Bi-level charge pulse apparatus to facilitate nerve location during peropheral nerve block procedures

摘要

An electrolocation apparatus is provided for locating a nerve to which anesthesia may be delivered. The apparatus includes a needle assembly having an electrically conductive needle cannula non-conductive tube secured over the needle cannula, and a conductive plating on the tube. The conductors are connected to a stimulator that generates alternating high and low charge pulses with a constant low current level. The high charge pulses generate noticeable muscle twitches immediately after insertion of the needle into .the patient. Muscle twitches responsive to the high charge pulses will peak in magnitude, and muscle twitches responsive to the low charge pulses will become observable as the needle approaches the targeted nerve, and will be indistinguishable from the muscle twitches responsive to the high charge pulses when the needle is in a position for administration of anesthetic.