Overview of current development in patient-controlled analgesia.

Over the past two decades, numerous trials have assessed the safety and efficacy of patient-controlled analgesia (PCA). Advantages over conventional parenteral narcotics reported from these trials include equivalent to superior pain relief, superior patient satisfaction, decreased sedation and anxiety, faster return to normal functional status, and reduction in nursing time and hospitalization. The majority of these trials have been conducted in the postoperative patient population. In the mid to late 1980s, interest arose in applying PCA technology to the management of cancer pain. Factors that served as an impetus for the use of PCA in cancer pain included favorable reports from the postoperative setting and the often-cited statistics regarding the magnitude of the cancer pain problem. Advances in PCA technology coupled with advances in vascular access technology that allow the placement of long-term ports and catheters to facilitate intravenous, epidural, or intrathecal administration of opioid analgesics have made the applicability of PCA in ambulatory cancer patients an attractive option. The greatest breakthrough in PCA technology came with the introduction of devices making it possible to choose between intermittent (demand bolus) and continuous administration (continuous infusion) or both intermittent and continuous modes. A comparison of these types of PCA devices is described. The limitations of the literature involving PCA therapy in cancer patients make it difficult to identify optimal patient selection criteria, PCA administration schedules, drug selection and dosing, and optimal route of administration. The current status and pertinent issues related to these topics are addressed.