Jiang 2012.

Study characteristics
Methods	Single‐centre randomised controlled double‐blind trial
Participants	46 full‐term or premature neonates who required MV were recruited Exclusion criteria: history of severe asphyxia and hypoxia (5‐minute Apgar score < 4, umbilical blood pH < 7.0); severe intraventricular haemorrhage; severe congenital malformation (e.g. congenital heart disease, diaphragmatic hernia, cleft palate); paralysis; history of use of neuromuscular blocker agents
Interventions	Morphine group (n = 22): i.v. infusion (> 1 hour) of 5% glucose‐saline 10 mL + morphine 100 mcg/kg, followed by continuous i.v. infusion of 5% glucose‐saline 24 mL + morphine 10 mcg/kg/hour for several days until criteria for withdrawal were met Control group (n = 24): i.v. infusion (> 1 hour) of 5% glucose‐saline 10 mL, followed by continuous i.v. infusion of 5% glucose‐saline 24 mL for several days until criteria for withdrawal were met
Outcomes	Respiratory rate (RR); peak inspiratory pressure (PIP); positive end‐expiratory pressure (PEEP); fraction of inspired oxygen (FiO₂); mean arterial pressure (MAP); heart rate (HR). Pain assessment by N‐PASS score and COMFORT score was measured at 30 minutes, 2 hours, 6 hours, 12 hours, 24 hours, and 48 hours after administration; brain ultrasound was done at Day 1 (before administration), 5, 7, and 14. Total ventilation time, total time from withdrawal to extubation, total oxygen time after ventilation, and adverse events were evaluated
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was done with 15 sets of opaque envelopes containing 4 cards reporting A or B (A = intervention; B = control). A member of the research group took out a random card from a random set for each newborn included
Allocation concealment (selection bias)	Low risk	Envelopes were opaque
Blinding of participants and personnel (performance bias)	Low risk	The nurse knew only the meaning of "A" and "B" as intervention or control and labelled drugs so they were not different in volume, appearance, and odour
Blinding of outcome assessment (detection bias)	Low risk	Assessors were blinded to treatment
Incomplete outcome data (attrition bias)	Low risk	All infants were accounted for
Selective reporting (reporting bias)	Unclear risk	Trial not registered; protocol not available Not reported in results: total ventilation time, total time from withdrawal to extubation, total oxygen time after ventilation, brain ultrasound
Other bias	Low risk	Study appears to be free of other sources of bias