Role of small calibre chest tube drainage for iatrogenic pneumothorax. A 2 mm Teflon catheter was used as a chest tube in 28 patients with iatrogenic pneumothorax. Frequent aspirations through the catheter were performed in 16 of the patients. In the remaining 12 patients the catheter was connected to a one way flutter valve. The treatment was successful in 27 of the 28 patients--one patient required a large calibre chest tube. The mean drainage time was 48 hours. The small catheter technique is superior to the use of a large intercostal drain as it is much less traumatic and troublesome. The small calibre chest tube with a one way valve is recommended as a safe and easy technique. 