Fever and leukocytosis in critically ill trauma patients: it's not the urine.

BACKGROUND: Infectious complications are a major cause of morbidity and mortality in critically ill trauma patients. Therefore, fever and leukocytosis often trigger an extensive laboratory workup that includes a urine culture (UCx). The purposes of this study were to: 1) Define the current practice for obtaining UCxs in trauma patients admitted to the surgical and trauma intensive care unit (STICU); and 2) determine if there is an association between fever or leukocytosis and urinary tract infections (UTIs) during the initial 14 hospital days.
METHODS: An 18-month retrospective cohort analysis was performed on consecutive trauma patients admitted for at least two days to the STICU at a level I trauma center. Data collected included demographics, injuries, and daily maximal temperature (T(max)), leukocyte count, and UCx results for the first 14 days. Fever and leukocytosis were defined as T(max) > or =38.5 degrees C and leukocyte count > or =12,000/mm(3), respectively. Urinary tract infections were diagnosed with a positive UCx (> or =10(5) organisms/mL of urine).
RESULTS: Five hundred ten patients were evaluated for a total of 3,839 patient-days. Their mean age and Injury Severity Score were 49 +/- 1 years and 19 +/- 1 points, respectively. Seventy-two percent were men, and 91% had sustained blunt injuries. Four hundred seven UCxs were obtained; 42 patients (8%) had 60 UTIs. The cohort had an indwelling urinary catheter for 97% of the patient-days, yielding an infection density of 16 UTIs/1,000 urinary catheter-days. There was a significant association between obtaining a UCx and fever and between fever and leukocytosis (both, p < 0.001), but no association of UTI with fever, leukocytosis, or the combination of fever and leukocytosis. Analysis using temperature and leukocyte count as continuous variables identified no temperature or leukocyte range associated with UTIs. Independent risk factors for UTI calculated by logistic regression were female sex, older age, low Injury Severity Score, and no antibiotics within 24 h before the UCx was obtained.
CONCLUSIONS: The practice of obtaining a UCx from the STICU trauma patient was related to fever and fever with leukocytosis. However, neither fever nor leukocytosis nor both were associated with UTIs. These data suggest that there is an unnecessary emphasis on UTI as a source of fever and leukocytosis in injured patients during their first 14 STICU days. Our results suggest that the paradigm for evaluating UTI as a cause of fever needs to be reevaluated in critically ill trauma patients.