Outcomes and complications of intracranial pressure monitoring in acute liver failure: a retrospective cohort study

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.

Advancements in Ultrasound Techniques for Evaluating Intracranial Pressure Through Optic Nerve Sheath Diameter Measurement

Elevated intracranial pressure (ICP) in patients with cerebral lesions has garnered considerable attention in research. It often manifests as a common symptom in conditions such as intracranial tumors, intracerebral hemorrhage, and cerebral edema. This paper provides an overview of ICP concepts, discusses the advantages and disadvantages of traditional monitoring methods, explores the physiological and anatomical aspects of the optic nerve sheath, examines the utility of ultrasound measurement of optic nerve sheath diameter (ONSD) in both nervous system and nonnervous system disorders, and outlines the cutoff values and normal ranges for assessing elevated ICP using ultrasound measurement of ONSD. The review underscores ultrasound measurement of ONSD as a promising noninvasive, safe, straightforward, and repeatable examination technique for various diseases. Nevertheless, the lack of standardized cutoff values for elevated ICP remains a challenge. Summarizing studies on optic nerve sheaths is crucial for enhancing the efficacy of ultrasound measurement of ONSD in assessing ICP.

Acute liver failure

Acute liver failure (ALF) is a life-threatening disorder characterised by rapid deterioration of liver function, coagulopathy, and hepatic encephalopathy in the absence of pre-existing liver disease. The cause of ALF varies across the world. Common causes of ALF in adults include drug toxicity, hepatotropic and non-hepatotropic viruses, herbal and dietary supplements, antituberculosis drugs, and autoimmune hepatitis. The cause of liver failure affects the management and prognosis, and therefore extensive investigation for cause is strongly suggested. Sepsis with multiorgan failure and cerebral oedema remain the leading causes of death in patients with ALF and early identification and appropriate management can alter the course of ALF. Liver transplantation is the best current therapy, although the role of artificial liver support systems, particularly therapeutic plasma exchange, can be useful for patients with ALF, especially in non-transplant centres. In this Seminar, we discuss the cause, prognostic models, and management of ALF.

Altered Mental Status in the Solid-Organ Transplant Recipient

Patients undergoing solid-organ transplantation (SOT) face a tumultuous journey. Prior to transplant, their medical course is characterized by organ dysfunction, diminished quality of life, and reliance on organ support, all of which are endured in hopes of reaching the haven of organ transplantation. Peritransplant altered mental status may indicate neurologic insults acquired during transplant and may have long-lasting consequences. Even years after transplant, these patients are at heightened risk for neurologic dysfunction from a myriad of metabolic, toxic, and infectious causes. This review provides a comprehensive examination of causes, diagnostic approaches, neuroimaging findings, and management strategies for altered mental status in SOT recipients. Given their complexity and the numerous etiologies for neurologic dysfunction, liver transplant patients are a chief focus in this review; however, we also review lesser-known contributors to neurological injury across various transplant types. From hepatic encephalopathy to cerebral edema, seizures, and infections, this review highlights the importance of recognizing and managing pre- and posttransplant neurological complications to optimize patient outcomes.

Acute liver failure: Management update and prognosis

Acute liver failure is a rare but serious syndrome, with an incidence of approximately 2,000 to 3,000 cases per year in North America. Its pathophysiology and clinical course vary, depending on the cause of the primary liver injury, and can lead to high morbidity and mortality or the need for liver transplantation, despite available therapies. This syndrome involves excessive activation of the immune system, with damage in other organs, contributing to its high mortality rate. The most accepted definition includes liver injury with hepatic encephalopathy and coagulopathy within the past 26 weeks in a patient with no previous liver disease. The main causes are paracetamol poisoning, viral hepatitis, and drug-induced liver injury, among others. Identifying the cause is crucial, given that it influences prognosis and treatment. Survival has improved with supportive measures, intensive therapy, complication prevention, and the use of medications, such as N-acetylcysteine. Liver transplantation is a curative option for nonresponders to medical treatment, but adequate evaluation of transplantation timing is vital for improving results. Factors such as patient age, underlying cause, and severity of organ failure influence the post-transplant outcomes and survival.

An international, multicenter, survey-based analysis of practice and management of acute liver failure

Acute liver failure (ALF) is an acute liver dysfunction with coagulopathy and HE in a patient with no known liver disease. As ALF is rare and large clinical trials are lacking, the level of evidence regarding its management is low-moderate, favoring heterogeneous clinical practice. In this international multicenter survey study, we aimed to investigate the current practice and management of patients with ALF. An online survey targeting physicians who care for patients with ALF was developed by the International Liver Transplantation Society ALF Special-Interest Group. The survey focused on the management and liver transplantation (LT) practices of ALF. Survey questions were summarized overall and by geographic region. A total of 267 physicians completed the survey, with a survey response rate of 21.36%. Centers from all continents were represented. More than 90% of physicians specialized in either transplant hepatology/surgery or anesthesiology/critical care. Two hundred fifty-two (94.4%) respondents' institutions offered LT. A total of 76.8% of respondents' centers had a dedicated liver-intensive or transplant-intensive care unit ( p < 0.001). The median time to LT was within 48 hours in 12.7% of respondents' centers, 72 hours in 35.6%, 1 week in 37.6%, and more than 1 week in 9.6% ( p < 0.001). Deceased donor liver graft (49.6%) was the most common type of graft offered. For consideration of LT, 84.8% of physicians used King's College Criteria, and 41.6% used Clichy Criteria. Significant differences were observed between Asia, Europe, and North America for offering LT, number of LTs performed, volume of patients with ALF, admission to a dedicated intensive care unit, median time to LT, type of liver graft, monitoring HE and intracranial pressure, management of coagulopathy, and utilization of different criteria for LT. In our study, we observed significant geographic differences in the practice and management of ALF. As ALF is rare, multicenter studies are valuable for identifying global practice.

