Moderate hypothermia with intracranial pressure monitoring as a therapeutic paradigm for the management of acute liver failure: a systematic review. Intensive Care Med. 2010;36:210-213. [PMID: 19847396 DOI: 10.1007/s00134-009-1702-2]

General Critical Care, Temperature Control, and End-of-Life Decision Making in Patients Resuscitated from Cardiac Arrest

Cardiac arrest affects millions of people per year worldwide. Although advances in cardiopulmonary resuscitation and intensive care have improved outcomes over time, neurologic impairment and multiple organ dysfunction continue to be associated with a high mortality rate. The pathophysiologic mechanisms underlying the post-resuscitation disease are complex, and a coordinated, evidence-based approach to post-resuscitation care has significant potential to improve survival. Critical care management of patients resuscitated from cardiac arrest focuses on the identification and treatment of the underlying cause(s), hemodynamic and respiratory support, organ protection, and active temperature control. This review provides a state-of-the-art appraisal of critical care management of the post-cardiac arrest patient.

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.

Activation of immune signals during organ transplantation

The activation of host's innate and adaptive immune systems can lead to acute and chronic graft rejection, which seriously impacts graft survival. Thus, it is particularly significant to clarify the immune signals, which are critical to the initiation and maintenance of rejection generated after transplantation. The initiation of response to graft is dependent on sensing of danger and stranger molecules. The ischemia and reperfusion of grafts lead to cell stress or death, followed by releasing a variety of damage-associated molecular patterns (DAMPs), which are recognized by pattern recognition receptors (PRRs) of host immune cells to activate intracellular immune signals and induce sterile inflammation. In addition to DAMPs, the graft exposed to 'non-self' antigens (stranger molecules) are recognized by the host immune system, stimulating a more intense immune response and further aggravating the graft damage. The polymorphism of MHC genes between different individuals is the key for host or donor immune cells to identify heterologous 'non-self' components in allogeneic and xenogeneic organ transplantation. The recognition of 'non-self' antigen by immune cells mediates the activation of immune signals between donor and host, resulting in adaptive memory immunity and innate trained immunity to the graft, which poses a challenge to the long-term survival of the graft. This review focuses on innate and adaptive immune cells receptor recognition of damage-associated molecular patterns, alloantigens and xenoantigens, which is described as danger model and stranger model. In this review, we also discuss the innate trained immunity in organ transplantation.

NLRP3 inflammasome-mediated choroid plexus hypersecretion contributes to hydrocephalus after intraventricular hemorrhage via phosphorylated NKCC1 channels

Background

Hydrocephalus is a severe complication of intracerebral hemorrhage with ventricular extension (ICH-IVH) and causes cerebrospinal fluid (CSF) accumulation. The choroid plexus epithelium plays an important role in CSF secretion and constitutes the blood–CSF barrier within the brain–immune system interface. Although the NLRP3 inflammasome, as a key component of the innate immune system, promotes neuroinflammation, its role in the pathogenesis of hydrocephalus after hemorrhage has not been investigated. Therefore, this study aimed to investigate the potential mechanism of NLRP3 in hydrocephalus to discover a potential marker for targeted therapy.

Methods

A rat model of hydrocephalus after ICH-IVH was developed through autologous blood infusion in wild-type and Nlrp3^−/− rats. By studying the features and processes of the model, we investigated the relationship between the NLRP3 inflammasome and CSF hypersecretion in the choroid plexus.

Results

The ICH-IVH model rats showed ventricular dilation accompanied by CSF hypersecretion for 3 days. Based on the choroid plexus RNA-seq and proteomics results, we found that an inflammatory response was activated. The NLRP3 inflammasome was investigated, and the expression levels of NLRP3 inflammasome components reached a peak at 3 days after ICH-IVH. Inhibition of NLRP3 by an MCC950 inflammasome inhibitor or Nlrp3 knockout decreased CSF secretion and ventricular dilation and attenuated neurological deficits after ICH-IVH. The mechanism underlying the neuroprotective effects of NLRP3 inhibition involved decreased phosphorylation of NKCC1, which is a major protein that regulates CSF secretion by altering Na⁺- and K⁺-coupled water transport, via MCC950 or Nlrp3 knockout. In combination with the in vitro experiments, this experiment confirmed the involvement of the NLRP3/p-NKCC1 pathway and Na⁺ and K⁺ flux.

