PURPOSE:VAP is difficult to diagnose in trauma patients due to non-infectious conditions that mimic pneumonia. Diagnosis based on clinical indices such as the clinical pulmonary infection score (CPIS) has been problematic. Quantitative bronchoalveolar lavage (BAL) cultures are superior, but require an invasive procedure. Biologic markers of neutrophil activation may improve diagnostic accuracy of VAP. s-TREM1 has been shown to correlate with community acquired pneumonia and with VAP in a medical ICU population. This study was undertaken to assess the value of s-TREM1 in the diagnosis of VAP in trauma patients.
METHODS:Nineteen critically injured, ventilated patients in whom the diagnosis of VAP was suspected underwent bronchoscopy with BAL according to a defined protocol. VAP was confirmed if the quantitative culture was ≥ 104 CFU/ml. The aspirate was analyzed qualitatively and quantitatively for the presence of s-TREM1 by an enzyme linked immunosorbant assay.
RESULTS:The average age of the patients was 46.5 ± 19.8 years. All but one sustained blunt injuries. VAP was clinically suspected 14±15 days (d) following initiation of mechanical ventilation (range 2–62d) and was confirmed based on quantitative culture in 10 patients. CPIS was 5.5 ± 1.9 for the group. s-TREM1 was qualitatively positive in 9 of 10 patients with confirmed VAP (sensitivity 90%) and was qualitatively negative in four of nine patients in whom VAP was not present (specificity 44%). In three of the five non-pneumonia patients with a positive s-TREM1, a significant alternate infection was present. By quantitative analysis s-TREM1 was 26.4 ± 21.8 pg/ml in the BAL positive pneumonia group and 5.55 ± 4.61 pg/ml in the BAL negative patients (p<0.03, 95% CI = 6.24).
CONCLUSION:This study shows that s-TREM1 may be a valuable adjunct in the diagnosis of VAP in trauma patients. When pneumonia is not confirmed, a qualitatively positive s-TREM1 may indicate significant systemic infection elsewhere.
CLINICAL IMPLICATIONS:sTREM1 is useful in trauma patients and others in whom the diagnostic certainty of VAP is limited by confounding clinical events.
DISCLOSURE:Justin Baker, No Financial Disclosure Information; No Product/Research Disclosure Information