Clinical monitoring of intracranial pressure in fulminant hepatic failure

[WITHDRAWN] Serum biomarkers of liver fibrosis identify changes in striatal metabolite levels

The full text of this preprint has been withdrawn by the authors due to author disagreement with the posting of the preprint. Therefore, the authors do not wish this work to be cited as a reference. Questions should be directed to the corresponding author.

Issues of intensive care and liver transplantation tactics in fulminant liver failure

Fulminant liver failure is usually characterized as severe acute liver injury with encephalopathy and synthetic dysfunction (international normalized ratio [INR] ≥1.5) in a patient without cirrhosis or previous liver disease. Management of patients with acute liver failure includes ensuring that the patient is cared for appropriately, monitoring for worsening liver failure, managing complications, and providing nutritional support. Patients with acute liver failure should be treated at a liver transplant center whenever possible. Serial laboratory tests are used to monitor the course of a patient's liver failure and to monitor for complications. It is necessary to monitor the level of aminotransferases and bilirubin in serum daily. More frequent monitoring (three to four times a day) of blood coagulation parameters, complete blood count, metabolic panels, and arterial blood gases should be performed. For some causes of acute liver failure, such as acetaminophen intoxication, treatment directed at the underlying cause may prevent the need for liver transplantation and reduce mortality. Lactulose has not been shown to improve overall outcomes, and it can lead to intestinal distention, which can lead to technical difficulties during liver transplantation. Early in acute liver failure, signs and symptoms of cerebral edema may be absent or difficult to detect. Complications of cerebral edema include increased intracranial pressure and herniation of the brain stem. General measures to prevent increased intracranial pressure include minimizing stimulation, maintaining an appropriate fluid balance, and elevating the head of the patient's bed. For patients at high risk of developing cerebral edema, we also offer hypertonic saline prophylaxis (3%) with a target serum sodium level of 145 to 155 mEq/L (level 2C). High-risk patients include patients with grade IV encephalopathy, high ammonia levels (>150 µmol/L), or acute renal failure, and patients requiring vasopressor support. Approximately 40 % of patients with acute liver failure recover spontaneously with supportive care. Predictive models have been developed to help identify patients who are unlikely to recover spontaneously, as the decision to undergo liver transplant depends in part on the likelihood of spontaneous recovery of the liver. However, among those who receive a transplant, the one-year survival rate exceeds 80 %, making this treatment the treatment of choice in this difficult patient population.

An update on the pharmacological management and prevention of cerebral edema: current therapeutic strategies

Introduction: Cerebral edema is a common complication of multiple neurological diseases and is a strong predictor of outcome, especially in traumatic brain injury and large hemispheric infarction.Areas Covered: Traditional and current treatments of cerebral edema include treatment with osmotherapy or decompressive craniectomy at the time of clinical deterioration. The authors discuss preclinical and clinical models of a variety of neurological disease states that have identified receptors, ion transporters, and channels involved in the development of cerebral edema as well as modulation of these receptors with promising agents.Expert opinion: Further study is needed on the safety and efficacy of the agents discussed. IV glibenclamide has shown promise in preclinical and clinical trials of cerebral edema in large hemispheric infarct and traumatic brain injury. Consideration of underlying pathophysiology and pharmacodynamics is vital, as the synergistic use of agents has the potential to drastically mitigate cerebral edema and secondary brain injury thusly transforming our treatment paradigms.

Guidelines for the Acute Treatment of Cerebral Edema in Neurocritical Care Patients

BACKGROUND

Acute treatment of cerebral edema and elevated intracranial pressure is a common issue in patients with neurological injury. Practical recommendations regarding selection and monitoring of therapies for initial management of cerebral edema for optimal efficacy and safety are generally lacking. This guideline evaluates the role of hyperosmolar agents (mannitol, HTS), corticosteroids, and selected non-pharmacologic therapies in the acute treatment of cerebral edema. Clinicians must be able to select appropriate therapies for initial cerebral edema management based on available evidence while balancing efficacy and safety.

METHODS

The Neurocritical Care Society recruited experts in neurocritical care, nursing, and pharmacy to create a panel in 2017. The group generated 16 clinical questions related to initial management of cerebral edema in various neurological insults using the PICO format. A research librarian executed a comprehensive literature search through July 2018. The panel screened the identified articles for inclusion related to each specific PICO question and abstracted necessary information for pertinent publications. The panel used GRADE methodology to categorize the quality of evidence as high, moderate, low, or very low based on their confidence that the findings of each publication approximate the true effect of the therapy.

RESULTS

The panel generated recommendations regarding initial management of cerebral edema in neurocritical care patients with subarachnoid hemorrhage, traumatic brain injury, acute ischemic stroke, intracerebral hemorrhage, bacterial meningitis, and hepatic encephalopathy.

CONCLUSION

The available evidence suggests hyperosmolar therapy may be helpful in reducing ICP elevations or cerebral edema in patients with SAH, TBI, AIS, ICH, and HE, although neurological outcomes do not appear to be affected. Corticosteroids appear to be helpful in reducing cerebral edema in patients with bacterial meningitis, but not ICH. Differences in therapeutic response and safety may exist between HTS and mannitol. The use of these agents in these critical clinical situations merits close monitoring for adverse effects. There is a dire need for high-quality research to better inform clinicians of the best options for individualized care of patients with cerebral edema.

