Predictive Factors for Hypotensive Bradycardic Events During Arthroscopic Shoulder Surgery

After sterile draping around interscalene groove with povidone, a nerve stimulating needle connected to a nerve stimulator is inserted through the interscalene groove. Following involuntary contraction of shoulder, arm, forearm, or hand muscles with 0.5 milliamperes at 1 Hz using the nerve stimulator, 30 to 40 ml of mixture of 1% mepivacaine 20 ml and 0.75% ropivacaine 20 ml are injected.