Lung Ultrasound to Detect Residual Pneumothorax After Chest Drain Removal in Lung Resections

Indication for postdrain removal imaging after lung resection is debated. Chest roentgenogram (CR) is widely used to confirm lung expansion but not evidence based. We propose to introduce lung ultrasound (LUS) as alternative to exclude significant pneumothorax (PTx) in this setting.

The study enrolled 50 patients undergoing lung resections. Inclusion criteria were complete expansion of the lung at postoperative CR, pleural effusion of less than 300 mL/24 h, air leak of 10 to 20 mL/min for 6 hours. Two hours after chest drain removal, LUS was performed at the second and third intercostal spaces to assess pleural sliding. Patients with no detected PTx or with apical PTx were considered for discharge. The same patients were blindly evaluated with CR by a second operator, and a comparison between the two methods was performed. Clinical decisions were taken based on CR results.

LUS confirmed large PTxs in 7 patients, apical PTxs in 10 patients, and no PTx in 33 patients. CR confirmed 5 of 7 significant PTxs (1 chest drain reinserted, 4 patients observed), and 2 of 7 PTx were considered irrelevant. Apical PTxs were confirmed in 8 of 10 patients, and in 2 patients there was no PTx at CR. The 33 patients with no PTx at LUS had full lung expansion at CR. LUS has a negative predictive value of 100% in excluding large PTxs and a positive predictive value of 71%.

In this subgroup of patients with air leak of 10 to 20 mL/min, performing an imaging study to verify the absence of PTx is desirable; however, when LUS confirms lung expansion or the presence of apical PTx, CR does not seem to be needed.