Systemic inflammatory response syndrome and nosocomial infection in trauma

BACKGROUND: Admission systemic inflammatory response syndrome (SIRS) score has been previously reported to be an accurate predictor of infection and outcome in trauma. However, the data were limited to the first 7 days of admission. Our objective in this follow-up study was to prospectively evaluate the utility of daily SIRS scores in the second and third week of admission as compared with the first week in prediction of nosocomial infection and outcome in high-risk trauma patients. METHODS: Prospective data were collected on 1,277 consecutive trauma patients admitted during a 28-month period to the intensive care unit. SIRS scores were calculated daily for the first week and every other day for the following 2 weeks. Patients were categorized into SIRS occurring "early" (week 1), "middle" (week 2), and "late" (week 3). Centers for Disease Control and Prevention guidelines were used for the diagnosis of infection. Multivariate linear and logistic regression analyses were utilized for statistical analyses, controlling for the covariates of age, Injury Severity Score, and admission Glasgow Coma Scale score. RESULTS: The trauma cohort included patients with blunt injuries (84%) and penetrating injuries (16%). The mean age was 43 ± 21 years with an overall mortality of 14.7%. Nosocomial infection developed in 580 (45.4%) of the study patients (respiratory site most common) with a total of 1,001 infections (some patients with multiple infections). SIRS (defined as SIRS score ≥2) was common, with 92.4% of patients manifesting SIRS at admission. SIRS was most prevalent during the first week postinjury (91% of patients manifesting SIRS), decreasing to 69% and 50% during postinjury weeks 2 and 3. SIRS was more common in patients who acquired nosocomial infections compared with noninfected patients. Logistic regression analysis confirmed that patients with "middle" SIRS during week 2 (odds ratio [OR] 17.62, confidence interval [CI] 12.95-23.97, p <0.0001, receiver operating characteristic [ROC] 0.83) and "late" SIRS during week 3 (OR18.12, CI 12.71-25.84, p <0.0001, ROC 0.81) had significantly greater risk for nosocomial infection compared with patients with "early" SIRS during week 1 (OR 4.55, CI 2.57-8.06, p <0.0001, ROC 0.65) postinjury. CONCLUSION: SIRS is predictive of nosocomial infection in trauma through postinjury day 21. Nosocomial infection should be considered as a treatable cause of SIRS in trauma patients, and early diagnostic interventions should be initiated to evaluate for potential causes.