It's usually to do with beds. There's so much competition for beds and when one becomes available, a decision is made about which patient from a group waiting gets it. Emergency admissions have to be managed alongside normal admissions.
As an emergency admission, last year I spent 5 days on an A&E ward waiting for a bed on the neurology ward. A&E beds are for short term patients and I saw beds used for at least 5 patients in a 24 hour period. The disruption made sleep impossible, especially as some patients were very noisy e.g. they were drunk, on drugs, angry or upset and shouting. Some patients were like me, waiting to get moved to the relevant ward.
Once you get a bed you stay in it and are wheeled everywhere. Fingers crossed your husband gets a bed today and his surgery goes ahead. 