Accuracy and Applications of Lung Ultrasound to Diagnose Ventilator-Associated Pneumonia: A Systematic Review.

BACKGROUND

Lung ultrasound (LUS) is an accurate tool to diagnose community-acquired pneumonia. However, it is not yet an established tool to diagnose ventilator-associated pneumonia (VAP).

PURPOSE

To assess the evidence about LUS in the diagnosis of VAP, we conducted a systematic review of the literature.

METHODS

We searched PubMed, Embase, Scopus, Web of Science, and LILACS. Two researchers independently selected the studies that met the inclusion criteria. Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool was used to assess the quality of the studies. In a qualitative synthesis, 3 questions guided the review: Q1. What are the sonographic signs of VAP? Q2. How can LUS be combined with others tests or signs of VAP? Q3. What is the role of LUS in VAP screening?

MAIN RESULTS

Three studies (n = 377 patients) with different designs were included. In terms of Q1, the 3 studies assessed the accuracy of sonographic consolidations. In patients suspected for VAP, lobar or hemilobar consolidation alone was not sufficient to diagnose VAP but seems useful to exclude it. The most useful signs were small subpleural consolidations (sensitivity: 81%; specificity: 41%) and dynamic air bronchograms (sensitivity: 44%; specificity: 81%). Two studies were assessed for Q2, when the 2 signs above were included in a clinical score (Ventilator-associated Pneumonia Lung Ultrasound Score associated with quantitative culture of endotracheal aspirate-VPLUS-EAquant), the accuracy was amplified (sensitivity: 48% and specificity: 97% for score ≥4; sensitivity: 78% and specificity: 77% for score ≥3 points). Finally, regarding Q3, no studies have assessed the use of LUS in screening of VAP.

CONCLUSION

Small subpleural consolidations and dynamic air bronchograms were the most useful sonographic signs to diagnose VAP in suspected patients. Clinical scores including LUS had better diagnosis accuracy than LUS alone. There are no data on LUS for VAP screening.