PROJECT SUMMARY / ABSTRACT Respiratory illness is the leading cause of hospitalization and death in children with severe cerebral palsy (CP). Improving these outcomes is limited because interventions to help caregivers identify and manage them at the right time and context are absent. Severe respiratory illnesses, defined as respiratory diagnoses requiring hospitalization, begin in the children’s homes, where families are the first in line to manage these technically challenging and nuanced events. Caregivers report limited knowledge, skill, and confidence to handle them. To improve these respiratory mortality and hospitalization outcomes, parents need clinical teams to provide the right support, at the right time, in the right context, i.e., just-in-time and adaptive. Just-in-time adaptive interventions hold promise to help children with CP with respiratory illness. Our previously efficacious behavioral intervention gave families of children with complex illnesses, including CP, action plans and coaching to manage crises; however, plans were pre-specified, static, and did not adjust to real-time issues. To prevent severe respiratory illness in CP, responses must be dynamic, addressing the changing contexts and comorbidities that drive these illnesses. Moreover, clinicians and families need simple tools to signal when attention is most needed, which our mHealth platform was designed to accomplish. The aims of this application are to (1) refine and adapt the Respiratory Exacerbation Plans for Action and Care Transitions (RE-PACT) intervention program to severe respiratory illness for children with severe CP across two clinical programs with racial/ethnic and socioeconomic patient diversity; and (2) establish RE- PACT’s feasibility, acceptability and effect sizes in preparation for a future fully powered multisite randomized controlled trial of RE-PACT. We will also conduct exploratory analyses of the mediating influence of changes in caregiver capability, opportunity and motivation on intervention outcomes to test the theoretical intervention mechanism. Using the evidence-based Replicating Effective Programs adaptation framework, RE-PACT will add longitudinal mHealth surveillance of parent confidence to avoid hospitalization, triggering just-in-time action planning and coaching when confidence of low. Focus groups with target family and clinical teams caring for children with severe CP, and a national Design and Intervention Strategy expert group will guide intervention revisions. A sample of 90 caregivers of children with severe CP will then be randomized to receive RE-PACT or active control. Outcome data will be collected at 6 months using mixed methods to evaluate intervention: 1) feasibility, 2) acceptability, 3) fidelity, and 4) preliminary efficacy, measured by differences in severe respiratory illnesses compared to control. This intervention offers a high potential for widespread dissemination and scalability to address a key public hea...