Objectives: This study was designed to determine whether a continuous thoracic paravertebral infusion of bupivacaine (continuous TPVI) offers a higher quality of analgesia than a bolus regimen after thoracotomy.
Design: A prospective and randomized study.
Setting: It was conducted by an anesthesiology and pain clinic department in a university hospital.
Participants: Thirty patients were included in this study.
Interventions: As postoperative analgesia, the patients received either 20 mL of 0.375% bupivacaine every 6 hours (n = 15; bolus group), or a loading dose of 15 mL of 0.375% bupivacaine, plus an infusion of 5 mL of 0.25% bupivacaine every hour (n = 15; infusion group).
Measurements and main results: Pain intensity was assessed at rest and on movement (coughing) at 0, 1, 4, 10, 20, and 48 hours by means of the visual analog scale. The need for additional rescue analgesia, bupivacaine plasma concentration in the infusion group, blockade level (pinprick), and vital signs were also recorded. There were no significant differences regarding the additional rescue analgesia, vital signs, and pinprick level. However, the pain scores were significantly higher in the bolus group at rest and on movement (p < 0.01). The bupivacaine plasma concentration was low with a Cmax of 1.841 +/- 0.20 micrograms/mL at 15 hours. No systemic toxicity or other side effects were seen.
Conclusion: Results suggest that continuous TPVI provides better pain control than the bolus regimen after this kind of surgery.