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

Perioperative care in acute liver failure: An anaesthesiologist perspective in the operating theatre

Acute liver failure (ALF) is a life-threatening condition characterized by rapid liver function deterioration, necessitating a multidisciplinary approach for optimal perioperative care. This comprehensive review focuses on the critical role of the anaesthesiologist throughout the preoperative, intraoperative, and postoperative phases, addressing the unique challenges posed by ALF. The article begins with an exploration of ALF, underlining the urgency of timely referral to specialized hepatology centres. Liver transplantation emerges as a life-saving intervention, and the complex decision-making process is discussed, emphasizing the need for a multidisciplinary team to assess transplantation candidacy based on established prognostic criteria. In the preoperative phase, the review stresses the importance of early engagement with tertiary liver centres for timely referrals and identifies patients suitable for transplantation. Safe transport protocols are detailed, highlighting the meticulous planning required for the secure transfer of ALF patients between healthcare facilities. The intraoperative management section delves into the anaesthesiologist's key concerns, including neurological status, sepsis, acute kidney injury, body mass index, and preoperative fasting. Hemodynamic stability, fluid management, and coagulation balance during surgery are emphasized, with insights into anaesthesia techniques, vascular access, monitoring, and hemodynamic management tailored to the challenges posed by ALF patients. The postoperative care is thoroughly examined covering neurological, hemodynamic, metabolic, renal, and nutritional aspects. Management of ALF involves multidisciplinary team, including nephrology for continuous renal replacement therapy, transfusion medicine for plasma exchange, critical care for overall patient care, nutritionists for ensuring adequate nutrition, and hepatologists as the primary guides. In conclusion, the review recognizes the anaesthesiologist as a linchpin in the perioperative care of ALF patients. The integration of safe transport protocols and multidisciplinary approach is deemed crucial for navigating complexities of ALF, contributing to improved patient outcomes. This article serves as an invaluable resource for gastroenterologist and intensivists, enhancing their understanding of the anaesthesiologist's indispensable role in the holistic care of ALF patients in an ever-evolving healthcare landscape.

Insights into the liver-eyes connections, from epidemiological, mechanical studies to clinical translation

Maintenance of internal homeostasis is a sophisticated process, during which almost all organs get involved. Liver plays a central role in metabolism and involves in endocrine, immunity, detoxification and storage, and therefore it communicates with distant organs through such mechanisms to regulate pathophysiological processes. Dysfunctional liver is often accompanied by pathological phenotypes of distant organs, including the eyes. Many reviews have focused on crosstalk between the liver and gut, the liver and brain, the liver and heart, the liver and kidney, but with no attention paid to the liver and eyes. In this review, we summarized intimate connections between the liver and the eyes from three aspects. Epidemiologically, we suggest liver-related, potential, protective and risk factors for typical eye disease as well as eye indicators connected with liver status. For molecular mechanism aspect, we elaborate their inter-organ crosstalk from metabolism (glucose, lipid, proteins, vitamin, and mineral), detoxification (ammonia and bilirubin), and immunity (complement and inflammation regulation) aspect. In clinical application part, we emphasize the latest advances in utilizing the liver-eye axis in disease diagnosis and therapy, involving artificial intelligence-deep learning-based novel diagnostic tools for detecting liver disease and adeno-associated viral vector-based gene therapy method for curing blinding eye disease. We aim to focus on and provide novel insights into liver and eyes communications and help resolve existed clinically significant issues.

Future directions in acute liver failure

Acute liver failure (ALF) describes a clinical syndrome of rapid hepatocyte injury leading to liver failure manifested by coagulopathy and encephalopathy in the absence of pre-existing cirrhosis. The hallmark diagnostic features are a prolonged prothrombin time (ie, an international normalized ratio of prothrombin time of ≥1.5) and any degree of mental status alteration (HE). As a rare, orphan disease, it seemed an obvious target for a multicenter network. The Acute Liver Failure Study Group (ALFSG) began in 1997 to more thoroughly study and understand the causes, natural history, and management of ALF. Over the course of 22 years, 3364 adult patients were enrolled in the study registry (2614 ALF and 857 acute liver injury-international normalized ratio 2.0 but no encephalopathy-ALI) and >150,000 biosamples collected, including serum, plasma, urine, DNA, and liver tissue. Within the Registry study sites, 4 prospective substudies were conducted and published, 2 interventional ( N -acetylcysteine and ornithine phenylacetate), 1 prognostic [ 13 C-methacetin breath test (MBT)], and 1 mechanistic (rotational thromboelastometry). To review ALFSG's accomplishments and consider next steps, a 2-day in-person conference was held at UT Southwestern Medical Center, Dallas, TX, entitled "Acute Liver Failure: Science and Practice," in May 2022. To summarize the important findings in the field, this review highlights the current state of understanding of ALF and, more importantly, asks what further studies are needed to improve our understanding of the pathogenesis, natural history, and management of this unique and dramatic condition.

Liver Transplantation for Acute Liver Failure- Indication, Prioritization, Timing, and Referral

Acute liver failure (ALF) is a major success story in gastroenterology, with improvements in critical care and liver transplant resulting in significant improvements in patient outcomes in the current era compared to the dismal survival rates in the pretransplant era. However, the ever-increasing list of transplant candidates and limited organ pool makes judicious patient selection and organ use mandatory to achieve good patient outcomes and prevent organ wastage. Several scoring systems exist to facilitate the identification of patients who need a liver transplant and would therefore need an early referral to a specialized liver unit. The timing of the liver transplant is also crucial as transplanting a patient too early would lead to those who would recover spontaneously receiving an organ (wastage), and a late decision might result in the patient becoming unfit for transplant (delisted) or have an advanced disease which would result in poor post-transplant outcomes. The current article reviews the indications and contraindications of liver transplant in ALF patients, the various prognostic scoring systems, etiology-specific outcomes, prioritization and timing of referral.

Acute Liver Failure Guidelines

Acute liver failure (ALF) is a rare, acute, potentially reversible condition resulting in severe liver impairment and rapid clinical deterioration in patients without preexisting liver disease. Due to the rarity of this condition, published studies are limited by the use of retrospective or prospective cohorts and lack of randomized controlled trials. Current guidelines represent the suggested approach to the identification, treatment, and management of ALF and represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence was reviewed using the Grading of Recommendations, Assessment, Development and Evaluation process to develop recommendations. When no robust evidence was available, expert opinions were summarized using Key Concepts. Considering the variety of clinical presentations of ALF, individualization of care should be applied in specific clinical scenarios.

Intracranial pressure monitoring in the perioperative period of patients with acute liver failure undergoing orthotopic liver transplantation

Acute liver failure (ALF) may result in severe neurological complications caused by cerebral edema and elevated intracranial pressure (ICP). Multiple pathogenic mechanisms explain the elevated ICP, and newer hypotheses have been described. While invasive ICP monitoring (ICPM) may have a role in ALF management, these patients are typically coagulopathic and at risk for intracranial hemorrhage. ICPM is the subject of much debate, and significant heterogeneity exists in clinical practice regarding its use. Contemporary ICPM techniques and coagulopathy reversal strategies may be associated with a lower risk of hemorrhage; however, most of the evidence is limited by its retrospective nature and relatively small sample size.

