Acute lung injury in fulminant hepatic failure following paracetamol poisoning

[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.

Pulmonary implications of acetaminophen exposures independent of hepatic toxicity

Both preclinical and clinical studies have demonstrated that exposures to acetaminophen (APAP) at levels that cause hepatic injury cause pulmonary injury as well. However, whether exposures that do not result in hepatic injury have acute pulmonary implications is unknown. Thus, we sought to determine how APAP exposures at levels that do not result in significant hepatic injury impact the mature lung. Adult male ICR mice (8-12 wk) were exposed to a dose of APAP known to cause hepatotoxicity in adult mice [280 mg/kg, intraperitoneal (ip)], as well as a lower dose previously reported to not cause hepatic injury (140 mg/kg, ip). We confirm that the lower dose exposures did not result in significant hepatic injury. However, like high dose, lower exposure resulted in increased cellular content of the bronchoalveolar lavage fluid and induced a proinflammatory pulmonary transcriptome. Both the lower and higher dose exposures resulted in measurable changes in lung morphometrics, with the lower dose exposure causing alveolar wall thinning. Using RNAScope, we were able to detect dose-dependent, APAP-induced pulmonary Cyp2e1 expression. Finally, using FLIM we determined that both APAP exposures resulted in acute pulmonary metabolic changes consistent with mitochondrial overload in lower doses and a shift to glycolysis at a high dose. Our findings demonstrate that APAP exposures that do not cause significant hepatic injury result in acute inflammatory, morphometric, and metabolic changes in the mature lung. These previously unreported findings may help explain the potential relationship between APAP exposures and pulmonary-related morbidity.

Activation of vagovagal reflex prevents hepatic ischaemia-reperfusion-induced lung injury via anti-inflammatory and antioxidant effects

NEW FINDINGS

What is the central question of this study? Does vagus nerve stimulation have protective effects against both direct liver damage and distant lung injury in a rat model of hepatic ischaemia-reperfusion? What is the main finding and its importance? Vagus nerve stimulation provides protection through anti-inflammatory and anti-oxidative stress effects, possibly achieved by the vagovagal reflex.

ABSTRACT

Hepatic ischaemia-reperfusion (I/R) is not an isolated event; instead, it can result in remote organ dysfunction. The aim of this study was to investigate whether vagus nerve stimulation (VNS) can alleviate hepatic I/R-induced lung injury and to explore the underlying mechanism. Thirty male Sprague-Dawley rats were randomly allocated into five groups (n = 6 each): the sham group (without I/R or VNS), the I/R group (hepatic I/R) and three different VNS treatment groups (hepatic I/R plus VNS). The hepatic I/R group was subjected to occlusion of the portal vein and hepatic artery for 1 h, followed by 6 h of reperfusion. The intact afferent and efferent cervical vagus nerves were stimulated throughout the I/R process. During VNS, cervical neural activity was recorded. At the end of the experiment, liver function, the wet-to-dry lung weight ratio, histology of the liver and lung and inflammatory/oxidative indices were evaluated. We found that VNS significantly mitigated lung injury, as demonstrated by alleviation of pulmonary oedema and pathological alterations, by limiting inflammatory cytokine infiltration and increasing antioxidant capability. This proof-of-concept study suggested that VNS might protect patients from lung injury induced by hepatic I/R related to various circumstances.

The developing murine lung is susceptible to acetaminophen toxicity

Acetaminophen (n-acetyl-p-aminophenol, APAP) use in the neonatal intensive care unit is rapidly increasing. Although APAP-related hepatotoxicity is rarely reported in the neonatal literature, other end-organ toxicity can occur with toxic exposures. APAP-induced lung injury has been reported with toxic exposures in adults, but whether this occurs in the developing lung is unknown. Therefore, we tested whether toxic APAP exposures would injure the developing lung. Neonatal C57BL/6 mice (PN7, early alveolar stage of lung development) were exposed to a dose of APAP known to cause hepatotoxicity in adult mice (280 mg/kg, IP). This exposure induced significant lung injury in the absence of identifiable hepatic toxicity. This injury was associated with increased pulmonary expression of Cyp2e1, the xenobiotic enzyme responsible for the toxic conversion of APAP. Exposure was associated with increased pulmonary expression of antioxidant response genes and decreased pulmonary glutathione peroxidase activity level. Furthermore, we observed an increase in pulmonary expression of proinflammatory cytokines and chemokines. Lastly, we were able to demonstrate that this toxic APAP exposure was associated with a shift in pulmonary metabolism away from glycolysis with increased oxidative phosphorylation, a finding consistent with increased mitochondrial workload, potentially leading to mitochondrial toxicity. This previously unrecognized injury and metabolic implications highlight the need to look beyond the liver and evaluate both the acute and long-term pulmonary implications of APAP exposure in the perinatal period.

A/J mice are more susceptible than C57BL/6 to acetaminophen-induced hepatotoxicity

Acetaminophen (APAP) is commonly used to treat fever and pain. However, when in overdose is the predominant cause of hepatotoxicity. Despite advances in understanding the mechanisms of APAP-induced hepatotoxicity, the management of acute liver failure remains a challenge. Thus, more relevant experimental models are crucial to provide a better understanding of this condition. The aim of this study is to evaluate the effect of APAP-induced hepatotoxicity on A/J mice using C57BL/6 as reference experimental model. Eight- to ten-week-old male A/J and C57BL/6 mice were treated with APAP (300 or 500 mg/kg) by intraperitoneal injection. After 24 h total blood leukocyte counting, plasma levels of alanine amino transferase (ALT) and aspartate amino transferase (AST), histopathological analysis of liver, lung and kidney were evaluated. A/J mice presented reduction in circulating leukocytes concomitant with the increase in plasma levels of ALT and AST, and liver necrosis when treated with 300 and 500 mg/kg of APAP. C57BL/6 mice presented similar results only with 500 mg/kg of APAP. Our results show that A/J mice have a marked susceptibility to the effects of APAP and could be considered as an experimental model to study APAP-induced toxicity.

