The study will be conducted as a, prospective, open label, non-inferiority, randomized controlled trial. In the intervention group; chest tube removal will be determined by air flow criteria as indicated by the digital drainage system data. In the control group removal will be determined by the same criteria of the digital drainage system but before removal, a chest tube clamping test will be performed. Primary outcome measure: recurrent pneumothorax after chest tube removal requiring chest tube reinsertion

Determining and timing of chest tube removal has been a continuous topic of debate amongst both surgeons and pulmonologist. It is plausible that provocative clamping tests are no longer necessary when a digital continuous recording drainage device is used that demonstrates the absence of (intermittent) air leak. However, clamping trials are still performed in clinical care, it is an expert opinion's policy prompted by fear of recurrent pneumothorax and no comparative studies exist. We hypothesize that chest tube removal exclusively based on digital drainage system data is as safe as adding a clamping test before removal in patients treated for pneumothorax or after lung surgery.

The study will be conducted as a, prospective, open label, non-inferiority, randomized controlled trial. In the intervention group; chest tube removal will be determined by air flow criteria as indicated by the digital drainage system data. In the control group removal will be determined by the same criteria of the digital drainage system but before removal, a chest tube clamping test will be performed.

Inclusion Criteria:

• Digital chest tube drainage system
• Pneumothorax (primary, secondary, pulmonary surgery)

Exclusion Criteria:

• Pleural effusion as primary indication for chest tube placement.
• Empyema
• Suspected chest tube malfunction (e.g., leaking, occlusion, malposition)
• Intubated during chest tube removal