Liver Status Assessment by Spectrally and Time Resolved IR Detection of Drug Induced Breath Gas Changes

The actual metabolic capacity of the liver is crucial for disease identification, liver therapy, and liver tumor resection. By combining induced drug metabolism and high sensitivity IR spectroscopy of exhaled air, we provide a method for quantitative liver assessment at bedside within 20 to 60 min. Fast administration of C-13-labelled methacetin induces a fast response of liver metabolism and is tracked in real-time by the increase of (CO2)-C-13 in exhaled air. The (CO2)-C-13 concentration increase in exhaled air allows the determination of the metabolic liver capacity (LiMAx-test). Fluctuations in CO2 concentration, pressure and temperature are minimized by special gas handling, and tracking of several spectrally resolved CO2 absorption bands with a quantum cascade laser. Absorption measurement of different (CO2)-C-12 and (CO2)-C-13 rotation-vibration transitions in the same time window allows for multiple referencing and reduction of systematic errors. This FLIP (Fast liver investigation package) setup is being successfully used to plan operations and determine the liver status of patients.