IntroductionChildren and youth with mental health and addiction crises are a vulnerable patient group that often are brought to the hospital for emergency department care. We propose to evaluate the effect of a novel, acute care bundle that standardises a patient-centred approach to care.Methods and analysisTwo paediatric emergency departments in Alberta, Canada are involved in this prospective, pragmatic, 29-month interventional quasi-experimental study. The acute care bundle comprises three components, applied when appropriate: (1) assessing self-harm risk at triage using the Ask Suicide-Screening Questionnaire (ASQ) to standardise the questions administered, enabling risk stratification; (2) use of the HEADS-ED (Home, Education, Activities/peers, Drug/alcohol, Suicidality, Emotions and behaviour, Discharge Resources) to focus mental health evaluations for those who screen high risk on the ASQ; and (3) implementation of a Choice And Partnership Approach to enable shared decision making in care following the emergency department visit. The overarching goal is to deliver the right care at the right place and time for the patients. The study design involves a longitudinal collection of data 12 months before and after the introduction of the bundle and the use of quality improvement strategies such as Plan-Do-Study-Act cycles during a 5-month run-in period to test and implement changes. The primary study end-point is child/youth well-being 1 month after the emergency department visit. Secondary outcomes include family functioning, child/youth well-being at 3 and 6 months, satisfaction with emergency department care, and health system outcomes (hospital admissions, length of emergency department stays, emergency department revisits).Ethics and disseminationThe study is registered at www.ClinicalTrials.gov and has received ethics and operational approvals from study sites. The results of the study will be reported in accordance with the Strengthening the Reporting of Observational
Studies in Epidemiology statement. Results will be shared broadly with key policy and decision makers and disseminated in peer-reviewed academic journals and presentations at conferences.Trial registration numberNCT04292379.