Optimizing efficiency in the acute care chain: a systematic review on the implementation and impact of interdisciplinary short-term monitoring in acute care units

The growing number of patients with multimorbidity and increasing disease complexity presenting to the Emergency Department (ED) poses a global challenge, with overcrowding as a major consequence. To address these pressures, various interdisciplinary short-term monitoring and treatment units, such as Acute Medical Units, Frailty Units, Observation Units, and Chest Pain Units, have been implemented to improve patient flow from presentation to discharge. This systematic review, conducted according to PRISMA guidelines, aimed to evaluate the reported effects of these units on patient outcomes and ED crowding. We searched multiple databases and included studies reporting at least one primary outcome measure (length of stay, mortality, costs, readmissions, or staff satisfaction) following implementation of such a unit. The search yielded 2972 results, of which 50 studies met the inclusion criteria. Reported outcomes included reductions in hospital length of stay (0.24 to 6.16 days), cost savings (ranging from €162 to nearly €2 million across eight studies), and stable or decreased mortality in some settings. However, the evidence base is heterogeneous, with units differing substantially in patient populations, aims, and models of care, and cost analyses often relying on limited methods. Consequently, strong general conclusions across all unit types are not possible. Nonetheless, these findings suggest that when well-matched to local system bottlenecks and patient populations, specialized acute care units can improve patient flow and contribute to the accessibility of emergency care without compromising quality. Trial Registration: https://doi.org/10.17605/OSF.IO/A9EF7