Hybrid Extracorporeal Therapies as a Bridge to Pediatric Liver Transplantation

Diagnosis and management of pediatric acute liver failure: consensus recommendations of the Indian Society of Pediatric Gastroenterology, Hepatology, and Nutrition (ISPGHAN)

Timely diagnosis and management of pediatric acute liver failure (PALF) is of paramount importance to improve survival. The Indian Society of Pediatric Gastroenterology, Hepatology, and Nutrition invited national and international experts to identify and review important management and research questions. These covered the definition, age appropriate stepwise workup for the etiology, non-invasive diagnosis and management of cerebral edema, prognostic scores, criteria for listing for liver transplantation (LT) and bridging therapies in PALF. Statements and recommendations based on evidences assessed using the modified Grading of Recommendations Assessment, Development and Evaluation (GRADE) system were developed, deliberated and critically reappraised by circulation. The final consensus recommendations along with relevant published background information are presented here. We expect that these recommendations would be followed by the pediatric and adult medical fraternity to improve the outcomes of PALF patients.

Therapeutic plasma exchange in critically ill children: A single center experience

INTRODUCTION

Therapeutic plasma exchange (TPE) is used in a wide spectrum of diseases in critically ill pediatric patients. We aim to review the indications, complications, safety, and outcomes of critically ill children who received TPE.

METHODS

All of the TPE procedures performed in a pediatric intensive care unit providing tertiary care during 19 years (January 2013-January 2023) were evaluated retrospectively. A total of 154 patients underwent 486 TPE sessions.

RESULTS

Median age was 6 years (2-12.5) and 35 children had a body weight of <10 kg (22.7%). Number of organ failure was 4 (2-6). Liver diseases were the most common indication for TPE (31.2%) followed by sepsis with multiorgan dysfunction syndrome (27.3%). Overall survival rate was 72.7%. The highest mortality was observed in hemophagocytic lymphohistiocytosis group. Non-survivors had significantly higher number of organ failure (p < 0.001), higher PRISM score (p < 0.001), and higher PELOD score on admission (p < 0.001). Adverse events were observed in 68 (13.9%) sessions. Hypotension (7.8%) and hypocalcemia (5.1%) were the most frequent adverse events.

CONCLUSION

TPE is safe for critically ill pediatric patients with experienced staff. Survival rate may vary depending on the underlying disease. Survival decreases with the increase in the number of failed organs.

Identifying drivers of cost in pediatric liver transplantation

Understanding the economics of pediatric liver transplantation (LT) is central to high-value care initiatives. We examined cost and resource utilization in pediatric LT nationally to identify drivers of cost and hospital factors associated with greater total cost of care. We reviewed 3295 children (<21 y) receiving an LT from 2010 to 2020 in the Pediatric Health Information System to study cost, both per LT and service line, and associated mortality, complications, and resource utilization. To facilitate comparisons, patients were stratified into high-cost, intermediate-cost, or low-cost tertiles based on LT cost. The median cost per LT was $150,836 [IQR $104,481-$250,129], with marked variance in cost within and between hospital tertiles. High-cost hospitals (HCHs) cared for more patients with the highest severity of illness and mortality risk levels (67% and 29%, respectively), compared to intermediate-cost (60%, 21%; p <0.001) and low-cost (51%, 16%; p <0.001) hospitals. Patients at HCHs experienced a higher prevalence of mechanical ventilation, total parental nutrition use, renal comorbidities, and surgical complications than other tertiles. Clinical (27.5%), laboratory (15.1%), and pharmacy (11.9%) service lines contributed most to the total cost. Renal comorbidities ($69,563) and total parental nutrition use ($33,192) were large, independent contributors to total cost, irrespective of the cost tertile ( p <0.001). There exists a significant variation in pediatric LT cost, with HCHs caring for more patients with higher illness acuity and resource needs. Studies are needed to examine drivers of cost and associated outcomes more granularly, with the goal of defining value and standardizing care. Such efforts may uniquely benefit the sicker patients requiring the strategic resources located within HCHs to achieve the best outcomes.

Continuous renal replacement therapy and therapeutic plasma exchange in pediatric liver failure

