Pulmonary function of patients with spontaneous pneumothorax in relation to the extent of emphysema-like changes

The aim of the present study was to analyse pulmonary function parameters of patients with spontaneous pneumothorax (SP) in relation to the extent of emphysema-like changes (ELCs). Pulmonary function tests were performed in 85 patients with unilateral SP, 6 weeks after video-assisted thoracoscopy (VAT). In 63 patients, thoracic computer tomography (CT) was obtained. An ELCs score, based on findings of CT and VAT, was used to quantify ELCs, ranging from 0 (expressing no ELCs) to 3 (expressing extensive ELCs). Emphysema-like changes were detected during VAT in 74% of patients, of which 70% were considered larger than 2 cm. An ELCs score > or = 2 was found in 27 patients. Clinical characteristics of the patients grouped according to thoracoscopical findings and ELCs score did not differ, except for age. Patients with large ELCs were significantly older than patients without ELCs or small ELCs (P = 0.0009). In patients with large ELCs and ELCs score > or = 2, increased mean percentages of predicted total lung capacity and decreased diffusing capacity (KCO) were found. None of the patients exhibited all pulmonary function criteria of emphysema, in contrast to 43% of the patients with an ELCs score > or = 2. KCO was the only pulmonary function parameter which was decreased in smokers, especially in patients with large ELCs or ELCs score > or = 2. Static lung compliance (Cstat) was the only pulmonary function parameter which was increased in patients with recurrent SP. The authors concluded that KCO is related to smoking behaviour and ELCs in patients with SP. Cstat is the only parameter which is increased in patients with recurrent SP. The discrepancy between pulmonary function and macroscopical parenchymal changes could be explained by the fact that not all patients with SP are old enough at presentation to show all signs of emphysema with pulmonary function testing. On the other hand, it might be possible that ELCs in SP cause different pulmonary function abnormalities than in centriacinar or panacinar emphysema.