Guidelines for the Management of Adult Acute and Acute-on-Chronic Liver Failure in the ICU: Neurology, Peri-Transplant Medicine, Infectious Disease, and Gastroenterology Considerations

OBJECTIVES

To develop evidence-based recommendations for clinicians caring for adults with acute liver failure (ALF) or acute on chronic liver failure (ACLF) in the ICU.

DESIGN

The guideline panel comprised 27 members with expertise in aspects of care of the critically ill patient with liver failure or methodology. We adhered to the Society of Critical Care Medicine standard operating procedures manual and conflict-of-interest policy. Teleconferences and electronic-based discussion among the panel, as well as within subgroups, served as an integral part of the guideline development.

INTERVENTIONS

In part 2 of this guideline, the panel was divided into four subgroups: neurology, peri-transplant, infectious diseases, and gastrointestinal groups. We developed and selected Population, Intervention, Comparison, and Outcomes (PICO) questions according to importance to patients and practicing clinicians. For each PICO question, we conducted a systematic review and meta-analysis where applicable. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used the evidence to decision framework to facilitate recommendations formulation as strong or conditional. We followed strict criteria to formulate best practice statements.

MEASUREMENTS AND MAIN RESULTS

We report 28 recommendations (from 31 PICO questions) on the management ALF and ACLF in the ICU. Overall, five were strong recommendations, 21 were conditional recommendations, two were best-practice statements, and we were unable to issue a recommendation for five questions due to insufficient evidence.

CONCLUSIONS

Multidisciplinary, international experts formulated evidence-based recommendations for the management ALF and ACLF patients in the ICU, acknowledging that most recommendations were based on low quality and indirect evidence.

Evaluation of transcranial Doppler use in patients with acute liver failure listed for emergency liver transplantation

PURPOSE

Acute liver failure (ALF) is characterized by hepatic encephalopathy (HE) often due to intracranial hypertension (ICH). The risk/benefit-balance of intraparenchymal pressure catheter monitoring is controversial during ALF.

AIMS

Perform an evaluation of transcranial Doppler (TCD) use in patients with ALF listed for emergency liver transplantation.

MATERIAL AND METHODS

Single center retrospective cohort study including all patients registered on high emergency LT list between 2012 and 2018. All TCD measurements performed during ICU stay after listing and after LT (when performed) were recorded. TCD was considered abnormal when pulsatility index (PI) was >1.2.

RESULTS

Among 106 patients with ALF, forty-seven (44%) had a TCD while on list. They had more severe liver and extrahepatic organ failure. When performed, TCD was abnormal in 51% of patients. These patients more frequently developed ICH events (45% vs. 13%, p = .02) and more frequently required increase in sedative drugs and vasopressors. While 22% of patients with normal TCD spontaneously survived, all of those with abnormal TCD died or were transplanted (p = .02). All transplanted patients who had abnormal exams normalized their TCD within 2 (1-2) days after LT.

CONCLUSION

TCD may be a useful non-invasive tool for ICH detection and management, then guide sedation withdrawal.

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

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

Management of Acute Liver Failure: Update 2022

Abbreviated pathogenesis and clinical course of the acute liver failure syndrome. The pathogenesis and clinical course of the syndrome of acute liver failure (ALF) differs depending upon the etiology of the primary liver injury. In turn, the severity of the liver injury and resulting synthetic failure is often the primary determinant of whether a patient is referred for emergency liver transplantation. Injuries by viral etiologies trigger the innate immune system via pathogen-associated molecular patterns (PAMPs), while toxin-induced (and presumably ischemia-induced) injuries do so via damage-associated molecular patterns (DAMPs). The course of the clinical syndrome further depends upon the relative intensity and composition of cytokine release, resulting in an early proinflammatory phenotype (SIRS) and later compensatory anti-inflammatory response phenotype (CARS). The outcomes of overwhelming immune activation are the systemic (extrahepatic) features of ALF (cardiovascular collapse, cerebral edema, acute kidney injury, respiratory failure, sepsis) which ultimately determine the likelihood of death.Acute liver failure (ALF) continues to carry a high risk of mortality or the need for transplantation despite recent improvements in overall outcomes over the past two decades. Optimal management begins with identifying that liver failure is indeed present and its etiology, since outcomes and the need for transplantation vary widely across the different etiologies. Most causes of ALF can be divided into hyperacute (ischemia and acetaminophen) and subacute types (other etiologies), based on time of evolution of signs and symptoms of liver failure; the former evolve in 3 to 4 days and the latter typically in 2 to 4 weeks. Both involve intense release of cytokines and hepatocellular contents into the circulation with multiorgan effects/consequences.Management involves optimizing fluid balance and cardiovascular support, including the use of continuous renal replacement therapy, vasopressors, and pulmonary ventilation. Early evaluation for liver transplantation is advised particularly for acetaminophen toxicity, which evolves so rapidly that delay is likely to lead to death.Vasopressor support, high-grade hepatic encephalopathy, and unfavorable (subacute) etiologies heighten the need for urgent listing for liver transplantation. Prognostic scores such as Kings Criteria, Model for End-Stage Liver Disease, and the Acute Liver Failure Group prognostic index take these features into account and provide reasonable but imperfect predictive accuracy. Future treatments may include liver support devices and/or agents that improve hepatocyte regeneration.

Neurological monitoring and sedation protocols in the Liver Intensive Care Unit

Patients with liver disease often have alteration of neurological status which requires admission to an intensive care unit. Patients with acute liver failure (ALF), acute-on-chronic liver failure (ACLF) and rarely cirrhosis are at risk of cerebral edema. These patients require prompt assessment of neurological status including assessment of intra-cranial pressure (ICP) and monitoring metabolic parameters like arterial/venous ammonia levels, serum creatinine and serum electrolytes so that timely specific therapy for raised ICP can be instituted to prevent permanent neurological dysfunction. The overall aims of neuromonitoring and sedation protocols in a liver intensive care unit are to identify the level of multifactorial metabolic encephalopathy, individualize sedation and analgesia requirements for patients on mechanical ventilation, institute specific therapy to correct the neurological insult in ALF and ACLF, provide clear physiological data for guided therapy of drugs like muscle relaxants, antiepileptics, and cerebral edema reducing agents, and assist with overall prognostication. In this review article we will outline the clinical scenarios related to liver disease requiring intensive care and neuromonitoring, current techniques of neurological assessment, sedation protocols and point of care tests which enable the treating physician and intensivist guide therapy for raised ICP.

Variation in the Care of Acute Liver Failure: A Survey of Intensive Care Professionals

INTRODUCTION

Acute liver failure (ALF) is a rare disease with potentially high mortality. We sought to assess the individual approach to ALF by intensive care unit (ICU) professionals.