Acute liver failure

Acute liver failure is a rare and severe consequence of abrupt hepatocyte injury, and can evolve over days or weeks to a lethal outcome. A variety of insults to liver cells result in a consistent pattern of rapid-onset elevation of aminotransferases, altered mentation, and disturbed coagulation. The absence of existing liver disease distinguishes acute liver failure from decompensated cirrhosis or acute-on-chronic liver failure. Causes of acute liver failure include paracetamol toxicity, hepatic ischaemia, viral and autoimmune hepatitis, and drug-induced liver injury from prescription drugs, and herbal and dietary supplements. Diagnosis requires careful review of medications taken, and serological testing for possible viral exposure. Because of its rarity, acute liver failure has not been studied in large, randomised trials, and most treatment recommendations represent expert opinion. Improvements in management have resulted in lower mortality, although liver transplantation, used in nearly 30% of patients with acute liver failure, still provides a life-saving alternative to medical management.

Are Changes in Intracranial Pressure during Intermittent Machine Haemofiltration Dependent upon Membrane Biocompatibility?

We measured the intracranial pressure, using a subdural catheter in three patients admitted with grade 4 hepatic encephalopathy following paracetamol (aminocetaphen) self poisoning. Acute oliguric renal failure was present in all cases and was treated with daily intermittent machine haemofiltration. Hypovolaemia prior to treatment was corrected and a total of 14 isovolaemic 17 litre exchanges carried out using either a Gambro FH77 (8) or Hospal 3600 (6) haemofilter. Intracranial pressure (ICP) increased during treatment with both types of filter, but the increase was greater in the Gambro FH77 treated group, mean ICP increased from 7.6 ± 2 mmHg to 12 ± 3 mmHg at 3 hours (p< 0.05), this was associated with a greater fall in the percentage change from the pretreatment value of both arterial oxygen tension and total peripheral white blood cell count during the first hour of treatment compared to the Hospal 3600 treated group, 8 ± 2% vs 1 ± 2% (p< 0.05) and 5 ± 2% vs 3 ± 2% (p< 0.05).

This suggests that membrane biocompatibility may also play a role in the development of increased intracranial pressure during intermittent machine haemofiltration.

Protocol based invasive intracranial pressure monitoring in acute liver failure: feasibility, safety and impact on management

Background

Acute liver failure (ALF) may result in elevated intracranial pressure (ICP). While invasive ICP monitoring (IICPM) may have a role in ALF management, these patients are typically coagulopathic and at risk for intracranial hemorrhage (ICH). Contemporary ICP monitoring techniques and coagulopathy reversal strategies may be associated with a lower risk of hemorrhage. Our objective was to evaluate the safety, feasibility, impact on clinical management and outcomes associated with protocol-directed use of IICPM in ALF.

Methods

Adult patients admitted between June 2011 and October 2016, with ALF and grade-4 encephalopathy with a reasonable likelihood of survival, were eligible for IICPM. The coagulopathy reversal protocol included administration of recombinant Factor VIIa (rFVIIa) and desmopressin, a goal platelet count >50,000/mm³ and fibrinogen >100 mg/dL. Monitor insertion was performed within an hour of the rFVIIa dose. Only intraparenchymal monitors were used. Computed tomography of the brain was performed prior to and within 24 hours of monitor placement. Outcomes of interest included ICH, sustained intracranial hypertension, therapeutic intensity level (TIL) for ICP management, mortality and functional outcome on the Glasgow Outcome Scale (GOS) at discharge and 6 months.

Results

A total of 24/37 patients (65%) with ALF underwent IICPM. The most common reason for exclusion was encephalopathy grade <4. Four patients underwent liver transplantation. There was one asymptomatic ICH following IICPM, in a patient who had an excellent outcome. Sustained intracranial hypertension occurred in 13/24 monitored patients (54%), 5/24 (21%) required extreme measures (TIL-4) for ICP control, which were successful in 4 patients: 12/24 patients (50%) died but only 4 deaths (17%) were attributed to intracranial hypertension. Six of the 8 survivors with 6-month follow up had good functional outcome (GOS >3).

Conclusions

Protocol-directed use of IICPM in ALF is feasible, associated with a low incidence of serious complications and has a significant impact on clinical management.

Multimodal brain monitoring in fulminant hepatic failure

Acute liver failure, also known as fulminant hepatic failure (FHF), embraces a spectrum of clinical entities characterized by acute liver injury, severe hepatocellular dysfunction, and hepatic encephalopathy. Cerebral edema and intracranial hypertension are common causes of mortality in patients with FHF. The management of patients who present acute liver failure starts with determining the cause and an initial evaluation of prognosis. Regardless of whether or not patients are listed for liver transplantation, they should still be monitored for recovery, death, or transplantation. In the past, neuromonitoring was restricted to serial clinical neurologic examination and, in some cases, intracranial pressure monitoring. Over the years, this monitoring has proven insufficient, as brain abnormalities were detected at late and irreversible stages. The need for real-time monitoring of brain functions to favor prompt treatment and avert irreversible brain injuries led to the concepts of multimodal monitoring and neurophysiological decision support. New monitoring techniques, such as brain tissue oxygen tension, continuous electroencephalogram, transcranial Doppler, and cerebral microdialysis, have been developed. These techniques enable early diagnosis of brain hemodynamic, electrical, and biochemical changes, allow brain anatomical and physiological monitoring-guided therapy, and have improved patient survival rates. The purpose of this review is to discuss the multimodality methods available for monitoring patients with FHF in the neurocritical care setting.

