ACNP in the ICU

I posted this a year or so ago, but never got any responses....

Anyone have any experience with NPs working as Intensivists? I know that you can get an ACNP with specialization in critical care, but how does this work in the real world?

Also, curious if anyone has experience with a private practice set up like this. I used to work in a decent-sized (~450 beds) community hospital. There were 2 main groups who operated hospitalist practices there. One of the groups had 4 physicians and they took call. (Their practice was essentially just like IM except no clinic). One of them was in favor of trying to get an intensivist service started to cover the 4 ICUs, but the hospital wouldn't go for it because they couldn't afford to bring on a full-time intensivist staff of MDs (enough to provide round-the-clock in-house coverage). I was wondering if they ran it with ACNPs in addition to the MDs if that would be less expensive and how that sort of thing would work.

There was another hospitalist service that was one MD and the rest were ACNPs. But they were, again, general hospitalists, not specific to the ICU.

Any of you have experience? If so:

How many MDs and how many ACNPs?

What size service (ie how many ICU beds covered and what kind of patient)?

I assume that it's shift work, how does that sort out? MDs cover days only with NPs at night? Both take turns? What?

Any problems with having NPs cover without MDs in house at the time?