Infiltration of the sternotomy wound and the mediastinal tube sites with 0.25% levobupivacaine as adjunctive treatment for postoperative pain after cardiac surgery.

BACKGROUND AND

OBJECTIVE

This study aimed to investigate the effect of 0.25% levobupivacaine infiltration of the sternotomy wound and the mediastinal tube sites on postoperative pain, morphine consumption and side-effects in patients undergoing cardiac surgery.

METHODS

After obtaining Ethics Committee approval and informed consent,50 patients aged 18-65 yr, undergoing coronary artery bypass grafting, were included in this study. Anaesthesia was induced with 5 microg kg (-1) fentanyl, 0.3 mg kg (-1) etomidate, 1 mg kg (-1) lidocaine, 0.1 mg kg (-1) vecuronium and maintained with 1-2% sevoflurane, 50% oxygen in air and fentanyl. Patients were randomized into two groups before sternal wire placement: sternotomy and mediastinal tube sites were infiltrated with either 60 mL 0.25% levobupivacaine (infiltration group, n = 25) or 60 mL saline placebo (control group, n = 25). All patients received intravenous morphine patient-controlled analgesia (bolus dose: 2 mg, lock-out time: 15 min, 4 h limit: 20 mg) after extubation. Postoperative pain at rest and on coughing was assessed by a visual analogue scale (0-10). Pain scores,sedation scores (Ramsay scale), haemodynamic and respiratory parameters, arterial blood gases and morphine consumption were recorded.

RESULTS

The times to extubation and visual analogue scale scores were similar between groups. Morphine consumption at 24 h was significantly lower in the infiltration group compared with the control group (29.5 +/- 5.1 vs. 42.8 +/- 4.7 mg, respectively, P < 0.05). The sedation scores were found to be significantly higher in the control group when compared with the infiltration group at 1, 2 and 4 h after extubation (P < 0.05), whereas sedation scores after 4 h were similar between groups.

CONCLUSION

Infiltration of the median sternotomy incision and the mediastinal tube insertion sites with 0.25% levobupivacaine in addition to morphine patient-controlled analgesia was found to be effective in reducing postoperative morphine consumption when compared with morphine patient-controlled analgesia alone during the initial 24 h after cardiac surgery.