Light 1996.
| Methods | Randomised, crossover study Exercise study Incremental cycle ergometer |
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| Participants | COPD 7 male participants Mean age 66.4 years SD 3.25 years FEV1 0.99 SD 0.3 FEV1/FVC 0.35 SD 0.07 Exercise limited by breathlessness Stable disease Exclusion criteria: PaCO2 > 45 mmHg, FEV1 > 1.39 L, long‐term oxygen supplementation, cardiac disease, history of narcotic abuse, other significant disease affecting exercise performance, use of tranquillisers, hypnotics, mood altering drugs or opioids in week prior to study, alcoholism in past 5 years |
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| Interventions | Morphine 30 mg or placebo once orally 60 minutes before exercise test, compared to 30 mg morphine plus 10 mg prochlorperazine, or compared to 30 mg morphine plus 25 mg promethazine Tests on separate days |
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| Outcomes | Modified Borg score each minute of exercise Workload Exercise duration VO2 VCO2 VE PETO2 PETCO2 Heart rate SaO2 |
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| Notes | The study authors concluded that the administration of 30 mg morphine plus promethazine significantly improved the exercise tolerance of participants with COPD, without significantly impairing the mental capabilities of the participants The dose is equivalent to 30 mg oral morphine |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | The study authors did not state the methods of random sequence generation. |
| Allocation concealment (selection bias) | Unclear risk | The study authors did not state the methods of allocation concealment. |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Placebos were identical in appearance; the participants were blinded to the intervention and the placebo. |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | The study authors did not clearly state the methods of blinding of outcome assessment. |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | The study authors did not state the number of participants enrolled or recruited, and only provided a statement about the number that completed the study. It is unclear whether or not this had impact on the trial outcomes. |
| Selective reporting (reporting bias) | Low risk | We did not detect any evidence of selective reporting bias. |
| Other bias | Low risk | We judged that this trial appeared to be free of other sources of bias. |
| Size bias | High risk | This study had a small sample size; there were < 50 participants per arm. |