How do ICU fellowships work?

[MarsRover]

I have read about how the royal college allows you to truncate a residency to do a fellowship. Essentially how IM does all their fellowships. I have heard about it for palliative or chronic pain for anesthesia as well. So it only requires an extra year. 
 

Does this still work for ICU if one is in anesthesia? What if your residency program doesn’t have an ICU/chronic pain/palliative program. I am assuming this truncated system is only possible with doing it at the same school? 
 

How would it work if I was an R4 in anesthesia and then got accepted to ICU at a different site? Do most people (anesthesia and gen surg) practically just finish their 5yr residency and then do a two year icu fellowship after that?

[BCelectrophile]

From what I understand with anesthesia you would ensure you have enough ICU rotations/electives before pgy5 to satisfy the requirements of year 1 of the fellowship (doesn’t need to be at an institution that offers the fellowship). I think gen surg usually does 5+2 yrs for icu.