The 50% effective dose of dexmedetomidine for sedation in the brachial plexus block / 中国医师进修杂志

ABSTRACT

Objective To determine the 50%effective dose (ED 50) of dexmedetomidine for sedation in the brachial plexus block, so as to provide reference for clinical. Methods Twenty-three patients underwent the brachial plexus block using an ultrasound guided technique. After blocked for 30 min, the dexmedetomidine was infused by a intravenous continuous pump,and an observer' s assessment of alertness/sedation score (OAA/S) and auditory evoked potential index (AEPI) were used for monitoring the depth of sedation. The dexmedetomidine was adjusted according to the response of the previous patient using a up-and-down sequential method until the sequential response curve appeared seven fold points. The initial dexmedetomidine of the first patient was 1μg/kg. Each time the dosage increased/decreased by 0.1μg/kg. The OAA/S score of no more than 3 was defined an effective sedation. Results The ED50 of dexmedetomidine for sedation was 0.78μg/kg (95%CI 0.66-0.86μg/kg). The AAI was positively correlated to the OAA/S score, and linear regression equation was Y=-1.43+0.109 X, R2=0.919. Conclusion The ED50 of dexmedetomidine for sedation in the brachial plexus block is 0.78μg/kg (95%CI 0.66-0.86μg/kg).