Generally Perioperative nurses are nurses that work in the Preop\Holding area and also work in the Post Anesthesia Care Unit (PACU aka Recovery Room).
Holding nurses help to get patients ready for surgery. It varies from instituition to institution on what is done, but many get IVs started, give any preop meds, make sure labs and paper work are done, etc.
PACU nurses take care of patients right after they leave the operating room in a monitored environment. At some institutions, the pt can be extubated per anesthesia protocol by th RN. PACU RNs also deal with getting pain under control. PACU RNs work very closely with anesthesia staff.
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