Patient-controlled analgesia in postoperative cardiac surgery

The purpose of this study was to assess, in the early postoperative period of cardiac surgery, the efficacy of patient-controlled analgesia (PCA) versus nurse-administered intravenous morphine followed by oral acetaminophen with or without codeine. Patients undergoing coronary bypass and/or valvular surgery were recruited. All were under 75 years of age and were in stable angina with no ischaemic attacks within the last three months. Visual analog scores (VAS) were used for pain assessment. Pulmonary function tests were done preoperatively and measured every six hours after surgery until discharge from the intensive care unit. Patients allocated to the PCA group received morphine intravenously by a PCA Plus Micro Delivery Device for at least 48 hours. Patients entered into the nurse-administered intravenous morphine group received intravenous morphine followed by oral acetaminophen with or without codeine in 24 to 36 hours according to the clinical assessment of the critical care nurse. The data showed that the quality of pain control and pulmonary function were comparable in both groups. The equipotent morphine dosage requirements were also not statistically different. It was concluded that there was no significant advantage in using PCA routinely in the early postoperative period after cardiac surgery. Furthermore, repetition of PCA instructions was often required during the study period.