Extracorporeal carbon dioxide removal (ECCO2-R) over a membrane lung is a new therapy for patients with adult respiratory distress syndrome (ARDS) who frequently suffer from lung complications caused by long-term artificial ventilation and who may require major thoracic surgery. This is a report of 76 patients with severe ARDS who were treated by ECCO2-R. Twenty-six of these 76 patients required thoracotomy: 19 for pneumothorax and pneumatocele, and seven for haemothorax, infected lung necrosis or oesophagotracheal fistula. Most pneumothoraces were bilateral. Ten of these 26 patients required reoperation, usually for extensive persisting alveolar air leaks. Sixteen (62 per cent) of the 26 patients who had a thoracotomy and 22 (44 per cent) of the 50 patients without surgery survived. These results demonstrate that performing a thoracotomy, if necessary, does not diminish the survival chance of high-risk patients with severe ARDS.