Patients with acute liver failure (ALF) and acute on chronic liver failure (ACLF) have significant morbidity and mortality. They require extracorporeal blood purification modalities like continuous renal replacement therapy (CRRT) and therapeutic plasma exchange (TPE) as a bridge to recovery or liver transplantation. Limited data are available on the outcomes of patients treated with these therapies. This is a retrospective single-center study of 23 patients from 2015 to 2022 with ALF/ACLF who underwent CRRT and TPE. We aimed to describe the clinical characteristics and outcomes of these patients. Median (IQR) age was 0.93 years (0.57, 9.88), range 16 days to 20 years. Ten (43%) had ALF and 13 (57%) ACLF. Most (n = 19, 82%) started CRRT for hyperammonemia and/or hepatic encephalopathy and all received TPE for refractory coagulopathy. CRRT was started at a median of 2 days from ICU admission, and TPE started on the same day in most. The liver transplant was done in 17 (74%), and 2 recovered native liver function. Four patients, all with ACLF, died prior to ICU discharge without a liver transplant. The median peak ammonia pre-CRRT was 131 µmol/L for the whole cohort. The mean (SD) drop in ammonia after 48 h of CRRT was 95.45 (43.72) µmol/L in those who survived and 69.50 (21.70) µmol/L in those who did not (p 0.26). Those who survived had 0 median co-morbidities compared to 2.5 in non-survivors (aOR (95% CI) for mortality risk of 2.5 (1.1-5.7), p 0.028).  Conclusion: In this cohort of 23 pediatric patients with ALF or ACLF who received CRRT and TPE, 83% survived with a liver transplant or recovered with their native liver. Survival was worse in those who had ACLF and those with co-morbid conditions. What is Known: •  Pediatric acute liver failure is associated with high mortality. •  Patients may require extracorporeal liver assist therapies (like CRRT, TPE, MARS, SPAD) to bridge them over to a transplant or recovery of native liver function. What is New: • Standard volume plasma exhange has not been evaluated against high volume plasma exchange for ALF. • The role, dose, and duration of therapeutic plasma exchange in patients with acute on chronic liver failure is not well described.

Role of high-volume plasmapheresis in the management of paediatric acute liver failure

OBJECTIVES

Paediatric acute liver failure (PALF) is a life-threatening disease. Management aims to support hepatic regeneration or to bridge to liver transplantation. High-volume plasmapheresis (HVP) removes protein-bound substances, alleviates inflammation, and improves survival in adult acute liver failure. However, experience with HVP in PALF is limited. Aim of this study is to report on feasibility, safety, efficacy and outcomes of HVP in PALF.

METHODS

Retrospective observational study in children with PALF. HVP was performed upon identification of negative prognostic indicators, in toxic aetiology or multiorgan failure (MOF). Exchanged volume with fresh-frozen plasma corresponded to 1.5-2.0 times the patient's estimated plasma volume. One daily cycle was performed until the patient met criteria for discontinuation, that is, liver regeneration, liver transplantation, or death.

RESULTS

Twenty-two children with PALF (body weight 2.5-106 kg) received 1-7 HVP cycles. No bleeding or procedure-related mortality occurred. Alkalosis, hypothermia and reduction in platelets were observed. Haemolysis led to HVP termination in one infant. Seven children (32%) survived with their native livers, 13 patients (59%) underwent liver transplantation. Two infants died due to MOF. Overall survival was 86%. International normalization ratio (INR), alanine aminotransaminases (ALT), bilirubin and inotropic support were reduced significantly (p < 0.05) after the first HVP-cycle (median): INR 2.85 versus 1.5; ALT 1280 versus 434 U/L; bilirubin 12.7 versus 6.7 mg/dL; norepinephrine dosage 0.083 versus 0.009 µg/kg/min. Median soluble-interleukin-2-receptor dropped significantly following HVP (n = 7): 2407 versus 950 U/mL (p < 0.02).

CONCLUSIONS

HVP in PALF is feasible, safe, improves markers of liver failure and inflammation and is associated with lowering inotropic support. Prospective and controlled studies are required to confirm efficacy of HVP in PALF.

Management of pediatric liver failure with therapeutic plasma exchange and continuous renal replacement therapy: A retrospective observational study

Liver failure represents a critical medical condition, marked by the rapid decline of hepatic functions. Emerging therapies, notably therapeutic plasma exchange (TPE) and continuous venovenous hemodiafiltration (CVVHDF), have demonstrated potential in mitigating these conditions through their roles in detoxification and hepatic support. The utility of these treatments, whether applied individually or in tandem, constitutes a significant area of research concerning the management of liver failure in pediatric patients. This study aims to evaluate the role and efficacy of TPE or TPE combined with CVVHDF in the treatment of liver failure among children. This retrospective study was conducted in a LTICU by reviewing the medical history of pediatric patients aged 1 month to 18 years. Patients were admitted between January 1, 2021 and December 1, 2023 due to acute liver failure or acute-chronic liver failure. The study evaluated those who received TPE or continuous renal replacement therapy combined with TPE. In statistical analyses, a P-value of <.05 was considered statistically significant. The study involved 24 patients with liver failure, comprising 13 males and 11 females. Sixteen patients (66.6%) received only TPE, while 8 patients (33.4%) were treated with TPE and CVVHDF. For patients treated only with TPE, the median INR reduced from 3.1 to 1.26, alanine aminotransferase from 1255 to 148, and aspartate aminotransferase from 2189 to 62. Similar significant reductions were observed in the TPE and CVVHDF group: INR from 3.9 to 1.26, alanine aminotransferase from 1749 to 1148, and aspartate aminotransferase from 1489 to 62. These changes were statistically significant with P-values of .01 for each parameter in both groups. Overall, 14 patients survived without requiring a liver transplant, while 4 patients underwent liver transplantation. Our study on pediatric liver failure treatment shows that both standalone TPE and its combination with CVVHDF are effective, especially as a bridge to transplantation. With 58% transplant-free survival, these therapies demonstrate significant clinical improvements. Future multicentric studies are needed for broader validation of these findings in liver failure management.

