[Current aspects of diagnostics of hepatic dysfunction in critically ill]

Hepatic dysfunction may develop in critically ill patients in the course of extrahepatic diseases such as sepsis and is frequently limiting prognosis. Conventional "static" laboratory parameters assess hepatocellular damage, synthetic function or cholestasis, providing informations about (differential) diagnostic aspects, while their significance to assess rapid changes in flow and function in the critical care setting is limited. In contrast, quantitative (or "dynamic") liver function tests, such as measurement of plasma disappearance rate of indocyanine green (PDRICG) or 13C-methacetin metabolism, assess specific metabolic and/or excretory function of the liver together with sinusoidal perfusion at the time of measurement and can detect liver dysfunction early in the course of critical illness. In addition, PDRICG demonstrated prognostic significance, albeit, severity of canalicular excretory dysfunction might be underestimated. For chronic liver disease, scoring systems, such as the Child-Turcotte-Pugh-score or the MELD, were developed to assess severity of disease and probability of survival. Scoring systems are also used for graft allocation. Combining scoring systems with dynamic tests holds the potential to improve predictive value, e.g. in the transplant setting.