Intensive care unit occupancy after introduction of the emergency department 4-hour discharge rule at a tertiary referral hospital in Western Australia

Background: The 4-hour rule has been introduced in Western Australia, requiring that emergency department (ED) patients be admitted to hospital or discharged from the ED within 4 hours of presentation. We hypothesised that this rule might have been associated with changes in medical emergency team (MET) calls and intensive care unit exit bed block.