Dose-response relationship of 0.2％ ropivacaine for ultrasound-guided stellate ganglion block

Abstract

Objective To determine the dose-response relationship of 0.2％ ropivacaine for ultrasoundguided stellate ganglion block (SGB).Methods Seventy-five ASA physical status [or Ⅱ patients with migraine,aged 23-55 yr,with body mass index of 22-28 kg/m2,scheduled for elective ultrasound-guided SGB,were randomly divided into R1-5 groups (n =15 each) using a random number table.In R1,R2,R3,R4 and R5 groups,the patients underwent ultrasound-guided SGB with 0.2％ ropivacaine 1,2,3,4 and 5 ml,respectively.A successful SGB block was confirmed by the onset of ptosis (Horner syndrome) on the injected side.Probit analysis was used to calculate the effective dose of 0.2 ％ ropivacaine in 50 ％ and 95 ％ of the patients (ED50 and ED95) and 95％ confidence interval (95％ CI).Results The ED50 of 0.2％ ropivacaine for ultrasound-guided SGB was 2.2 ml (95％CI 1.9-2.5 ml) and ED95 was 3.2 ml (95％CI 2.8-4.1 ml).Conclusion The ED50 and ED95 of 0.2％ ropivacaine for ultrasound-guided SGB are 2.2 and 3.2 ml,respectively. Key words: Amides; Dose-response relationship, drug; Ultrasonography ; Stellate ganglion ; Nerve block