Carbon dioxide production during acetazolamide and medroxyprogesterone treatment.

more cost-effective than chest-tube drainage, a well accepted treatment for PSP requiring a chest tube. In other words, our study, performed with a randomised, prospective design, definitely showed that TT poudrage is superior to conservative treatment by chest-tube drainage. This is important information which has never been reported before. SCHRAMEL et al. [1] performed a different study. They compared retrospectively, in two historical series, video-assisted thoracoscopic surgery (VATS) under general anaesthesia to chest-tube drainage alone, as treatment of PSP requiring chest-tube drainage. They showed that the more expensive technique, VATS, was more cost-effective than conservative treatment. The same authors further concluded that using simple talc poudrage would have resulted in an additional 62% reduction of the cost [2]. A mini-invasive technique, such as thoracoscopy with talc pleurodesis, is very effective in preventing recurrence of a spontaneous pneumothorax either for a first episode of PSP or secondary pneumothorax, even it is an old technique performed for a 100 yrs, as suggested by WEISSBERG and REFAELY [3]. We think that in today9s standard of care, the patient with a first episode of PSP requiring a chest tube should be offered the choice between a treatment which importantly reduces the recurrence rate (TT), versus a treatment with a higher recurrence rate (pleural drainage), both treatments implying the same duration of hospital stay. Secondly, we agree that there is ongoing discussion about when and how long to apply suction through the chest tube in either group. Unfortunately, there is currently no answer to this question because of lack of scientific data. We decided to use suction immediately in the TT group because it is performed in this way in all centres participating in the study, based on the idea that the sooner parietal and visceral pleural are brought in contact with each other, the better. Thirdly, we do not agree with the comment about the method of cost calculation as proposed. Our study was a multicentre European trial conducted in five countries with different health systems and different hospital reimbursement policies. The only economically reliable method to look at the real costs was to unify the method of calculation, after having meticulously recorded all procedures material and manpower used for each patient. Finally, although it is very easy to insert a second drain under visual control at the end of thoracoscopy, we agree that the same hole can be used for this purpose.