Procalcitonin as a diagnostic marker of ventilator-associated pneumonia in cardiac surgery patients

The aim of the present study was to assess whether procalcitonin (PCT) can be used as a diagnostic marker for ventilator-associated pneumonia (VAP) in cardiac surgery patients. Between January 2012 and June 2013, a total of 92 patients were recruited and divided into non-YAP (59 patients) and YAP (33 patients) groups. The preoperative and postoperative characteristics of the patients were recorded. Serum levels of PCT, interleukin (IL)-6 and C-reactive protein (CRP) were measured using an electrochemiluminescence immunoassay. Subsequently, receiver operating characteristic curves of the PCT, IL-6 and CRP levels were constructed. In addition, associations between the sequential organ failure assessment (SOFA) scores and the serum levels of PCT, IL-6 and CRP in the YAP patients were analyzed. No statistically significant difference was observed between the non-YAP and YAP patients in the occurrence of postoperative complications. However, the SOFA scores (days 1 and 7), the duration of stay in the intensive care unit and the mechanical ventilation time were all significantly higher in the YAP group when compared with the non-YAP group (P<0.05). The optimum PCT cut-off value for YAP diagnosis on day 1 was 5.0 ng/ml, with a sensitivity of 91% and a specificity of 71%. The serum PCT levels on days 1 and 7 were found to correlate positively with the SOFA scores (r=0.54 and r=0.66 for days 1 and 7, respectively). Therefore, the results suggested that serum PCT may be used as diagnostic marker for YAP in patients following cardiac surgery.