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.

Early life acetaminophen exposure, glutathione S-transferase genes, and development of adolescent asthma in a high-risk birth cohort

BACKGROUND

Although the impact of early life acetaminophen on asthma risk is still not clear, potential interactions with glutathione S-transferase (GST) genes due to reduced antioxidant function in particular polymorphisms, and possible impact on lung function, have never been investigated in adolescents.

OBJECTIVE

We aimed to investigate associations between early life acetaminophen use and adolescent asthma and lung function and to assess potential interactions by GST polymorphisms.

METHODS

Acetaminophen use was recorded 18 times up to age 2 years (n = 575 [92.7%]). Participants were genotyped for GST polymorphisms (GSTM1/T1/P1) (n = 429 [69.2%]). Asthma and lung function were measured at 12 (n = 365 [58.9%]) and 18 years (n = 413 [66.6%]). Regression models assessed associations and interactions.

RESULTS

Doubling of days of acetaminophen use was associated with reduced prebronchodilator FEV₁/forced vital capacity (β coefficient, -0.10; 95% CI, -0.19 to -0.01) and midexpiratory flow (-0.09; 95% CI, -0.18 to 0) at 18 years, but this association was not found when restricted for nonrespiratory reasons, suggesting confounding by indication. However, in children with GSTM1 null and GSTT1 present, increasing acetaminophen use for nonrespiratory reasons was associated with reduced FEV₁ and midexpiratory flow at 18 years (interaction between GSTM1/T1 and acetaminophen P < .05). Increased acetaminophen use was associated with asthma at 18 years for children with GSTP1 Ile/Ile (odds ratio, 1.66; 95% CI, 1.07 to 2.57), but not other GSTP1 genotypes.

CONCLUSIONS

These novel findings need to be investigated for consistency in other studies but suggest that children carrying risk genotypes may be susceptible to respiratory consequences from acetaminophen use.

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.

Toxic Acetaminophen Exposure Induces Distal Lung ER Stress, Proinflammatory Signaling, and Emphysematous Changes in the Adult Murine Lung

Clinical studies have demonstrated a strong association between both acute toxic exposure and the repetitive, chronic exposure to acetaminophen (APAP) with pulmonary dysfunction. However, the mechanisms underlying this association are unknown. Preclinical reports have demonstrated that significant bronchiolar injury occurs with toxic APAP exposure, but very little information exists on how the distal lung is affected. However, cells in the alveolar space, including the pulmonary epithelium and resident macrophages, express the APAP-metabolizing enzyme CYP2E1 and are a potential source of toxic metabolites and subsequent distal lung injury. Thus, we hypothesized that distal lung injury would occur in a murine model of toxic APAP exposure. Following exposure of APAP (280 mg/kg, IP), adult male mice were found to have significant proximal lung histopathology as well as distal lung inflammation and emphysematous changes. Toxic APAP exposure was associated with increased CYP2E1 expression in the distal lung and accumulation of APAP-protein adducts. This injury was associated with distal lung activation of oxidant stress, endoplasmic reticulum stress, and inflammatory stress response pathways. Our findings confirm that following toxic APAP exposure, distal lung CYP2E1 expression is associated with APAP metabolism, tissue injury, and oxidant, inflammatory, and endoplasmic reticulum signaling. This previously unrecognized injury may help improve our understanding of the relationship between APAP and pulmonary-related morbidity.

Drug-induced interstitial lung disease: role of pharmacogenetics in predicting cytotoxic mechanisms and risks of side effects

PURPOSE OF REVIEW

The diagnosis of drug-induced interstitial lung disease (DI-ILD) is challenging and mainly made by exclusion of other possible causes. Toxicity can occur as a cause of drug(s) or drug-drug interactions. In this review, we summarize the possible role of pharmacogenetics of metabolizing enzymes in DI-ILD.

RECENT FINDINGS

Knowledge of the genetic predispositions of enzymes involved in drug metabolization and their relation with proposed cytotoxic mechanisms of DI-ILD, in particular direct cell toxicity and free oxygen radical production is increasing. The cytochrome P450 enzyme family and other enzymes play an important role in the metabolism of all sorts of ingested, injected, or inhaled xenobiotic substances. The liver is the major site for metabolism. Metabolic cytotoxic mechanisms have however also been detected in lung tissue. Polymorphisms in genes coding for enzymes that influence metabolic activity may lead to localized (toxic) reactions and tissue damage. This knowledge may be helpful in preventing the risk of DI-ILD.

SUMMARY

Drug toxicity can be the consequence of absence or very poor enzyme activity, especially if no other metabolic route is available. In the case of reduced enzyme activity, it is recommended to reduce the dose or to prescribe an alternative drug, which is metabolized by a different, unaffected enzyme system to prevent toxic side effects. However, enhanced enzyme activity may lead to excessive formation of toxic and sometimes reactive metabolites. Therefore, knowing a patient's drug-metabolizing profile before drug prescription is a promising way to prevent or explain DI-ILD.

Hepatic encephalopathy: Lessons from preclinical studies

Hepatic encephalopathy (HE) is a major complication that is closely related to the progression of end-stage liver disease. Metabolic changes in advanced liver failure can promote cognition impairment, attention deficits and motor dysfunction that may result in coma and death. HE can be subdivided according to the type of hepatic injury, namely, type A, which results from acute liver failure, type B, which is associated with a portosystemic shunting without intrinsic liver disease, and type C, which is due to chronic liver disease. Several studies have investigated the pathogenesis of the disease, and most of the mechanisms have been explored using animal models. This article aimed to review the use of preclinical models to investigate HE. The most used animal species are rats and mice. Experimental models of type A HE include surgical procedures and the administration of hepatotoxic medications, whereas models of types B and C HE are generally surgically induced lesions in liver tissue, which evolve to hepatic cirrhosis. Preclinical models have allowed the comprehension of the pathways related to HE.

