Randomised-controlled trials (RCT) that compared the effects of the PEP using a mechanical device with the effects of other chest physiotherapy technique or no treatment in spontaneously breathing adult patients after an open upper abdominal or thoracic surgery via thoracotomy were eligible for inclusion in the review. Studies were excluded if the study population had undergone thoracic surgery via sternotomy. All outcome measures were eligible for inclusion.
Included studies evaluated PEP treatments using a PEP-mask or a blow-bottle system. PEP-mask treatment was compared with other breathing treatments that included: CPAP (10-15cm H2O), inspiratory resistance-positive expiratory pressure (IR-PEP), incentive spirometry and placebo PEP (no resistance). In most studies PEP was given in addition to conventional chest physiotherapy. Blow-bottle treatment was compared with conventional chest physiotherapy (breathing exercises and postural drainage, plus physiotherapist visits) or combined with preoperative and postoperative physiotherapy and compared with preoperative and postoperative physiotherapy. Two thirds of included participants had undergone abdominal surgery and the others had undergone thoracic surgery. Studies were mostly performed in Scandinavia and published between 1979 and 1993. Follow-up periods ranged from one to nine days post procedure.
The main reported outcome was atelectasis (evaluated in chest roentgenograms); other outcomes included temperature, expectoration, time to chest tube removal, subjective experiences, postoperative complications, alveolar-arteriolar oxygen difference, cough, dyspnoea, pain, antibiotic use, bronchodilator use, pulse rate, oxygen and pulmonary ausculatation.
Two reviewers independently assessed each study for inclusion in the review.