Pleural Ultrasound Compared with Chest Radiographic Detection of Pneumothorax Resolution After Drainage

Background: Pleural ultrasonography (PU) is more sensitive than chest radiograph (CXR) for diagnosing pneumothorax and could be useful for detecting resolution of pneumothorax after drainage. The aim of this prospective double-blind observational study was to assess PU accuracy during pneumothorax follow-up after drainage.

Methods: All patients hospitalized with pneumothorax requiring drainage were eligible. After drainage, residual pneumothorax was assessed by CXR and PU (1) 24 h after bubbling in the aspiration device had stopped, (2) 6 h after clamping the pleural catheter, and (3) 6 h after removing the pleural catheter. Pneumothorax indicated by PU but not CXR was confirmed by CT scan or by aspiration of > 10 mL of air.

Results: Forty-four unilateral pneumothoraces were studied (primary spontaneous: 70.5%), and 162 pairs of examinations (CXR and PU) were performed. Twenty residual pneumothoraces were detected by both CXR and PU. Furthermore, PU suspected 14 pneumothoraces that were not identified by CXR; 13 were confirmed. All of these pneumothoraces resulted in therapeutic intervention. Thus, 39% (13/33) of the confirmed residual pneumothoraces were missed by CXR. In patients with primary spontaneous pneumothorax, the positive predictive value of PU for residual pneumothorax diagnosis was 100%; for other pneumothoraces, this value ranged from 90% in the absence of a lung point to 100% when a lung point was observed. PU results were obtained faster than results from CXR (35 +/- 34 min vs 71 +/- 56 min, P < .0001).

Conclusions: The accuracy of PU is excellent for detecting residual pneumothorax during pneumothorax follow-up after drainage.