Electrical stimulation for preservation and restoration of diaphragm function
Inventors
O'Mahony, John • Wethington, Patrick J.
Assignees
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Publication Number
US-10293157-B2
Publication Date
2019-05-21
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
A percutaneous electrical phrenic nerve stimulation (PEPNS) system is described for patients on mechanical ventilation, in which electrical stimulation of the phrenic nerve during inspiration is used to preserve or restore diaphragm function. The system includes a lead system having pacing electrodes and an identifying resistor, and a controller circuit that provides electrical stimulus to the patient's phrenic nerve to provoke diaphragm motion during inspiration in response to a resistance indicated by the identifying resistor and diaphragm work exerted by the patient.
The document describes measuring or obtaining a diaphragm work value during a selected inspiratory breath cycle and using the diaphragm work to calculate work/power and derive parameters such as a Pmus value. The work/power calculation is described as being based on predicted wye pressure obtained from a respiratory equation of motion that uses lung compliance and lung resistance, compared with actual measured wye pressure, and then computing work/power for the stimulated inspiratory phase.
The controller uses this diaphragm work information to titrate or modify the stimulation during the selected breath based on whether the diaphragm work is within a clinician-selected range. The system is further described with an instrumented ventilator wye sensor for flow and pressure measurement, connection between the sensor and a stimulator/controller that includes a CPU and an integrated pulse generator, and user interaction via a graphical user interface (GUI).
Claims Coverage
The independent claim and dependent claims cover a PEPNS lead system using pacing electrodes and an identifying resistor to provide phrenic-nerve stimulation during inspiration, with controller circuitry that accounts for resistance indication and diaphragm work. Four inventive features are reflected across the claims, with additional sensing and lead configuration features.
Lead system with pacing electrodes and identifying resistor for phrenic-nerve stimulation responsive to resistance indication
A lead system having pacing electrodes and an identifying resistor, with a controller circuit in separate electrical communication with each pacing electrode and the identifying resistor to provoke motion of a patient's diaphragm during inspiration by providing an electrical stimulus to the patient's phrenic nerve in response to the resistance indicated by the identifying resistor and diaphragm work exerted by the patient.
Controller circuitry that controls stimulation for prompting diaphragm motion during inspiration
A controller circuit configured with the pacing electrodes and the identifying resistor to provoke motion of a patient's diaphragm during inspiration by providing an electrical stimulus to the patient's phrenic nerve in response to resistance indicated by the identifying resistor and diaphragm work exerted by the patient.
Single selected breath stimulation with diaphragm-work measurement and stimulus modification
The controller circuit provides electrical phrenic-nerve stimulation at a set level during a selected single breath of the patient, obtains a measurement of diaphragm work exerted by the patient during the inspiratory breath cycle, and modifies the stimulus based on the obtained measurement of diaphragm work.
Range-based stimulus modification when diaphragm work is outside a selected range
The controller circuit modifies the stimulus when the measured diaphragm work is outside a selected range.
Across the independent and dependent claims, the inventive subject matter centers on PEPNS using pacing electrodes with an identifying resistor for lead type indication, controller circuitry that provides phrenic-nerve stimulation during inspiration responsive to resistance indication and diaphragm work, and closed-loop modification of stimulus for a selected single breath based on measured diaphragm work and, in some embodiments, whether the diaphragm work is outside a selected range.
Stated Advantages
Preserve or restore diaphragm function.
Documented Applications
Patients on mechanical ventilation.
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