I have been on the other end of this issue... In the past I have worked "regular" prn in ICU at a local small town hospital... I was practically part time, in that my hours were almost guaranteed, and I worked almost every weekend. The pay difference for prn vs regular staff was minimal, maybe $2-3/hr more than some of the less experienced nurses, but probably quite a bit less than the certified ICU regulars. Agency nurses also helped fill the staffing needs, and their pay was significantly higher than my pay as prn.
I worked prn for a couple of reasons. First, I already had a FT nursing job in industry. Second, I needed the experience of hands on patiend care that I couldn't get by filling out paperwork behind a desk at my regular job.
As prn help, I accepted the fact that I would be pulled or sent home when ICU census was low. I felt the ICU "regular staff" had the expertise and the "right" to maintain their territory. Because I was paid less as prn vs agency, I at least had some level of "seniority" before being pulled or sent home.
Overall, I agree with most of you... Hospitals need to open their eyes to several needs. One, the need to provide consistent quality, safe, and competent care for patients, which includes adequately staffed units. From the first need is where you see the need to keep staff consistent and happy. There are so many ways that big organizations "waste" money. From the eyes of a consumer, you know we all pay for that waste. Unfortunately, there are no easy answers.
Just my humble thoughts...