Hepatocyte-secreted extracellular vesicles modify blood metabolome and endothelial function by an arginase-dependent mechanism

Hepatocytes release extracellular vesicles (EVs) loaded with signaling molecules and enzymes into the bloodstream. Although the importance of EVs in the intercellular communication is already recognized, the metabolic impact of the enzymes carried by these vesicles is still unclear. We evaluated the global effect of the enzymatic activities of EVs by performing untargeted metabolomic profiling of serum samples after their exposure to EVs. This approach revealed a significant change in the abundance of 94 serum metabolic signals. Our study shows that these vesicles modify the concentration of metabolites of different chemical nature including metabolites related to arginine metabolism, which regulates vascular function. To assess the functional relevance of this finding, we examined the levels of arginase-1 protein and its activity in the hepatic EVs carrying the exosomal markers CD81 and CD63. Remarkably, the arginase activity was also detected in EVs isolated from the serum in vivo, and this vesicular activity significantly increased under liver-damaging conditions. Finally, we demonstrated that EVs secreted by hepatocytes inhibited the acetylcholine-induced relaxation in isolated pulmonary arteries, via an arginase-dependent mechanism. In summary, our study demonstrates that the hepatocyte-released EVs are metabolically active, affecting a number of serum metabolites involved in oxidative stress metabolism and the endothelial function.

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.

Proteomics-based analysis of lung injury-induced proteins in a mouse model of common bile duct ligation

BACKGROUND

Lung injury is a life-threatening complication in patients with liver dysfunction. We recently provided an experimental lung injury model in mouse with common bile duct ligation. In this study, we aimed to characterize the pathologic and biochemical features of lung tissues in common bile duct ligation mice using a proteomic approach.

METHODS

Common bile ducts of BALB/c mice, 8 weeks of age, were ligated operatively. CD31-expressing pulmonary cells were sorted with immunomagnetic microbeads, and protein profiles were examined by 2-dimensional gel electrophoresis. Based on the results of protein identification, immunohistochemistry and quantitative reverse transcription polymerase chain reaction were carried out in pulmonary and hepatic tissues.

RESULTS

Two-dimensional gel electrophoresis revealed 3 major inflammation-associated proteins exhibiting considerable increases in the number of CD31-positive pulmonary cells after common bile duct ligation. Mass spectrometry analysis identified these proteins as SerpinB1a (48 kDa), ANXA1 (46 kDa), and S100A9 (16 kDa). Furthermore, the 3 proteins were more highly expressed in dilated pulmonary blood vessels of common bile duct ligation mice, in which neutrophils and monocytes were prominent, as shown by immunohistochemistry. More importantly, SerpinB1a mRNA and protein were significantly upregulated in the liver, whereas S100A9 and ANXA1 mRNA and protein were upregulated in the lungs, as shown by quantitative reverse transcription polymerase chain reaction and Western blotting.

CONCLUSION

We identified 3 proteins that were highly expressed in the lung after common bile duct ligation using a proteomics-based approach.

Emerging strategies for the treatment of patients with acute hepatic failure

PURPOSE OF REVIEW

The objective of this article is to review the latest developments related to the treatment of patients with acute liver failure (ALF).

RECENT FINDINGS

As the treatment of ALF has evolved, there is an increasing recognition regarding the risk of intracranial hypertension related to advanced hepatic encephalopathy. Therefore, there is an enhanced emphasis on neuromonitoring and therapies targeting intracranial hypertension. Also, new evidence implicates systemic proinflammatory cytokines as an etiology for the development of multiorgan system dysfunction in ALF; the recent finding of a survival benefit in ALF with high-volume plasmapheresis further supports this theory.

SUMMARY

Advances in the critical care management of ALF have translated to a substantial decrease in mortality related to this disease process. The extrapolation of therapies from general neurocritical care to the treatment of ALF-induced intracranial hypertension has resulted in improved neurologic outcomes. In addition, recognition of the systemic inflammatory response and multiorgan dysfunction in ALF has guided current treatment recommendations, and will provide avenues for future research endeavors. With respect to extracorporeal liver support systems, further randomized studies are required to assess their efficacy in ALF, with attention to nonsurvival end points such as bridging to liver transplantation.

The association between paracetamol and asthma is still under debate

OBJECTIVE

To analyse the relationship between paracetamol and asthma.

DATA SOURCES

An English literature search using electronic search engines (PubMed and EMBASE) was conducted.

STUDY SELECTIONS

Articles published in peer-review journals, from 1990 to December 2015 were included. To perform the search for the most suitable and representative articles, keywords were selected ("asthma," "paracetamol" and "acetaminophen"). The evidence level was rated according to the criteria of the Oxford Centre For Evidence-Based Medicine.

RESULTS

The exposure to paracetamol during pregnancy was analysed in several cohort studies, showing an association between the prenatal exposure to paracetamol with suffering from asthma or presence of wheezing in childhood, especially for persistent wheezing. Nevertheless, a recent study concluded that the relationship between asthma and paracetamol is explained, at least in part, by confounding factors. Several works have also associated the exposure to paracetamol in the first years of life or in adults with the development of childhood asthma. Several pathophysiological mechanisms are known that could explain this relationship, such as the glutathione pathway, the decrease in the release of Th1 cytokines that are normally produced during febrile episodes, which would then lead to a predominance of Th2 cytokines, the cytotoxic effect of paracetamol for pneumocytes, a modulator effect on the activity of myeloperoxidase, as well as the possible antigenic effect of paracetamol, mediated by IgE.

CONCLUSIONS

There are many arguments that suggest a relationship between the use of paracetamol with the appearance of asthmatic symptoms, however the evidence is inconclusive.

