Role of soluble triggering receptor expressed on myeloid cells-1 for diagnosing ventilator-associated pneumonia after cardiac surgery: an observational study

Alessandra K Matsuno,Ana Pcp Carlotti

doi:10.1186/1471-2261-13-107

Abstract

BackgroundThe diagnosis of ventilator-associated pneumonia (VAP) is a challenge, particularly after cardiac surgery. The use of biological markers of infection has been suggested to improve the accuracy of VAP diagnosis. We aimed to evaluate the usefulness of soluble triggering receptor expressed on myeloid cells (sTREM)-1 in the diagnosis of VAP following cardiac surgery.MethodsThis was a prospective observational cohort study of children with congenital heart disease admitted to the pediatric intensive care unit (PICU) after surgery and who remained intubated and mechanically ventilated for at least 24 hours postoperatively. VAP was defined by the 2007 Centers for Disease Control and Prevention criteria. Blood, modified bronchoalveolar lavage (mBAL) fluid and exhaled ventilator condensate (EVC) were collected daily, starting immediately after surgery until the fifth postoperative day or until extubation for measurement of sTREM-1.ResultsThirty patients were included, 16 with VAP. Demographic variables, Pediatric Risk of Mortality (PRISM) and Risk Adjustment for Congenital Heart Surgery (RACHS)-1 scores, duration of surgery and length of cardiopulmonary bypass were not significantly diferent in patients with and without VAP. However, time on mechanical ventilation and length of stay in the PICU and in the hospital were significantly longer in the VAP group. Serum and mBAL fluid sTREM-1 concentrations were similar in both groups. In the VAP group, 12 of 16 patients had sTREM-1 detected in EVC, whereas it was undetectable in all but two patients in the non-VAP group over the study period (p = 0.0013) (sensitivity 0.75, specificity 0.86, positive predictive value 0.86, negative predictive value 0.75, positive likelihood ratio (LR) 5.25, negative LR 0.29).ConclusionMeasurement of sTREM-1 in EVC may be useful for the diagnosis of VAP after cardiac surgery.

Highlights

The diagnosis of ventilator-associated pneumonia (VAP) is a challenge, after cardiac surgery
The use of biological markers of infection as the triggering receptor expressed on myeloid cells (TREM)-1 has been suggested to improve the accuracy of the diagnosis of VAP [8,9,10]
Twelve of 16 (75%) patients who developed VAP had Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) detected in exhaled ventilator condensate (EVC) on the day of VAP diagnosis and/or the preceding day, while it was detectable in only 2 of 14 (14.3%) patients in the non-VAP group over the study period (p = 0.0013) (sensitivity 0.75, 95% CI 0.480.93; specificity 0.86, 95% CI 0.57-0.98; positive predictive value 0.86, 95% CI 0.57-0.98; negative predictive value 0.75, 95% CI 0.48-0.93; positive likelihood ratio (LR) 5.25, 95% CI 3.99-6.9; negative LR 0.29, 95% CI 0.22-0.39)

Summary

Introduction

The diagnosis of ventilator-associated pneumonia (VAP) is a challenge, after cardiac surgery. In critically ill patients with severe bacterial infections early initiation of appropriate antibiotic therapy is crucial for survival, in patients with the systemic inflammatory response syndrome associated with non-infectious processes unnecessary treatment with antibiotics may lead to increased bacterial resistance and increased costs, with no treatment benefit. This highlights the importance of making an accurate diagnosis of VAP. The use of biological markers of infection as the triggering receptor expressed on myeloid cells (TREM)-1 has been suggested to improve the accuracy of the diagnosis of VAP [8,9,10]

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