Transthoracic ultrasound in severe asthmatic patients: a pilot study

Background: Transthoracic ultrasound (TU) is a validated complementary technique gold standard for studying pleural effusion, echo-guided thoracentesis, detection and ultrasound guided biopsy of pleural and sub-pleural lesions. We proposed to study patients affected by severe asthma (SA) with TU with the aim of identify eventually typical echografic pattern of this disease. Methods: We enrolled SA patients attended at the accredited outpatient clinic (Chung KF et al. Eur Respir J. 2014). Ultrasound scanner with thoracic set up, with convex probe (3.5-5 MHz) and linear probe (8-12 MHz), was used to perform complete TU scans, while the patient was sitting. The ultrasound signs were compared with thoracic high resolution computed tomography (HRCT) images. Results: We enrolled 30 severe asthmatics. At TU we found a lack of “gliding sign”, “Bar Code” sign in M-mode and presence of lung point in all our patients in middle thoracic anterior e posterior. These patterns mimic ultrasound pneumothorax. Therefore, in all our patients we highlighted a thickening of the hyperechoic pleural line (Figure 1). Conclusions: In TU the lack of “gliding sign” is a typical feature of pneumothorax. Although there are other pathologies that mimic this sign, we have found a new false positive of pneumothorax. Moreover, we may have identified patterns of ultrasound signs which could be used in follow up of SA patients.