venous hemodiafiltration and plasma exchange were applied to all the infants until liver transplantation. Bilirubin, ammonia, prothrombin time/international normalized ratio and creatinine decreased significantly after continuous veno-venous hemodiafiltration + plasma exchange (p < 0.001). The median value of catecholamine index changed from 10 to 0 (range, 0-20.6). Notably, among the 16 infants who underwent electroencephalography assessment, five did not show slow waves throughout their stay, and one who did so before treatment ceased to show any after treatment. The all patients underwent living-donor liver transplantation and were subsequently discharged from the PICU. The overall survival rate was 88% (15/17) with a median follow-up period of 28 months (range, 2-64 mo). Regarding the neurological outcomes of the survivors, 73% (11/15) had no neurological morbidities and 20% (3/15) had mild disabilities.

CONCLUSIONS

Our multidisciplinary approach for infants with acute liver failure achieved favorable outcomes. Further investigations are needed to examine the efficacy of the artificial liver support.

Experience with molecular adsorbent recirculating system treatment in 20 children listed for high-urgency liver transplantation

For more than 10 years, children at our national center for pediatric liver transplantation (LT) have been treated with Molecular Adsorbent Recirculating System (MARS) liver dialysis as a bridging therapy to high-urgency LT. Treatment was reserved for 20 patients with the highest degrees of hepatic encephalopathy (HE; median grade = 3.5). Death from neurological sequelae was considered imminent for these patients, and this was further reflected in significantly higher international normalized ratios and ammonia levels and worse prognostic liver indices (Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease scores and liver injury units) in comparison with 32 wait-listed patients who did not receive MARS dialysis. MARS therapy was generally well tolerated, with a reduction in thrombocytes and hemorrhaging as the most common side effects. HE improvement was documented in 30% of the treated patients, but progression to grade IV encephalopathy occurred in 45% of the patients despite the treatment. Serum ammonia, bilirubin, bile acid, and creatinine levels significantly decreased during treatment. Eighty percent of MARS-treated patients survived to undergo LT, and their survival was equivalent to that of non-MARS-treated patients with severe liver failure (69%, P = 0.52). The heterogeneity between MARS-treated patients and non-MARS-treated patients in our cohort precluded a statistical evaluation of a benefit from MARS for patient survival. Our data demonstrate the safety of MARS even in the most severely ill patients awaiting LT, but strategies that promote the more rapid and widespread availability of high-quality donor organs remain of critical importance for improving patient survival in cases of severe acute liver failure.

Safety and efficacy of tandem hemodialysis and plasma exchange in children

BACKGROUND AND OBJECTIVES

Patients with immune-mediated kidney disease and liver failure often require plasma exchange (PE) and hemodialysis (HD). Combining both methods (i.e., connecting the PE and HD circuits in series [tandem dialysis]) should allow for a more efficient treatment. This work reviews the authors' experience with tandem blood purification.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Chart review was utilized to retrospectively analyze the efficacy and tolerability of 92 combined PE/HD (cPE/HD) sessions in 26 children in comparison with 113 sequential PE/HD (sPE/HD) treatments performed in 32 children between 1988 and 2012 at the University of Heidelberg Center for Pediatric and Adolescent Medicine. Eleven children received both treatment modalities.

RESULTS

The mean treatment duration was 3.8 ± 2.2 hours per cPE/HD and 5.9 ± 1.6 hours per sPE/HD session (P<0.001). Dialyzer surface areas per body surface area (in meters squared) and blood flow rates were similar. Although a 3-fold higher initial bolus of heparin was administered with cPE/HD, the heparin dose per hour was similar with both modalities and the total heparin load was only slightly lower with cPE/HD, with a median 2939 IU/m(2) per session (interquartile range, 1868, 4189) versus 3341 IU/m(2) per session (interquartile range, 2126, 4792). In sessions with regional anticoagulation, equal citrate and calcium infusion rates were applied. Plasma turnover, ultrafiltration rates, and solute removal were comparable. Procedure-related problems developed in 14.0% of cPE/HD and 7.0% of sPE/HD sessions (P=0.37). Clinical symptoms occurred in 19.6% and 6.2% (P=0.05), necessitating treatment discontinuation in 12.0% and 5.3% of the sessions (P=0.14). Intra-individual comparison of both dialysis methods in 11 children reconfirmed these findings.

CONCLUSIONS

cPE/HD is a time-saving procedure relative to sPE/HD, but may be associated with a higher rate of procedure-related and clinical adverse events.

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.