Application of intensive care medicine principles in the management of the acute liver failure patient

Acute Liver Failure

Acute liver failure, also known as fulminant hepatic failure, is a rare life-threatening disease that has a high mortality rate and affects many organ systems. Causes of acute liver failure vary-it can be attributed to drugs, viruses, and other uncommon sources. Complications of liver failure can include encephalopathy, cerebral edema, sepsis, renal failure, gastrointestinal bleeding, and respiratory failure. Fortunately, with advances in critical care medicine and emergent liver transplant, mortality rates have decreased in the past decade. This article reviews acute liver failure, its manifestations in different organ systems, and its treatment.

Thrombocytopenia Is Associated With Multi-organ System Failure in Patients With Acute Liver Failure

BACKGROUND & AIMS

Acute liver failure (ALF) is a syndrome characterized by an intense systemic inflammatory response (SIRS) and multi-organ system failure (MOSF). Platelet-derived microparticles increase in proportion to the severity of the SIRS and MOSF, and are associated with poor outcome. We investigated whether patients with ALF develop thrombocytopenia in proportion to the SIRS, MOSF, and poor outcome.

METHODS

In a retrospective study, we collected data on the post-admission platelet counts of 1598 patients included in the ALF Study Group Registry from 1998 through October 2012. We investigated correlations between platelet counts and clinical features of ALF, laboratory test results, and outcomes. Of the patients studied, 752 (47%) survived without liver transplantation, 390 (24%) received liver transplants, and 517 (32%) died.

RESULTS

In patients with SIRS, platelet counts decreased 2 to 7 days after admission, compared with patients without SIRS (P ≤ .001). Patients with abnormal levels of creatinine, phosphate, lactate, or bicarbonate had significantly lower platelet counts than patients with normal levels of these laboratory values (all P ≤ .001). The decrease in platelets during days 1 to 7 after admission was proportional to the grade of hepatic encephalopathy and requirement for vasopressor and renal replacement therapy. Although platelet numbers decreased after admission in the overall population, platelets were significantly lower 2 to 7 days after admission in patients with outcomes of death or liver transplantation than in patients who made spontaneous recoveries and survived. In contrast, international normalized ratios over time were not associated with SIRS, laboratory test results associated with poor outcomes, grade of hepatic encephalopathy, or requirement for renal replacement therapy.

CONCLUSIONS

The development of thrombocytopenia in patients with ALF is associated with the development of MOSF and poor outcome. We speculate that SIRS-induced activation of platelets, yielding microparticles, results in clearance of platelet remnants and subsequent thrombocytopenia.

Role of procoagulant microparticles in mediating complications and outcome of acute liver injury/acute liver failure

Microparticles (MPs), membrane fragments of 0.1-1.0 μm, are derived from many cell types in response to systemic inflammation. Acute liver failure (ALF) is a prototypical syndrome of systemic inflammatory response syndrome (SIRS) associated with a procoagulant state. We hypothesized that patients with ALF develop increased procoagulant MPs in proportion to the severity of systemic complications and adverse outcome. Fifty patients with acute liver injury (ALI), 78% of whom also had hepatic encephalopathy (HE; ALF), were followed until day 21 after admission. MPs were characterized by Invitrox Sizing, Antigen Detection and Enumeration, a light-scattering technology that can enumerate MPs as small as 0.15 μm, and by flow cytometry. Procoagulant activity was assessed by a functional MP-tissue factor (MP-TF) assay. Sixteen patients (32%) died and 27 (54%) recovered without liver transplantation (LT). Total MPs (0.15-1.0 μm) were present in nearly 19-fold higher concentrations in ALI/ALF patients, compared to healthy controls (P < 0.0001). MP-TF assays revealed high procoagulant activity (9.05 ± 8.82 versus 0.24 ± 0.14 pg/mL in controls; P = 0.0008). MP concentrations (0.28-0.64 μm) were higher in patients with the SIRS and high-grade HE, and MPs in the 0.36-0.64-μm size range increased in direct proportion to SIRS severity (P < 0.001) and grade of HE (P < 0.002). Day 1 MPs (0.28-0.64 μm) correlated with laboratory predictors of death/LT (higher phosphate and creatinine; lower bicarbonate), and day 1 and 3 MPs were higher in patients who died or underwent LT, compared to spontaneous survivors (P ≤ 0.01). By flow cytometry, 87% of patients had circulating CD41(+) MPs, indicating platelet origin.

