Neurological Monitoring in Acute Liver Failure

Critical care management of acute liver failure

The management of acute liver failure (ALF) in modern hepatology intensive care units (ICU) has improved patient outcomes. Critical care management of hepatic encephalopathy, cerebral edema, fluid and electrolytes; prevention of infections and organ support are central to improved outcomes of ALF. In particular, the pathogenesis of encephalopathy is multifactorial, with ammonia, elevated intra-cranial pressure and systemic inflammation playing a central role. Although ALF remains associated with high mortality, the availability of supportive care, including organ failure support such as plasma exchange, timely mechanical ventilation or continuous renal replacement therapy, either conservatively manages patients with ALF or offers bridging therapy until liver transplantation. Thus, appropriate critical care management has improved the likelihood of patient recovery in ALF. ICU care interventions such as monitoring of cerebral edema, fluid status assessment and interventions for sepsis prevention, nutritional support and management of electrolytes can salvage a substantial proportion of patients. In this review, we discuss the key aspects of critical care management of ALF.

[Acute Liver Failure: Current Updates and Management]

Acute liver failure (ALF) is a rare disease condition with a dynamic clinical course and catastrophic outcomes. Several etiologies are involved in ALF. Hepatitis A and B infections and indiscriminate use of untested herbs or supplemental agents are the most common causes of ALF in Korea. Noninvasive neurological monitoring tools have been used in patients with ALF in recent times. Ongoing improvements in intensive care, including continuous renal replacement therapy, therapeutic plasma exchange, vasopressor, and extracorporeal membrane oxygenation, have reduced the mortality rate of patients with ALF. However, liver transplantation is still the most effective treatment for patients with intractable ALF. There is a need for further research in the areas of better prognostication and precise selection of patients for emergency transplantation.

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.

Standard-Volume Plasma Exchange Improves Outcomes in Patients With Acute Liver Failure: A Randomized Controlled Trial

BACKGROUND

High volume plasma-exchange (HVPE) improves survival in patients with acute liver failure (ALF), but apprehension regarding volume overload and worsening of cerebral edema remain.

METHODS

In an open-label randomized controlled trial, 40 consecutive patients of ALF were randomized 1:1 to either standard medical treatment (SMT) or SMT with standard-volume plasma-exchange (SVPE). SVPE was performed using centrifugal apheresis [target volume of 1.5 to 2.0 plasma volumes per session] until desired response was achieved. Cerebral edema was assessed by brain imaging. Results were analyzed in an intention-to-treat analysis. Primary outcome was 21-day transplant-free survival. The levels of cytokines, damage-associated molecular patterns (DAMPs) and endotoxins were analyzed at baseline and day 5.

RESULTS

ALF patients [aged 31.5 ± 12.2 years, 60% male, 78% viral, 83% hyperacute, 70% with SIRS were included. At day 5, SVPE [mean sessions 2.15 ± 1.42, median plasma volume replaced 5.049 L] compared to SMT alone, resulted in higher lactate clearance (p = .02), amelioration of SIRS (84% vs. 26%; P = .02), reduction in ammonia levels [(221.5 ± 96.9) vs.(439 ± 385.6) μg/dl, P = .02) and SOFA scores [9.9(±3.3) vs. 14.6(±4.8); P = .001]. There were no treatment related deaths. SVPE was associated with a higher 21-day transplant free-survival [75% vs. 45%; P = .04, HR 0.30, 95%CI 0.01-0.88]. A significant decrease in levels of pro-inflammatory cytokines and an increase in anti-inflammatory cytokines along with a decrease in endotoxin and DAMPs was seen with SVPE.

CONCLUSION

In ALF patients with cerebral edema, SVPE is safe and effective and improves survival possibly by a reduction in cytokine storm and ammonia.

CLINICALTRIAL

gov (identifier: NCT02718079).

Brain-derived neurotrophic factor as a potential diagnostic marker in minimal hepatic encephalopathy

Introduction

Minimal hepatic encephalopathy (MHE) is a common complication of liver cirrhosis not only leading to a decrease in the quality of life, but also predicting development of overt encephalopathy. The diagnosis of MHE usually relies on a combination of neuropsychological tests, while robust serum biomarkers are lacking. We aimed to assess serum concentrations of brain-derived neurotrophic factor (BDNF) in MHE patients.

Material and methods

Serum BDNF was assessed in 78 patients with liver cirrhosis (53 male, median age 55 years) and 40 healthy individuals. 43 subjects underwent extensive evaluation for MHE by psychometric hepatic encephalopathy score (PHES) and inhibitory control test (ICT) or critical flicker frequency (CFF).

Results

Serum BDNF was twofold lower in liver cirrhosis compared to healthy subjects [13.6 (7.8-22.6) vs. 33.0 (24.1-40.7) ng/ml, p < 0.001] and its decrease reflected a degree of liver insufficiency assessed by model for end-stage liver disease (MELD). BDNF showed a negative correlation with bilirubin (R = –0.35, p = 0.005) and international normalized ratio (INR) (R = –0.37, p = 0.003), and positive with platelets (PLT) (R = 0.36, p = 0.004), while no associations with age, sex, body mass index (BMI), waist-hip ratio (WHR), creatinine and ammonia were noted. Importantly, subjects with a diagnosis of MHE by at least two modalities showed the lowest levels of BDNF [10.9 (2.5-14.4) vs. 19.9 (9.3-29.4) ng/ml, p < 0.01]. Patients with self-reported sleep disturbances had significantly lower serum BDNF [13.0 (2.5-23.4) vs. 20.0 (8.4-31.3) ng/ml, p = 0.04].

