Catheter drainage of spontaneous pneumothorax: suction or no suction, early or late removal?

Twenty-three patients with primary spontaneous pneumothorax and 30 patients with secondary spontaneous pneumothorax treated by intercostal catheter drainage with underwater seal were divided randomly into two groups, one receiving suction drainage (up to 20 cm H2O pressure) and the other no suction. The success rate was 57% for the former and 50% for the latter. The suction group spent an average of five days in hospital, whereas the non-suction group averaged four days. Suction drainage therefore did not have any advantage. To determine how soon the catheter could be removed without complication, patients were also divided randomly into two subgroups--one had the catheter removed, without previous clamping, as soon as the lung was expanded; the other had the catheters left in situ for a further three days. The success rate was 52% for the former, and 53% for the latter. But most of the failure in the early removal group was caused by re-collapse of the lung rather than persistent air leakage; hence removal of the catheter too early was not recommended.