Conclusions

This study demonstrates that NKCC1 phosphorylation in the choroid plexus epithelium promotes NLRP3 inflammasome-mediated CSF hypersecretion and that NLRP3 plays an important role in the pathogenesis of hydrocephalus after hemorrhage. These findings provide a new therapeutic strategy for treating hydrocephalus.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02530-x.

Targeted temperature management in acute liver failure: A systematic review

BACKGROUND

Targeted temperature management is the modern term for therapeutic hypothermia, where cooling is induced by intensive care clinicians to achieve body temperatures below 36°C. Its use in acute liver failure to improve refractory intracranial hypertension and patient outcomes is not supported by strong quality evidence.

AIM

This systematic review aims to determine if targeted temperature management improves patient outcome as opposed to normothermia in acute liver failure.

METHODS

A computerized and systematic search of six academic and medical databases was conducted using the following keywords: "acute liver failure", "fulminant hepatic injury", "targeted temperature management", "therapeutic hypothermia", and "cooling". Broad criteria were applied to include all types of primary observational studies, from case reports to randomized controlled trials. Standardized tools were used throughout to critically appraise and extract data.

FINDINGS

Nine studies published between 1999 and 2016 were included. Early observational studies suggest a benefit of targeted temperature management in the treatment of refractory intracranial hypertension and in survival. More recent controlled studies do not show such a benefit in the prevention of intracranial hypertension. All studies revealed that the incidence of coagulopathy is not higher in patients treated with targeted temperature management. There remains some uncertainty regarding the increased risk of infection and dysrhythmias. Heterogeneity was found between study types, design, sample sizes, and quality.

CONCLUSION

Although it does not significantly improve survival, targeted temperature management is efficient in treating episodes of intracranial hypertension and stabilizing an unstable critical care patient without increasing the risk of bleeding. It does not, however, prevent intracranial hypertension. Data heterogeneity may explain the contradictory findings.

RELEVANCE TO CLINICAL PRACTICE

Controlled studies are needed to elucidate the true clinical benefit of targeted temperature management in improving patient outcome.

Clinical Experience of Therapeutic Hypothermia in Cases of Near-Hanging and Recovered from Cardiac Arrest Due to Hanging

Objective

There is no specific treatment for comatose patients after near-hanging or in those who recover from cardiac arrest (CA) caused by hanging. Since 2009, we have used therapeutic hypothermia (TH) to treat all comatose survivors of near-hanging and in patients who recovered from CA caused by hanging. The purpose of this study was to describe the outcomes in comatose patients after near-hanging.

Design

Case series.

Setting

Emergency departments of two regional hospitals.

Methods

We collected patient data from the Samsung Medical Center hypothermia database between November 2009 and November 2011. We included all patients presented with near-hanging or CA caused by hanging; who remained comatose and received TH after resuscitation for analysis. Clinical characteristics and outcome of patients were presented. Results During the study period, 26 patients were admitted to the emergency department after near-hanging or CA caused by hanging; 21 patients were enrolled in this study. Twelve patients with CA and 9 comatose patients without CA were treated with TH. Only 1 patient with CA had a good neurological outcome. By contrast, all near-hanging patients without CA had a good neurological outcome.

Conclusions

TH can be an effective therapeutic modality in cases of near-hanging without CA. However, the effectiveness of TH is questionable in patients who survive from CA caused by hanging. (Hong Kong j.emerg.med. 2014;21:316-321)

Perioperative Care of the Liver Transplant Patient

With the evolution of surgical and anesthetic techniques, liver transplantation has become "routine," allowing for modifications of practice to decrease perioperative complications and costs. There is debate over the necessity for intensive care unit admission for patients with satisfactory preoperative status and a smooth intraoperative course. Postoperative care is made easier when the liver graft performs optimally. Assessment of graft function, vigilance for complications after the major surgical insult, and optimization of multiple systems affected by liver disease are essential aspects of postoperative care. The intensivist plays a vital role in an integrated multidisciplinary transplant team.

