Incorporating lung ultrasound in clinical pulmonary infection score as an added tool for diagnosing ventilator-associated pneumonia: A prospective observational study from a tertiary care center

Abstract

Background: Clinical pulmonary infection score (CPIS) is an established diagnostic parameter for ventilator-associated pneumonia (VAP). Lung ultrasound (LUS) is an evolving tool for diagnosing VAP. Various scores have been proposed for the diagnosis of VAP, taking LUS as a parameter. We proposed whether replacing LUS with chest radiograph in CPIS criteria will add to the diagnosis of VAP. The current study was done to evaluate the diagnostic accuracy of LUS alone and in combination with clinical and microbiological criteria for VAP by replacing chest radiograph with LUS in CPIS. Materials and methods: We conducted a prospective single-center observational study including 110 patients with suspected VAP to investigate the diagnostic accuracy of LUS. Quantitative mini-bronchoalveolar lavage (mini-BAL) culture was considered the gold standard for diagnosis of VAP. Here, the authors have explored the combination of LUS, clinical, and microbiology parameters for diagnosing VAP. On replacing chest radiograph with LUS, sono-pulmonary infection score (SPIS) and modified SPIS (SPIS-mic, SPIS-cult) was formulated as a substitute for CPIS. Results: Overall LUS performance for VAP diagnosis was good with sensitivity, specificity, positive or negative predictive value, and positive or negative likelihood ratios of 91.3%, 70%, 89%, 75%, 3, and 0.1, respectively. Adding microbiology culture to LUS increased diagnostic accuracy. The area under the curve for SPIS and modified SPIS were 0.808, 0.815, and 0.913, respectively. Conclusions: The diagnosis of VAP requires agreement between clinical, microbiological, and radiological criteria. Replacing chest radiograph with LUS in CPIS criteria (SPIS) increases diagnostic accuracy for VAP. Adding clinical and culture data to SPIS provided the highest diagnostic accuracy. Clinical parameters along with lung ultrasound increase diagnostic accuracy for VAP.