Intraoperative renal replacement therapy during liver transplantation in children: Safety, efficacy and impact on survival

BACKGROUND

Intraoperative Continuous Renal Replacement Therapy (iCRRT) can prevent life-threatening complications, facilitate fluid management, and maintain metabolic homeostasis during liver transplantation (LT) in adults. There is a paucity of data in pediatric LT. We evaluated the safety, efficacy, and impact on survival of iCRRT in pediatric LT.

METHODS

We conducted a retrospective cohort study of all children requiring CRRT pre-OLT at a quaternary children's hospital from 2014 to 2022. Demographic characteristics, intraoperative events, and post-LT outcomes were compared between those who received iCRRT and those who did not.

RESULTS

Out of 306 patients who received LT, 30 (10%) were supported with CRRT at least 24 h prior to LT, of which 11 (36%) received iCRRT. The two cohorts were similar in demographics, diagnosis of liver disease, and severity of illness. The iCRRT patients experienced massive blood loss and increased transfusion requirements. There was no difference in intraoperative metabolic balance. One-year post-LT mortality rates were similar.

CONCLUSION

ICRRT is safe in critically ill children with pre-LT renal dysfunction. It optimizes fluid and blood product resuscitation while maintaining metabolic homeostasis. Candidates need to be carefully chosen for this highly resource-intensive therapy to benefit this fragile population.

Estimating risk of prolonged mechanical ventilation after liver transplantation in children: PROVE-ALT score

BACKGROUND

Children at high risk for prolonged mechanical ventilation (PMV) after liver transplantation (LT) need to be identified early to optimize pulmonary support, allocate resources, and improve surgical outcomes. We aimed to develop and validate a metric that can estimate risk for Prolonged Ventilation After LT (PROVE-ALT).

METHODS

We identified preoperative risk factors for PMV by univariable analysis in a retrospective cohort of pediatric LT recipients between 2011 and 2017 (n = 205; derivation cohort). We created the PROVE-ALT score by mapping multivariable logistic regression coefficients as integers, with cutoff values using the Youden Index. We validated the score by C-statistic in a retrospectively collected separate cohort of pediatric LT recipients between 2018 and 2021 (n = 133, validation cohort).

RESULTS

Among total 338 patients, 21% (n = 72) were infants; 49% (n = 167) had cirrhosis; 8% (n = 27) required continuous renal replacement therapy (CRRT); and 32% (n = 111) required management in hospital (MIH) before LT. Incidence of PMV post-LT was 20% (n = 69) and 3% (n = 12) required tracheostomy. Independent risk factors (OR [95% CI]) for PMV were cirrhosis (3.8 [1-14], p = .04); age <1-year (8.2 [2-30], p = .001); need for preoperative CRRT (6.3 [1.2-32], p = .02); and MIH before LT (12.4 [2.1-71], p = .004). PROVE-ALT score ≥8 [Range = 0-21] accurately predicted PMV in the validation cohort with 73% sensitivity and 80% specificity (AUC: 0.81; 95% CI: 0.71-0.91).

CONCLUSION

PROVE-ALT can predict PMV after pediatric LT with a high degree of sensitivity and specificity. Once externally validated in other centers, PROVE-ALT will empower clinicians to plan patient-specific ventilation strategies, provide parental anticipatory guidance, and optimize hospital resources.

Therapeutic Plasma Exchange in Children With Acute and Acuteon-Chronic Liver Failure: A Single-Center Experience

OBJECTIVES

Acute liver failure is a life-threatening condition that may result in death if liver transplant is not performed. The aim of our study was to evaluate patients with acute liver failure or acute-on-chronic liver failure who were followed and treated with therapeutic plasma exchange in a pediatric intensive care unit until they achieved clinical recovery or underwent liver transplant.

MATERIALS AND METHODS

In this retrospective, singlecenter study, we included patients with acute liver failure or acute-on-chronic liver failure who received therapeutic plasma exchange between April 2020 and December 2021. Clinical findings, laboratory findings, extracorporeal therapies, Pediatric Risk of Mortality III and liver injury unit scores and pretherapy and posttherapy hepatic encephalopathy scores, Model for End-Stage Liver Disease score, and Pediatric End-Stage Liver Disease score were retrospectively analyzed.

RESULTS

Nineteen patients were included in the study. One patient was excluded because of positivity for COVID-19. The mean age of children was 62.06 months, ranging from 5 months to 16 years (12 boys, 6 girls). Thirteen patients (72.2%) had acute liver failure, and 5 patients (27.8%) had acute-on-chronic liver failure. No significant difference was shown for mean liver injury unit score (P = .673) and Pediatric Logistic Organ Dysfunction score (P = .168) between patients who died and patients who received treatment at the inpatient clinic and transplant center. However, Pediatric Risk of Mortality score and the mean Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease scores before therapeutic plasma exchange and after therapeutic plasma exchange (after 3 consecutive days of treatment) were statistically significant (P = .001 and P = .004).

