Consulting with users is considered best practice and is highly recommended in designing new trials. As part of our feasibility work, we undertook a consultation exercise with parents, ex-patients and young people prior to designing a trial of protocol-based ventilator weaning. Our aims were to (1) ascertain views on the relevance and importance of the trial; (2) determine the important parent/patient outcome measures; and (3) ascertain views on informed consent in a cluster randomized controlled trial. We conducted audio-recorded face-to-face, telephone and focus group interviews with parents and young people. Data were content analysed to generate information to address our specific consultation objectives. The setting was the north-western region of England. A total of 16 participants were interviewed: 2 parents of paediatric intensive care unit (PICU) survivors; 1 PICU survivor; and 13 young people from the former Medicines for Children Research Network. The trial objectives were deemed important and relevant, and participants considered the most important outcome measure to be the length of time on ventilation. Parents and young people did not consider written informed consent to be a necessary requirement in the context of this trial, rather awareness of unit participation in the trial was important with the opportunity of opting out of data collection. This consultation provided useful, pragmatic insights to inform trial design. We encountered significant challenges in recruiting parents and young people for this consultation exercise, and novel recruitment methods need to be considered for future work in this field. Patient and public involvement is essential to ensure that future trials answer parent-relevant questions and have meaningful outcome measures, as well as involving parents and young people in the general development of health care services.