Patient-Controlled Analgesia

Patient-controlled analgesia (PCA) is a method for controlling pain in which a patient is able to self-administer pain medications via activation of a mechanical distribution system. The key element of PCA is that the patient is in control of the analgesia. Respiratory depression is preceded by sedation, and a sedated patient is unable or unlikely to push the PCA button. The pump can also be programmed to have a continuous infusion rate, which is administered to the patient regardless of whether the patient activates a dose. Basal rates bypass the safety mechanism of patient control and can place the patient at higher risk for respiratory depression and sedation. Initiation of a PCA is often most appropriate in patients requiring frequent as-needed dosing of medications or when such dosing is anticipated. Patients’ acceptance of the technique is high, related in part to a sense of control over their own pain relief, a reduction in the delay for the receipt of pain medications, not receiving injections, and not having to interrupt or to bother nurses. This review contains 2 tables and 20 references.  Key words: analgesic delivery systems, morphine metabolism, multimodal pain management, opioid pharmacology, opioid side effects, patient-controlled analgesia, patient safety, respiratory depression