A technical note concerning emergency bed demand.

A common method for modelling emergency referrals to a hospital in-patient unit is to assume that they follow a Poisson distribution. If lengths of stay are independent and identically distributed, then the distribution of bed demand can be derived by analysis of a queueing system with an infinite number of servers. Undemanding analysis can be used to express the mean and variance of bed demand in terms of simple formulae involving mean referral rates and the distribution of lengths of stay.