| Study characteristics |
| Methods |
Randomised double‐blind controlled trial |
| Participants |
20 preterm infants (26 to 35 weeks), birth weight 810 to 2750 grams, receiving mechanical ventilation
Exclusion criteria: not stated |
| Interventions |
Morphine group (n = 10): loading dose 100 mcg/kg over 30 minutes followed by continuous infusion of 20 mcg/kg/hour for 1 to 5 days
Control group (n = 10): no intervention |
| Outcomes |
PIPP and COMFORT scores; ventilatory setting; mean airways pressure, ventilatory rate, FiO₂; pneumothorax; grade IV intraventricular haemorrhage; periventricular leukomalacia; BPD |
| Notes |
Data on pain scores were obtained by personal communication with the study author |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Method of randomisation was not stated |
| Allocation concealment (selection bias) |
Low risk |
The use of sealed envelopes was reported (study author's communication) |
| Blinding of participants and personnel (performance bias) |
High risk |
Caregivers were stated to be not blinded |
| Blinding of outcome assessment (detection bias) |
High risk |
Assessors were stated to be not blinded |
| Incomplete outcome data (attrition bias) |
Unclear risk |
Loss to follow‐up not reported; number of patients evaluated for each outcome not reported |
| Selective reporting (reporting bias) |
Unclear risk |
Trial not registered; protocol not available |
| Other bias |
Low risk |
Study appears to be free of other sources of bias |
