| Methods |
Design: stratified randomized trial. Single‐centre. Period: not reported. Sample size calculations: reported (the prevalence of respiratory complications was predicted to be between 10% and 15%. an overall sample size of 430 patients was estimated to be necessary to detect an absolute 10% difference in the prevalence of postoperative respiratory complications with type I error of 5% and a power of 70%). Generation of allocation sequence: adequate (computer generated numbers). Allocation concealment: adequate (sealed opaque envelopes). Blinding of assessment of treatment effect: adequate (outcome checked by a clinician who was unaware of the nature of the respiratory therapy). 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: not reported |
| Participants |
155 eligible participants. Sex (male/female): 68/87. Age (median): 38 years, incentive spirometry group and 34 years, deep breathing group. Setting: general surgical service of an Australian urban teaching hospital. Inclusion criteria: patients undergoing abdominal surgery, less than 60 years of age with an American Society of Anesthesiologists' physical status classification of I (low risk). Exclusion criteria: pulmonary embolism and pulmonary oedema (both cardiogenic and non‐cardiogenic) were not regarded as respiratory complications |
| Interventions |
Patients randomized to receive deep breathing therapy were seen once and encouraged to take 10 deep breaths each hour. Patients randomized to receive incentive spirometry were provided with a laminated information sheet, an Airx Incentive Spirometer fitted with a one way valve and were encouraged to use the incentive spirometer at least 10 times each hour by taking slow maximal inspirations and holding each breath for as long as possible |
| Outcomes |
Respiratory complications and the time that staff devoted to prophylactic respiratory therapy |
| 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 |
