A prospective, randomized comparison of preoperative and continuous balanced epidural or paravertebral bupivacaine on post-thoracotomy pain, pulmonary function and stress responses

Both epidural and paravertebral blocks are effective in controlling post-thoracotomy pain, but comparison of preoperative and balanced techniques, measuring pulmonary function and stress responses, has not been undertaken previously. We studied 100 adult patients, premedicated with morphine and diclofenac, allocated randomly to receive thoracic epidural bupivacaine or thoracic paravertebral bupivacaine as preoperative bolus doses followed by continuous infusions. All patients also received diclofenac and patient-controlled morphine. Significantly lower visual analogue pain scores at rest and on coughing were found in the paravertebral group and patient-controlled morphine requirements were less. Pulmonary function was significantly better preserved in the paravertebral group who had higher oxygen saturations and less postoperative respiratory morbidity. There was a significant increase in plasma concentrations of cortisol from baseline in both the epidural and paravertebral groups and in plasma glucose concentrations in the epidural group, but no significant change from baseline in plasma glucose in the paravertebral group. Areas under the plasma concentration vs time curves for cortisol and glucose were significantly lower in the paravertebral groups. Side effects, especially nausea, vomiting and hypotension, were troublesome only in the epidural group. We conclude that with these regimens, paravertebral block was superior to epidural bupivacaine.