Effects of Preoperative Breathing Exercise on Postoperative Outcomes for Patients With Lung Cancer Undergoing Curative Intent Lung Resection: A Meta-analysis.

Almost every trial combined breathing exercises with aerobic exercise, so the effect cannot be credited to any one part of the programme. Only 10 trials were included and the breathing interventions differed widely, from incentive spirometry to a threshold training device, so it is unclear which type works best. Patients and staff could never be blinded, and several trials did not describe how patients were allocated to groups or whether the person assessing outcomes knew the allocation. Most trials measured lung function and walking distance before surgery only, so it is unknown whether those changes altered anything after the operation. Quality of life was not measured after surgery, so any later benefit or harm would have been missed. In the subgroup analysis, the breathing-plus-aerobic group had 440 patients from 6 trials against 163 patients from 2 trials, so the apparent advantage of adding aerobic exercise is unreliable.

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Do not credit the breathing exercises alone for the shorter hospital stays and fewer complications. Nearly every trial in the pooled analysis also put patients through aerobic exercise, and the paper's own subgroup comparison pits 440 patients from 6 trials against 163 patients from 2, so the contribution of any single component cannot be separated.