Lidocaine Combined Dexmedetomidine for Obturator Nerve Block

A selective obturator nerve block(ONB) is an effective alternative to suppress the obturator nerve reflex which is defined as a sudden, violent adductor muscle spasm when the obturator nerve is stimulated directly by the electronic resector during transurethral resection of the tumor on the lateral bladder wall. Studies showed Dexmedetomidine as an adjuvant to local anesthetic prolongs peripheral nerve block duration without any nerve toxicity. In the following randomized, non-crossover study, the investigators test if Dexmedetomidine as an adjuvant can decrease the median effective concentration(EC50) of lidocaine for obturator nerve block during transurethral resection of bladder tumor.

Inclusion criteria

• Subjects scheduled to undergo elective operation of TURBT on lateral wall for whom ONB was needed diagnosed through cystoscopy or CT examination preoperatively.
• Subject's American Society of Anesthesiologists physical status is I-II.
• The subject's parent/legally authorized guardian has given written informed consent to participate.

Exclusion criteria

• Subject has a diagnosis of abnormal coagulation function.
• Subject has a diagnosis of Diabetes mellitus.
• Subject has a preexisting neurologic deficits of the lower extremities.
• Subject has a history of alcohol or drug abuse.
• Subject is pregnant or breast-feeding.
• Subject is obese (body mass index >30kg/m2).