Comparison study of two different patient-controlled anesthesia regiments after cardiac surgery.

Introduction: Acute and severe pain is frequent in patients who undergo cardiothoracic surgery. Patient controlled analgesia (PCA) can be used to manage postoperative pain.

Objective: To compare analgesia of morphine PCA alone without continuous infusion with morphine PCA plus a continuous infusion on postoperative period after cardiac surgery and to evaluate pain scores, morphine consumption, number of demand, patient satisfaction and side effects.

Methods: Randomized trial was conducted to assess patients who underwent cardiac surgery receiving either morphine PCA alone or morphine PCA plus continuous infusion. In the post operative period, PCA was started at extubation in both regiments according to randomization. Pain intensity, morphine consumption, number of demand, satisfaction and side effects were assessed at zero, six, twelve, eighteen, twenty four and thirty hours after patients' extubation.

Results: The study enrolled 100 patients. 50 patients received morphine PCA alone, (Group A) and 50 patients received morphine PCA plus a background infusion, (Group B). Group B patients had less demand, consumed more morphine and were more satisfied regarding analgesia. No statistical differences were shown between groups related to pain intensity, and side effects.

Conclusions: Pain control was effective and similar in both groups. Morphine PCA alone seems to be better for postoperative pain manage in cardiac surgery, due to its less morphine expense with the same effectiveness.