Intravenous patient-controlled analgesia (PCA) can provide improved postoperative pain control compared with traditional methods, while maintaining safety. However, poorly managed PCA cannot be expected to provide good analgesia and may increase the risk of adverse events. Effective use of PCA comes with experience in using this technique; the learning process may, however, be accelerated by taking advantage of the published experience of others. PCA is most effective when used in an environment where a high priority is given to pain control and patient comfort. This may be achieved by establishing an acute pain service (APS) to advise on, supervise and monitor acute pain management. This may consist of a multidisciplinary team or a nurse dedicated to pain control; in any case the benefits will outweigh the cost and effort involved in establishing the service. The APS can play an important role in staff education. All staff involved with PCA management need specialised knowledge. All should be aware of the basic principals of PCA; specific staff groups will need to know how to program PCA pumps, how to prepare drug solutions, how to prescribe PCA and vary the PCA prescription to suit individual patients, and how to monitor patients and resolve problems such as inadequate analgesia or excessive adverse effects. Patients need to be carefully selected for PCA. PCA is most suitable for patients having major surgery which would normally lead to pain requiring opioids for more than a day. Selected patients should have a positive attitude toward involvement in their own pain management. Some patients, e.g. those with sleep apnoea, substance abusers and patients likely to become hypovolaemic pose special problems, but PCA may still be used with additional precautions. All patients require education about PCA; at the very minimum they must understand that the button is to be pressed when they have pain and want relief, but most patients will benefit from more detailed information. Safety will be enhanced if initial PCA prescriptions are standardised, e.g. drug = morphine, demand dose size = 1.0mg (this should be reduced in elderly patients), lockout interval = 8 minutes. The addition of a background infusion or other drugs such as antiemetics into the PCA drug solution, should not be routinely employed. During PCA therapy, the patient's respiratory rate and level of consciousness should be monitored, and the recorded and observed use of PCA drug solution checked at least hourly. If the patient is stable during the first 8 hours subsequent monitoring may be reduced to 2 hourly. Patients with risk factors, e.g. sleep apnoea, hypovolaemia or with poor pain control, need more frequent monitoring. A protocol for the management of adverse effects such as nausea and vomiting should be instituted to ensure prompt and effective treatment.
