Objective To share innovative practice with enough detail to be useful for paediatricians involved in planning services.

Design A review of practice, adopting a realist approach.

Setting We collected detailed information about five initiatives which were presented at two meetings in July and October 2014 and telephone interviews between July and November 2014 with key informants, updating information again in February 2015.

Results The five case studies involved three clinical commissioning groups (CCGs): Islington CCG and Southwark and Lambeth CCG in London and Taunton CCG in the Southwest. All five initiatives involved acute paediatric units. We heard about four distinct types of services designed to bring paediatric expertise into primary care and/or improve joint working between paediatricians and primary care professionals: telephone multidisciplinary team, hospital at home, general practitioner (GP) outreach clinics, and advice and guidance. We defined four common ways that initiatives might work: promoting shared responsibility; upskilling GPs; establishing relationships between paediatricians and primary healthcare professionals; and by taking specialist care to the patient.

Conclusions We derived common aims and mechanisms and generated programme (mid-level) theory for each integrated care initiative about how they might work. These descriptions of what is being done can inform debate about which interventions should be prioritised for wider implementation. There is an urgent need for evaluation of these interventions and more indepth research into how mechanisms and their effectiveness could be assessed.