Breath ammonia and ethanol increase in response to a high protein challenge.

Quantifying changes in ammonia and ethanol in blood and body fluid assays in response to food is cumbersome. We used breath analysis of ammonia, ethanol, hydrogen (an accepted standard of gut transit) and acetone to investigate gastrointestinal physiology. In 30 healthy participants, we measured each metabolite serially over 6 h in control and high protein trials. Two-way repeated measures ANOVA compared treatment (control versus intervention), change from baseline to maximum and interaction of treatment and time change. Interaction was significant for ammonia (p < 0.0001) and hydrogen (p < 0.0001). We describe the dynamic measurement of multiple metabolites in response to an oral challenge.

N-acetylcysteine treats intravenous amiodarone induced liver injury.

We report a case of intravenous (IV) amiodarone drug induced liver injury (DILI). The patient received IV N-acetylcysteine (NAC) which resulted in a rapid improvement in liver enzymes. While the specific mechanisms for the pathogenesis of IV amiodarone DILI and the therapeutic action of IV NAC are both unknown, this case strongly implies at least some commonality. Because IV amiodarone is indicated for the treatment of serious cardiac arrhythmias in an intensive care unit setting, some degree of ischemic hepatitis is likely a cofactor in most cases.

Fast and accurate exhaled breath ammonia measurement.

This exhaled breath ammonia method uses a fast and highly sensitive spectroscopic method known as quartz enhanced photoacoustic spectroscopy (QEPAS) that uses a quantum cascade based laser. The monitor is coupled to a sampler that measures mouth pressure and carbon dioxide. The system is temperature controlled and specifically designed to address the reactivity of this compound. The sampler provides immediate feedback to the subject and the technician on the quality of the breath effort. Together with the quick response time of the monitor, this system is capable of accurately measuring exhaled breath ammonia representative of deep lung systemic levels. Because the system is easy to use and produces real time results, it has enabled experiments to identify factors that influence measurements. For example, mouth rinse and oral pH reproducibly and significantly affect results and therefore must be controlled. Temperature and mode of breathing are other examples. As our understanding of these factors evolves, error is reduced, and clinical studies become more meaningful. This system is very reliable and individual measurements are inexpensive. The sampler is relatively inexpensive and quite portable, but the monitor is neither. This limits options for some clinical studies and provides rational for future innovations.