Postoperative patient-controlled analgesia (PCA): How much control and how much analgesia?

Postoperative patients received one of the three, alternative pain-management treatments: patient-controlled analgesia (PCA); perceived PCA (PPCA without actual control) and continuous intravenous infusion of analgesics (CII). Pain reports, morphine consumption and satisfaction of the groups were compared, and influences of individual differences in preferences for control and trait anxiety were tested. The main findings were: (1) PCA patients consumed less morphine and reported more pain and somewhat higher satisfaction; (2) PPCA patients were intermediate between the other two groups in pain reports and morphine consumption and lowest in satisfaction and (3) individual differences did not moderate the effects of PCA. The findings were interpreted as indicating that the main effect of PCA is increased pain tolerance, and that a bio-psycho-social framework is most appropriate to explain these effects.