I have been working in PACU for 8 years and have seen many ER nurses make the transition beautifully. Your biggest risk is being bored! As long as you have "good" anesthesiologists and you are not being left alone to deal with extubations you should be fine. Our hospital always staffs 2 nurses on call from 2300 to 0700 but we do not have "good" anesthesiologists and often hold ICU pt's. Your biggest problem will be getting food and potty breaks! Good luck and let me know how it goes.