Postoperative oxygenation is not improved by a combination of a lung recruitment manoeuvre and maintenance of a positive airway pressure until extubation. Further research is needed to elucidate the mechanism of atelectasis on emergence from anaesthesia and to evaluate more invasive clinical strategies such as post-extubation CPAP. Trial registered at URL http://www.controlled-trials.com Identification number: ISRCTN32464251 (http://www.controlled-trials.com/ISRCTN32464251).