Drug-Induced Acute Liver Failure

Drug-induced acute liver failure (ALF) disproportionately affects women and nonwhites. It is most frequently caused by antimicrobials and to a lesser extent by complementary and alternative medications, antiepileptics, antimetabolites, nonsteroidals, and statins. Most drug-induced liver injury ALF patients have hepatocellular injury pattern. Cerebral edema and intracranial hypertension are the most serious complications of ALF. Other complications include coagulopathy, sepsis, metabolic derangements, and renal, circulatory, and respiratory dysfunction. Although advances in intensive care have improved outcome, ALF has significant mortality without liver transplantation. Liver-assist devices may provide a bridge to transplant or to spontaneous recovery.

Blood purification for treatment of patients with acute liver failure: Clinical efficacy and nursing strategy

AIM: To analyze the clinical efficacy of blood purification in the treatment of patients with acute liver failure and to explore the nursing strategy.

METHODS: Forty-one patients with acute liver failure treated at our hospital from June 2006 to May 2013 were included. The patients received conventional treatment, plasmapheresis combined with continuous venovenous hemodiafiltration, and targeted nursing. Clinical efficacy was observed.

RESULTS: Total bilirubin (TBIL), direct bilirubin (DBIL), aspartate transaminase (AST), alanine transaminase (ALT), prothrombin time (PT), activated partial prothrombin time (APTT) and NH₃ levels after treatment were 215.6 μmol/L ± 53.2 μmol/L, 105.9 μmol/L ± 42.3 μmol/L, 593.4 U/L ± 134.5 U/L, 981.8 U/L ± 239.4 U/L, 21.8 s ± 4.9 s, 74.3 s ± 34.3 s and 92.1 μmol/L ± 53.3 μmol/L, respectively, and TBIL, DBIL, AST, ALT, PT and NH₃ levels were significantly improved after treatment (P < 0.05). Na⁺, K⁺, Ca²⁺, Cl^-, SCr and BUN levels after treatment were 2.11 mmol/L ± 0.63 mmol/L, 4.19 mmol/L ± 1.41 mmol/L, 2.31 mmol/L ± 0.81 mmol/L, 94.33 mmol/L ± 11.94 mmol/L, 168.28 μmol/L ± 39.25 μmol/L and 15.49 mmol/L ± 3.48 mmol/L, respectively, and only SCr and BUN levels were significantly improved after treatment (P < 0.05).

CONCLUSION: Blood purification for treatment of patients with acute liver failure is effective.

Neurologic manifestations of acute and chronic liver disease

PURPOSE OF REVIEW

This article summarizes the most common neurologic sequelae of acute and chronic liver failure, liver transplantation, and other treatments for liver disease, and outlines the pathogenesis, neurologic manifestations, and treatment of Wilson disease.

RECENT FINDINGS

The neurologic manifestations of liver disease are caused by the liver's failure to detoxify active compounds that have deleterious effects on the central and peripheral nervous systems. In addition, treatments for liver disease such as liver transplantation, transjugular intrahepatic portosystemic shunt, and antiviral medications can also be neurotoxic. Wilson disease affects the liver and nervous system simultaneously and may often initially be diagnosed by a neurologist; treatment options have evolved over recent years.

SUMMARY

Acute and chronic liver diseases are encountered commonly in the general population. Neurologic dysfunction will eventually affect a significant number of these individuals, especially if the disease progresses to liver failure. Early recognition of these neurologic manifestations can lead to more effective management of these patients.

Monitoring and managing hepatic disease in anaesthesia

Patients with liver disease have multisystem organ dysfunction that leads to physiological perturbations ranging from hyperbilirubinaemia of no clinical consequence to severe coagulopathy and metabolic disarray. Patient-specific risk factors, clinical scoring systems, and surgical procedures stratify perioperative risk for these patients. The anaesthetic management of patients with hepatic dysfunction involves consideration of impaired drug metabolism, hyperdynamic circulation, perioperative hypoxaemia, bleeding, thrombosis, and hepatic encephalopathy.

