Effectiveness and safety of compound lidocaine hydrochloride and menthol solution for the rabbit superior cervical sympathetic ganglion block

Abstract

Objective To investigate the effectiveness and safety of compound lidocaine hydrochloride and menthol solution for the superior cervical sympathetic ganglion block in rabbits. Methods Seventy-two healthy pathogen-free New Zealand rabbits of both sexes, aged 4 months, weighing 2.5-3.5 kg, were divided into 2 groups using a random number table: lidocaine group (Group L) and compound lidocaine hydrochloride group (Group K), 36 cases in each group. All rabbits were anesthetized with katamine. Then the left superior cervical ganglions were exposed, 0.4 ml 2% lidocaine was dropped near the ganglion in group L, while 0.4 ml compound lidocaine hydrochloride and menthol solution was dropped at the same place in group K. The persistence time of Horner's syndrome was observed, the extent of ptosis and the skin temperature were also recorded before the block, and 5 min, 30 min, 1 week, 2 weeks after the block. Furthermore, 6 rabbits were anesthetized and their left superior cervical ganglions were taken out before the block and 2 h, 1 week, 2 weeks after the block. Cytomorphology and ultrastructure were observed with HE staining, toluidine blue staining and electromicroscope. Results Horner's syndrome appeared in all rabbits, but it appeared later and lasted longer in group K than that in group L (P 0.05). But the content of Nissl bodies was still less at 2 weeks after the block than that before the block in group K (P 0.05). Conclusion Compound lidocaine hydrochloride and menthol solution is effective and safe with longer action for block superior cervical ganglion in rabbits. Key words: Ganglia, sympathetic; Nerve block; Lidocaine; Nissl body; Rabbit