Feasibility of using dexmedetomidine as supplement to stellate ganglion block in treatment of trigeminal post-herpetic neuralgia in elderly patients

Abstract

Objective To evaluate the feasibility of using dexmedetomidine (Dex) as supplement to stellate ganglion block (SGB) in the treatment of trigcminal post-herpetic neuralgia in elderly patients.Methods Forty-five ASA Ⅱ patients with trigeminal post-herpetic neuralgia aged 65-85 yr weighing 45-85 kg undergoing stellate ganglion block were randomly divided into 3 groups ( n =15 each): group SGB; group Dex 0.4 and 0.6 μg/kg +SGB (groups DS1 and DS2).SGB was performed on the affected side with 0.5％ ropivacaine 8-10 ml.Dex 0.4 and 0.6 μg/kg in normal saline were infused iv over 15 min before SGB in groups DS1 and DS2 respectively.The onset time and duration of block were recorded.Bradycardia,hypotension and respiratory depression were also recorded.The intensity of pain was assessed with VAS scores (0=no pain,10 =worst pain) before and at 1,2,4,8 weeks after SGB.VAS score ≤3 was defined as satisfactory analgesia.The rate of satisfactory analgesia was calculated.Results There was no significant difference in the incidence of bradycardia,hypotension and respiratory depression among the 3 groups.The duration of block was significantly longer and the rate of satisfactory analgesia at 2,4,8 weeks after SGB was significantly higher in groups DS1 and DS2 than in group SGB.There was no significant difference in the onset time,duration of block and the rate of satisfactory analgesia between groups DS1 and DS2.Conclusion SGB with Dex has better therapeutic effect than SGB in elderly patients with trigeminal post-herpetic neuralgia. Key words: Dexmedetomidine; Stellate ganglion; Autonomic nerve block; Neuralgia, postherpetic; Elderly; Analgesia