CONCLUSIONS

Therapeutic plasma exchange may assist bridge to liver transplant or assist with spontaneous recovery of liver failure in pediatric patients with acute liver failure or acute-on-chronic liver failure.

Molecular Adsorbent Recirculating System for Acute Liver Failure in a New Pediatric-Based Extracorporeal Liver Support Program

IMPORTANCE

Acute liver failure (ALF) carries significant morbidity and mortality, for both pediatric and adult patients. Albumin dialysis via the molecular adsorbent recirculating system (MARS) is a form of extracorporeal liver support (ELS) that can reduce hepatic encephalopathy (HE), a main driver of mortality in ALF. However, data on MARS and its benefit on mortality have been inconsistent.

OBJECTIVES

We sought to report our experiences and patient outcomes from the first 2 years of operation of a new ELS program, within an established pediatric liver transplantation center.

DESIGN SETTING AND PARTICIPANTS

Retrospective review of outcomes in pediatric and adult patients treated with MARS therapy for ALF, from 2021 to 2022.

MAIN OUTCOMES AND MEASURES

Outcomes included reduction in HE and biochemical markers of ALF after MARS therapy, survival, and transplant-free survival. Comparisons were made via Wilcoxon signed-rank test.

RESULTS

Five pediatric and two adult patients underwent MARS for ALF. Ages ranged from 2 to 29 years. Overall, 21 MARS runs were performed (median 3 runs per patient, 12.4 hr per run [interquartile range, IQR 10.1-17]). Overall survival was 85.7%, and transplant-free survival was 71.4%. There was a statistically significant reduction in HE score with MARS therapy (median 3 [IQR 3-4] to 1 [IQR 0-1], p = 0.03), and in ALF biomarkers including ammonia (256 µL/dL [195-265] to 75 µL/dL [58-101], p = 0.02), aspartate aminotransferase (6,362 U/L [920-8,305] to 212 U/L [72-431], p = 0.02), alanine aminotransferase (8,362 U/L [3,866-9,189] to 953 U/L [437-1,351], p = 0.02), and international normalized ratio (4.5 [3.3-6.7] to 1.3 [1.2-1.4], p = 0.02).

CONCLUSIONS AND RELEVANCE

MARS therapy for ALF was well tolerated by both pediatric and adult patients, and resulted in significant improvement in clinical and biochemical parameters. We demonstrated encouraging overall and transplant-free survival, suggesting that early initiation of MARS with relatively long and frequent cycle times may be of significant benefit to ALF patients, and is worthy of additional study in larger cohorts.

Single-center experience in 127 adult patients, mono or dual artificial liver support therapy, in patients with acute liver failure

Background

Acute liver failure (ALF) is a serious condition characterized by sudden liver dysfunction, jaundice and hepatic encephalopathy. Its mortality rate of approximately 80% underscores the urgent need for effective treatments. Supportive extracorporeal therapies (SET), which temporarily support liver function and remove toxins, have shown promise in improving outcomes in acute liver failure (ALF). The aim of this study was to compare the outcomes of dual supportive extracorporeal therapy (SET) and mono supportive extracorporeal therapy in patients with acute liver failure.

Methods

A total of 127 patients with acute liver failure were included in this retrospective, single-center study. Of these, 62 patients received dual supportive extracorporeal therapy and 65 patients received mono supportive extracorporeal therapy. Primary endpoints were survival without the need for liver transplantation and mortality. Secondary endpoints included resolution of encephalopathy and normalization of International Normalized Ratio (INR).

Results

In the dual supportive extracorporeal therapy group, 59.6% of patients survived without the need for liver transplantation, while 27.4% achieved recovery with liver transplantation. The mortality rate in this group was 12.9%. Significant regression of encephalopathy grade was observed in 87% of patients, and the 1 year mortality rate for liver transplant recipients was 10.7%. In the mono supportive extracorporeal therapy group, 61.5% of patients experienced a successful recovery without the need for liver transplantation, with a mortality rate of 29.2%. Significant improvement in the grade of encephalopathy was observed in 70.7% of patients.

Conclusion

Both dual supportive extracorporeal therapy (CVVHDF and PE) and mono supportive extracorporeal therapy (PE) were associated with significant improvements in renal and hepatic biochemical parameters, blood ammonia levels, and neurological status in patients with acute liver failure associated with grade III-IV hepatic encephalopathy. In particular, dual support was associated with improved hemodynamic stability, lactic acidosis and acid-base balance. Survival in acute liver failure in our retrospective cohort using a protocolized approach to extracorporeal therapies is higher compared to previously published large ALF studies. This protocolized approach warrants further prospective studies.

