Randomisation and blinding
’s taste reaction, head and neck, gastroenterology and MRI
Participants were randomly assigned in a 1:1 ratio to either control (midazolam) or treatment (melatonin) arms. Randomisation was computer-generated and completed using minimisation based on centre, surgical speciality (head and neck, gastroenterology and MRI, and other) and sex (male/female). All hospitals involved in the trial were assessed before inclusion by a pre-trial audit and feasibility assessment to ensure comparability, including case lists, anaesthetic teams, use of paediatric wards/recovery facilities, and midazolam prescribing practices. Hospitals were similar in that they were either teaching hospitals or large district general hospitals serving comparable general populations, with appropriate dedicated paediatric lists from which patients were further carefully specified by means of the trial’s inclusion/exclusion criteria.The trial was double-blind, with the participant, clinical care team, and assessor (research nurse or trained member of clinical staff) all blinded to treatment allocation. Allocation concealment was achieved using a centralised web-based randomisation system, with treatment allocation revealed solely to an unblinded trial pharmacist for drug dispensation. Trial medication for both arms was supplied in matching single-use plastic bottles of identical dosage strengths, raspberry flavourant, and volume. There was a risk that the staff member administering the Investigational Medicinal Product (IMP) may become unblinded; either through observing the child’s taste reaction as a result of midazolam being associated with unfavourable taste/rejection