The acute medical unit model: a characterisation based upon the National Health Service in Scotland.

Acute medical units (AMUs) receive the majority of acute medical patients presenting to hospital as an emergency in the United Kingdom (UK) and in other international settings. They have emerged as a result of local service innovation in the context of a limited evidence base. As such, the AMU model is not well characterised in terms of its boundaries, patient populations and components of care. This makes service optimisation and development through strategic resource planning, quality improvement and research challenging. Aim: This study aims to evaluate a national set of AMUs with the intent of characterising the AMU model. Methods: Twenty-nine AMUs in Scotland were identified. Data were collected by semi-structured interviews with multidisciplinary healthcare professionals working in each AMU. A draft report was produced for each unit and verified by a unit representative. The unit reports were then analysed to develop a conceptual framework of key components of AMUs and a service definition of the boundaries of acute medical care. Results: Acute medical care in Scotland can be described as being delivered in 'acute medical services' rather than geographically distinct AMUs. Twelve key components of AMU care were identified: care areas, functions, populations, patient flow, support services, communication, nurse care, allied healthcare professional care, non-consultant medical care, consultant care, patient assessment and specialty care. Discussion: This empirically derived characterisation of the AMU model is likely to be of utility to practitioners, managers, policy makers and researchers: it is relevant on an operational level, will aid quality improvement and is a foundation to needed further research into how best to deliver care in AMUs. This is important given the central role AMUs play in the journey of the majority of patients presenting to hospital acutely in Scotland, the UK and internationally