Diagnostic implications of soluble triggering receptor expressed on myeloid cells-1 in BAL fluid of patients with pulmonary infiltrates in the ICU

Objective: Prospective single-center study to determine whether the presence of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) has diagnostic utility in patients with pulmonary infiltrates receiving mechanical ventilation and undergoing BAL. Design: Prospective cohort study. Setting: Barnes-Jewish Hospital, a 1,200-bed urban teaching hospital. Patients: Adult patients with acute respiratory failure undergoing BAL for pulmonary infiltrates. Interventions: BAL fluid measurement of sTREM-1 concentration using a Quantikine Human TREM-1 Immunoassay (R&D Systems; Minneapolis, MN). Measurements and main results: A total of 105 consecutive patients receiving mechanical ventilation and undergoing BAL were enrolled. Of those, 19 patients (18.1%) met definite microbiologic criteria for bacterial or fungal ventilator-associated pneumonia (VAP). Though the mean sTREM-1 concentration was greater in patients with definite VAP (n = 19; 171.9 ± 158.7 pg/mL) than in patients with definite absence of VAP (n = 21; 96.7 ± 76.2 pg/mL), this difference was not statistically significant (p = 0.06). A cutoff value for sTREM-1 ≥ 200 pg/mL yielded a diagnostic sensitivity of 42.1% and a specificity of 75.6% for definite VAP. Patients with alveolar hemorrhage had the greatest values for sTREM-1 concentration (n = 9; 555 ± 440 pg/mL). Receiver operating curve analysis and multivariate logistic regression analysis demonstrated that measurement of sTREM-1 was inferior to clinical parameters for the diagnosis of VAP. Conclusions: Measurement of sTREM-1 in BAL fluid appears to have minimal diagnostic value for VAP.