Acute Liver Failure Induced by Thioacetamide: Selection of Optimal Dosage in Wistar and Lewis Rats

Acute liver failure (ALF) is a clinical condition with very high mortality rate. Its pathophysiological background is still poorly understood, which necessitates a search for optimal experimental ALF models with features resembling those of the human disorder. Taking into consideration reproducibility of induction of ALF, adequate animal size, cost of animals, the required time gap between insult and death of animals (“therapeutic window”), potential risk to investigator and other aspects, administration of thioacetamide (TAA) in rats is currently most recommended. However, the fundamental details of this ALF model have not yet been evaluated. This prompted us to investigate, first, the course of ALF as induced by intraperitoneal TAA at doses increasing from 175 to 700 mg/kg BW per day. The animals’ survival rate, plasma alanine and aspartate aminotransferase activities, and bilirubin and ammonia levels were determined over the follow-up period. Second, we examined whether Wistar and Lewis rats exhibit any differences in the course of ALF induced by different TAA doses. We found that the optimal dose for ALF induction in rats is 350 mg.kg-1 i.p., given as a single injection. Wistar rats proved more susceptible to the development of TAA-induced ALF compared with Lewis rats. Collectively, our present findings provide a sound methodological background for experimental studies aimed at evaluation of pathophysiology and development of new approaches in the therapy of ALF.

Lung injury and its prognostic significance in acute liver failure

OBJECTIVE

Hypoxemia is a feared complication of acute liver failure, and high oxygen requirements will frequently lead to removal of patients from the transplant list. As data regarding the prevalence and outcome of acute respiratory distress syndrome in acute liver failure are scant and hypoxemia being a commonly encountered systemic complication, we analyzed radiological, gas exchange, and ventilator data in consecutive patients admitted with acute liver failure.

PATIENTS

Acute liver failure patients receiving mechanical ventilation admitted between January 2007 and February 2011 were included.

INTERVENTIONS

Patients were categorized according to the Berlin definition as: no acute respiratory distress syndrome, acute respiratory distress syndrome (PaO2/FIO2 < 300 mm Hg), and subdivisions of mild, moderate, and severe acute respiratory distress syndrome (200-300 mm Hg, 100-200 mm Hg, and < 100 mm Hg, respectively). Chest radiographs were independently assessed by two observers for the presence or absence of acute respiratory distress syndrome. Absence of left atrial pressure elevation was based on combined hemodynamic and echocardiographic assessment.

MEASUREMENTS AND MAIN RESULTS

Two hundred acute liver failure patients were admitted during the study period of whom 148, median age 39 years (16-74 yr), were included. Thirty-one (21%) had acute respiratory distress syndrome (17 mild acute respiratory distress syndrome [12%], 9 moderate acute respiratory distress syndrome [12%], and 5 severe acute respiratory distress syndrome) within the first 72 hours following admission. Acute respiratory distress syndrome patients required higher positive end-expiratory pressure (7 vs 6 vs 10 vs 15 cm H2O for no, mild, moderate, or severe acute respiratory distress syndrome, p = 0.014), had reduced respiratory system compliance (34 vs 29 vs 30 vs 23 L/cm H2O, p = 0.028), and an increased number of ventilator days (no acute respiratory distress syndrome, 10 d; mild acute respiratory distress syndrome acute lung injury, 12 d; moderate acute respiratory distress syndrome, 23 d; severe acute respiratory distress syndrome, 22 d; p = 0.097). Duration of liver intensive therapy unit stay (p = 0.175), survival (p = 0.877), inotrope requirements (p = 0.495), need for extracorporeal renal support (p = 0.565), and severity of organ failure scores were not affected. Extravascular lung water index had a moderate sensitivity of 65% and specificity of 77% for the prediction of acute respiratory distress syndrome.

CONCLUSION

The prevalence of lung injury is relatively low in acute liver failure, where 21% fulfilled acute respiratory distress syndrome criteria. Overall presence of acute respiratory distress syndrome appeared to have a limited impact on outcome.

Fulminant viral hepatitis

Acute liver failure (ALF) is a condition wherein the previously healthy liver rapidly deteriorates, resulting in jaundice, encephalopathy, and coagulopathy. There are approximately 2000 cases per year of ALF in the United States. Viral causes (fulminant viral hepatitis [FVH]) are the predominant cause of ALF in developing countries. Given the ease of spread of viral hepatitis and the high morbidity and mortality associated with ALF, a systematic approach to the diagnosis and treatment of FVH is required. In this review, the authors describe the viral causes of ALF and review the intensive care unit management of patients with FVH.

A reproducible, clinically relevant, intensively managed, pig model of acute liver failure for testing of therapies aimed to prolong survival

BACKGROUND

A clinically relevant, translational large animal model of acute liver failure (ALF) is required for testing of novel therapies to prolong survival in acute liver failure, to permit spontaneous liver recovery or to act as a bridge to transplantation.

AIMS

The aim was to establish a pig model of acetaminophen-induced ALF that mimics the human clinical syndrome, is managed as in a human intensive care unit and has a predictable survival time.

METHODS

Nine female pigs were anaesthetised and instrumented for continuous intensive care monitoring and management using: target-driven protocols for treatment of cardiovascular collapse, metabolic acidosis and electrolyte abnormalities; intermittent positive pressure ventilation; and continuous renal replacement therapy. Six animals were induced to ALF with acetaminophen (paracetamol). Three animals acted as controls.

RESULTS

Irreversible acute liver failure, defined as rise in prothrombin time >3 times normal, occurred 19.3 ± 1.8 h after the onset of acetaminophen administration. Death occurred predictably 12.6 ± 2.7 h thereafter, with acute hepatocellular necrosis in all animals. Clinical progression of liver failure mimicked the human condition including development of coagulopathy, intracranial hypertension, hyperammonaemia, cardiovascular collapse, elevation in creatinine, metabolic acidosis and hyperlactataemia. In addition, cardiovascular monitoring clearly demonstrated progressive cardiac dysfunction in ALF.

CONCLUSIONS

A reproducible, clinically relevant, intensively managed, large animal model of acute liver failure, with death as a result of multi-organ failure, has been successfully validated for translational studies of disease progression and therapies designed to prolong survival in man.

