Background: Postoperative pneumonia (PP) is a complication after cardiac surgery. This study aimed to investigate the ability of procalcitonin (PCT) variation to diagnose postoperative pneumonia.
Method: In this prospective observational study, patients with PP and age- and sex-matched cases in our center from October 10, 2020, to January 31, 2021, were included. Patients diagnosed with PP in this study met both clinical and microbiological diagnostic criteria. Blood samples were collected in all patients from the first postoperative day (POD1) to POD5 to measure PCT, white blood cells (WBCs), and C-reactive protein (CRP). PCT variation was calculated by the equation: (PCTdelayed - PCTPOD1)/PCTPOD1. The receiver operating characteristic and area under the curve (AUC) analyses were used to evaluate the diagnostic performance of different biomarkers.
Results: Our study enrolled 272 patients, including 24 patients with PP and 248 age- and sex-matched cases. From POD1 to POD5, the absolute value of PCT showed diagnostic significance for pneumonia (P < .05), WBC showed no differences, and CRP had no diagnostic value until POD4. Furthermore, PCT variation showed the best diagnostic value among those biomarkers (AUC 0.84, 95% confidence interval [CI] 0.71, 0.91). Multivariable logistic regression showed that PCT variation on POD2 had significant value to predict PP (odds ratio 5.602, 95% CI 2.178, 14.409, P < .01).
Conclusion: Compared with PCT level, WBC count, and CRP level, PCT variation had the best diagnostic value in predicting PP.