CONTINUOUS THORACIC EPIDURAL ANALGESIA VERSUS COMBINED SPINAL THORACIC EPIDURAL ANALGESIA ON PAIN, PULMONARY-FUNCTION AND THE METABOLIC RESPONSE FOLLOWING COLONIC RESECTION/

Background: The neuroendocrine response following major surgery has no t been previously influenced by either regional anaesthetic techniques or opioid analgesia probably due to insufficient intraoperative affer ent neural blockade. In this study we attempted to determine whether s ignificant inhibition of these pathways could be achieved by combining preoperative high spinal anaesthesia with postoperative thoracic epid ural anaesthesia. In theory too, there may be additional benefits over perioperative thoracic epidural anaesthesia on pain and pulmonary dys function. Methods: 20 ASA 1-3 patients undergoing elective colonic sur gery were studied. Gp 1 (n=10) received a high spinal intraoperative b lock to T4 using 6mls of 0.5% bupivacaine plus continuous epidural 0.1 25% bupivacaine/0.0025% diamorphine. Gp 2 (n=10) patients received epi dural 0.5% bupivacaine block to T4 plus continuous epidural infusion o f 0.125% bupivacaine/0.0025% diamorphine. We measured a) plasma glucos e and cortisol at 0, 1, 2, 3, 4, 8 and 24 h; b) forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and peak fl ow rate (PFR) preoperatively, at 8 and 24 h; c) visual analogue pain s cores (VAS 0-10) at rest, cough and mobilisation at 8 and 24 h; d) blo ck height every hour for 12 hows then 3 hourly; e) 24-hour urine volum es for dopamine, adrenaline and noradrenaline f) 24-hour PCA morphine requirements. Results: The two groups did not differ in age, sex, heig ht, weight, duration of surgery, blood loss or serum albumin. Pain rel ief was excellent and similar in both groups. The average 24 hour morp hine consumption was 10 mg in both groups with no differences in the b lock height. All the patients had a 30-50% reduction in FEV1, FVC and PFR (P>0.05). Metabolically, there was no statistical difference betwe en the 2 groups except a higher rise in glucose in Gp1 at 2 and 3 h (P =0.0312 and 0.014). 24-hour catecholamine studies showed no difference s for noradrenaline (P=0.8), adrenaline (P=0.47) and dopamine (P=0.36) . Conclusions: Thoracic epidural bupivacaine/diamorphine infusion prov ided excellent postoperative analgesia following colonic surgery. An i ntraoperative combined spinal/epidural technique conferred no addition al benefit on analgesia, pulmonary function and the neuroendocrine res ponse.