Management in acute liver failure

Acute liver failure (ALF) is a rare, potentially fatal complication of severe hepatic illness resulting from various causes. In a clinical setting, severe hepatic injury is usually recognised by the appearance of jaundice, encephalopathy and coagulopathy. The central and most important clinical event in ALF is occurrence of hepatic encephalopathy (HE) and cerebral edema which is responsible for most of the fatalities in this serious clinical syndrome. The pathogenesis of encephalopathy and cerebral edema in ALF is unique and multifactorial. Ammonia plays a central role in the pathogenesis. The role of newer ammonia lowering agents is still evolving. Liver transplant is the only effective therapy that has been identified to be of promise in those with poor prognostic factors, whereas in the others, aggressive intensive medical management has been documented to salvage a substantial proportion of patients. A small fraction of patients undergo liver transplant and the remaining are usually treated with medical therapy. Therefore, identification of the complications and causes of death in such patients, and use of appropriate prognostic models to identify those who need liver transplant and those who can be managed with medical treatment is a vital component of therapeutic strategy. In this review, we discuss the various pathogenetic mechanisms and treatment options available.

Preventing cerebral oedema in acute liver failure: the case for quadruple-H therapy

Severe cerebral oedema is a life-threatening complication of acute liver failure. Hyperammonaemia and cerebral hyperaemia are major contributing factors. A multimodal approach, which incorporates hyperventilation, haemodiafiltration, hypernatraemia and hypothermia (quadruple-H therapy), may prevent or attenuate severe cerebral oedema. This approach is readily administered by critical care clinicians and is likely to be more effective than the use of single therapies. Targeting of PaCO2 in the mild hyperventilation range, as seen in acute liver failure patients before intubation, aims to minimise hyperaemic cerebral oedema. Haemodiafiltration aims to achieve the rapid control of elevated blood ammonia concentrations by its removal and to reduce production via the lowering of core temperature. The administration of concentrated saline increases serum tonicity and further reduces cerebral swelling. In addition, the pathologically increased cerebral blood-flow is further attenuated by therapeutic hypothermia. The combination of all four treatments in a multimodal approach may be a safe and effective means of attenuating or treating the cerebral oedema of acute liver failure and preventing death from neurological complications.

Structured approach to treat patients with acute liver failure: A hepatic emergency

Acute liver failure (ALF) is a condition of acute hepatic emergency where rapid deterioration of hepatocyte function leads to hepatic encephalopathy, coagulopathy, cerebral edema (CE), infection and multi-organ dysfunction syndrome resulting in a high mortality rate. Urgent liver transplantation is the standard of care for most of these patients in Western countries. However, in India, access to liver transplantation is severely limited and, hence, the management is largely based on intensive medical care. With earlier recognition of disease, better understanding of pathophysiology and improved intensive care, ALF patients have shown a significant improvement in spontaneous survival. An evidence base for practice for supportive care is still lacking; however, intensive organ support as well as control of infection and CE are likely to be key to the successful outcome in this acute and potentially reversible condition without any sequel. A structured approach to decision making about intensive care is important in each case. Unlike in Western countries where acetamenophen is the most common cause of ALF, the role of a specific agent, such as N-acetylcysteine, is limited in India. Ammonia-lowering therapy is still in an evolving phase. The current review highlights the important medical management issues in patients with ALF in general as well as the management of major complications associated with ALF. We performed a MEDLINE search using combinations of the key words such as acute liver failure, intensive treatment of acute liver failure and fulminant hepatic failure. We reviewed the relevant publications with regard to intensive care of patients with ALF.

Management of hepatic encephalopathy

Hepatic encephalopathy (HE), the neuropsychiatric presentation of liver disease, is associated with high morbidity and mortality. Reduction of plasma ammonia remains the central therapeutic strategy, but there is a need for newer novel therapies. We discuss current evidence supporting the use of interventions for both the general management of chronic HE and that necessary for more acute and advanced disease.

Correction of coagulopathy in the setting of acute liver failure

The depletion of vital coagulation factors and proteins in the setting of acute liver failure (ALF) is common and multifactorial. The management of critically ill patients with ALF is difficult and requires a multidisciplinary approach to effective treatment. Critical care nurses are essential in identifying potential sources of bleeding, monitoring for transfusion reactions, and staying vigilant for medication-related adverse reactions. Prevention and treatment of bleeding disorders is a priority because ineffective therapy can lead to hazardous consequences. Correction of coagulopathy for treatment of bleeding and reversal for invasive procedures should include a multifactorial therapeutic plan emphasizing the correction of all coagulation factors. The limitations of current knowledge in effective correction should serve as a stimulus for future research.

Management of acute liver failure

Acute liver failure (ALF) is a syndrome of diverse etiology, in which patients without previously recognized liver disease sustain a liver injury that results in rapid loss of hepatic function. Depending on the etiology and severity of the insult, some patients undergo rapid hepatic regeneration and spontaneously recover. However, nearly 60% of patients with ALF in the US require and undergo orthotopic liver transplantation or die. Management decisions made by clinicians who initially assess individuals with ALF can drastically affect these patients' outcomes. Even with optimal early management, however, many patients with ALF develop a cascade of complications often presaged by the systemic inflammatory response syndrome, which involves failure of nearly every organ system. We highlight advances in the intensive care management of patients with ALF that have contributed to a marked improvement in their overall survival over the past 20 years. These advances include therapies that limit the extent of liver injury and maximize the likelihood of spontaneous recovery and approaches to enable prevention, recognition and early treatment of complications that lead to multi-organ-system failure, the most common cause of death. Finally, we summarize the role of orthotopic liver transplantation in salvage of the most severely affected patients.

