I-Corps: Quantitative Train-of-Four monitoring device for quantitatively monitoring neuromuscular blockade in patients undergoing surgery

The broader impact/commercial potential of this I-Corps project is the development of a Train-of-Four (TOF) device to provide a method of quantitatively monitoring neuromuscular blockade in patients undergoing surgery. Neuromuscular blocking agents (NMBAs) are used extensively to temporarily paralyze patients during surgery. Current methods of measurement have a risk of postoperative residual neuromuscular blockade, where NMBAs remaining in the body after surgery.

This postoperative problem can cause muscle weakness and critical respiratory episodes. The current standard Train-of-Four (TOF) monitoring method is qualitative, and anesthesiologists must depend on their eyesight and experience to judge the correct dosing of patients. The proposed device produces a quantitative output, TOF data, to help anesthesiologists gauge how much neuromuscular blockade to administer to each patient and when to reverse its effects.

By ensuring complete neuromuscular recovery, the proposed device minimizes respiratory complications and the unpleasant symptom of muscle weakness caused by residual neuromuscular blocking agents in the body post-surgery. The device may prevent unwanted post-operative stress, while potentially saving money for hospitals.

This I-Corps project is based on the development of a mechanomyography device that uses medical grade balloons for converting patient response to Train-of-Four (TOF) data. In the device, the use of a peripheral nerve stimulator on the ulnar nerve causes thumb twitches that apply pressure on a balloon. These pressure fluctuations are picked up by a sensor and converted into TOF data to accurately measure the level of neuromuscular blockade in the body by using pressure as the physical analog of muscle numbness and converting it into an electrical signal.

The proposed device utilizes mechanomyography, which is thought to be the gold standard and most accurate technology for monitoring neuromuscular blockade, since it directly measures the motion generated as the muscle responds to the ulnar nerve stimulation. There is currently no mechanomyography device on the market to monitor neuromuscular blockade.

Furthermore, the proposed device assesses the TOF count and TOF ratio even in positions where the thumb’s movement is restricted; for example, when the hands are tucked beside the body. These types of surgical positions are becoming more frequent with increased use of laparoscopic surgeries. The current technologies in assessing neuromuscular blockade are not functional in these types of surgical positions.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.