METHODS

Cross-sectional survey of ICU professionals. Web-based survey capturing data on respondents' demographics, characteristics of patients with ALF admitted to ICU, and their management.

RESULTS

Among 204 participants from 50 countries, 140 (68.6%) worked in Europe, 146 (71.6%) were intensivists, 142 (69.6%) admitted <25 patients with ALF per year, and 166 (81.8%) reported <25% of patients had paracetamol-related ALF. On patients' outcomes, 126 (75.0%) reported an emergency liver transplantation (ELT) rate <25% and 140 (73.3%) a hospital mortality rate <50%. The approach to ALF in the ICU varied with age, region, level of training, type of hospital, and etiology (prescribing N-acetylcysteine for paracetamol toxicity, triggers for endotracheal intubation, measurement of and strategies for lowering serum ammonia, extracorporeal device deployment, and prophylactic antibiotics).

CONCLUSIONS

The management of patients with ALF by ICU professionals differed substantially concerning the relevant clinical measures taken. Further education and high-quality research are warranted.

Mannitol Is Comparable to Hypertonic Saline for Raised Intracranial Pressure in Acute Liver Failure (MAHAL Study): A Randomized Controlled Trial

BACKGROUND

Raised intracranial pressure (ICP) due to cerebral edema (CE) is central to development of hepatic encephalopathy in acute liver failure (ALF). Mannitol (MT) and hypertonic saline (HS) have been shown to improve CE. We compared the efficacy and safety of the 2 modalities.

METHODS

ALF with CE was prospectively randomized in an open study to receive either 5 mL/kg of either 3% HS, as continuous infusion; titrated every 6 hourly to achieve serum sodium of <160 (Group A; n = 26) or 1 g/kg of 20% MN as a IV bolus, repeated every 6 hourly (Group B; n = 25) in addition to standard ALF care. Primary end-point was reduction of ICP defined as optic nerve sheath diameter <5 mm and middle cerebral arterial pulsatility index <1.2 at 12 h.

RESULTS

Fifty-one patients with ALF, hepatitis E being commonest (33.3%), median jaundice to HE interval of 8 (1-16) days, were randomized to HS (n = 26) or MN (n = 25). Baseline characteristics were comparable including King's college criteria (>2: 38.4% vs.40%). Overall, 61.5% patients in the HS and 56% in the MN group showed reduction in ICP at 12 h (p = 0.25). Rebound increase in ICP indices was noted in 5 (20%) patients in MT and none in HS (p < 0.05) group. New onset acute kidney injury was common in the MT group than in the HS group. The ICU stay and 28-day transplant-free survival were not different between the groups.

CONCLUSIONS

While both agents had comparable efficacy in reducing ICP and mortality in ALF patients was comparable, HS was significantly better in preventing reducing rebound CE with lower renal dysfunction.

Management of Cerebral Edema, Brain Compression, and Intracranial Pressure

PURPOSE OF REVIEW

This article reviews the pathophysiology and management of cerebral edema, brain compression, and elevated intracranial pressure (ICP). It also provides a brief introduction to the concept of the glymphatic system and select cellular contributors to cerebral edema.

RECENT FINDINGS

Cerebral edema and brain compression should be treated in a tiered approach after the patient demonstrates a symptomatic indication to start treatment. All patients with acute brain injury should be treated with standard measures to optimize intracranial compliance and minimize risk of ICP elevation. When ICP monitors are used, therapies should target maintaining ICP at 22 mm Hg or less. Evidence exists that serial clinical examination and neuroimaging may be a reasonable alternative to ICP monitoring; however, clinical trials in progress may demonstrate advantages to advanced monitoring techniques. Early decompressive craniectomy and hypothermia are not neuroprotective in traumatic brain injury and should be reserved for situations refractory to initial medical interventions. Medical therapies that acutely lower plasma osmolality may lead to neurologic deterioration from osmotic cerebral edema, and patients with acute brain injury and renal or liver failure are at elevated risk.

SUMMARY

A tiered approach to the management of cerebral edema and brain compression can reduce secondary brain injury when implemented according to core physiologic principles. However, our knowledge of the pathophysiology of acute brain injury is incomplete, and the conceptual framework underlying decades of clinical management may need to be revised in response to currently evolving discoveries regarding the pathophysiology of acute brain injury.

Acute liver failure following paracetamol overdose

Background

Acute liver failure is a rare syndrome comprising a coagulopathy of liver origin, jaundice and encephalopathy in a patient with no prior history of liver disease. Paracetamol overdose is the leading cause of acute liver failure in the United Kingdom and often presents with extrahepatic organ dysfunction requiring critical care. Presentation: We present the case of a patient with hyper acute liver failure secondary to paracetamol overdose. Management and discussion: Management focused on ensuring the correct diagnosis had been made, administering N-acetyl cysteine, fluid resuscitation and broad spectrum antimicrobials. Early intubation and transfer to a transplant centre were undertaken following development of hepatic encephalopathy. Neuroprotective measures and hypertonic saline were instituted to reduce the risk of intracranial hypertension. High dose haemofiltration was also started to help reduce ammonia levels. Aggressive critical care therapies with specialised input results in good outcomes for patients admitted with paracetamol induced hyper acute liver failure. Liver transplant is reserved for those patients unlikely to survive with medical treatment alone.

Optic Nerve Sheath Diameter in Acute Liver Failure: A Prospective Cohort Study

Introduction

Acute liver failure (ALF) is a rare disease that may lead to cerebral edema and death. An increased optic nerve sheath diameter (ONSD) may reflect an early increase in intracranial pressure. We assessed the feasibility and safety of the ONSD measurement and its association with outcomes in patients with ALF.

Methods

This was an open-label prospective cohort study including adult patients with ALF admitted to a liver-specialized intensive care unit (ICU) in an academic center between October 2018 and February 2020 (among 24): 20 as intention-to-treat and 17 as per-protocol analyses. The ONSD measurement (primary exposure) used an ultrasound transducer (3 determinations on each eye per patient). The primary outcome was hospital mortality.

