Postoperative pain relief and respiratory performance after thoracotomy: a controlled trial comparing the effect of epidural morphine and subcutaneous nicomorphine.
Twenty patients scheduled for lateral thoracotomy were randomly allocated to receive either epidural morphine at regular intervals or subcutaneous nicomorphine on demand for postoperative pain relief. The daily dose of opiate administered was greater in the group receiving subcutaneous nicomorphine than in the epidural group although four patients in the latter needed additional subcutaneous injections of opiate. During the first three days of the postoperative course, a profound decrease of the forced vital capacity (FVC), the forced expiratory volume in one second (FEV1), peak expiratory flow rate (PEF) and the arterial oxygen tension (PaO2) was found in both groups, whereas the visual analogue pain score showed a marked increase, and the arterial pH and carbon dioxide tension (PaCO2) remained unchanged. No significant difference could be demonstrated between the group;s. The conclusion is that epidural morphine may produce sufficient pain relief after thoracotomy, but compared with conventional pain treatment the benefits are limited.