Prescription-acquired acetaminophen use and the risk of asthma in adults: a case-control study

BACKGROUND

Studies have examined the association between acetaminophen use and asthma; however, their interpretation is limited by several methodologic issues.

OBJECTIVE

To investigate the association between recent and chronic prescription-acquired acetaminophen use and asthma.

METHODS

This retrospective case-control study used a 10% random sample of the IMS LifeLink commercial claims data from 1997 to 2009. Cases had to have at least 1 incident claim of asthma; 3:1 controls matched on age, sex, and region were randomly chosen. Acetaminophen exposure, dose, and duration were measured in the 7- and 30-day (recent) and the 1-year (chronic) look-back periods. Multivariable conditional logistic regression was used to estimate the risk of asthma associated with acetaminophen use adjusted for comorbidities, other drugs increasing asthma risk, and health system factors.

RESULTS

There were 28,892 cases and 86,676 controls, with mean age of 42.8 years; 37.7% were males, and 22.6% of cases and 18.2% of controls had acetaminophen exposure in the pre-index year, with mean cumulative doses of 78.7 g and 59.8 g, respectively. There was no significant association between recent prescription acetaminophen exposure and asthma (7 days: OR 1.02, p = 0.74; 30 days: OR 0.97, p = 0.38). Cumulative prescription acetaminophen dose in the year prior increased asthma risk compared to acetaminophen nonusers (≤1 kg: OR 1.09, p < 0.001 and >1 kg: OR = 1.60, p = 0.02). Duration of prescription acetaminophen use greater than 30 days was associated with elevated asthma risk (OR 1.39, p < 0.001).

CONCLUSIONS

Chronic prescription-acquired acetaminophen use was associated with an increased risk of asthma, while recent use was not. However, over-the-counter acetaminophen use was not captured in this study and further epidemiologic research with complete acetaminophen exposure ascertainment and research on pathophysiologic mechanisms is needed to confirm these relationships.

Diffuse alveolar damage of the lungs in forensic autopsies: assessment of histopathological stages and causes of death

Introduction. Diffuse alveolar damage (DAD) is a morphological prototype of acute interstitial pneumonia. Hospital autopsies or open-lung biopsies are used to monitor common alveolar damage and hyaline membrane (HM) development histopathologically. The aim of this study was to detect histopathological profiles and frequency of DAD and HM in adult forensic autopsies. Materials and Methods. In total, 6813 reports with histopathological samples in 12,504 cases on which an autopsy was performed between 2006 and 2008 were investigated. Sixty-six individuals >18 years of age who were diagnosed with DAD were included. Hematoxylin- and eosin-stained lung preparations were reexamined in line with the 2002 American Thoracic Society/European Respiratory Society idiopathic interstitial pneumonia consensus criteria. Results. Histopathological examination revealed that 50 cases (75.7%) were in the exudative phase and 16 (24.2%) were in the proliferative phase. Only the rate of alveolar exudate/oedema in exudative phase cases (P = 0.003); those of alveolar histiocytic desquamation (P = 0.037), alveolar fibrosis (P = 0.017), chronic inflammation (P = 0.02), and alveolar fibrin (P = 0.001) in proliferative cases were significantly higher. The presence of alveolar fibrin was the only independent variable in favour of proliferative cases (P = 0.016). Conclusion. The detection of all DAD morphological criteria with the same intensity is not always possible in each case. Forensic autopsies may provide a favourable means for expanding our knowledge about acute lung damage, DAD, and interstitial lung disease.

Exposure to paracetamol and asthma symptoms

BACKGROUND

Paracetamol is one of the factors that have been associated with the observed increase in asthma prevalence in the last few years. The influence of environmental or genetic factors in this disease may be different in some countries than in others. The purpose of this study was to analyse the relationship between the paracetamol consumption and asthma prevalence in our community.

METHODS

A cross-sectional study was conducted on more than 20,000 children and adolescents in Galicia, Spain. The International Study of Asthma and Allergies in Childhood methodology was used to collect the information on asthma symptoms in children, paracetamol consumption, body mass index (BMI), pets in the home, education level of the mother and parental asthma and smoking habits. The influence of paracetamol consumption on the prevalence of asthma symptoms was calculated using logistic regression, adjusted for the other parameters included in the study.

RESULTS

After adjusting for gender, BMI, having a cat or dog, maternal education, parental asthma and smoking, in 6- to 7-year-old children, the consumption of paracetamol during the first year of life is associated with asthma [odds ratio (OR) 2.04 (1.79-2.31) for wheezing at some time]. Paracetamol consumption in the previous year leads to a significant increase in the probability of wheezing at some time [OR 3.32 (2.51-4.41)] in young children and adolescents [OR 2.12 (1.68-2.67)].

CONCLUSIONS

Paracetamol consumption is associated with a significant increase in asthma symptoms. The effect is greater the more often the drug is taken.

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.

Acute liver failure

ALF is a multisystem disorder necessitating both predictive and reactive management strategies to support and protect organs from the initial and subsequent insults encountered. Early referral to a specialist liver centre with the option of liver transplantation is recommended. Furthermore, a good understanding of the poor prognostic variables is necessary to determine those most at risk of developing ALF in order to facilitate timely, safe transfer and listing for liver transplantation.

Critical care management of patients before liver transplantation

The critical care management of patients before liver transplantation is aimed at optimizing hepatic and extrahepatic organ function before the transplant operation, with a goal to favorably influence perioperative and postoperative graft and patient outcomes. Critical illness in liver disease can present in the context of acute liver failure or acute on chronic liver failure. The differing pathophysiologic processes underlying these 2 types of liver failure necessitate specific approaches to their intensive care management. In their extreme presentations, both types of liver failure present as multiorgan system failure; and therefore, the critical care management of these entities requires a systematic multiorgan system approach to address hepatic and extrahepatic organ dysfunction. This review provides a multiorgan system-based description of critical care management of acute liver failure and acute on chronic liver failure before liver transplantation.