Therapeutic hypothermia for acute liver failure

Cerebral edema is a potentially life-threatening complication of acute liver failure, the syndrome of abrupt loss of liver function in a patient with a previously healthy liver. Although the prevalence of cerebral edema appears to be decreasing, patients with rapidly progressive (hyperacute) liver failure, such as after acetaminophen overdose, remain at highest risk. In severe cases of cerebral edema, intracranial hypertension develops and leads to brain death after brainstem herniation or to anoxic brain injury and permanent neurologic impairment. Intracranial hypertension in patients with acute liver failure often can be temporarily controlled by manipulating body position, increasing the degree of sedation, and increasing blood osmolarity through pharmacologic means. However, these maneuvers often postpone, but do not eliminate, the risk of brainstem herniation unless orthotopic liver transplantation or spontaneous liver regeneration follows in short order. To buy time, the induction of therapeutic hypothermia (core temperature 32 degrees C-35 degrees C) has been shown to effectively bridge patients to transplant. Similar to the experience in patients with cerebral edema after other neurologic insults, hypothermia reduces cerebral edema and intracranial hypertension in patients with acute liver failure by decreasing splanchnic ammonia production, restoring normal regulation of cerebral hemodynamics, and lowering oxidative metabolism within the brain. Hypothermia may also ameliorate the degree of liver injury. Hypothermia has not been adequately studied for its safety and theoretically may increase the risk of infection, cardiac dysrhythmias, and bleeding, all complications independently associated with acute liver failure. Therefore, although an ample body of experimental and human data provides a rationale for the use of therapeutic hypothermia in patients with acute liver failure, multicenter, randomized, controlled clinical trials are needed to confirm that hypothermia secures brain viability and improves survival without causing harm.

Critical management decisions in patients with acute liver failure

Few admissions to the ICU present a greater clinical challenge than the patient with acute liver failure (ALF), the syndrome of abrupt loss of liver function in a previously unaffected individual. Although advances in the intensive care management of patients with ALF have improved survival, the prognosis of ALF remains poor, with a 33% mortality rate and a 25% liver transplant rate in the United States. ALF adversely affects nearly every organ system, with most deaths occurring from sepsis and subsequent multiorgan system failure, and cerebral edema, resulting in intracranial hypertension (ICH) and brainstem herniation. Unfortunately, the optimal management of ALF remains poorly defined, and practices are often based on local experience and case reports rather than on randomized, controlled clinical trials. The paramount question in any patient presenting with ALF remains defining an etiology, since specific antidotes can save lives and spare the liver. This article will consider recent advances in the assignment of an etiology, the administration of etiology-specific treatment to abate the liver injury, and the management of complications (eg, infection, cerebral edema, and the bleeding diathesis) in patients with ALF. New data on the administration of N-acetylcysteine to patients with non-acetaminophen ALF, the treatment of ICH, and assessment of the need for liver transplantation will also be presented.

Therapeutic hypothermia for acute liver failure: toward a randomized, controlled trial in patients with advanced hepatic encephalopathy

Acute liver failure (ALF), the abrupt loss of liver function in a patient without previous liver disease, remains a highly mortal condition. Patients with ALF often succumb to their liver injury after the development of cerebral edema, resulting in intracranial hypertension and brain herniation. While the management of cerebral edema in ALF always includes the administration of osmotically active agents, osmotherapy often reduces intracranial pressure (ICP) insufficiently, such that herniation may be delayed but not prevented. Therapeutic hypothermia, the intentional reduction of body core temperature, has been increasingly used to treat cerebral edema in patients with traumatic and hypoxic brain injury. Data in animal models of ALF also suggest that hypothermia is effective in the prevention and treatment of cerebral edema, and case reports in humans have suggested that hypothermia is an effective bridge to orthotopic liver transplantation. A randomized, controlled trial comparing the management of ALF patients under normothermic and hypothermic conditions is a logical extension of these preliminary observations. Herein, we consider the many difficulties which will be encountered in the design of such a trial in patients with ALF at high risk of developing cerebral edema.

Prevention and management of brain edema in patients with acute liver failure

1. Intracranial pressure is the pressure exerted by the cranial contents on the dural envelope and consists of the partial pressures of the brain, blood, and cerebrospinal fluid. 2. Severe cases of acute liver failure are frequently complicated by brain edema (due to cytotoxic edema) and an increase in cerebral blood flow while the cerebrospinal fluid volume remains constant. 3. The development of intracranial hypertension in patients with acute liver failure may be controlled by manipulation of the position, body temperature, plasma tonicity, arterial carbon dioxide tension, and arterial pressure. 4. If intracranial hypertension evolves despite these first-tier interventions, increased sedation, induction of hypothermia (body temperature of 33 degrees C to 34 degrees C), and the use of anti-inflammatory drugs may help secure brain viability.

