According to WebMD, "PCA" stands for patient controlled analgesic. With this type of pain control, the patient is able to increase or lower the medication as they need it. Sometimes, the pump gives out a small, steady flow of pain medication that allows a patiend to add more if needed.
Patient controlled analgesics are made up of a computerized mechanism consisting of a pump and an IV line, according to WebMD. There are safety features built in so that the patient cannot administer more than the safe dosage, even if they continue to hit the controls to keep increasing. Patient controlled analgesics can be in place for adults or even children as young as 7 years of age.