Development of an invasively monitored porcine model of acetaminophen-induced acute liver failure

BACKGROUND

The development of effective therapies for acute liver failure (ALF) is limited by our knowledge of the pathophysiology of this condition, and the lack of suitable large animal models of acetaminophen toxicity. Our aim was to develop a reproducible invasively-monitored porcine model of acetaminophen-induced ALF.

METHOD

35kg pigs were maintained under general anaesthesia and invasively monitored. Control pigs received a saline infusion, whereas ALF pigs received acetaminophen intravenously for 12 hours to maintain blood concentrations between 200-300 mg/l. Animals surviving 28 hours were euthanased.

RESULTS

Cytochrome p450 levels in phenobarbital pre-treated animals were significantly higher than non pre-treated animals (300 vs 100 pmol/mg protein). Control pigs (n = 4) survived 28-hour anaesthesia without incident. Of nine pigs that received acetaminophen, four survived 20 hours and two survived 28 hours. Injured animals developed hypotension (mean arterial pressure; 40.8 +/- 5.9 vs 59 +/- 2.0 mmHg), increased cardiac output (7.26 +/- 1.86 vs 3.30 +/- 0.40 l/min) and decreased systemic vascular resistance (8.48 +/- 2.75 vs 16.2 +/- 1.76 mPa/s/m3). Dyspnoea developed as liver injury progressed and the increased pulmonary vascular resistance (636 +/- 95 vs 301 +/- 26.9 mPa/s/m3) observed may reflect the development of respiratory distress syndrome.Liver damage was confirmed by deterioration in pH (7.23 +/- 0.05 vs 7.45 +/- 0.02) and prothrombin time (36 +/- 2 vs 8.9 +/- 0.3 seconds) compared with controls. Factor V and VII levels were reduced to 9.3 and 15.5% of starting values in injured animals. A marked increase in serum AST (471.5 +/- 210 vs 42 +/- 8.14) coincided with a marked reduction in serum albumin (11.5 +/- 1.71 vs 25 +/- 1 g/dL) in injured animals. Animals displayed evidence of renal impairment; mean creatinine levels 280.2 +/- 36.5 vs 131.6 +/- 9.33 mumol/l. Liver histology revealed evidence of severe centrilobular necrosis with coagulative necrosis. Marked renal tubular necrosis was also seen. Methaemoglobin levels did not rise >5%. Intracranial hypertension was not seen (ICP monitoring), but there was biochemical evidence of encephalopathy by the reduction of Fischer's ratio from 5.6 +/- 1.1 to 0.45 +/- 0.06.

CONCLUSION

We have developed a reproducible large animal model of acetaminophen-induced liver failure, which allows in-depth investigation of the pathophysiological basis of this condition. Furthermore, this represents an important large animal model for testing artificial liver support systems.

Review article: the current management of acute liver failure

BACKGROUND

Acute liver failure is a devastating clinical syndrome with a persistently high mortality rate despite critical care advances. Orthotopic liver transplantation (OLT) is a life-saving treatment in selected cases, but effective use of this limited resource requires accurate prognostication because of surgical risks and the requirement for subsequent life-long immunosuppression.

AIM

To review the aetiology of acute liver failure, discuss the evidence behind critical care management strategies and examine potential treatment alternatives to OLT.

METHODS

Literature review using Ovid, PubMed and recent conference abstracts.

RESULTS

Paracetamol remains the most common aetiology of acute liver failure in developed countries, whereas acute viral aetiologies predominate elsewhere. Cerebral oedema is a major cause of death, and its prevention and prompt recognition are vital components of critical care support, which strives to provide multiorgan support and 'buy time' to permit either organ regeneration or psychological and physical assessment prior to acquisition of a donor organ. Artificial liver support systems do not improve mortality in acute liver failure, whilst most other interventions have limited evidence bases to support their use.

CONCLUSION

Acute liver failure remains a truly challenging condition to manage, and requires early recognition and transfer of patients to specialist centres providing intensive, multidisciplinary input and, in some cases, OLT.

Management of acute liver failure

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

Effect of gamma irradiation on the efficacy of beta-glucan against acetaminophen induced toxicity in mice

The present study was conducted to compare the efficacy of unirradiated beta-glucan (UBG) and gamma irradiated beta-glucan (GIBG) against acetaminophen (APAP) induced hepatotoxicity in mice. Mice of BALB/c strain were pretreated with UBG and GIBG (50mg/kg, p.o.) for 7 days and on the 8th day they received an overdose of APAP (500 mg/kg, i.p.). Eight hours after the APAP injection, the levels of serum aminotransferase (AST) and alanine aminotransferase (ALT) were measured and liver, kidney and lung tissue were examined for morphological changes. A significant elevation (p<0.001) of the levels of AST and ALT was observed in mice toxicated with APAP. Histology data revealed severe liver centrilobular necrosis, portal vein damage with apparent toxicity in renal glomerulus and lung inflammation associated with edema. However, a significant inhibition (p<0.05) in the elevation of AST and ALT was observed in mice that received UBG and GIBG compared with APAP-treated mice. Histology examination revealed the non-statistical difference between the protective effects of GIBG and UBG against acetaminophen challenge. In conclusion, it was demonstrated that gamma irradiation induced no severe alteration in the protective activity of beta-glucan against APAP-induced hepatotoxicity.

Intensive care management of acute liver failure

PURPOSE OF REVIEW

The mortality of acute liver failure remains unacceptably high and liver transplantation is the only effective treatment available to date. This review focuses on new research developments in the field and aims to provide a pragmatic organ-based treatment approach for liver failure patients requiring intensive care support.