Liver replacement therapy with extracorporeal blood purification techniques current knowledge and future directions

Clinically, it is highly challenging to promote recovery in patients with acute liver failure (ALF) and acute-on-chronic liver failure (ACLF). Despite recent advances in understanding the underlying mechanisms of ALF and ACLF, standard medical therapy remains the primary therapeutic approach. Liver transplantation (LT) is considered the last option, and in several cases, it is the only intervention that can be lifesaving. Unfortunately, this intervention is limited by organ donation shortage or exclusion criteria such that not all patients in need can receive a transplant. Another option is to restore impaired liver function with artificial extracorporeal blood purification systems. The first such systems were developed at the end of the 20^th century, providing solutions as bridging therapy, either for liver recovery or LT. They enhance the elimination of metabolites and substances that accumulate due to compromised liver function. In addition, they aid in clearance of molecules released during acute liver decompensation, which can initiate an excessive inflammatory response in these patients causing hepatic encephalopathy, multiple-organ failure, and other complications of liver failure. As compared to renal replacement therapies, we have been unsuccessful in using artificial extracorporeal blood purification systems to completely replace liver function despite the outstanding technological evolution of these systems. Extracting middle to high-molecular-weight and hydrophobic/protein-bound molecules remains extremely challenging. The majority of the currently available systems include a combination of methods that cleanse different ranges and types of molecules and toxins. Furthermore, conventional methods such as plasma exchange are being re-evaluated, and novel adsorption filters are increasingly being used for liver indications. These strategies are very promising for the treatment of liver failure. Nevertheless, the best method, system, or device has not been developed yet, and its probability of getting developed in the near future is also low. Furthermore, little is known about the effects of liver support systems on the overall and transplant-free survival of these patients, and further investigation using randomized controlled trials and meta-analyses is needed. This review presents the most popular extracorporeal blood purification techniques for liver replacement therapy. It focuses on general principles of their function, and on evidence regarding their effectiveness in detoxification and in supporting patients with ALF and ACLF. In addition, we have outlined the basic advantages and disadvantages of each system.

Elevated bile acids are associated with left ventricular structural changes in biliary atresia

BACKGROUND

In children with biliary atresia (BA), pathologic structural changes within the heart, which define cirrhotic cardiomyopathy, are associated with adverse perioperative outcomes. Despite their clinical relevance, little is known about the pathogenesis and triggers of pathologic remodeling. Bile acid excess causes cardiomyopathy in experimental cirrhosis, but its role in BA is poorly understood.

METHODS

Echocardiographic parameters of left ventricular (LV) geometry [LV mass (LVM), LVM indexed to height, left atrial volume indexed to BSA (LAVI), and LV internal diameter (LVID)] were correlated with circulating serum bile acid concentrations in 40 children (52% female) with BA listed for transplantation. A receiver-operating characteristic curve was generated to determine optimal threshold values of bile acids to detect pathologic changes in LV geometry using Youden index. Paraffin-embedded human heart tissue was separately analyzed by immunohistochemistry for the presence of bile acid-sensing Takeda G-protein-coupled membrane receptor type 5.

RESULTS

In the cohort, 52% (21/40) of children had abnormal LV geometry; the optimal bile acid concentration to detect this abnormality with 70% sensitivity and 64% specificity was 152 µmol/L (C-statistics=0.68). Children with bile acid concentrations >152 µmol/L had ∼8-fold increased odds of detecting abnormalities in LVM, LVM index, left atrial volume index, and LV internal diameter. Serum bile acids positively correlated with LVM, LVM index, and LV internal diameter. Separately, Takeda G-protein-coupled membrane receptor type 5 protein was detected in myocardial vasculature and cardiomyocytes on immunohistochemistry.

CONCLUSION

This association highlights the unique role of bile acids as one of the targetable potential triggers for myocardial structural changes in BA.

Acute liver failure and unique challenges of pediatric liver transplantation amidst a worldwide cluster of adenovirus-associated hepatitis

Investigation into a recent cluster of acute hepatitis in children from the southeastern United States identified human adenovirus (HAdV) DNAemia in all 9 cases. Molecular genotyping in 5 of 9 (56%) children identified HAdV type 41 in all cases (100%). Importantly, 2 children from this cluster progressed rapidly to pediatric acute liver failure (PALF) and required liver transplantation. HAdV type 41, a known cause of self-limited gastroenteritis, has not previously been associated with severe cholestatic hepatitis and liver failure in healthy children. Adenovirus polymerase chain reaction assay and sequencing of amplicons performed on DNA extracted from formalin-fixed, paraffin-embedded liver tissue also identified adenovirus species F (HAdV type 40 or 41) in these 2 children with PALF. Transplant considerations and successful liver transplantation in such situations remain scarce. In this report, we describe the clinical course, laboratory results, liver pathology, and treatment of 2 children with PALF associated with HAdV type 41, one of whom developed secondary hemophagocytic lymphohistiocytosis. Their successful posttransplant outcomes demonstrate the importance of early multidisciplinary medical management and the feasibility of liver transplantation in some children with PALF and HAdV DNAemia.

Therapeutic plasma exchange in children with acute liver failure (ALF): is it time for incorporation into the ALF armamentarium?

