Effects of Uremia on Brachial Plexus Electrophysiology and Brachial Plexus Block

Adjust the neural stimulator, with a stimulation duration of 0.1 ms, a stimulation frequency of 1Hz, and a stimulation current of 1.0mA. Under ultrasound guidance, the needle tip is used to touch the radial nerve, ulnar nerve, median nerve, and musculocutaneous nerve respectively, until a clear motor response is observed in the corresponding muscles. Thereafter, the minimum stimulation threshold current is verified by reducing the current until the distal motor response disappears. If no motor response is elicited, the current intensity is appropriately increased to achieve a motor response of the extensor tendon of the radial nerve, and the flexor tendon motor responses of the ulnar nerve, median nerve, and musculocutaneous nerve.