RESUMO
Objective To determine the dose-response relationship of ropivacaine for paravertebral nerve block in treating acute severe herpetic neuralgia.Methods One hundred patients with herpetic neuralgia,with the course of disease ≤ 1 month,of numeric rating scale score ≥ 7 points,scheduled for elective paravertebral nerve block with ropivacaine under ultrasound guidance,were divided into 5 groups n=20 each) using a random number table method:5 different concentrations of ropivacaine groups R1.5 groups).The herpes zoster-affected thoracic spinal nerves were identified,and the mixture 5 ml was injected into the paravertebral space corresponding to the spinal nerves.The mixture solution contained ropivacaine with the concentrations of 0.075 0％ (group R1),0.112 5％ (group R2),0.150 0％ (group R3),0.187 5％ (group R4) and 0.225 0％ (group R5),compound betamethasone 1 ml,and mecobalamin injection 1 ml diluted to 20 ml with normal saline.Effective block was defined as numeric rating scale score≤ 1 point at 10 min after paravertebral nerve block with ropivacaine.The median effective concentration (EC50),95％ effective concentration (EC9s) and 95％ confidence interval of ropivacaine for paravertebral nerve block in treating acute severe shingles neuralgia were calculated by Probit analysis.Results The EC50 and EC95 (95％ confidence interval) of ropivacaine for paravertebral nerve block in treating acute severe shingles neuralgia were 0.150 0％ (0.097 0％-0.216 0％) and 0.216 0％ (0.175 0％-0.541 0％),respectively.Conclusion The EC50and EC95 of ropivacaine for paravertebral nerve block in treating acute severe herpetic neuralgia are 0.150 0％ and 0.216 0％,respectively.