Clinical Aspects of Continuous Epidural Blockade for Postoperative Pain Relief

Abstract

Continuous epidural blockade using a 0.4% lidocaine drip during two days was given for the relief of pain in a total of 46 patients of which 41 were otherwise healthy patients who underwent cholecystectomy. A detailed physiological investigation was performed in 23 patients, of whom 13 had blockade of thoracic type with an epidural catheter inserted at the T₅-T₆ interspace and a mean dermatome spread from T₂ to T₁₂. Ten patients had blockade of lumbar type with a catheter inserted at the L₁-L₂ interspace with a mean dermatome spread from T₄ to L₄. The rest of the patients constituted a clinical control group and received the thoracic type of blockade. Successful analgesia was obtained in 92% of the patients with thoracic and in only 10% of the patients with lumbar blockade. Fluids were supplied richly and adequately to the condition of the patients. In a representative period of analgesia about 17 hours after surgery there were in both groups of investigated patients fairly similar changes in physiological variables. On an average there was a significant increase in cardiac output by 43% and in heart rate by 17%, a significant decrease in total peripheral vascular resistance by 27%, a probably significant decrease in mean arterial blood pressure by 9% and no significant increase in heart work. There was a relative improvement of ventilation. The need of lidocaine to obtain analgesia for patients with lumbar blockade was considerably larger, about 50%, compared with patients with thoracic blockade. Clinical signs of toxicity were occasionally seen in all patients with lumbar analgesia but in only three of the patients with thoracic analgesia. Urinary retention requiring bladder catheterization occurred in 6/13 of the investigated patients with thoracic analgesia and in 8/9 of the patients with lumbar analgesia. In this material of high laparotomies, continuous epidural blockade of thoracic type has shown several advantages to blockade of lumbar type concerning some physiological variables but especially concerning the analgesia obtained, the clinical condition and ambulation of the patients.