Letters To The Editor: Letters & Announcements
We welcome Dr. Cole’s comments and interest in our paper. He describes complete success after the use of interpleural bupivacaine to manage shoulder pain in 20 patients after a number of surgical procedures.
After our demonstration of the effect of phrenic nerve block for shoulder pain in patients with thoracic epidural analgesia, we also considered interpleural analgesia as a potentially simple and repeatable method of managing this common clinical problem. It should be noted that, in the absence of a functioning thoracic epidural, interpleural analgesia alone is not effective for postthoracotomy pain (1).
Our initial clinical impression was that interpleural bupivacaine is indeed effective in reducing ipsilateral shoulder pain in some patients after thoracotomy. However, it had little effect after esophagogastrectomy. These patients have much more extensive surgical involvement of the diaphragm, and it may be that interpleural bupivacaine causes topical analgesia at the site of contact between the diaphragm and the drain, rather than along the entire course of the phrenic nerve, as Dr. Cole suggests.
Although clinical observations such as those of Dr. Cole are interesting, they need to be rigorously tested by scientific study. In addition, interpleural bupivacaine is not without the potential for harm (2). For these reasons, we have undertaken a double-blinded, randomized placebo-controlled study of patients undergoing thoracotomy with thoracic epidural analgesia. Those who develop characteristic ipsilateral shoulder pain receive either 40 mL bupivacaine 0.25% with 1:200,000 adrenaline or 40 mL normal saline administered via the basal (diaphragmatic) drain. Our study is still in progress and it is blinded until recruitment is complete. We hope to have the data in the public domain in the near future, which will define the role of interpleural analgesia in this very specific clinical situation.
N. D. A. Scawn, FRCA
G. N. Russell, FRCA
1. Silomon M, Claus T, Huwer H, et al. Interpleural analgesia does not influence post-thoracotomy pain. Anesth Analg 2000; 9144–50.
2. Gallart L, Gea J, Aguar MC, et al. Effects of interpleural bupivacaine on respiratory muscle strength and pulmonary function. Anesthesiology 1995; 83: 48–55.