Therapy of intracranial hypertension in patients with fulminant hepatic failure

Severe intracranial hypertension (IH) in the setting of fulminant hepatic failure (FHF) carries a high mortality and is a challenging disease for the critical care provider. Despite considerable improvements in the understanding of the pathophysiology of cerebral edema during liver failure, therapeutic maneuvers that are currently available to treat this disease are limited. Orthotopic liver transplantation is currently the only definitive therapeutic strategy that improves outcomes in patients with FHF. However, many patients die prior to the availability of donor organs, often because of cerebral herniation. Currently, two important theories prevail in the understanding of the pathophysiology of IH during FHF. Ammonia and glutamine causes cytotoxic cerebral injury while cerebral vasodilation caused by loss of autoregulation increases intracranial pressure (ICP) and predisposes to herniation. Although ammonia-reducing strategies are limited in humans, modulation of cerebral blood flow seems promising, at least during the early stages of hepatic encephalopathy. ICP monitoring, transcranial Doppler, and jugular venous oximetry offer valuable information regarding intracranial dynamics. Induced hypothermia, hypertonic saline, propofol sedation, and indomethacin are some of the newer therapies that have been shown to improve survival in patients with severe IH. In this article, we review the pathophysiology of IH in patients with FHF and outline various therapeutic strategies currently available in managing these patients in the critical care setting.

Cerebral hemodynamic and metabolic profiles in fulminant hepatic failure: relationship to outcome

The purpose of this retrospective study was to examine the potential role of cerebral hemodynamic and metabolic factors in the outcome of patients with fulminant hepatic failure (FHF). Based on the literature, a hypothetical model was proposed in which physiologic changes progress sequentially in five phases, as defined by intracranial pressure (ICP) and cerebral blood flow (CBF) measurements. Seventy-six cerebral physiologic profiles were obtained in 26 patients (2 to 5 studies each) within 6 days of FHF diagnosis. ICP was continuously measured by an extradural fiber optic monitor. Global CBF estimates were obtained by xenon clearance techniques. Jugular venous and peripheral artery catheters permitted calculation of cerebral arteriovenous oxygen differences (AVDO2), from which cerebral metabolic rate for oxygen (CMRO2) was derived. A depressed CMRO2 was found in all patients. There was no evidence of cerebral ischemia as indicated by elevated AVDO2s. Instead, over 65% of the patients revealed cerebral hyperemia. Eight of the 26 patients underwent orthotopic liver transplantation-all recovered neurologically, including 6 with elevated ICPs. Of the 18 patients receiving medical treatment only, all 7 with increased ICP died in contrast to 9 survivors whose ICP remained normal (P < 0.004). Hyperemia, per se, was not related to outcome, although it occurred more frequently at the time of ICP elevations. Six patients were studied during brain death. All 6 revealed malignant intracranial hypertension, preceded by hyperemia. In conclusion, the above findings are consistent with the hypothetical model proposed. Prospective longitudinal studies are recommended to determine the precise evolution of the pathophysiologic changes.

Intracranial Pressure Monitoring in Patients with Fulminant Hepatic Failure Treated with Plasma Exchange and Continuous Hemodiafiltration

BACKGROUND/AIMS

To study the influence of our artificial liver support (ALS) on intracranial pressure (ICP) and to evaluate the significance of ICP monitoring in fulminant hepatic failure (FHF) patients treated with ALS.

METHODS

ICP was measured in 13 consecutive FHF patients treated with ALS. Maximum value in ICP every day was employed as ICPmax of the day. We analyzed the correlation: (a) between ICPmax and consciousness level; (b) between ICP and colloid osmotic pressure (COP), and (c) between ICP and PaCO2.

RESULTS

ICP in 11 patients of 13 was controlled < 20 mm Hg through our ALS. A significant positive correlation between ICPmax and consciousness level was found (p < 0.01). Although there was a significantly negative correlation between ICP and COP (p < 0.001), there was no correlation between ICP and PaCO2.

CONCLUSIONS

We conclude that our ALS does not have any adverse effects on ICP and that ICP monitoring is one of the inevitable monitorings in the management of FHF.

Management of patients with fulminant hepatic failure and brain edema

Cerebral edema in acute liver failure is associated with a poor prognosis. Optimization of cerebral perfusion pressure and blood flow plays a key role in contemporary management of these patients. However, understanding of the pathophysiology of brain edema is required for optimal patient management. This review explains the relationships between cerebral perfusion and edema and summarizes therapies that are currently used in patients with acute liver failure to prevent and reduce intracranial pressure.

[Acute liver failure]

Acute liver failure is characterized by a dynamic clinical course associated with high mortality. The main prognostic determinant is the development of extrahepatic complications. Close monitoring is mandatory, and prophylactic measures to avoid complications should be initiated. In case of complications, early and aggressive treatment is indicated. To date, artificial liver support devices are still in the experimental phase. Liver transplantation should be considered in patients with predictors of a poor spontaneous prognosis. Therefore, a transplant center should be contacted in every case of acute liver failure.

Acute liver failure

Acute liver failure in children is associated with a high mortality. Most cases in our setup are due to water borne hepatotropic viruses HAV and HEV. The clinician must be aware of the earliest and the subtle signs of acute liver failure to identify cases early enough and institute supportive therapy. Focus of therapy has to be on prevention, early recognition and appropriate management of complications. Despite good intensive care, about 40-60% children with liver failure die. As and when liver transplantation becomes available in India, it would be an attractive option.

Identification of patients best suited for combined liver-kidney transplantation: part II

Liver-kidney transplantation (LKT) should be reserved for those recipients with primary disease affecting both organs. However, increasing transplant list waiting times have increased the development and duration of acute renal failure before liver transplantation. Furthermore, the need for posttransplant calcineurin inhibitors can render healing from acute renal failure difficult. Because of the increasing requests for and controversy over the topic of a kidney with a liver transplant (OLT) when complete failure of the kidney is not known, the following article will review the impact of renal failure on liver transplant outcome, treatment of peri-OLT renal failure, rejection rates after LKT, survival after LKT, and information on renal histology and progression of disease into the beginnings of an algorithm for making a decision about combined LKT.

