Critical care hepatology: definitions, incidence, prognosis and role of liver failure in critically ill patients

Organ dysfunction or overt failure is a commonplace event in the critically ill affecting up to 70% of patients during their stay in the ICU. The outcome depends on the resolution of impaired organ function, while a domino-like deterioration of organs other than the primarily affected ones paves the way for increased mortality. Acute Liver Failure was defined in the 1970s as a rare and potentially reversible severe liver injury in the absence of prior liver disease with hepatic encephalopathy occurring within 8 weeks. Dysfunction of the liver in general reflects a critical event in Multiple Organ Dysfunction Syndrome due to immunologic, regulatory and metabolic functions of liver parenchymal and non-parenchymal cells. Dysregulation of the inflammatory response, persistent microcirculatory (hypoxic) impairment or drug-induced liver injury are leading problems that result in secondary liver failure, i.e., acquired liver injury without underlying liver disease or deterioration of preexisting (chronic) liver disease (Acute-on-Chronic Liver Failure). Conventional laboratory markers, such as transaminases or bilirubin, are limited to provide insight into the complex facets of metabolic and immunologic liver dysfunction. Furthermore, inhomogeneous definitions of these entities lead to widely ranging estimates of incidence. In the present work, we review the different definitions to improve the understanding of liver dysfunction as a perpetrator (and therapeutic target) of multiple organ dysfunction syndrome in critical care.

Automated summary

Organ dysfunction or overt failure is common in critically ill patients, affecting up to 70% of patients in the ICU. Acute Liver Failure is a rare and potentially reversible severe liver injury, and dysfunction of the liver plays a critical role in Multiple Organ Dysfunction Syndrome. Conventional laboratory markers are limited in understanding liver dysfunction, and inconsistent definitions of these entities result in widely ranging estimates of incidence.