In this single-center study of 110 subjects, breath samples will be collected 6 times per day and blood samples will be collected once per day for 7 days. Subjects will be followed for an additional 3 days. Analysis results of these samples will be combined with data that is abstracted from the subjects' medical records. The investigators hypothesize that the measurement of 13C/12C delta value in the exhaled breath of adults is an early indicator of infection in subjects with systemic inflammatory response syndrome secondary to trauma.