Impact of patient-controlled analgesia on pain relief after coronary artery bypass graft surgery: a randomized clinical trial.

Introduction: Pain has been pointed out as one of the concerns of cardiac surgery patients. Acute pain management has been a challenge for health professionals and several regiments have been described. We designed this study to evaluate the effectiveness of pain control with patient-controlled analgesia (PCA) versus conventional nurse-controlled analgesia (NCA) during the postoperative period in the intensive care unit (ICU) after coronary artery bypass graft (CABG) surgery.

Methods: In this randomized clinical trial, 80 elective CABG candidates were selected by convenience sampling. They were randomly allocated to two groups to receive either PCA or NCA. PCA plus continuous infusion of morphine started immediately after transferring the patients to the ICU. NCA was based on intravenous injections of morphine on demand. Pain was assessed using a verbal rating scale (VRS). Sedation level and morphine consumption were also evaluated from extubation until 48 hours after surgery. Data was analyzed using SPSS13.

Results: VRS scores were higher in the NCA group compared to the PCA group [3.27 (1.17) vs. 0.75 (0.66); p < 0.001]. Morphine consumption was significantly higher in the PCA group compared to the NCA group [28.43 (7.15) mg vs. 8.37 (5.36) mg; p < 0.001]. PCA was safe and respiratory depression was not observed in any of the subjects. Mean sedation scores did not differ between the two groups.

Conclusion: PCA with background infusion of morphine increases morphine consumption and improves pain relief. It appears to be superior to NCA and can be recommended for patients after CABG surgery.