Electrical stimulation for preservation and restoration of diaphragm function
Inventors
O'Mahony, John • Wethington, Patrick J.
Assignees
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Publication Number
US-9682235-B1
Publication Date
2017-06-20
Expiration Date
Abstract
A system and method are presented that electrically stimulates the phrenic nerve whereby said stimulation results in muscle activation of the diaphragm as observed by a measurement of work or power of breathing associated with the inspiratory portion of a stimulated breath.
Core Innovation
The invention relates to a percutaneous electrical phrenic nerve stimulation (PEPNS) medical device for use with a mechanical ventilator and a breathing circuit coupled to a patient. The device includes subcutaneous multipolar electrodes positioned proximate at least one phrenic nerve in the neck, and a stimulator/controller connected to the electrode pair via a lead cable. The stimulator/controller delivers electrical stimulation to at least partially activate the patient’s diaphragm.
An instrumented wye is coupled to the patient and the mechanical ventilator via tubing of the breathing circuit, providing a wye flow measurement and a wye pressure measurement to the stimulator/controller. The stimulator/controller selects one of several breaths defining a single selected breath. Stimulation begins at the beginning of an inspiratory event in response to an inspiratory trigger event corresponding to a preset specific flow at the instrumented wye, and ends at the end of an inspiratory event triggered by an end inspiratory trigger event corresponding to a specific flow at the instrumented wye.
The disclosure further provides a power/work measuring device coupled to the instrumented wye that measures instantaneous work throughout the inspiratory phase of the single selected breath. This measurement is performed by comparing a predicted pressure at the wye and a measured pressure at the wye, and indicating work only if the predicted pressure differs from the measured pressure. The predicted pressure is derived from respiratory mechanics, including compliance and resistance, to compute Pmus and thereby determine work/power (WOB) for the stimulated breath.
Claims Coverage
The relevant set includes one independent claim. The claim includes five main inventive features that together define selective breath-targeted PEPNS using an instrumented wye and inspiratory-phase power/work measurement based on predicted versus measured wye pressure.
Subcutaneous electrode pair proximate a phrenic nerve
A subcutaneous electrode pair positioned proximate at least one phrenic nerve in the neck of the patient.
Stimulator/controller delivering diaphragm-activating stimulation
A stimulator/controller connected to the electrode pair via a lead cable, delivering electrical stimulation at a pulse repetition rate, with a current and a waveform sufficient to at least partially activate the patient's diaphragm.
Instrumented wye providing flow and pressure measurements
An instrumented wye coupled to the patient and to the mechanical ventilator via tubing of the breathing circuit, providing a wye flow measurement and a wye pressure measurement to the stimulator/controller.
Breath selection with inspiratory trigger and end inspiratory trigger
The stimulator/controller selecting one of several breaths defining a single selected breath, beginning stimulation at the beginning of an inspiratory event in response to an inspiratory trigger event corresponding to a preset specific flow at the instrumented wye, and ending stimulation at the end of an inspiratory event triggered by an end inspiratory trigger event corresponding to a specific flow at the instrumented wye.
Instantaneous work measuring by predicted versus measured wye pressure
A power/work measuring device coupled to the instrumented wye measuring instantaneous work throughout the inspiratory phase of the single selected breath by comparing a predicted pressure at the wye and a measured pressure at the wye, and indicating work only if the predicted pressure differs from the measured pressure at the instrumented wye.
Overall, the claim coverage centers on a ventilator-integrated PEPNS system that stimulates a subcutaneous phrenic-nerve electrode pair, uses an instrumented wye to define a single selected breath and a stimulation duration within the inspiratory phase, and measures instantaneous work by comparing predicted versus measured wye pressure.
Stated Advantages
Indicating work only if the predicted pressure differs from the measured pressure at the instrumented wye.
Selecting one of several breaths to define a single selected breath for stimulation timing within the inspiratory phase.
Documented Applications
No documented applications found
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