Results

Among the 20 patients, 11 (55.0%) were females and the mean age was 45 ± 16 years. On the day of ONSD measurement (median 32.4 h post-ICU admission; IQR 19.8-59.8): 8 patients (40.0%) were in a coma, the mean international normalized ratio (INR) was 3.3 ± 1.4, median bilirubin was 12.3 mg/dL (IQR 4.7-24.5), mean ammonia was 163 ± 101 µmol/L, and mean SOFA score was 11 ± 5. The mean bilateral ONSD was 5.6 ± 0.7 mm, with a very good correlation between right and left eyes (Pearson's r = 0.90). Ten (50.0%) patients were transplanted and 13 (65.0%) patients survived the hospital stay (all with a 2-month extended Glasgow Outcome Scale of 8). The mean ONSD was significantly higher for hospital non-survivors than survivors both in the intention-to-treat (6.2 vs. 5.3 mm; p = 0.004) and per-protocol (6.2 vs. 5.2 mm; p = 0.004) analyses. No adverse effects from ONSD measurements were reported.

Conclusions

In patients with ALF, a higher ONSD was associated with higher hospital mortality. ONSD measurement is feasible and safe and may have prognostic value.

Hemorrhagic Complications of Invasive Intracranial Pressure Monitor Placement in Acute Liver Failure: Outcomes of a Single-Center Protocol and Comprehensive Literature Review

BACKGROUND

Elevated intracranial pressure due to cerebral edema is associated with very poor survival in patients with acute liver failure (ALF). Placing an intracranial pressure monitor (ICPm) aids in management of intracranial hypertension, but is associated with potentially fatal hemorrhagic complications related to the severe coagulopathy associated with ALF.

METHODS

An institutional Acute Liver Failure Clinical Protocol (ALF-CP) was created to correct ALF coagulopathy prior to placing parenchymal ICP monitoring bolts. We aimed to investigate the frequency, severity, and clinical significance of hemorrhagic complications associated with ICPm bolt placement in the setting of an ALF-CP. All assessed patients were managed with the ALF-CP and had rigorous radiologic follow-up allowing assessment of the occurrence and chronology of hemorrhagic complications. We also aimed to compare our outcomes to other studies that were identified through a comprehensive review of the literature.

RESULTS

Fourteen ALF patients were included in our analysis. There was no symptomatic hemorrhage after ICP monitor placement though four patients were found to have minor intraparenchymal asymptomatic hemorrhages after liver transplant when the ICP monitor had been removed, making the rate of radiographically identified clinically asymptomatic hemorrhage 28.6%. These results compare favorably to those found in a comprehensive review of the literature which revealed rates as high as 17.5% for symptomatic hemorrhages and 30.4% for asymptomatic hemorrhage.

CONCLUSION

This study suggests that an intraparenchymal ICPm can be placed safely in tertiary referral centers which utilize a protocol such as the ALF-CP that aggressively corrects coagulopathy. The ALF-CP led to advantageous outcomes for ICPm placement with a 0% rate of symptomatic and low rate of asymptomatic hemorrhagic complications, which compares well to results reported in other series. A strict ICPm placement protocol in this setting facilitates management of ALF patients with cerebral edema during the wait time to transplantation or spontaneous recovery.

Indian National Association for the Study of Liver Consensus Statement on Acute Liver Failure (Part-2): Management of Acute Liver Failure

Acute liver failure (ALF) is not an uncommon complication of a common disease such as acute hepatitis. Viral hepatitis followed by antituberculosis drug-induced hepatotoxicity are the commonest causes of ALF in India. Clinically, such patients present with appearance of jaundice, encephalopathy, and coagulopathy. Hepatic encephalopathy (HE) and cerebral edema are central and most important clinical event in the course of ALF, followed by superadded infections, and determine the outcome in these patients. The pathogenesis of encephalopathy and cerebral edema in ALF is unique and multifactorial. Ammonia plays a crucial role in the pathogenesis, and several therapies aim to correct this abnormality. The role of newer ammonia-lowering agents is still evolving. These patients are best managed at a tertiary care hospital with facility for liver transplantation (LT). Aggressive intensive medical management has been documented to salvage a substantial proportion of patients. In those with poor prognostic factors, LT is the only effective therapy that has been shown to improve survival. However, recognizing suitable patients with poor prognosis has remained a challenge. Close monitoring, early identification and treatment of complications, and couseling for transplant form the first-line approach to manage such patients. Recent research shows that use of dynamic prognostic models is better for selecting patients undergoing liver transplantation and timely transplant can save life of patients with ALF with poor prognostic factors.

Current concepts in acute liver failure

Acute liver failure (ALF) is a severe condition secondary to a myriad of causes associated with poor outcomes. The prompt diagnosis and identification of the aetiology allow the administration of specific treatments plus supportive strategies and to define the overall prognosis, the probability of developing complications and the need for liver transplantation. Pivotal issues are adequate monitoring and the institution of prophylactic strategies to reduce the risk of complications, such as progressive liver failure, cerebral oedema, renal failure, coagulopathies or infections. In this article, we review the main aspects of ALF, including the definition, diagnosis and complications. Also, we describe the standard-of-care strategies and recent advances in the treatment of ALF. Finally, we include our experience of care patients with ALF.

Ultrasonographic optic nerve sheath diameter correlation with ICP and accuracy as a tool for noninvasive surrogate ICP measurement in patients with decompressive craniotomy

OBJECTIVE

Increased intracranial pressure (ICP) results in enlarged optic nerve sheath diameter (ONSD). In this study the authors aimed to assess the association of ONSD and ICP in severe traumatic brain injury (TBI) after decompressive craniotomy (DC).

METHODS

ONSDs were measured by ocular ultrasonography in 40 healthy control adults. ICPs were monitored invasively with a microsensor at 6 hours and 24 hours after DC operation in 35 TBI patients. ONSDs were measured at the same time in these patients. Patients were assigned to 3 groups according to ICP levels, including normal (ICP ≤ 13 mm Hg), mildly elevated (ICP = 14-22 mm Hg), and severely elevated (ICP > 22 mm Hg) groups. ONSDs were compared between healthy control adults and TBI cases with DC. Then, the association of ONSD with ICP was analyzed using Pearson's correlation coefficient, linear regression analysis, and receiver operator characteristic curves.

RESULTS

Seventy ICP measurements were obtained among 35 TBI patients after DC, including 25, 27, and 18 measurements in the normal, mildly elevated, and severely elevated ICP groups, respectively. Mean ONSDs were 4.09 ± 0.38 mm in the control group and 4.92 ± 0.37, 5.77 ± 0.41, and 6.52 ± 0.44 mm in the normal, mildly elevated, and severely elevated ICP groups, respectively (p < 0.001). A significant linear correlation was found between ONSD and ICP (r = 0.771, p < 0.0001). Enlarged ONSD was a robust predictor of elevated ICP. With an ONSD cutoff of 5.48 mm (ICP > 13 mm Hg), sensitivity and specificity were 91.1% and 88.0%, respectively; a cutoff of 5.83 mm (ICP > 22 mm Hg) yielded sensitivity and specificity of 94.4% and 81.0%, respectively.

