Comparison of anesthetic effects of epidural and intravenous administration of buprenorphine during operation

Abstract

Thirty six patients were received epidural anesthesia with or without buprenorphine (BPN) during upper abdominal surgery. They were divided into three groups of 12 patients as follows; G-I received 20 ml of 1% lidocaine epidurally, G-II received 20 rnl of 1% lidocaine epidurally and 0.6 mg BPN intravenously, G-III received 20 ml of 1% lidocaine with 0.6 mg BPN epidurally. Additional 5 rnl of 1% lidocaine was given to any patient if systolic blood pressure or heart rate increased 10% compared to control value. Trachea was intubated following anesthetic induction with thiopental. The lungs were ventilated with a mixture of N₂O/O₂ (33%) and pancuronium was used for muscle relaxation. The total required doses of lidocaine in G-II and G-III were decreased 60% compared to control group (G-I) (P< 0.05). The mean period of time until the first administration of pentazocine for postoperative pain was 13 ± 10 hr (mean ± SD) in G-II and 19 ± 24 hr in G-III compared to 5 ± 4 hr in G-I (P< 0.001). The dose of the administration of pentazocine that was required for pain relief during the first 48 postoperative hr in G-III was 54 ± 10 mg (mean ± SD) compared to 150 ± 21 mg in G-I (P< 0.02) and 106 ± 28 mg in G-II (P< 0.05). Recovery from anesthesia in G-III was more rapid than that in G-I (P< 0.05). The$Pa_{CO_2 }$ values in G-II and G-III increased 15% compared to control group at about 4 hr and 8 hr after administration of BPN, but any clinical treatment was not needed for them. Nonrespiratory side effects, e.g., nausea, vomiting, fatigue and headache, were comparably common in all groups. Mild hematuria associated with acute hypotension occurred in two patients in G-II (17%) immediately after the intravenous injection of 0.6 mg of BPN. The results showed that 0.6 mg of BPN given epidurally demonstrated better anesthetic and more potent postoperative analgesic effects and lesser side effects than 0.6 mg of BPN given intravenously in patients undergoing upper abdominal surgery.