Paediatric acute liver failure (PALF) is a rare but devastating condition with high mortality. An exaggerated inflammatory response is now recognised as pivotal in the pathogenesis and prognosis of ALF, with cytokine spill from the liver to systemic circulation implicated in development of multi-organ failure associated with ALF. With advances in medical management, especially critical care, there is an increasing trend towards spontaneous liver regeneration, averting the need for emergency liver transplantation or providing stability to the patient awaiting a graft. Hence, research is ongoing for therapies, including extracorporeal liver support devices, that can bridge patients to transplant or spontaneous liver recovery. Considering the immune-related pathogenesis and inflammatory phenotype of ALF, plasma exchange serves as an ideal liver assist device as it performs both the excretory and synthetic functions of the liver and, in addition, works as an immunomodulatory therapy by suppressing the early innate immune response in ALF. After a recent randomised controlled trial in adults demonstrated a beneficial effect of high-volume plasma exchange on clinical outcomes, this therapy was incorporated in European Association for the Study of Liver (EASL) recommendations for managing adult patients with ALF, but no guidelines exist for PALF. In this review, we discuss rationale, timing, practicalities, and existing evidence regarding the use of plasma exchange as an immunomodulatory treatment in PALF. We discuss controversies in delivery of this therapy as an extracorporeal device, and practicalities of use of plasma exchange as a 'hybrid' therapy alongside other extracorporeal liver assist devices, before finally reviewing outstanding research questions for the future.

Acute Liver Failure in Children

Acute liver failure (ALF) in children, irrespective of cause, is a rapidly evolving catastrophic clinical condition that results in high mortality and morbidity without prompt identification and intervention. Massive hepatocyte necrosis impairs the synthetic, excretory, and detoxification abilities of the liver, with resultant coagulopathy, jaundice, metabolic disturbance, and encephalopathy. Extrahepatic organ damage, multiorgan failure, and death result from circulating inflammatory mediators released by the hepatocytes undergoing necrosis. There are yet no treatment options available for reversing or halting hepatocellular necrosis, thus current therapy focuses on supporting failing organs and preventing life threatening complications pending either spontaneous liver recovery or transplantation. The aims of this review are to define pediatric acute liver failure (PALF), understand the pathophysiologic processes that lead to multiorgan failure, to describe the consequences of a failing liver on extrahepatic organs, to enumerate the critical care challenges encountered during PALF management, and to describe pharmacologic and extracorporeal options available to support a critically ill child with ALF in the intensive care unit.

Emergencies in paediatric hepatology

The aetiology of several liver diseases in children is age specific and many of these conditions have significant and potentially long-term clinical repercussions if not diagnosed early and managed in a timely fashion. We address 5 clinical scenarios that cover most of the diagnostic and therapeutic emergencies in children: infants with liver disease; acute liver failure; management of bleeding varices; liver-based metabolic disorders; and liver tumours and trauma. A wide spectrum of conditions that cause liver disease in infants may present as conjugated jaundice, which could be the only symptom of time-sensitive disorders - such as biliary atresia, metabolic disorders, infections, and haematological/alloimmune disorders - wherein algorithmic multistage testing is required for accurate diagnosis. In infantile cholestasis, algorithmic multistage tests are necessary for an accurate early diagnosis, while vitamin K, specific milk formulae and disease-specific medications are essential to avoid mortality and long-term morbidity. Management of paediatric acute liver failure requires co-ordination with a liver transplant centre, safe transport and detailed age-specific aetiological work-up - clinical stabilisation with appropriate supportive care is central to survival if transplantation is indicated. Gastrointestinal bleeding may present as the initial manifestation or during follow-up in patients with portal vein thrombosis or chronic liver disease and can be managed pharmacologically, or with endoscopic/radiological interventions. Liver-based inborn errors of metabolism may present as encephalopathy that needs to be recognised and treated early to avoid further neurological sequelae and death. Liver tumours and liver trauma are both rare occurrences in children and are best managed by a multidisciplinary team in a specialist centre.

Role of therapeutic apheresis in the treatment of pediatric kidney diseases

Therapeutic apheresis utilizes apheresis procedures in the treatment of a variety of conditions including kidney disease. Therapeutic plasma exchange (TPE) is the most common modality employed with the rationale of rapid reduction of a pathogenic substance distributed primarily in the intravascular compartment; however other techniques which adsorb such pathogenic substances or alter the immune profile have been utilized in diseases affecting native and transplanted kidneys. This article discusses the modalities and technical details of therapeutic apheresis and summarizes its role in individual diseases affecting the kidney. Complications related to pediatric apheresis procedures and specifically related to apheresis in kidney disease are also discussed. Though therapeutic apheresis modalities are employed frequently in children with kidney disease, most experiences are extrapolated from adult studies. International and national registries need to be established to elucidate the role of apheresis modalities in children with kidney disease.

Association of duration and etiology with the effect of the artificial liver support system in pediatric acute liver failure

BACKGROUND

We aimed to assess the efficacy of the artificial liver support system (ALSS) in pediatric acute liver failure (PALF) patients and to examine the risk factors associated with the effect of ALSS. Similar data are limited in PALF.

METHODS

All patients diagnosed with PALF who received ALSS from June 2011 to June 2021 in the pediatric intensive care unit of the First Hospital of Jilin University were included in this retrospective cohort analysis. The effect of ALSS was measured using difference tests before and after treatments. The risk factors associated with the effect of ALSS were evaluated according to whether the total bilirubin (TBIL) and serum ammonia decreased after ALSS (TBIL-unresponsive group vs. TBIL-responsive group, serum ammonia-unresponsive group vs. serum ammonia-responsive group).

