Comparative study of lung ultrasonography and chest radiography in suspected cases of pneumonia in critically ill patients

Abstract

Objective: To evaluate the diagnostic performance of lung ultrasonography (LUS) in comparison to chest radiography in suspected cases of pneumonic consolidation in critically ill patients. Setting and Design: From October 2012 to May 2014, bedside lung ultrasonography was performed on 55 patients presenting to the emergency room with respiratory symptoms suggestive of pneumonia. Materials and Methods: Patients fitting the above criteria were evaluated with a chest radiograph and lung ultrasonography on the same day. A CT scan of chest was performed in cases with clinical suspicion of complications or wherever it was clinically indicated. Clinical course of the patient in hospital, lab parameters and CT scan of the chest (wherever available) was taken as a confirmation of pneumonia. Estimation of the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio and overall diagnostic accuracy of chest sonography and chest radiography was done. Results: Out of 55 patients, a final diagnosis of pneumonic consolidation was made by the treating senior physician in 40 patients. Pneumonia was correctly diagnosed by LUS in 39 of 40 cases (97.5%) and by X-ray in 28 of 40 cases (70%). On the other hand, pneumonia was correctly ruled out by LUS in 14 of 15 patients (93.3%) and by X-ray in 13 of 15 patients (86%). Conclusion: Sensitivity, specificity and diagnostic accuracy of lung ultrasound is better than chest radiography in diagnosing pneumonic consolidation in critically ill patients.