The amount of air leaking from a chest tube can be measured in two main ways:

1. electronic monitor connected to the chest tube
2. numerical (non-electronic) monitor connected to the chest tube

For people who have had lung surgery, it is important to understand the impact of measuring air leaks accurately in both the short term and the long term. An electronic medical device called Thopaz measures air leak electronically. Another medical device called Pleur-evac measures air leak numerically. The purpose of this study is to understand the accuracy of the method used by doctors and nurses to determine if a chest tube has an air leak. It is also important to determine the size or severity of an air leak.

Patients with air leaks following lung surgery will be assessed by a target number of 6 observers each (three nurses and three MDs) who will be randomly asked to participate. Patients will first be connected to the numerical air leak detector, followed by the electronic air leak detector. Observers will record their responses for each device. They will be blinded to responses from other observers.

Inclusion Criteria:

• 18 years of age or over
• Male and Female.
• Air leak occuring after any pulmonary resection
• Air leak persisting on or after the first post-op day of pleural drainage
• Air leak not entirely secondary to poor air seal at the pleural drainage incision site
• Pulmonary resection for benign or neoplastic diagnosis

Exclusion Criteria:

• Tension pneumothorax
• Traumatic or iatrogenic pneumothorax
• Primary or recurrent spontaneous pneumothorax awaiting surgery
• Pneumonectomy patient (history of or current)

A target of 30 patients at the Ottawa Hospital who experienced pulmonary air leak following pulmonary resection will be recruited.