Role of ultrasound in the decision algorithm for pneumothorax – a pilot study

Pulmonary transbronchial criobiopsy (PTC) has gained an important role in the diagnostic approach to diffuse pulmonary diseases. The most frequent complication is pneumothorax (PTX). Chest ultrasound (CUS) has previously been described as a useful diagnostic tool in PTX detection. We aimed to evaluate the role of CUS in the assessment of PTX volume. Ten consecutive post procedure PTX were selected. Patients were evaluated by CUS (at 30 minutes and 2 hours after PTC) and chest X-ray (CXR; 2 hours after PTC). PTX with a visible rim of >2 cm between the lung margin and the chest wall (at the level of the hilum) on CXR were considered large volume PTX (LVPTX). On CUS, a LVPTX was considered when “lung point” was detected lower or more lateral than medium axillary line (in the supine position) or no “lung point” with no “lung sliding/lung pulse” were detected (total lung collapse). Symptomatic patients were considered for chest tube drainage. There was a good strength of agreement on PTX detection between both methods, with agreement in 90% of cases (κ=0.615; p<0.05). There were 4 and 5 LVPTX detected on CXR and CUS, respectively; CXR and CUS were concordant in PTX volume evaluation in 90% of cases, with a significant strength of agreement (κ =0.8; p<0.05). One PTX was only seen on expiratory CXR, therefore lowering the strength of agreement on PTX detection and showing a better diagnostic sensitivity of CUS. There was a loculated PTX in the inferior aspect of the hemithorax on CXR that simulated a LVPTX on CUS. In spite of our small sample, US shows a promising role when used by experienced operators. Some pitfalls can be found in the evaluation of more complex types of PTX.