Liver transplantation. The pediatric challenge

Successful liver transplantation in a child is often a hard-won victory, requiring all the combined expertise of a dedicated pediatric transplant team. This article outlines the considerable challenges still facing pediatric liver transplant physicians and surgeons. In looking to the future, where should priorities lie to enhance the success already achieved? First, solutions to the donor shortage must be sought aggressively by increasing the use of from split-liver transplants, judicious application of living-donor programs, and increasing the donation rate, perhaps by innovative means. The major immunologic barriers, to successful xenotransplantation make it unlikely that this option will be tenable in the near future. Second, current immunosuppression is nonspecific, toxic, and unable to be individually adjusted to the patient's immune response. The goal of achieving donor-specific tolerance will require new consideration of induction protocols. Developing a clinically applicable method to measure the recipient's immunoreactivity is of paramount importance, for future studies of new immunosuppressive strategies and to address the immediate concern of long-term over-immunosuppression. The inclusion of pediatric patients in new protocols will require the ongoing insistence of pediatric transplant investigators. Third, the current immunosuppressive drugs have a long-term morbidity and mortality of their own. These long-term effects are particularly important in children who may well have decades of exposure to these therapies. There is now some understanding of their long-term renal toxicity and the risk of malignancy. New drugs may obviate renal toxicity, whereas the risk of malignancy is inherent in any nonspecific immunosuppressive regimen. Although progress is being made in preventing and recognizing PTLD, this entity remains an important ongoing concern. The global effect of long-term immunosuppression on the child's growth, development, and intellectual potential is unknown. Of particular concern is the potential for neurotoxicity from the calcineurin inhibitors. Fourth, recurrent disease and new diseases, perhaps potentiated by immunosuppressive drugs, must be considered. Already the recurrence of autoimmune disease and cryptogenic cirrhosis have been documented in pediatric patients. Now, a new lesion, a nonspecific hepatitis, sometimes with positive autoimmune markers, that may progress to cirrhosis has been recognized. It is not known whether this entity is an unusual form of rejection, an unrecognized viral infection, or a response to immunosuppressive drugs themselves. Finally, pediatric transplant recipients, like any other children, must be protected and nourished physically and mentally if they are to fulfill their potential. After liver transplantation the child's growth, intellectual functioning, and psychologic adaptation may all require special attention from parents, teachers, and physicians alike. There is limited understanding of how the enormous physical intervention of a liver transplantation affects a child's cognitive and psychologic function as the child progresses through life. The persons caring for these children have the difficult responsibility of providing services to evaluate these essential measures of children's health over the long term and to intervene if necessary. Part of the transplant physician's our duty to protect and advocate for children is to fight for equal access to health care. In most of the developing world, economic pressures make it impossible to consider liver transplantation a health care priority. In the United States and in other countries with the medical infrastructure to support liver transplantation, however, health care professionals must strive to be sure that the policies governing candidacy for transplantation and allocation of organs are applied justly and uniformly to all children whose lives are threatened by liver disease. In the current regulatory climate that increasingly takes medical decisions out of the hands of physicians, pediatricians must be even more prepared to protect the unique and often complicated needs of children both before and after transplantation. Only in this way can the challenges of the present and the future be met.

Animal models of acute hepatic failure

The understanding and treatment of acute hepatic failure has developed rapidly over the last 40 years reducing morbidity and mortality from this syndrome. Progress has been made by the study of animal models that reflect the clinical, biochemical and histological pattern of the syndrome seen in man. This is of increasing importance with the use of therapeutic intervention, liver transplantation and the use of extra-corporeal liver support devices. This review examines and critically appraises the various approaches to the study of acute hepatic failure in animal models, including both surgical and pharmacological approaches.

Fulminant hepatic failure

Fulminant hepatic failure is a disease of varied causes and a high mortality rate. A sudden onset, jaundice, hepatic encephalopathy, and multiorgan failure are the hallmarks of this syndrome. The management of patients with FHF requires a multidisciplinary approach and intense monitoring. The availability of liver transplantation has provided the means to rescue such patients from near-certain death. Early prognostication and timely availability of donor livers are requirements for a successful outcome. The development of effective artificial liver support devices may greatly prolong the window of opportunity to provide a donor liver, or alternatively, to allow the native liver to regenerate.

Review article: the management of acute liver failure

Acute liver failure (ALF) is a relatively uncommon but dramatic clinical syndrome with high mortality rates, in which a previously normal liver fails within days or weeks. Paracetamol overdose remains the major cause of ALF in the UK, while viral hepatitis is the commonest cause world-wide. Cerebral oedema is the leading cause of death in patients with ALF. Despite advances in intensive care and the development of new treatment modalities, ALF remains a condition of high mortality best managed in specialist centres. Orthotopic liver transplantation is the only new treatment modality that has made a significant impact in improving outcome. Bioartificial liver support systems and hepatocyte transplantation are new promising treatment options that may change the management of ALF in the future.

Neurologic complications of transplantation

Organ transplantation is a marvel of 20th century medicine. However, it is not without costs. Complications of transplant procedures, particularly neurologic complications, are a significant cause of morbidity and mortality. Neurologic complications in the transplant population may be divided into three groups: those occurring prior to transplantation, those in the perioperative period, and those arising weeks to months after the procedure. This review discusses neurologic complications associated with organ failure and transplantation in the perioperative period.

