Just to pick up on this, yes, ITU resources are extremely limited.
I don't know if this is true for kids (I assume it is, but don't know for sure) but plenty of major adult surgery requires that the patient go to ITU for a night or two afterwards, until they're stable enough to go to a ward. If there's no bed, their sugery is cancelled. As you can imagine, this is invariably the big stuff, so not the type of procedures you want cancelled.
If a patient comes in needing an emergency ITU admission and there's no bed, then they're shipped to the nearest hospital who has space. That may be hundreds of miles away. This isn't good for the patient (travelling long distances in an ambulance when you're critically ill is always a risk) or the vamily, who find it hard to visit. It's also expensive.
So, yes, there are wider implications beyond Archie's individual care.