Dynamics of bed use in accommodating emergency admissions: stochastic simulation model

Objective To examine the daily bed requirements arising from the now of eme rgency admissions to an acute hospital, to identify the implications of flu ctuating and unpredictable demands for emergency admission for the manageme nt of hospital bed capacity, and to quantify the daily risk of insufficient capacity for patients requiring immediate admission. Design Modelling of the dynamics of the hospital system, using a discrete-e vent stochastic simulation model, which reflects the relation between deman d and available bed capacity. Setting Hypothetical acute hospital in England. Subjects Simulated emergency admissions of all types except mental disorder . Main outcome measures The risk of having no bed available for any patient r equiring immediate admission; the daily risk that there is no bed available for at least one patient requiring immediate admission; the mean bed occup ancy rate. Results Risks are discernible when average bed occupancy rates exceed about 85%, and an acute hospital can expect regular bed shortages and periodic b ed crises if average bed occupancy rises to 90% or more. Conclusions There are limits to the occupancy rates that can be achieved sa fely without considerable risk to patients and to the efficient delivery of emergency care. Spare bed capacity is therefore essential for the effectiv e management of emergency admissions, and its cost should be borne by purch asers as an essential element of an acute hospital service.