RESULTS

Thirty-nine patients who received ALSS during the study period were eligible for inclusion. The most common cause of PALF was undetermined causes (n = 14, 35.9%) followed by infection (n = 11, 28.2%). Four patients received pediatric liver transplantation. The overall survival rate was 76.9% (30/39). Fifteen (38.4%) patients received only one modality, whereas 61.6% patients received hybrid treatments. The most commonly used modality of ALSS was plasma exchange combined with continuous renal replacement therapy (n = 14, 35.9%). Alanine aminotransferase, TBIL, the international normalized ratio, and serum ammonia were significantly decreased after ALSS (P < 0.001). Compared with other causes, more patients with infection and toxication were observed in the TBIL-unresponsive group. A longer ALSS duration was significantly related to blood ammonia reduction.

CONCLUSIONS

ALSS can effectively reduce serum alanine aminotransferase, TBIL, international normalized ratio, and serum ammonia and may reduce mortality. The reduction in TBIL levels after ALSS is dependent on etiology. A longer ALSS duration was associated with blood ammonia reduction. Prospective multicenter studies are needed for further validation.

North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition Position Paper on the Diagnosis and Management of Pediatric Acute Liver Failure

ABSTRACT

Pediatric acute liver failure (PALF) is a rare, rapidly progressive clinical syndrome with significant morbidity and mortality. The phenotype of PALF manifests as abrupt onset liver dysfunction, which can be brought via disparate etiology. Management is reliant upon intensive clinical care and support, often provided by the collaborative efforts of hepatologists, critical care specialists, and liver transplant surgeons. The construction of an age-based diagnostic approach, the identification of a potential underlying cause, and the prompt implementation of appropriate therapy can be lifesaving; however, the dynamic and rapidly progressive nature of PALF also demands that diagnostic inquiries be paired with monitoring strategies for the recognition and treatment of common complications of PALF. Although liver transplantation can provide a potential life-saving therapeutic option, the ability to confidently determine the certainness that liver transplant is needed for an individual child has been hampered by a lack of adequately tested clinical decision support tools and accurate predictive models. Given the accelerated progress in understanding PALF, we will provide clinical guidance to pediatric gastroenterologists and other pediatric providers caring for children with PALF by presenting the most recent advances in diagnosis, management, pathophysiology, and associated outcomes.

Mechanistic insights into the pathophysiology of cirrhotic cardiomyopathy

Myocardial dysfunction in end stage cirrhotic liver disease, termed cirrhotic cardiomyopathy, is a long known, but little understood comorbidity seen in ∼50% of adults and children who present for liver transplantation. Structural, functional, hemodynamic and electrocardiographic aberrations that occur in the heart as a direct consequence of a damaged liver, is associated with multi-organ failure and increased mortality and morbidity in patients undergoing surgical procedures such as porto-systemic shunt placement and liver transplantation. Despite its clinical significance and rapid advances in science and pharmacotherapy, there is yet no specific treatment for this disease. This may be due to a lack of understanding of the pathogenesis and mechanisms behind how a cirrhotic liver causes cardiac pathology. This review will focus specifically on insights into the molecular mechanisms that drive this liver-heart interaction. Deeper understanding of the etio-pathogenesis of cirrhotic cardiomyopathy will allow us to design and test treatments that can be targeted to prevent and/or reverse this co-morbid consequence of liver failure and improve health care delivery and outcomes in patients with cirrhosis.

Therapeutic plasma exchange in critically ill children: experience of the pediatric intensive care unit of two centers in Chile

INTRODUCTION

Therapeutic plasma exchange (TPE) is an extracorporeal blood purification technique used in a wide spectrum of diseases. We aim to review the indications, complications, and outcomes of critically ill children who received TPE and to compare a membrane versus centrifugal method in this cohort.

METHODS

A retrospective observational study in two pediatric intensive care units in Chile during eight years (2011-2019) Results: A total of 36 patients underwent 167 TPE sessions (20 centrifugation and 16 membrane-based). The more frequent indications for TPE were autoimmune neurological diseases in 14 cases, renal diseases (9), and rheumatological disorders (5). 58 % of children received other immunomodulatory therapy. According to ASFA, 45 % of cases were I-II category, 50 % to III, and 5% not classified. Response to treatment was complete in 64 % (23/36) and partial in 33 % (12/36). Complications occurred in 17.4 % of sessions, and the most frequent was transient hypotension during the procedure. Overall survival at discharge from the PICU was 92 %. Patients who received TPE as a single therapy (n = 26) survived 96 %. The clinical outcomes between the two apheresis methods were similar. Survivors had a significantly lower PELOD score on admission (14.5 vs. 6.5, p = 0.004).

CONCLUSIONS

TPE is mainly indicated as a rescue treatment in neurological autoimmune diseases refractory to conventional immunomodulatory treatment. Complications in critically ill children are mild and low. The outcome in children requiring TPE as a single therapy is good, and no differences were observed with centrifugation or membrane method.

