Patient-controlled analgesia.

In appropriately selected patients, PCA safely provides analgesia superior to that obtained with traditional IM prn opioid administration; however, to date, no compelling evidence shows that PCA is associated with a reduction in morbidity or a more rapid recovery. PCA is deceptively easy to prescribe; however, to use it effectively and safely requires experience, frequent patient assessment, and a skilled and knowledgeable nursing staff.