Conclusions

The lowest serum BDNF concentration was noted in patients with MHE and sleep disturbances, which suggests a role in pathophysiology of hepatic encephalopathy but also as a potential biomarker.

Fatal cerebral edema in patients with decompensated cirrhosis: A case series

PURPOSE

Unlike patients with acute liver failure, patients with cirrhosis are not traditionally thought to be at risk for developing cerebral edema. In the largest case series to date, we document clinical characteristics of cirrhotic patients who develop cerebral edema.

MATERIALS AND METHODS

In this retrospective case series, seventeen adult patients with acute-on-chronic liver failure (ACLF) were identified using Morbidity & Mortality data. Neurological decompensation was defined by focal neurological deficits or abnormal movements. Elevated ICP was diagnosed clinically by pupillary reflex change improving with hyperosmolar therapy, or by herniation on CT. Pulsatility indices >1.2 on transcranial Dopplers (TCDs) and/or optic nerve sheath diameter (ONSD) >0.5 cm were acceptable alternatives.

RESULTS

Median MELD-Na was 36 (IQR 31.5,43) compared with 20 (IQR 19,23) prior to admission. Neurological decompensation was associated with abnormal pupil reactivity in 76% and abnormal movements in 65%. Cerebral edema was diagnosed by CT (n = 14). For those too ill to transport, elevated ICP was confirmed with TCDs for three patients and ONSD for two. Mortality was 100% a median of 3 days (IQR 1.5,5) from neurologic decompensation.

CONCLUSIONS

ACLF patients with neurological decompensation exhibit distinct clinical changes. Noninvasive bedside techniques may serve as surrogate measures for ICP.

Analysis of weekend effect in severe acute liver injury: A nationwide database study

Background and Aims

Severe acute liver injury (ALI) can lead to poor outcomes without timely management. Comparatively worse outcomes in various severe, emergent conditions have been attributed to reduced hospital resources experienced by patient weekend admissions, a phenomenon termed "weekend effect." To date, a weekend effect has not been studied in severe ALI, an emergency also necessitating timely management. We aimed to evaluate such an effect in this condition by analyzing a large national inpatient database in the United States.

Methods

We analyzed the Nationwide/National Inpatient Sample (NIS) 2000 to 2014, the largest inpatient, all-payer database in the United States (US), containing sociodemographic, clinical, patient-, and hospital-level data. We identified severe ALI using International Classification of Disease, 9^th Revision diagnosis codes for acute/subacute hepatic necrosis (570) with encephalopathy (572.2). Our primary outcome was in-hospital mortality. Using a full-model approach for covariate selection, we performed multiple logistic regression modeling to assess for weekend effect and identify predictors of in-hospital mortality.

Results

We identified 15 762 eligible hospitalizations, with 12 182 (77.3%) having complete covariate data. This sample comprised 53.3% males, 69.3% White race, and had an average (± SD) age of 55.0 ± 14.1 years. We utilized a full-model approach for covariate inclusion but did not include patient transfer data due to limited availability. We observed no significant mortality differences in weekend admissions (OR = 1.06, 95% CI: 0.97-1.15, P = 0.02). However, significantly higher mortality was associated with male sex, older age, Black or Hispanic race, Northeast US hospitalization, urban teaching status, and larger hospital size. Sensitivity analyses using multiple imputation datasets and transfer covariates did not change our results.

Conclusion

We did not observe a weekend effect of in-hospital mortality for weekend admissions for severe ALI, but our overall diagnosis ascertainment yield was low-indicating that lack of accurate documentation for the etiology of severe ALI may be masking an effect. Additionally, our findings suggest that racial differences and hospital-level characteristics in the context of severe ALI may be associated with varying outcomes, regardless of admission day, which warrants further research.

Intensive Care Management of Acute Liver Failure: Considerations While Awaiting Liver Transplantation

Acute liver failure is a unique clinical phenomenon characterized by abrupt deterioration in liver function and altered mentation. The development of high-grade encephalopathy and multisystem organ dysfunction herald poor prognosis. Etiologic-specific treatments and supportive measures are routinely employed; however, liver transplantation remains the only chance for cure in those who do not spontaneously recover. The utility of artificial and bioartificial assist therapies as supportive care-to allow time for hepatic recovery or as a bridge to liver transplantation-has been examined but studies have been small, with mixed results. Given the severity of derangements, intensive critical care is needed to successfully bridge patients to transplant, and evaluation of candidates occurs rapidly in parallel with serial reassessments of operative fitness. Psychosocial assessment is often suboptimal and relative contraindications to transplant, such as ventilator-dependence may be overlooked. While often employed to guide evaluation, no single prognostic model discriminates those who will spontaneously recover and those who will require transplant. The purpose of this review will be to summarize approaches in critical care, prognostic modeling, and medical evaluation of the acute liver failure transplant candidate.