Interpleural analgesia with bupivacaine following thoracotomy: ineffective results of a controlled study and pharmacokinetics.

STUDY OBJECTIVE

To evaluate intrapleural analgesia with bupivacaine following partial pulmonary resection and to determine pharmacokinetic parameters of bupivacaine with epinephrine.

DESIGN

Prospective, randomized study.

SETTING

Thoracic surgical clinic of a university-affiliated general hospital.

PATIENTS

Eighteen consecutive patients (13 men, 5 women) scheduled for pulmonary surgery by posterolateral thoracotomy.

INTERVENTIONS

Bupivacaine was administered through an intrapleural catheter as a bolus dose of either 40 ml of 0.25% bupivacaine with epinephrine (0.5 mg per 100 ml of solution) (n = 10) or 20 ml of 0.5% bupivacaine with epinephrine (0.5 mg per 100 ml of solution) (n = 8) up to three times daily for a maximum time of 4 days.

MEASUREMENTS AND MAIN RESULTS

Subjective evaluation of pain was performed using the visual analog scale (VAS) before and after each injection by response to spontaneous pain, coughing, deep breathing, and incision palpation. Maximum peak concentration (C Max) and maximum time to reach the peak concentration (T Max) were assessed after the first and last injections. Although VAS pain score decreased significantly, pain relief was not sufficient. C Max and T Max after the first and last injections were not significantly different between the two groups. In each group, C Max after the last injection was significantly higher than after the first injection.

CONCLUSIONS

Intrapleural analgesia conducted with 40 ml of 0.25% bupivacaine with epinephrine or 20 ml of 0.5% bupivacaine with epinephrine was insufficient for pain, despite high plasma bupivacaine concentration.