Dear Blue,
I'm in a similar situation where I am salaried and work in critical care; when census drops off, we get put on call. There have been a number of creative ways including a lottery developed to prevent using up all of your PTO. It's not really a problem but it does require us to be flexible. Since we're seeking Magnet certification, most of us are on committees now and have work to do there, the number crunchers in the unit like to do chart audits, some of us work in education, others opt to float and of course, you can use your earned time. Call-offs happen but they're not that frequent for us so, we don't really mind and in fact, usually enjoy the brief respite. If they happen a lot to you and you aren't receiving your guaranteed hours, you should have a recourse. It may be that when there are no cases in the surgicenter, you float into the main OR core, PACU or other procedure oriented area of the hospital. If those aren't options offered or ones that you prefer, but you otherwise like where you work, perhaps you can schedule perdiem hours elsewhere to make up the loss. Good luck
R