"Closed" ICU staffing concerns

Our 12-bed mixed ICU is discussing "closing" along with our 24-bed sister Step-Down Unit. As it stands now, our ICU staff floats to other units including the ER, med/surg (not to the NICU, L&D, mother/baby unless an absolute emergency). By "closing" ourselves with stepdown, we will only float there and floating INTO the ICU will be strictly limited to personnel deemed qualified ahead of time. We will have to make ourselves "available" at various times for when census is high. On the other hand, we will have to use PTO (or lose hours for PRN and non-benefitted folks) and take call when census is low.

Sounds OK, right? Maybe...maybe not. The main PRO is patient safety (no poor ICU RN running around like crazy in the E.R. or scrambling with 7 patients on ortho and no inexperienced med/surg RNs getting thrown to the wolves, so to speak, in the ICU). Now for the CON...how is "availability" going to work? As it is now, there are not many people that step up when we're short as it is. Forcing staff to be "available" without paying them on call pay and maybe using them, maybe not seems unfair to me. It is especially unfair to night shift staff who would need to sleep all day and then MAYBE get called in to work on their "available" days. Plus, it seems we're always staffed more heavily on days than on nights making the pool of "available" staff larger for days and in turn causing night shift to rotate "available" days more frequently. I don't relish the thought of working 4 12-hr night shifts then being "available" on a 5th night...even once a month. To complicate things further, we have a dedicated weekend team that may balk at being "available" during the week when their contract is for Fri, Sat, Sun only.

Now don't get me wrong...I hate to float out of the ICU but do so occassionally if necessary. I also feel it is especially dangerous to float inexperienced staff to the ER and the ICU. However, I'm afraid that we may be cutting our nose off to spite our face. Anyone out there have suggestions, experiences, concerns, etc. you would like to share so we can transition smoothly?