Longitudinal Gene Expression Profiling in Adults After Traumatic Injury

Consecutive patients who meet criteria (see below) will be enrolled. Whole blood will be drawn and stored in PAXgene tubes. Blood will be drawn within 24 hours of ICU admission (ICU day 1), and then every three days subsequently (ICU days 4, 7, 10, 13) for two weeks. In addition, a tube of blood will be drawn at the time of clinical diagnosis of infection, if an infection is diagnosed (see below). Patients who are discharged from the ICU prior to two weeks will no longer be profiled. The hour and date of admission, and the hour and date of each subsequent blood draw, will be recorded.

Rates of hospital-acquired infection after severe traumatic injury run around 30-50%. The investigators will enroll 50 patients, which should net around 20 patients with infections, and 30 time-matched non-infected controls. In total, an average of 4 samples/patient, or 200 total blood samples, are expected.

Diagnosis of Infection:

The main purpose of the study is to examine gene expression response to infections. As a result, careful attention must be paid to how infections are classified. First, two systemic inflammatory reaction syndrome (SIRS) criteria are NOT necessary to be designated as infected. Second, the time of diagnosis of infection (and the time of extra blood sampling) will be the time of clinical diagnosis, not the later time that cultures turn positive. It will thus be based on clinical judgement. Finally, post-hoc criteria for infections are described elsewhere. Patients need to eventually meet these criteria to be counted as infected; this will be done in the analysis phase, not the clinical phase.