Diagnostic Modalities for VAP Detection

Ventilator associated pneumonia (VAP) is a common cause of nosocomial infection, that can complicate mechanical ventilation and is related to significant utilization of health-care resources.

The diagnosis of VAP is subjected to considerable interobserver variability. The Centers for Disease Control and Prevention (CDC) definition of VAP uses a combination of clinical, radiographic, and micro-biological criteria for diagnosis, but in the absence of a definite diagnostic test, the accurate diagnosis and treatment of VAP is limited.

The clinical pulmonary infection score (CPIS) was developed to objectively diagnose VAP and assign points on the basis of clinical and radiographic data, but its role in diagnosing pneumonia remains controversial .

Lung ultrasound (LUS) is a simple, non irradiating, noninvasive, cost-effective, bedside technique. It has been successfully applied for monitoring aeration and monitoring antibiotic efficacy in ventilator-associated pneumonia (VAP). However, no scientific evidence is yet available on whether LUS reliably improves the diagnosis of VAP.

Quantitative bacterial cultures of the specimen obtained from the lower airways using bronchoscope were proposed for VAP diagnosis with a cut off value of 104 colony-forming unit/ml. However, microbiological cultures cannot guide the early clinical management of patients with a suspected VAP, as they need at least 24 hours for preliminary results. So, starting antibiotics remains a challenge. Moreover, bronchoscopy is not always easy to perform in hypoxemic patients and not promptly available in all ICUs. Therefore, it can be replaced by tracheal aspirate microbiological samples.