Abstract: Objective  To investigatethe clinical value of procalcitonin(PCT) in exhaled  ventilator condensate (EVC) in the early diagnosis of patients with ventilator  associated pneumonia (VAP). Methods  Totally fortyfive patients requiring assisted breathing with ventilator were divided into VAP group and nonVAP group depending on whether the patients developed VAP or not in 5 days after assisted breathing with ventilator.  PCT in  EVC was  measured on day  1, 3, 5 of intubation by enzyme linked immunosorbent assay(ELISA). At the same time, the peripheral blood Creactive protein (CRP) concentration,  and Clinical Pulmonary Infection Score(CPIS) were measured. The  accuracy of these indicators in the diagnosis of ventilator  associated pneumonia  were evaluated by receiver operating characteristic (ROC)  curve.Results  PCT and CPIS in EVC  of VAP group on day 3 and 5 were significantly higher than those of nonVAP group (P<0.05). ROC analysis indicated the area under the ROC curve (AUC) of PCT in EVC concentration was 0.777. Using 0.87 ng/ml as the best cutoff, the sensitivity was 81% and the specificity was 64.3%. The combined diagnosis of VAP with PCT(≥0.87) ng/ml and CPIS(≥6) showed no significant improvement in sensitivity (76.7%), but  significant improvement in specificity (88.0%).Conclusion  PCT in EVC had a great diagnostic value in early diagnosis of VAP. Using 0.87 ng/ml as the boundary value,  it had the best sensitivity. The combined diagnosis of VAP with PCT and CPIS can significantly improve the diagnostic specificity to reduce falsepositive of VAP.

Key words: pneumonia, ventilatorassociated, calcitonin；Creactive protein, diagnosis