Patient-controlled analgesia

Patient-controlled analgesia (PCA) is any method of allowing a person in pain to adminster their own pain relief. The most common form of this is the paracetamol that each of us keeps in our bathroom cabinet. We have a headache, we take some paracetamol, we wait for an improvement. If there is no improvement we take some more. Here we are in control, and as pain is a combination of tissue damage and emotional state, being in control means reducing the emotional component of pain.

PCA has now passed into medical jargon to mean the electronically controlled intravenous pump that delivers a prescribed amount of analgesic to the patient when he or she activates a button. Among the benefits of this device are that it saves time between when the patient feels pain and/or the need to receive analgesia and when it is administered (activation automatically pumps the dose into a pre- existing IV line into the patient), it reduces workload of the medical staff (an amount of the prescribed analgeisc is pre- loaded into the PCA, enough for multiple doses) and it reduces the chances for medication errors (the PCA is programmed per the physician's order for amount and interval between doses and "locks out" the patient if he or she attempts to self- administer too often.). Patients who use PCAs report better analgesia and lower pain scores than those patients who have to request analgesia from the nursing staff when they are in pain.

Disadvantages: Patients may be unwilling to use the PCA or be physically or mentally unable to. The pumps are expensive and may malfunction. More importantly, the dosing regimen may be set so that the patient does not receive enough analgesia (bolus doses set too small, lock-out too long). When the patient sleeps, the analgesic wears off so they wake in pain. This is sometimes countered by setting a background continuous infusion of the analgesia.