Combined therapy for acute hepatic failure

Acute hepatic failure (AHF) is a devastating clinical syndrome characterized by rapid impairment of liver functions and development of encephalopathy, multiple organ failure, and in most cases cerebral edema. AHF has a high mortality rate. Although advances in drug treatment, artificial liver and liver transplantation have significantly improved the prognosis of AHF, there is still a lack of effective treatment for AHF because of its complicated etiopathogenesis, rapid progression and less clinical knowledge about managing the disease. There is an urgent need to develop effective treatments for AHF. This article aims to review recent advances in the treatment of AHF.

Management and prognosis of acute liver failure in children

Although the etiologies of pediatric acute liver failure (ALF) are diverse, ultimate pathophysiologic pathways and management challenges for these disorders, usually lethal in the pre-transplant era, are similar. This review considers particularly the mechanisms of, and monitoring for, intracranial hypertension and coagulopathy; summarizes detailed advice for management of the ALF-associated failures of multiple body systems; and reviews the variety of prognostic scores available to guide management and assist in choosing the patients most apt to benefit from liver transplantation and the optimal timing for such transplantation.

Hypothermia for acute brain injury--mechanisms and practical aspects

Hypothermia is widely accepted as the gold-standard method by which the body can protect the brain. Therapeutic cooling--or targeted temperature management (TTM)--is increasingly being used to prevent secondary brain injury in patients admitted to the emergency department and intensive care unit. Rapid cooling to 33 °C for 24 h is considered the standard of care for minimizing neurological injury after cardiac arrest, mild-to-moderate hypothermia (33-35 °C) can be used as an effective component of multimodal therapy for patients with elevated intracranial pressure, and advanced cooling technology can control fever in patients who have experienced trauma, haemorrhagic stroke, or other forms of severe brain injury. However, the practical application of therapeutic hypothermia is not trivial, and the treatment carries risks. Development of clinical management protocols that focus on detection and control of shivering and minimize the risk of other potential complications of TTM will be essential to maximize the benefits of this emerging therapeutic modality. This Review provides an overview of the potential neuroprotective mechanisms of hypothermia, practical considerations for the application of TTM, and disease-specific evidence for the use of this therapy in patients with acute brain injuries.

Thrombocytopenia in the Intensive Care Unit

Thrombocytopenia is a common laboratory finding in critically ill patients admitted to the intensive care unit. Potential etiologies of thrombocytopenia are myriad, ranging from acute disease processes and concomitant conditions to exposures and drugs. The mechanism of decreased platelet counts can also be varied: laboratory measurement may be spurious, platelet production may be decreased, or platelet destruction or sequestration may be increased. In addition to evaluation for the cause of thrombocytopenia, the clinician must also guard against spontaneous bleeding due to thrombocytopenia, prophylax against bleeding resulting from an invasive procedure performed in the setting of thrombocytopenia, and treat active bleeding related to thrombocytopenia.

Acute liver failure: current practice and recent advances

ALF is an important cause of liver-related morbidity and mortality. Advances in the management of ICH and SIRS, and cardiorespiratory, metabolic, and renal support have improved the outlook of such patients. Early transfer to a liver transplant center is essential. Routine use of NAC is recommended for patients with early hepatic encephalopathy, irrespective of the etiology. The role of hypothermia remains to be determined. Liver transplantation plays a critical role, particularly for those with advanced encephalopathy. Several detoxification and BAL support systems have been developed to serve as a bridge to transplantation or to spontaneous recovery. However, such systems lack sufficient reliability and efficacy to be applied routinely in clinical practice. Hepatocyte and stem cell transplantation may provide valuable adjunctive therapy in the future.

A simple dummy liver assist device prolongs anhepatic survival in a porcine model of total hepatectomy by slight hypothermia

BACKGROUND

Advances in intensive care support such as therapeutic hypothermia or new liver assist devices have been the mainstay of treatment attempting to bridge the gap from acute liver failure to liver transplantation, but the efficacy of the available devices in reducing mortality has been questioned. To address this issue, the present animal study was aimed to analyze the pure clinical effects of a simple extracorporeal dummy device in an anhepatic porcine model of acute liver failure.

