Neuromuscular block monitor
First Claim
1. Apparatus for monitoring the neuromuscular transmission of a motor nerve and the muscle associated with the nerve in a patient, the apparatus comprisingstimulator means for generating a plurality of electrical stimulus signals which are spaced apart by predetermined periods of time and for applying such stimulus signals to the motor nerve to supramaximally stimulate it,amplifier and detector means connected to the stimulator means, and including a pair of sensing electrodes adapted to be attached to the patient, for sensing the electromyogram (EMG) produced by the associated muscle as a result of the stimulating electrical signals and for amplifying the EMG,electronic integrator means connected to the amplifier and detector means for receiving each amplified EMG in response to each stimulus signal and for integrating it with respect to time over periods which fall between stimulus signals,control standard means connected to the integrator means for storing a representation of a first integrated EMG,comparator means connected to the integrator means for generating an output signal which is representative of the ratio of a select, integrated EMG and the first, integrated EMG, andmeans for displaying the output signal of the comparator means.
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Abstract
To determine the degree of neuromuscular blockage, the apparatus of the invention electrically, supramaximally stimulates the motor nerve of a patient by stimulus means, applies the resulting electromyogram (EMG) produced by the muscle associated with that motor nerve and integrates the amplified EMG with respect to time. The integrated, amplified EMG is then displayed. In a preferred embodiment of the invention means are also provided for displaying the integrated, amplified EMG, taken after a muscle relaxant has been administered to the patient, as a ratio of a control EMG taken with the apparatus before the administration of the drug.
222 Citations
9 Claims
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1. Apparatus for monitoring the neuromuscular transmission of a motor nerve and the muscle associated with the nerve in a patient, the apparatus comprising
stimulator means for generating a plurality of electrical stimulus signals which are spaced apart by predetermined periods of time and for applying such stimulus signals to the motor nerve to supramaximally stimulate it, amplifier and detector means connected to the stimulator means, and including a pair of sensing electrodes adapted to be attached to the patient, for sensing the electromyogram (EMG) produced by the associated muscle as a result of the stimulating electrical signals and for amplifying the EMG, electronic integrator means connected to the amplifier and detector means for receiving each amplified EMG in response to each stimulus signal and for integrating it with respect to time over periods which fall between stimulus signals, control standard means connected to the integrator means for storing a representation of a first integrated EMG, comparator means connected to the integrator means for generating an output signal which is representative of the ratio of a select, integrated EMG and the first, integrated EMG, and means for displaying the output signal of the comparator means.
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7. A method of monitoring meuromuscular blockage in a patient comprising the steps of
electrically, supramaximally stimulating a motor nerve of a patient before the administration of a muscle relaxant drug, detecting amplifying the resulting electromyogram (EMG) produced by the muscle associated with the stimulated motor nerve, integrating and holding the amplified EMG with respect to time to obtain an integrated control EMG, repeating the stimulating, amplifying, integrating and holding steps after the administration of a muscle relaxant drug to the patient to obtain a second integrated EMG, and displaying the ratio of the second integrated EMG to the integrated control EMG.
Specification