Method and apparatus for determining the level of neuromuscular block in a patient

摘要

Electrical stimulus pulses are provided to the ulnar nerve of a patient and the adduction of the patient's thumb in response to the pulses is measured by a strain gage force transducer attached to the thumb and wrist of the patient. The force transducer provides an electrical output signal proportional to the magnitude of the thumb response, and this signal is subsequently amplified, filtered, digitized and then provided to a controller which includes a microprocesser. In a preferred procedure for determining the level of neuromuscular block in a patient by estimating twitch height depression without using control responses, a train of four pulses is applied to the patient over a two second interval, and a magnitude of the response as measured by the transducer is received and stored by the microprocesser. The four response magnitude peaks are then individually compared to preselected threshold values, and the degree twitch height depression estimated based on whether or not the response peaks are above or below the threshold levels, and indicia showing the degree of estimated twitch height depression is displayed to the operator.