Comparison Neuromuscular Blockade Monitors

The overall objective of this research is to evaluate different laboratory-built and commercially available sensors used to measure the effects of neuromuscular blocking drugs on neuromuscular function during surgery, by measuring evoked thumb twitch response to ulnar nerve stimulation (also known as "twitch monitoring"). The specific aim is to compare mechanomyography, which is the "gold standard" laboratory measurement to assess neuromuscular blockade, to the sensors used in commercially available neuromuscular blockade monitors, such as acceleromyography and electromyography. The study endpoints are the train-of-four count (TOFC), the ratio of the height of the 4th twitch to the height of the 1st twitch (train-of-four ratio, TOFR), and the post tetanic count (PTC). The mechanomyography devices have been constructed in our laboratory and are not commercially available.

Inclusion Criteria: 1. 18 years of age or greater 2. Undergoing anesthesia that requires neuromuscular blocking drugs Exclusion criteria: 1. Less than 18 years of age 2. Undergoing anesthesia that does not require neuromuscular blocking drugs 3. Undergoing a procedure in which access to one or both arms is limited 4. Anatomical abnormalities of the hands or arms that preclude twitch monitoring with ulnar nerve stimulation and evoked thumb twitch response