CONCLUSIONS

Ultrasonographic ONSD is strongly correlated with invasive ICP measurements and may serve as a sensitive and noninvasive method for detecting elevated ICP in TBI patients after DC.

Serum osmolality, cerebrospinal fluid specific gravity and overt hepatic encephalopathy severity in patients with liver failure

BACKGROUND AND AIMS

Hepatic encephalopathy (HE) is a leading contributor to morbidity in liver disease. While hyperammonaemia plays a key role, the mechanisms of cerebral toxicity are unclear. We hypothesized that serum hyperosmolality contributes to HE during acute (ALF) and acute-on-chronic liver failure (ACLF) through mechanisms that affect the water and solute composition of the cerebral environment.

METHODS

We performed a retrospective analysis of serum osmolality, cerebral spinal fluid (CSF) solute density (specific gravity, determined from computed tomography attenuation) and clinical HE severity (Glasgow Coma Score [GCS]) at the time of intensive care admission in a prospectively identified cohort of liver failure patients with overt HE.

RESULTS

Seventy-three patients (39 ALF and 34 ACLF) were included, of whom 28 (38%) were comatose. Serum osmolality (303.9 ± 15.4 mOsm/kg) was elevated despite normal serum sodium (136.6 ± 6.3 mEq/L). Increased osmolality was independently associated with more severe encephalopathy (ordinal adjusted OR 0.26 [95% CI 0.22, 0.31] for higher GCS per standard deviation increase in osmolality) and lower CSF-specific gravity (linear adjusted β = -0.039 [95% CI -0.069, -0.009] Hounsfield unit per 1 mOsm/kg).

CONCLUSIONS

In the context of related research, these data suggest that hyperosmolality increases brain exposure to metabolic toxins by blood-brain barrier alteration and may be a unique therapeutic target.

Indian National Association for the Study of the Liver Consensus Statement on Acute Liver Failure (Part 1): Epidemiology, Pathogenesis, Presentation and Prognosis

Acute liver failure (ALF) is an infrequent, unpredictable, potentially fatal complication of acute liver injury (ALI) consequent to varied etiologies. Etiologies of ALF as reported in the literature have regional differences, which affects the clinical presentation and natural course. In this part of the consensus article designed to reflect the clinical practices in India, disease burden, epidemiology, clinical presentation, monitoring, and prognostication have been discussed. In India, viral hepatitis is the most frequent cause of ALF, with drug-induced hepatitis due to antituberculosis drugs being the second most frequent cause. The clinical presentation of ALF is characterized by jaundice, coagulopathy, and encephalopathy. It is important to differentiate ALF from other causes of liver failure, including acute on chronic liver failure, subacute liver failure, as well as certain tropical infections which can mimic this presentation. The disease often has a fulminant clinical course with high short-term mortality. Death is usually attributable to cerebral complications, infections, and resultant multiorgan failure. Timely liver transplantation (LT) can change the outcome, and hence, it is vital to provide intensive care to patients until LT can be arranged. It is equally important to assess prognosis to select patients who are suitable for LT. Several prognostic scores have been proposed, and their comparisons show that indigenously developed dynamic scores have an edge over scores described from the Western world. Management of ALF will be described in part 2 of this document.

Acute Fatty Liver of Pregnancy: Pathophysiology, Anesthetic Implications, and Obstetrical Management

A narrative review of the pathophysiology, diagnosis, management, delivery implications, obstetric anesthesia care, and potential critical care needs in patients presenting with acute fatty liver of pregnancy.

Update on the management of acute liver failure

PURPOSE OF REVIEW

This review describes the current intensive care management of acute liver failure (ALF) and the latest evidence for emerging therapies.

RECENT FINDINGS

Mortality from ALF continues to improve and in some cases, medical therapy can negate the need for liver transplantation because of protocolized management in specialist centres. Liver transplantation remains the cornerstone of management for poor prognosis ALF. The reduced use of blood products in ALF reflects growing evidence of balanced haemostasis in severe liver disease. Prophylactic therapeutic hypothermia is no longer recommended for neuroprotection. In cases not suitable for liver transplantation, high-volume plasma exchange (HVP) has potential benefit, although further research on the optimal timing and dosing is needed. Although sepsis remains an important complication in ALF, the use of prophylactic antimicrobials is being questioned in the era of emerging bacterial resistance.

SUMMARY

ICU management of ALF has improved such that liver transplantation is not required in some cases. HVP has emerged as a potential therapy for patients who may not be good liver transplantation candidates. Nevertheless in suitable patients with poor prognosis liver transplantation remains the optimal therapy.

Significant lung injury and its prognostic significance in acute liver failure: A cohort analysis

BACKGROUND AND AIMS

Respiratory failure complicating acute liver failure (ALF) may preclude liver transplantation (LT). We evaluated the association between significant lung injury (SLI) and important clinical outcomes.

METHODS

Retrospective cohort study of 947 ALF patients with chest radiograph (CXR) and arterial blood gas (ABG) data enrolled in the US Acute Liver Failure Study Group (US-ALFSG) from January 1998 to December 2016. SLI was defined by moderate hypoxaemia (Berlin classification; PaO₂ /FiO₂  < 200 mm Hg) and abnormalities on CXR. Primary outcomes were 21-day transplant-free survival (TFS) and overall survival.

RESULTS

Of 947 ALF patients, 370 (39%) had evidence of SLI. ALF patients with SLI (ALF-SLI) had significantly worse oxygenation than controls on admission (median PF ratio 120 vs 300 mm Hg, P < .0001) and higher lactate (6.1 vs 4.6 mmol/l, P = .0008). ALF-SLI patients had higher rates of tracheal (19% vs 14%) and bloodstream (17% vs 11%, P < .005 for both) infections and were more likely to receive transfusions (red cells 55% vs 43%; FFP 74% vs 66%; P < .009 for both). ALF-SLI patients were less likely to receive LT (18% vs 25%, P = .02) and had significantly decreased 21-day TFS (34% vs 42%) and overall survival (49% vs 64%, P < .007 for both). After adjusting for significant covariates (INR, bilirubin, acetaminophen aetiology), the development of SLI was independently associated with decreased 21-day TFS (OR 0.71, P = .03) in ALF patients (C-index 0.78). The incorporation of SLI improved discriminatory ability of the King's College Criteria (P = .0061) but not the ALFSG prognostic index (P = .34).

CONCLUSION

Significant lung injury is a common complication in ALF patients that adversely affects patient outcomes.

