Bedside lung ultrasonography: comparison with chest radiography (BLUR), a diagnostic study in a developing country

This study determines the diagnostic utility of lung ultrasonography (LUS) in a medical ward in a developing country. In a low resource country like India, we hope that use of lung ultrasound in primary and secondary hospitals will assist in earlier and better bedside diagnosis.

This prospective diagnostic study was done to test the diagnostic accuracy of LUS against a composite reference standard, which included clinical history and examination, basic laboratory investigations, imaging and the diagnosis at discharge. We evaluated 321 consecutive patients, admitted in our medical wards with an LUS within 24 hours of the chest radiograph being done.

Between August 2016 and August 2017, we enrolled 321 patients. The sensitivity and specificity of the LUS for all pathologies were found to be 82.5% (76.50 to 87.20) and 78.2% (69.09 to 85.26) respectively. A subgroup analysis including the patients in whom CT was part of the composite reference standard showed sensitivity and specificity of 87.9% and 92.9% for all lung pathologies. It was found that there was superior sensitivity and specificity of LUS compared with chest radiograph in a subgroup analysis of pulmonary oedema and acute respiratory distress syndrome (ARDS).

We found that the LUS was better than chest radiograph and as good as CT in most pathologies, especially pulmonary oedema and ARDS. We believe that training in the basics of bedside LUS must be part of the medical curriculum and a low-cost ultrasound machine must be made available in medical wards, so that clinical diagnosis can be supplemented with this tool. In a low resource setting like India, where access to chest radiograph and CT may be difficult particularly in a rural setup, expertise in LUS would be helpful in easy bedside diagnosis and saving cost on a CT scan.