Received: 26 March 2019
Accepted: 25 June 2019
First Online: 16 July 2019
Ethics approval and consent to participate
: This is a prospective, randomized, double-blinded study which was done after obtaining the approval of the Ain Shams University ethical committee. A written informed consent was taken from 60 patients undergoing elective upper limb surgery.
: Not applicable.
: The authors declare that they have no competing interests.