| Methods |
Design: randomized controlled trial. Single‐centre. Period: July 1988‐August 1989. Sample size calculations: reported (the prevalence of pulmonary complications was predicted to be 20%, a sample size of 874 patients was necessary to detect an absolute 10% difference in the prevalence of pulmonary complications by use a two‐tailed comparison with a probability of a type I error of 1% and a power of 80%). Generation of allocation sequence: adequate (computer‐generated pseudo‐random numbers). Allocation concealment: adequate (sealed opaque envelopes). Blinding of assessment of treatment effect: not reported. Withdrawals: reported (less than 20%). Intention‐to‐treat analysis: reported, but did not include patients who were randomized and did not subsequently undergo abdominal surgery. Follow up: until the seventh postoperative day |
| Participants |
876 participants. Sex (male/female): 436/440. Age (mean): 55.0 years. Setting: Royal Perth Hospital, Australia. Inclusion criteria: patients who underwent a laparotomy which included manipulation of viscera. Exclusion criteria: patients who had elective operations for groin hernia, patients who did not give consent, were under 14 years of age, or had a pre‐existing pulmonary complication |
| Interventions |
Incentive spirometry (at least five minutes in every waking hour) or chest physiotherapy |
| Outcomes |
Pulmonary complication, blood gas analysis, and length of hospital stay |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Computer‐generated numbers |
| Allocation concealment (selection bias) |
Low risk |
Sealed opaque envelopes |
| Blinding of participants and personnel (performance bias)
All outcomes |
Unclear risk |
Not reported |
| Blinding of outcome assessment (detection bias)
All outcomes |
Unclear risk |
Not reported |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Less than 20% of the total of the participants |
| Selective reporting (reporting bias) |
Low risk |
No evidence |
| Other bias |
Unclear risk |
Conflict of interest: not reported |