METHODS

Total hepatectomy was performed in ten female pigs followed by standardized intensive care support until death. Five animals (dummy group, n = 5) underwent additional cyclic connection to an extracorporeal dummy device which consisted of a plasma separation unit. The separated undetoxified plasma was completely returned to the pigs circulation without any plasma substitution or exchange in contrast to animals receiving intensive care support alone (control group, n = 5). All physiological parameters such as vital and ventilation parameters were monitored electronically; laboratory values and endotoxin levels were measured every 8 hours.

RESULTS

Survival of the dummy device group was 74 ± 6 hours in contrast to 53 ± 5 hours of the control group which was statistically significant (p < 0.05). Body temperature 24 hours after hepatectomy was significantly lower (36.5 ± 0.5°C vs. 38.2 ± 0.7°C) in the dummy device group. Significant lower values were measured for blood lactate (1.9 ± 0.2 vs. 2.5 ± 0.5 mM/L) from 16 hours, creatinine (1.5 ± 0.2 vs. 2.0 ± 0.3 mg/dL) from 40 hours and ammonia (273 ± 122 vs. 1345 ± 700 μg/dL) from 48 hours after hepatectomy until death. A significant rise of endotoxin levels indicated the onset of sepsis at time of death in 60% (3/5) of the dummy device group animals surviving beyond 60 hours from hepatectomy.

CONCLUSIONS

Episodes of slight hypothermia induced by cyclic connection to the extracorporeal dummy device produced a significant survival benefit of more than 20 hours through organ protection and hemodynamic stabilisation. Animal studies which focus on a survival benefit generated by liver assist devices should especially address the aspect of slight transient hypothermia by extracorporeal cooling.

Diagnosis and management of acute liver failure

PURPOSE OF REVIEW

Acute liver failure (ALF) is a devastating syndrome afflicting previously healthy individuals. Early recognition of the illness is crucial, as aggressive treatment may improve outcomes. Despite significant advances in care, however, the mortality remains high (30-100%). This brief review will focus on the causes and overall management of the complications of ALF.

RECENT FINDINGS

Our knowledge of the causes of ALF has expanded significantly in the last decade. The mechanism of hepatic encephalopathy and cerebral edema in this setting continues to be elucidated and is discussed here.

SUMMARY

Improved outcomes can be achieved with the early recognition and aggressive management of ALF.

Moderate hypothermia with intracranial pressure monitoring as a therapeutic paradigm for the management of acute liver failure: a systematic review

OBJECTIVE

To systematically review the literature and present data on the safety and efficacy of induced moderate hypothermia combined with ICP monitoring in critically ill patients with acute liver failure.

DESIGN

We conducted a retrospective observational search of MEDLINE database using both OVID and PubMed with the following MeSH terms, "Hypothermia, Induced," "Brain Edema," "Intracranial Hypertension" (ICH), "Liver failure, Acute" and "Liver Failure, Fulminant." We limited our search to case series involving at least three human subjects and all other clinical trials. Baseline ICP, cerebral perfusion pressure (CPP) and cerebral blood flow (CBF) as well as the response of these variables to hypothermia were recorded when available. Additional clinical and demographic data were also recorded.

RESULTS

Five case series were identified. Pre-existing coagulopathy from liver failure was reversed by various modalities in all studies prior to insertion of ICP monitors. Induction of moderate hypothermia combined with ICP monitoring consistently improved ICP, CPP and CBF in four trials; one trial demonstrated the feasibility and effectiveness of moderate induced hypothermia as part of a protocolized strategy for the management of ICH.

CONCLUSIONS

Limited data exist concerning the safety and efficacy of moderate hypothermia and ICP monitoring for the treatment of ICH in acute liver failure. The available evidence shows that induction of moderate hypothermia in this clinical setting is feasible and possibly efficacious. Well-designed prospective clinical trials are warranted in this challenging context, given the potential of providing a bridge to liver transplantation or even clinical recovery.