Critical care management in patients with acute liver failure

Acute liver failure (ALF) is defined as severe hepatic dysfunction (marked transaminases elevation, detoxification disorder (jaundice and coagulopathy with international normal ratio (INR) > 1.5), the presence of hepatic encephalopathy, and exclusion of underlying chronic liver disease, and a secondary cause like sepsis or cardiogenic shock. Reasons for ALF include paracetamol and warfarin toxicity, autoimmune and viral (mainly hepatitis B and E) hepatitis, and herbal and dietary supplements. Even in terms of meticulous and careful review of the patient, around 20-30% of the reasons remains unknown. In order of its rarity, a randomized controlled trial could hardly be done. However, because of improved ICU treatment, the mortality, even in the advanced stage of ALF decreased. However, in 5-10% of the cases an emergency transplantation is required. This justifies the treatment of this patient cohort in institutions that can provide this kind of treatment.

Inconsistency in Reporting Variables Related to Intracranial Pressure Measurement in Scientific Literature

PURPOSE

To assess whether the collection and communication of intracranial pressure (ICP) values were standardized and reproducible.

METHODS

Integrative review of clinical trials (n = 357) reporting ICP as a variable.

RESULTS

Only 24.1% of studies reported adequate data required for replication. Of the 357 reports, 342 provided information about the design, 274 discussed sampling strategy, 294 identified the ICP device type, 312 provided a unit of measure, 121 provided anatomical localization for measuring ICP, and 83 provided information about patient positioning.

CONCLUSIONS

The majority of literature evaluated did not provide enough data for replication of results. Measuring and reporting ICP in the scientific literature is not standardized. A uniform standard would strengthen the quality of the evidence in neurocritical care and neurosurgical literature and better establish clinical guidelines for ICP management in neurologically injured patients.

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.

Relationship between intracranial pressure and phase-contrast cine MRI-derived measures of cerebrospinal fluid parameters in communicating hydrocephalus

Background

To explore the correlation between intracranial pressure (ICP) and cerebrospinal fluid (CSF) parameters assessed by phase-contrast cine MRI (PC-MRI).

Methods

Fifteen normal people and 80 subjects with communicating hydrocephalus who underwent PC-MRI examinations from a single center were included in this cross-sectional study. In addition to recording patient's age, heart rate, blood pressure and body mass index (BMI), ICP and CSF hemodynamic parameters, such as flow velocity and aqueduct diameter, were measured for correlation analysis.

Results

The mean ICP and CSF aqueduct diameter in hydrocephalus patients were 151.05 mmH₂O and 2.877 mm, respectively, and the maximum (6.938 cm/s) and mean (0.845 cm/s) CSF flow velocities were significantly higher in these patients compared with the controls (P<0.05). After adjusting for age, heart rate, blood pressure, and BMI, there was no significant relationship between peak velocity and ICP (P>0.05). Furthermore, a nonlinear relationship was observed between the ICP and the average velocity of CSF, and the ICP and aqueduct diameter. The ICP increased with the average velocity above 1.628 cm/s (P≤0.01), and the aqueduct diameter increased more than 3.6 mm (P<0.001).

Conclusions

This study found significant correlations between ICP and average velocity and aqueduct diameter. These findings can be useful in assisting clinicians in predicting ICP more effectively, thus improving patient management.

Optic nerve sheath diameter: present and future perspectives for neurologists and critical care physicians

BACKGROUND

Estimation of intracranial pressure (ICP) may be helpful in the management of neurological critically ill patients. It has been shown that ultrasonography of the optic nerve sheath diameter (ONSD) is a reliable tool for non-invasive estimation of increased intracranial pressure (ICP) at hospital admission or in intensive care. Less is known about the estimation of increased ICP and usefulness of ONSD in the prehospital setting. The aim of this review was to elucidate both prevailing and novel applications of ONSD for neurologists and critical care physicians.

METHODS

In this review, we discuss the technique and the novel approach of ONSD measurement, the clinical applications of ONSD in neurology and critical care patients.

RESULTS

ONSD measurement is simple, easy to learn, and has diverse applications. ONSD has utility for ICP measurement in intracranial hemorrhage and ischemic stroke, meningitis and encephalitis, and idiopathic intracranial hypertension (IIH). It is also valuable for lesser known syndromes, where an increase of ICP is postulated, such as acute mountain sickness and posterior reversible encephalopathy syndrome. ONSD changes develop in inflammatory or ischemic optic neuropathies. Some papers demonstrate the usefulness of ONSD studies in symptomatic intracranial hypotension.

CONCLUSIONS

ONSD is a safe and low-cost bedside tool with the potential of screening patients who need other neuroimaging and those who may need an invasive measurement of ICP.

Osmotic Shifts, Cerebral Edema, and Neurologic Deterioration in Severe Hepatic Encephalopathy

OBJECTIVES

We sought to determine the effect of acute electrolyte and osmolar shifts on brain volume and neurologic function in patients with liver failure and severe hepatic encephalopathy.

DESIGN

Retrospective analysis of brain CT scans and clinical data.

SETTING

Tertiary care hospital ICUs.

PATIENTS

Patients with acute or acute-on-chronic liver failure and severe hepatic encephalopathy.

INTERVENTIONS

Clinically indicated CT scans and serum laboratory studies.

MEASUREMENTS AND MAIN RESULTS

Change in intracranial cerebrospinal fluid volume between sequential CT scans was measured as a biomarker of acute brain volume change. Corresponding changes in serum osmolality, chemistry measurements, and Glasgow Coma Scale were determined. Associations with cerebrospinal fluid volume change and Glasgow Coma Scale change for initial volume change assessments were identified by Spearman's correlations (rs) and regression models. Consistency of associations with repeated assessments was evaluated using generalized estimating equations. Forty patients were included. Median baseline osmolality was elevated (310 mOsm/Kg [296-321 mOsm/Kg]) whereas sodium was normal (137 mEq/L [134-142 mEq/L]). Median initial osmolality change was 9 mOsm/kg (5-17 mOsm/kg). Neuroimaging consistent with increased brain volume occurred in 27 initial assessments (68%). Cerebrospinal fluid volume change was more strongly correlated with osmolality (r = 0.70; p = 4 × 10) than sodium (r = 0.28; p = 0.08) change. Osmolality change was independently associated with Glasgow Coma Scale change (p = 1 × 10) and cerebrospinal fluid volume change (p = 2.7 × 10) in initial assessments and in generalized estimating equations using all 103 available assessments.

CONCLUSIONS

Acute decline in osmolality was associated with brain swelling and neurologic deterioration in severe hepatic encephalopathy. Minimizing osmolality decline may avoid neurologic deterioration.

