(p. 826) Hepatic function in the critically ill 

The liver with its parenchymal and non-parenchymal cells plays a key role in the organism with manifold functions of metabolism, synthesis, detoxification, excretion, and host response. This requires a portfolio of different tests to obtain an overview of hepatic function. In the critically ill hepatic dysfunction is common and potentially leading to extrahepatic organ dysfunctions culminating in multi-organ failure. Conventional laboratory measures are used to evaluate hepatocellular damage, cholestasis, or synthesis. They provide valuable (differential) diagnostic data and can yield prognostic information in chronic liver diseases, especially when used in scoring systems such as the ‘model for end-stage liver disease’. However, they have short-comings in the critically ill in assessing rapid changes in hepatic function and liver blood flow. In contrast, dynamic quantitative liver function tests measure current liver function with respect to the ability to eliminate and/or metabolize a specific substance. In addition, they are dependent on sinusoidal blood flow. Liver function tests have prognostic significance in the critically ill and may be used to guide therapy.