The Role of Ultrasonography in the Diagnosis and Decision Algorithm for the Management of Pneumothorax after Transbronchial Lung Cryobiopsy.

Background: Pneumothorax is one of the main complications of transbronchial lung cryobiopsy (TBLC). Chest ultrasound (CUS) is a radiation-free alternative method for pneumothorax detection.

Objective: We tested CUS diagnostic accuracy for pneumothorax and assessed its role in the decision algorithm for pneumothorax management. Secondary objectives were to evaluate the post-procedure pneumothorax occurrence and risk factors.

Methods: Eligible patients underwent TBLC, followed by chest X-ray (CXR) evaluation 2 h after the procedure, as our standard protocol. Bedside CUS was performed within 30 min and 2 h after TBLC. Pneumothorax by CUS was defined by the absence of lung sliding and comet-tail artefacts and confirmed with the stratosphere sign on M-mode. Pneumothorax size was determined through lung point projection on CUS and interpleural distance on CXR and properly managed according to clinical status.

Results: Sixty-seven patients were included. Nineteen pneumothoraces were detected at 2 h after the procedure, of which 8 (42.1%) were already present at the first CUS evaluation. All CXR-detected pneumothoraces had a positive CUS detection. There were 3 discordant cases (κ = 0.88, 95% CI: 0.76-1.00, p < 0.001), which were detected by CUS but not by inspiration CXR. We calculated a specificity of 97.5% (95% CI: 86.8-99.9) and a sensitivity of 100% (95% CI: 87.2-100) for CUS. Pneumothorax rate was higher when biopsies were taken in 2 lobes and if histology had pleural representation. Final diagnosis was achieved in 79.1% of patients, with the most frequent diagnosis being hypersensitivity pneumonitis. Regarding patients with large-volume pneumothorax needing drainage, the rate of detection was similar between CUS and CRX.

Conclusion: CUS can replace CXR in detecting the presence of pneumothorax after TBLC, and the lung point site can reliably indicate its size. This useful method optimizes time spent at the bronchology unit and allows immediate response in symptomatic patients, helping to choose optimal treatment strategies, while preventing ionizing radiation exposure.