10 years of pediatric liver transplantation

PURPOSE

Pediatric liver transplantation is an accepted therapy for end-stage liver disease, but little long-term data exist.

METHODS

From October 1984 to October 1994, 202 patients underwent a total of 225 liver transplantations. There were 98 boys and 104 girls, the average age was 5.1 +/- 4.9 (range, 0.2 to 19.1) years. Thirty (16%) were under 1 year of age. The diseases that required transplantation included biliary atresia (BA) (45%), metabolic liver disease (MLD) (9.9%), acute hepatic failure (6.9%), and Alagille's syndrome (AS) (5.4%). Originally the immunosuppression was cyclosporine- and steroid-based; the later regimens also included azathioprine and antilymphocyte preparations. All reported survival rates were derived from life-table analysis.

RESULTS

The patient survival rates at 1, 5, and 10 years were 76%, 70%, and 61%; the retransplantation rate was 11%. The respective graft survival rates were 71%, 63%, and 59%. There were 60 deaths; 48 (81%) occurred in the first year. These first-year deaths were from sepsis (20; 42%), central nervous system problems (5; 11%), intraoperative complications (4; 8%), lymphoproliferative disease (LPD) (2; 4%), rejection (2; 4%), primary nonfunction (2; 4%), and miscellaneous other causes (7; 15%). There were 12 deaths after the first year, from LPD (3; 25%), sepsis (1; 8%), rejection (2; 18%), cancer (1; 9%), secondary hepatic failure (1; 9%), cerebral vascular accident (1; 9%), or pre- or postoperative complications (3; 25%). Compared with the overall survival rate, patients with MLD had a better chance of survival (83%; P <.012) than did those with AS (45%; P < .001). The 5- and 10-year survival rates for patients with BA were 61% and 58%. Over the past 2 years, the survival rate has increased (87% v 72%; P < .05) as early septic deaths have decreased (from 2.6 to 1.0 per year).

CONCLUSION

Liver transplantation is effective treatment for end-stage liver disease. Decreasing the number of early septic deaths has improved the chance of survival, and better diagnosis and treatment of LPD would improve the late survival rate.

Orthotopic liver transplantation in fulminant and subfulminant hepatitis. The Paul Brousse experience

OBJECTIVE

The authors report on the experience of orthotopic liver transplantation in fulminant hepatitis at Paul Brousse Hospital.

SUMMARY BACKGROUND DATA

Liver transplantation is a breakthrough in the treatment of patients with fulminant hepatitis. However, the indications, the timing for transplantation, the type of transplantation, and the use of ABO incompatible grafts in this setting still are debated.

METHODS

Transplantation was indicated in patients with confusion or coma and factor V less than 20%, younger than 30 years of age, and confusion or coma and factor V less than 30% older than 30 years of age.

RESULTS

Among 139 patients who met the aforementioned criteria for transplantation, 1 recovered, 22 died before transplantation, and 116 underwent transplants with a 1-year survival of 68%. Survival was 83% in patients with grade 1 and 2 comas at transplantation versus 56% (p < 0.001) in those with grade 3 comas; it was 51% versus 81% (p < 0.001) in those transplanted with high risk (ABO-incompatible, split, or steatotic) and low-risk grafts, respectively. In a multivariate analysis, steatotic and partial grafts were predictive of poorer patient survival, and ABO incompatibility was predictive of poorer graft survival.

CONCLUSIONS

Orthotopic liver transplantation is an effective treatment in fulminant hepatitis. Use of high-risk grafts permitted transplantation of 83% of patients, but was responsible for higher mortality.

Acute liver failure: results of a 5-year clinical protocol

This investigation summarizes and evaluates the results of a clinical protocol that we designed to care for patients with acute liver failure (ALF). Adult patients with ALF were enrolled in the protocol. Grade II portal-systemic encephalopathy prompted admission to the intensive care unit (ICU). Patients who met the clinical criterion were activated for liver transplantation. Intracranial pressure (ICP) was monitored in patients with grade III encephalopathy. An increase in ICP was treated with hyperventilation, diuretics, barbiturates, or a combination thereof. Survival was considered to have occurred if the patient left the hospital alive. Our series included 25 patients. Orthotopic liver transplantation (OLT) was performed on 19 patients, 12 of whom survived. Only 2 of 6 patients who did not undergo transplantation survived. Ten of 11 patients who underwent transplantation before reaching grade IV encephalopathy survived. Only 2 of 8 patients who underwent transplantation after reaching grade IV survived (P = .006). The causes of death included cerebral edema (3 patients), disseminated aspergillosis (3 patients), and other (5 patients). ICP was monitored in 11 patients. Increased pressure was documented by seven of the monitors placed. There was one focal hemorrhage secondary to a subdural monitor. Outcome is improved if transplantation occurs before grade IV encephalopathy. ICP monitoring can be accomplished without significant risk of hemorrhage. In our series, infection with aspergillus occurred frequently and with fatal outcome.

