What is patient-controlled analgesia (PCA)?

What is patient-controlled analgesia (PCA)?

PCA is a method by which patients self-administer opi-oids, by either the intravenous, epidural, or subcutaneous route. PCA devices consist of an infusion pump connected to a timing device (Figure 72.2). By pressing a button, the patient receives a predetermined bolus dose of medication. Another dose can only be obtained after a preset time interval (lock-out period) has passed. PCA devices also provide the option of administering a continuous infusion, called the basal infusion. Although patients determine when they will give themselves medication, the physicians prescribe the dose, as well as the frequency of administra-tion. With demand dosing, a negative closed loop enhances the system’s safety: excessive plasma opioid levels may induce a somnolent state, during which time the button is not depressed, and additional bolus doses are not adminis-tered until the plasma levels fall.

Features of PCA devices vary, but most include alarms noting occlusion in the line, low battery levels, and when the medication has run out or is low. The systems have a read-out, by which the prescription, as well as information regarding patient’s opioid utilization can be obtained. To prevent unauthorized tampering, the pre-scription can only be changed by the use of a key and by keying a numerical code into the machine. In addition, access to the opioid in the machine is only with the use of a key or combination.