RECENT FINDINGS

The pathophysiological basis for cerebral edema formation in acute liver failure continued to be the focus of various investigations. In-vivo observations confirmed the link between ammonia, cerebral glutamine content and intracranial hypertension. The role of arterial ammonia as an important prognostic indicator formed the basis of prospective, observational studies. Reduced monocytic HLA-DR expression linked acute liver failure with poor prognosis, and the cerebral effects and side effects of vasoactive therapy with terlipressin were investigated with two studies showing contradictory results.

SUMMARY

Despite increased knowledge of the pathophysiological events leading to organ dysfunction in acute liver failure, supportive treatment options remain limited in their efficacy and largely noncurative.

Acetaminophen decreases intracellular glutathione levels and modulates cytokine production in human alveolar macrophages and type II pneumocytes in vitro

Recent epidemiological observations suggest that acetaminophen (paracetamol) may contribute to asthma morbidity. Impaired endogenous antioxidant defences may have a role in the pathogenesis of a number of inflammatory pulmonary diseases, including asthma. We studied the effect of acetaminophen on the intracellular level of reduced glutathione (GSH) with and without inhibitors of cytochrome P450 or prostaglandin H synthetase, and TNF-alpha, IL-6 and IL-8 protein production in human alveolar macrophages and type II pneumocytes in vitro. Following a 20 h incubation with acetaminophen, cytotoxicity was apparent from > or = 5 and > or = 10 mM in macrophages and type II pneumocytes, respectively. A time- and concentration-dependent decrease of intracellular GSH occurred after acetaminophen (0.05-1 mM) exposure (1-4 h) in pulmonary macrophages (up to 53%) and type II pneumocytes (up to 34%). Diethyldithiocarbamic acid, potassium ethyl xanthate, and indomethacin decreased significantly acetaminophen-induced GSH depletion in the two cell types tested, suggesting the involvement of cytochrome P450 (mainly CYP2E1) and/or prostaglandin H synthetase. In macrophages, acetaminophen decreased the secretion of TNF-alpha (at 4 and 24 h, concentration-related) and IL-6 (at 24 h, at 0.1 mM), and did not affect significantly IL-8 production. These in vitro observations demonstrate that clinically relevant concentrations of acetaminophen decreased: (i) intracellular GSH in human pulmonary macrophages and type II pneumocytes and (ii) the secretion of TNF-alpha and possibly IL-6 by human pulmonary macrophages. These findings provide experimental plausibility to the challenging observations that frequent use of APAP may be a risk factor for asthma morbidity.

Acetaminophen and the risk of asthma: the epidemiologic and pathophysiologic evidence

The prevalence of asthma has increased worldwide. The reasons for this rise remain unclear. Various studies have reported an association between acetaminophen, a widely used analgesic, and diagnosed asthma. In a prospective cohort study, the rate of newly diagnosed asthma was 63% higher among frequent acetaminophen users than nonusers in multivariate analyses. Studies of patients with asthma suggest that acetaminophen challenge can precipitate a decline in FEV(1) > 15% among sensitive individuals. Plausible mechanisms to explain this association include depletion of pulmonary glutathione and oxidative stress. This article reviews the existing literature and evaluates the epidemiologic and pathophysiologic evidence underlying a possible link between acetaminophen and asthma.

Serum bilirubin levels and mortality after myeloablative allogeneic hematopoietic cell transplantation

Many patients who undergo hematopoietic cell transplantation experience liver injury. We examined the association of serum bilirubin levels with nonrelapse mortality by day +200, testing the hypothesis that the duration of jaundice up to a given point in time provides more prognostic information than either the maximum bilirubin value or the value at that point in time. We studied 1,419 consecutive patients transplanted from allogeneic donors. Total serum bilirubin values up to day +100, death, or relapse were retrieved-along with nonrelapse mortality by day +200 as an outcome measure--using Cox regression models with each bilirubin measure modeled as a time-dependent covariate. The bilirubin value at a particular point in time provided the best fit to the model for mortality. With bilirubin at a point in time modeled as an 8th-degree polynomial, an increase in bilirubin from 1 to 3 mg/dL is associated with a mortality hazard ratio of 6.42. An increase from 4 to 6 mg/dL yields a hazard ratio of 2.05, and an increase from 10 to 12 mg/dL yields a hazard ratio of 1.17. Among patients who were deeply jaundiced, survival was related to the absence of multiorgan failure and to higher platelet counts. In conclusion, the value of total serum bilirubin at a particular point in time after transplant carries more informative prognostic information than does the maximum or average value up to that point in time. The increase in mortality for a given increase in bilirubin value is larger when the starting value is lower.

Multiple organ engraftment by bone-marrow-derived myofibroblasts and fibroblasts in bone-marrow-transplanted mice

Myofibroblasts are ubiquitous cells with features of both fibroblasts and smooth muscle cells. We suggest that the bone marrow can contribute to myofibroblast populations in a variety of tissues and that this is exacerbated by injury. To assess this, female mice were transplanted with male bone marrow and the male cells were tracked throughout the body and identified as myofibroblasts. Skin wounding and paracetamol administration were used to assess whether myofibroblast engraftment was modulated by damage. Following radiation injury, a proportion of myofibroblasts in the lung, stomach, esophagus, skin, kidney, and adrenal capsule were bone-marrow derived. In the lung, there was significantly greater engraftment following paracetamol administration (17% versus 41% p < 0.005). Bone-marrow-derived fibroblasts were also found. We suggest that bone marrow contributes to a circulating population of cells and, in the context of injury, these cells are recruited and contribute to tissue repair.