Cerebral edema and intracranial pressure monitoring

With the wide acceptance of liver transplantation as a therapeutic alternative in fulminant hepatic failure (FHF), the successful management of patients with this syndrome has acquired a new urgency. Topping the list of medical problems is the development of brain swelling. Two decades after the recognition of its importance, brain edema and intracranial hypertension still constitute a major cause of death in these patients. In a more recent classification of FHF, brain edema was especially prominent in those subjects with "hyperacute failure," in whom a period of 7 days or less elapsed between the development of jaundice and encephalopathy. The goal of this review is to discuss two aspects of this clinical problem. On one hand, elucidation of its pathogenesis should lead to a more rational therapeutic approach; such an information would also be valuable to understand the relationship between hepatic encephalopathy and brain edema, a source of controversy. Studies of pathogenic mechanisms are difficult to perform in humans and animal models of FHF have proven valuable, as brain swelling can be detected with some regularity. On the other hand, an increasing array of techniques is now available in the intensive care setting to monitor patients with FHF. Of these, intracranial pressure monitoring has received the most critical attention. However, concerns with the risks of craniotomy and the need to acquire more dynamic information has led several groups to explore non-invasive methods that evaluate the consequences of intracranial hypertension. Their role, though potentially exciting, is still uncertain.

A multicenter study on the prognosis of fulminant viral hepatitis: early prediction for liver transplantation

To determine the risk of death at an early stage of fulminant viral hepatitis, we created severity indexes drawn from clinical data on the day of development of encephalopathy in 128 patients with fulminant hepatitis B and 103 with fulminant hepatitis non-A, non-B. In fulminant hepatitis B, the risk score was 2.75 x BL + 2.75 x BR + 2.7 x AG + 2.3 x WB + 1.67 x CD + 1.56 x AL - 0.098 x PR - 0.88, where BL is 1 if total bilirubin is higher than 20 mg/dl, BR is 1 if the ratio of total to direct bilirubin exceeds 2.2, AG is 1 if age is above 40 yr, WB is 1 if white blood cell count is less than 4,000 cells/mm3 or more than 18,000 cells/mm3, CD is 1 if a hazardous disease coexists and AL is 1 if ALT is less than 100 times the upper limit of normal (otherwise all are 0), and PR is prothrombin time (percentage of normal value). Using a cutoff score of 0, we found the positive predictive value, negative predictive value and predictive accuracy to be 0.90, 0.86 and 0.89, respectively. Sensitivity and specificity were 0.94 and 0.77, respectively. In fulminant non-A, non-B hepatitis, the risk score was 2.66 x BR + 2.25 x BL + 2.24 x DI + 2.05 x AL +/- 1.38 x AG + 0.00021 x WB - 6.33.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral hemodynamic and metabolic changes in fulminant hepatic failure: a retrospective study

The purpose of this retrospective study was to determine cerebral hemodynamic and metabolic changes in comatose patients with fulminant hepatic failure. Computerized tomography of the brain and cerebral blood flow measurements by the xenon-computerized tomography scan or intravenous xenon-133 methods were obtained in 33 patients with fulminant hepatic failure. In a subgroup of 22 patients, arteriojugular venous oxygen content difference and cerebral metabolic rate for oxygen were determined. Carbon dioxide reactivity was tested in 17 patients, and intracranial pressure was recorded by an epidural monitor in 8 patients. Cerebral blood flow and arteriojugular venous oxygen content difference were adjusted to the average arterial carbon dioxide pressure of the sample (32 mm Hg). Adjusted cerebral blood flow varied from 16.5 to 94.7 ml/100 gm/min; 52% of the patients had reduced adjusted cerebral blood flows (less than 33 ml/100 gm/min), whereas 24% had hyperemic values (greater than 50 ml/100 gm/min). Patients with higher adjusted cerebral blood flows showed cerebral swelling on computerized tomography scan (p < 0.002), were in deeper coma (p < 0.05) and had greater mortality (p < 0.002). The adjusted arteriojugular venous oxygen content difference was negatively correlated with adjusted cerebral blood flow (r = -0.61, p < 0.002). The majority of patients with reduced adjusted cerebral blood flows had low adjusted arteriojugular venous oxygen content differences (less than 5 vol%), indicating hyperemia rather than ischemia. The average cerebral metabolic rate for oxygen was 50% of normal (1.6 +/- 0.4 ml/100 gm/min); even patients with low cerebral metabolic rates for oxygen recovered neurologically.(ABSTRACT TRUNCATED AT 250 WORDS)

The safety and value of extradural intracranial pressure monitors in fulminant hepatic failure

Thirty-six of 68 consecutive patients with fulminant hepatic failure (FHF) progressing to grade 4 encephalopathy who had extradural ICP monitors inserted were reviewed to determine the safety and the value of ICP monitoring. Only minor complications were encountered. These included local wound bleeding at the burrhole site in four patients and a small cerebral hemorrhage in relation to the monitor in one other patient. No significant long-term sequelae were related to the operative procedure. ICP monitoring identified rises in ICP unaccompanied by clinical signs and as a consequence treatment was given to the monitored patients more often than the non-monitored group (median 6 vs. 2 treatments, P < 0.01). The duration of survival from the onset of grade 4 encephalopathy was significantly greater in the ICP monitored group (median 60 vs. 10 h, P < 0.01) although overall survival was unchanged. Monitoring also provided important prognostic information since the peak ICP was higher in non-survivors than in survivors (median 45 vs. 35 mmHg, P = 0.051). The pattern of clinical signs accompanying episodes of intracranial hypertension differed between survivors and non-survivors. Pupillary abnormalities were detected more often in non-survivors while systolic hypertension occurred more frequently amongst survivors with the peak systolic blood pressure being significantly higher. ICP monitoring proved safe and effective, provided valuable information regarding subclinical intracranial hypertension and prognosis and should be regarded as part of the routine management of intracranial hypertension complicating FHF.