Transcranial Doppler Non-invasive Assessment of Intracranial Pressure, Autoregulation of Cerebral Blood Flow and Critical Closing Pressure during Orthotopic Liver Transplant

Transcranial Doppler (TCD) ultrasonography allows continuous non-invasive monitoring of cerebral blood flow velocity in a variety of clinical conditions. Recently, signal processing of TCD signals has provided several comprehensive parameters for the assessment of cerebral haemodynamics. In this work, we applied a TCD multimodal approach in patients with acute liver failure undergoing orthotopic liver transplant (OLT) to assess the clinical feasibility of using TCD for cerebral haemodynamics assessment in this setting. We retrospectively studied six patients undergoing OLT with continuous monitoring of arterial blood pressure and blood flow velocity in the middle cerebral artery. The main cerebral haemodynamic parameters assessed were non-invasive intracranial pressure, cerebral perfusion pressure, cerebral autoregulation, pulsatility index, critical closing pressure and diastolic closing margin. TCD monitoring revealed marked alterations of these parameters in the OLT setting, which could provide relevant clinical information when there is imminent risk of neurologic impairment.

How to manage: acute liver failure

Acute liver failure (ALF) is a rare but life-threatening clinical syndrome with a broad range of causes. Significant improvements in outcome have occurred over the last 50 years, resulting not only from incremental improvements in specialist critical care and a step-change following the introduction of transplantation for this indication, but also better and more effective treatment started early at the site of first presentation.1 2 Emergency liver transplantation (LTx) remains an important intervention and the decision regarding the need for LTx remains key to management, though non-transplant therapies now appear effective for many causes of the condition. In this short review, we will outline issues in the recognition and management of ALF and ongoing challenges in its treatment.

Brain ultrasonography: methodology, basic and advanced principles and clinical applications. A narrative review

Brain ultrasonography can be used to evaluate cerebral anatomy and pathology, as well as cerebral circulation through analysis of blood flow velocities. Transcranial colour-coded duplex sonography is a generally safe, repeatable, non-invasive, bedside technique that has a strong potential in neurocritical care patients in many clinical scenarios, including traumatic brain injury, aneurysmal subarachnoid haemorrhage, hydrocephalus, and the diagnosis of cerebral circulatory arrest. Furthermore, the clinical applications of this technique may extend to different settings, including the general intensive care unit and the emergency department. Its increasing use reflects a growing interest in non-invasive cerebral and systemic assessment. The aim of this manuscript is to provide an overview of the basic and advanced principles underlying brain ultrasonography, and to review the different techniques and different clinical applications of this approach in the monitoring and treatment of critically ill patients.

Hepatic encephalopathy 2018: A clinical practice guideline by the Italian Association for the Study of the Liver (AISF)

Hepatic encephalopathy (HE) is a common, worrisome and sometimes difficult to manage complication of end-stage liver disease. HE is often recurrent, requiring multiple hospital admissions. It can have serious implications in terms of a patient's ability to perform complex tasks (for example driving), their earning capacity, their social and family roles. This guideline reviews current knowledge on HE definition, pathophysiology, diagnosis and treatment, both by general principles and by way of a summary of available drugs and treatment strategies. The quality of the published, pertinent evidence is graded, and practical recommendations are made. Where possible, these are placed within the Italian health service context, with reference to local diagnosis and management experience.

Outcome of Acetaminophen-Induced Acute Liver Failure Managed Without Intracranial Pressure Monitoring or Transplantation

Acetaminophen-induced acute liver failure (ALF) may require emergency liver transplantation (LT) in the presence of specific criteria, and its management may also include intracranial pressure (ICP) monitoring in selected patients at high risk of cerebral edema. We aimed to test the hypothesis that management of such patients without ICP monitoring or LT would yield outcomes similar to those reported with conventional management. We interrogated a database of all patients treated in an intensive care unit for acetaminophen-induced ALF between November 2010 and October 2016 and obtained relevant information from electronic medical records. We studied 64 patients (58 females) with a median age of 38 years. Such patients had a high prevalence of depression, substance abuse, or other psychiatric disorders and had ingested a median acetaminophen dose of 25 g. No patient received ICP monitoring or LT. Overall, 51 (79.7%) patients survived. Of the 42 patients who met King's College Hospital (KCH) criteria, 29 (69.0%) survived without transplantation. There were 45 patients who developed severe hepatic encephalopathy, and 32 (71.1%) of these survived. Finally, compared with the KCH criteria, the current UK Registration Criteria for Super-Urgent Liver Transplantation (UKRC) for super-urgent LT had better sensitivity (92.3%) and specificity (80.4%) for hospital mortality. In conclusion, in a center applying a no ICP monitoring and no LT approach to the management of acetaminophen-induced ALF, during a 6-year period, overall survival was 79.7%, and for patients fulfilling KCH criteria, it was 69.0%, which were both higher than for equivalent patients treated with conventional management as reported in the literature. Finally, the current UKRC may be a better predictor of hospital mortality in this patient population.

Neurological Monitoring in Acute Liver Failure

Cerebral oedema and Intracranial Hypertension (ICH) are serious complications of acute liver failure affecting approximately 30% of patients, resulting in neurological injury or death. Multiple pathogenetic mechanisms contribute to the pathogenesis of HE including circulating neurotoxins such as ammonia, systemic and neuro-inflammation, infection and cerebral hyperaemia due to loss of cerebral vascular autoregulation. Early recognition and diagnosis is often difficult as clinical signs of elevated Intracranial Pressure (ICP) are not uniformly present and maybe masked by other organ support. ICP monitoring provides early diagnosis and monitoring of ICH, allowing targeted therapeutic interventions for prevention and treatment. ICP monitoring is the subject of much debate and there exists significant heterogeneity of clinical practice regarding its use. The procedure is associated with risks of haemorrhage but may be considered in highly selected patients such as those with highest risk for ICH awaiting transplant to allow for patient selection and optimisation. There is limited evidence that ICP monitoring confers a survival benefit which may explain why in the context of risk benefit analysis there is reduced utilisation in clinical practice. Less or non-invasive techniques of neurological monitoring such as measurement of jugular venous oxygen saturation to assess cerebral oxygen utilisation, and transcranial Doppler CNS to measure cerebral blood flow can provide important clinical information. They should be considered in combination as part of a multi-modal platform utilising specific roles of each system and incorporated within locally agreed algorithms. Other tools such as near-infrared spectrophotometry, optic nerve ultrasound and serum biomarkers of brain injury are being evaluated but are not used routinely in current practice.