A patient care system in which a physiological parameter of a patient is monitored while the patient self-administers analgesic. A display presents a trend of the patient's physiological parameter along with the time of self-administration of the analgesic ("PCA"-patient controlled analgesic) such that the effect of the analgesic on the physiological parameter can be seen over selectable time periods. The physiological parameter may be ETCO 2 or SpO 2 or other. Also included is a drug library having acceptable pumping parameters as well as other PCA specific data. Should the operator program a pumping parameter that is outside an acceptable range, or should the patient attempt to self-administer more analgesic than the acceptable range permits, or should a patient's physiological parameter change during infusion such that a pumping parameter becomes outside an acceptable range, an indication of such will be given and action, such as stopping the pump, will be taken.