CONCLUSION

Highly procoagulant MPs of specific size ranges are associated with the SIRS, systemic complications, and adverse outcome of ALI/ALF. MPs may contribute to the multiorgan system failure and high mortality of ALF.

Cerebral microdialysis reflects the neuroprotective effect of fractionated plasma separation and adsorption in acute liver failure better and earlier than intracranial pressure: a controlled study in pigs

BACKGROUND

Cerebral edema is a well-recognized and potentially fatal complication of acute liver failure (ALF). The effectiveness of treatments that address intracranial hypertension is generally assessed by measuring intracranial pressure (ICP). The aim of this study was to determine the role of cerebral microdialysis in monitoring the efficacy of fractionated plasma separation and adsorption (FPSA) treatment for ALF. We hypothesized that in ALF cerebral microdialysis reflects the benefits of FPSA treatment on cerebral edema before ICP.

METHODS

A surgical resection model of ALF was used in 21 pigs. We measured plasma ammonia concentration, brain concentrations of glucose, lactate, pyruvate, glutamate and glutamine, and ICP. Animals were randomized into three groups: in one group eight animals received 6 hours of FPSA treatment 2 hours after induction of ALF; in another group 10 animals received supportive treatment for ALF only; and in the final group three underwent sham surgery.

RESULTS

The ICP was significantly higher in the ALF group than in the FPSA group 9 hours after surgery. The lactate/pyruvate (L/P) ratio was significantly lower in the FPSA group than the ALF group 5 hours after surgery, before any significant difference in ICP was detected. Indeed, significant changes in the L/P ratio could be observed within 1 hour of treatment. Glutamine levels were significantly lower in the FPSA group than the ALF group between 6 hours and 10 hours after surgery.

CONCLUSIONS

Brain lactate/pyruvate ratio and concentration of glutamine measured by cerebral microdialysis reflected the beneficial effects of FPSA treatment on cerebral metabolism more precisely and rapidly than ICP in pigs with fulminant ALF. The role of glutamine as a marker of the efficacy of FPSA treatment for ALF appears promising, but needs further evaluation.

Cardiovascular risk profile of patients with acute liver failure after liver transplantation when compared with the general population

BACKGROUND

As opposed to most solid-organ transplant recipients, patients with acute liver failure exhibit a pretransplant health status more comparable with the general population, and any posttransplant cardiovascular risk excess should thus be more attributable to transplantation-related factors alone.

METHODS

This study compared the cardiovascular risk of 77 consecutive patients with acute liver failure at 5 years after liver transplantation with that of the general population using age, sex, and residence area-standardized prevalence ratios (SPR).

RESULTS

At least one cardiovascular risk factor developed in 92% of patients. Treated hypertension, observed in 71% of patients at 5 years, was more common among patients than controls (SPR, 2.73; 95% confidence interval [CI], 2.06-3.55), whereas the 61% prevalence of dyslipidemia and 3% prevalence of impaired fasting glucose were significantly less frequent among patients (SPR, 0.69; 95% CI, 0.51-0.92 and SPR, 0.29; 95% CI, 0.04-1.00). The 5-year prevalence of diabetes (10%), overweight (32%), and obesity (13%) deviated nonsignificantly from controls (SPR 1.90, 0.85, and 0.58). Antibody therapy associated with a 1.49-fold increase in the risk of hypertension (95% CI, 1.15-1.94) and a 6.43-fold increase in the risk of diabetes (95% CI, 1.18-34.9). Immunosuppression-type, steroids, acute rejection, retransplantation, or graft steatosis revealed nonsignificant risk alterations.

CONCLUSIONS

Liver transplantation and associated immunosuppression evidently cause hypertension, and possibly elicit diabetes in susceptible individuals. Conversely, the often reported transplantation-associated increased burden of overweight/obesity and dyslipidemia might relate mostly to other factors.

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.

7 Leverfalen

De lever vervult tal van essentiële functies in het menselijk lichaam, waaronder ontgifting van het bloed en aanmaak van diverse eiwitten en hormonen. Tevens speelt de lever een rol in het afweersysteem. Leverfalen kan omschreven worden als een situatie van onvoldoende werking van de lever bij deze processen. Dit beeld ontstaat wanneer door het verlies van functionele cellen het totale effectieve levervolume beneden een kritische grens komt. In dit hoofdstuk wordt ingegaan op diverse vormen van leverfalen en twee specifieke bij leverfalen voorkomende problemen, namelijk hepatische encefalopathie en verhoogde bloedingsneiging.