Prospective study of acetaminophen use and newly diagnosed asthma among women

Acetaminophen decreases glutathione levels in the lung, which may predispose to oxidative injury and bronchospasm. Acetaminophen use has been associated with asthma in cross-sectional studies and a birth cohort. We hypothesized that acetaminophen use would be associated with newly diagnosed adult-onset asthma in the Nurses' Health Study, a prospective cohort study of 121,700 women. Participants were first asked about frequency of acetaminophen use in 1990. Cases with asthma were defined as those with a new physician diagnosis of asthma between 1990 and 1996 plus reiteration of the diagnosis and controller medication use. Proportional hazard models included age, race, socioeconomic status, body mass index, smoking, other analgesic use, and postmenopausal hormone use. During 352,719 person-years of follow-up, 346 participants reported a new physician diagnosis of asthma meeting diagnostic criteria. Increasing frequency of acetaminophen use was positively associated with newly diagnosed asthma (p for trend = 0.006). The multivariate rate ratio for asthma for participants who received acetaminophen for more than 14 days per month was 1.63 (95% confidence interval, 1.11-2.39) compared with nonusers. It would be premature to recommend acetaminophen avoidance for patients with asthma, but further research on pulmonary responses to acetaminophen is necessary to confirm or refute these findings and to identify subgroups whose asthma may be modified by acetaminophen.

Alterations in cytokine/chemokine expression during organ-to-organ communication established via acetaminophen-induced toxicity

A variety of studies have demonstrated that organ-to-organ communication circuits are established during various disease states. For example, an activated liver may release high levels of cytokines, which are carried to the lung and activate this organ. In the present study, we have examined the inflammation occurring as the liver-lung interact during the initiation of acetaminophen-induced toxicity. An overnight fast followed by an intraperitoneal acetaminophen challenge was required to elicit liver injury. In these animals, lung injury was most pronounced at 24 h post-challenge and was characterized by necrosis, edema and inflammation. Interestingly, the non-fasted/fed animals that received acetaminophen had only minor liver injury, but still presented with significant pathologic changes of the lung. BAL fluid contained increased neutrophils after acetaminophen challenge in the fasted (26%) and the fed (35%) animal groups. A significant vascular leak was found in the fasted, but not the fed, acetaminophen challenged animals. However, lung levels of the chemokine, eotaxin, and the cytokine, IL-12, were significantly elevated in the acetaminophen challenged animals that were fed, but not in the fasted group. The immunoneutralization of eotaxin, but not IL-12 or TNF-alpha, improved the histological appearance of the lung in fed mice challenged with acetaminophen.

Alterations in bronchoalveolar lavage fluid during ischemia-induced acute hepatic failure in the pig

The objective of this controlled experimental animal study was to evaluate whether acute hepatic failure (AHF) can cause acute lung injury (ALI) and to investigate possible pathophysiologic mechanisms. Seventeen domestic pigs were randomly assigned to AHF and sham groups. AHF was induced by surgical devascularization of liver in 10 animals. Seven animals were sham operated. Hemodynamics, lung mechanics, extravascular lung water (EVLW), and intracranial pressure, blood gas, liver function tests, and serum endotoxin levels were measured. Cells count, total protein, and phospholipids and phospholipases A(2) were determined in the bronchoalveolar lavage (BAL) fluid. Measurements were obtained after the insertion of central lines and 4 hours and 7 hours after the completion of the surgical procedure. Hemodynamic, biochemical, neuromonitoring, and histologic data confirmed the development of liver failure. Seven hours after devascularization, EVLW was higher in AHF (13.7 +/- 1.8 mL/kg) compared with the sham group (5.9 +/- 0.7 mL/kg) (P <.05); in AHF, increase of neutrophils (5% +/- 8% to 25% +/- 8%, P <.001), total protein (6.2 +/- 3.7 to 11.2 +/- 6.5 microg/mL, P <.048), and phospholipase A(2) (1.43 +/- 0.56 to 2.38 +/- 1.38 nmoL/mL/h, P <.03) and decrease in PAF-acetylhydrolase (0.114 +/- 0.128 to 0.039 +/- 0.038 nmol/mL/h, P <.01) compared with baseline were observed; total phospholipids decreased in AHF and increased in the sham model. Histologic examination confirmed lesions compatible with acute lung injury. In conclusion, AHF due to hepatic devascularization induced acute lung injury, confirmed by the increase of inflammatory cells in the alveoli as well as by histologic findings. The decreased PAF-AcH and the increased phospholipase A(2) may play a significant role in the perpetuation of inflammation accompanied by surfactant disorders.

Liver failure, transplantation, and critical care

The management of patients for end-stage liver disease in the ICU mandates a multidisciplinary approach and intense monitoring. Orthotopic liver transplantation still remains the only definitive therapy. Given the increasing disparity between the number of potential recipients and available cadaver organs, the current challenge is to optimize outcome with the limited resource. In recent years, considerable progress has been made in developing specific and supportive medical measures. Future research should target a better understanding of mechanisms responsible for liver cell death and liver regeneration, as well as developments in xenotransplantation, hepatocyte transplantation, and liver-directed gene therapy.

Relevance of two-stage total hepatectomy and liver transplantation in acute liver failure and severe liver trauma

Emergency liver transplantation frequently is the only life-saving procedure in cases of acute liver failure. It remains unclear whether emergency hepatectomy with portocaval shunt followed by liver transplantation as a two-stage procedure should be performed in cases in which a donor organ is not yet available. It has been stated that "toxic liver syndrome" could be treated by means of this strategy. From 1990 to 1995 we performed emergency hepatectomies in eight cases of acute liver failure or traumatic liver rupture with exsanguinating bleeding. In six cases we were able to perform a subsequent liver transplantation. Five of the six patients who underwent an emergency hepatectomy died. Emergency hepatectomy led to a significant increase in epinephrine dosage until the transplantation was performed. Only after transplantation did the need for epinephrine therapy decrease. The need for oxygen support did not change during the entire observation period. Plasmatic coagulation was stabilized by substitution, showing significantly higher values at 24 h after transplantation than at 48 h before transplantation. Fibrinogen increased significantly after transplantation in this group of patients. The experiences gathered at our clinic, however, do not show advantages that would allow a recommendation of emergency hepatectomy and subsequent liver transplantation as a two-stage procedure except for situations of severe and uncontrollable hepatic bleeding. Considering the progressive destabilization of our patients, fast procurement of donor organs seems to be of imminent importance for the outcome.