New diagnostic and prognostic markers of ventilator-associated pneumonia

The purpose of this review is to analyze the potential advantages and drawbacks of using biomarkers of bacterial infection for the diagnosis and prognosis of ventilator-associated pneumonia.

Whereas procalcitonin and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) have both greater diagnostic accuracies than most commonly used clinical parameters and other biomarkers of infection, such as C-reactive protein, they can be increased in noninfectious conditions or remain low in patients with true infection. Furthermore, these assays cannot determine the causative organisms and associated patterns of antibiotic susceptibility.

Procalcitonin and sTREM-1 should be used only as a complementary tool, to reinforce the usual diagnostic work-up. However, serial serum procalcitonin and sTREM-1 measurements may provide an opportunity to change the treatment early in the course of patients with ventilator-associated pneumonia, either to intensify treatment when their levels stay high, or to avoid unnecessary prolonged courses of antibiotics when their levels rapidly decrease. Whether procalcitonin and/or sTREM-1 guidance can reduce antibiotic use in such a setting will require additional studies, but such a strategy appears promising.