Safety of High-Volume Plasmapheresis in Children With Acute Liver Failure

OBJECTIVES

Paediatric acute liver failure (P-ALF) is a rare condition and is associated with a high mortality rate. Management of P-ALF aims to stabilise vital organ functions and to remove circulating toxins and provide vital plasma factors that are lacking. High-volume plasmapheresis (HVP) removes protein-bound substances and improves survival in adult ALF. It is unknown if this effect can be extrapolated to P-ALF. The aim of this study is to report the safety and feasibility of HVP in P-ALF.

METHODS

Children with P-ALF were offered HVP if bilirubin was higher than 200 μmol/L or if the aetiology was toxic hepatitis. HVP was performed with fresh frozen plasma corresponding to 10% of the body weight on a minimum of 3 consecutive days. Diagnostics, biochemical and clinical data during HVP as well as outcome data after 3 months were collected from 2012 to 2019 and retrospectively analysed.

RESULTS

Sixteen children were treated by HVP and completed at least one series of three treatment sessions with HVP. The only complication seen was an increase in pH > 7.55 in three children within the first 12 hours and was corrected with hydrochloric acid. No bleeding or septic episodes were noted during HVP. Eight children survived without liver transplantation, two survived after successful grafting and a total of six children died. The liver injury unit score between survivors with their own liver and the rest, the two groups was significantly different (P = 0.005).

CONCLUSION

HVP with fresh frozen plasma is feasible and well tolerated in children with P-ALF. No serious adverse events and no procedure-related mortality were observed.

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.

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.

Therapeutic Plasma Exchange with Continuous Renal Replacement Therapy for Pediatric Acute Liver Failure: A Case Series from Thailand

Aim and objective

Pediatric acute liver failure (PALF) is a life-threatening condition. Extracorporeal support has been applied for toxic metabolite clearance and serves as a bridging therapy to liver transplantation (LT) or to the regeneration of the liver, but evidence for treatment approaches is still lacking in the pediatric population. We aim to report our experience on therapeutic plasma exchange with high-volume continuous renal replacement therapy (TPE + HV-CRRT) as a promising supportive treatment for PALF.

Materials and methods

A total of eight PALF cases aged 9 months to 14 years, weighing 10–50 kg., who were admitted to PICU King Chulalongkorn Memorial Hospital, Thailand and treated with TPE + HV-CRRT from January 2016 to September 2019 were reviewed. Patient demographic data, indications, technical aspects, and clinical outcomes were recorded.

Results

All patients who underwent TPE + HV-CRRT showed clinical improvement regarding serum bilirubin levels and coagulation studies after the therapy. Complications from the therapy were hemodynamic instability, symptomatic fluid overload, and bleeding from catheter sites. Among these, 6 (75%) patients survived with 4 (50%) successful LTs and 2 (25%) spontaneous recovery. Two children (25%) died while on the transplantation list.

Conclusion

TPE + HV-CRRT can be used safely as a bridging therapy in children with PALF. As opposed to the adult population, higher volume of TPE or higher blood flow rate in pediatric patients might associate with hemodynamic instability during the procedure.

How to cite this article

Trepatchayakorn S, Chaijitraruch N, Chongsrisawat V, Chanakul A, Kongkiattikul L, Samransamruajkit R. Therapeutic Plasma Exchange with Continuous Renal Replacement Therapy for Pediatric Acute Liver Failure: A Case Series from Thailand. Indian J Crit Care Med 2021;25(7):812–816.

Extracorporeal Devices

Extracorporeal liver support (ECLS) emerged from the need stabilize high-acuity liver failure patients with the highest risk of death. The goal is to optimize the hemodynamic, neurologic, and biochemical parameters in preparation for transplantation or to facilitate spontaneous recovery. Patients with acute liver failure and acute-on-chronic liver failure stand to benefit from these devices, especially because they have lost many of the primary functions of the liver, including detoxifying the blood of various endogenous and exogenous substances, manufacturing circulating proteins, secreting bile, and storing energy. Existing ECLS devices are designed to mimic some of these functions.

Artificial liver support systems: what is new over the last decade?

The liver is a complex organ that performs vital functions of synthesis, heat production, detoxification and regulation; its failure carries a highly critical risk. At the end of the last century, some artificial liver devices began to develop with the aim of being used as supportive therapy until liver transplantation (bridge-to-transplant) or liver regeneration (bridge-to-recovery). The well-recognized devices are the Molecular Adsorbent Recirculating System™ (MARS™), the Single-Pass Albumin Dialysis system and the Fractionated Plasma Separation and Adsorption system (Prometheus™). In the following years, experimental works and early clinical applications were reported, and to date, many thousands of patients have already been treated with these devices. The ability of artificial liver support systems to replace the liver detoxification function, at least partially, has been proven, and the correction of various biochemical parameters has been demonstrated. However, the complex tasks of regulation and synthesis must be addressed through the use of bioartificial systems, which still face several developmental problems and very high production costs. Moreover, clinical data on improved survival are conflicting. This paper reviews the progress achieved and new data published on artificial liver support systems over the past decade and the prospects for these devices.