CONTINUOUS-INFUSION IS SUPERIOR TO BOLUS DOSES WITH THORACIC PARAVERTEBRAL BLOCKS AFTER THORACOTOMIES

Objectives: This study was designed to determine whether a continuous thoracic paravertebral infusion of bupivacaine (continuous TPVI) offer s a higher quality of analgesia than a bolus regimen after thoracotomy . Design: A prospective and randomized study. Setting: It was conducte d by an anesthesiology and pain clinic department in a university hosp ital. Participants: Thirty patients were included in this study. Inter ventions: As postoperative analgesia, the patients received either 20 mL of 0.375% bupivacaine every 6 hours (n = 15; bolus group), or a loa ding dose of 15 mt of 0.375% bupivacaine, plus an infusion of 5 mL of 0.25% bupivacaine every hour (n = 15; infusion group). Measurements an d Main Results: Pain intensity was assess at rest and on movement (cou ghing) at 0, 1, 4, 10, 20, and 48 hours by means of the visual analog scale. The need for additional rescue analgesia, bupivacaine plasma co ncentration in the infusion group, blockade level (pinprick), and vita l signs were also recorded. There were no significant differences rega rding the additional rescue analgesia, vital signs, and pinprick level . However, the pain scores were significantly higher in the bolus grou p at rest and on movement (p < 0.01). The bupivacaine plasma concentra tion was low with a C-max of 1.841 +/- 0.20 mu g/mL at 15 hours. No sy stemic toxicity or other side effects were seen. Conclusion: Results s uggest that continuous TPVI provides better pain control than the bolu s regimen after this kind of surgery. Copyright (C) 1996 by W.B. Saund ers Company