Percutaneous electrical phrenic nerve stimulation system

Abstract

A percutaneous electrical phrenic nerve stimulation (PEPNS) system that measures the patient Work of Breathing (WOB) of each type of ventilator breath and determines when to deliver electrical stimulus based upon the measured WOB. The PEPNS system alters its behavior based upon the type and origin of the ventilator breath delivered and provides warnings for certain identified interactions between the ventilator and the patient.

What is claimed is: 
     
       1. An apparatus comprising:
 a lead system; 
 a stimulator circuit configured to deliver electrical stimulus via the lead system; and 
 a controller circuit in operative communication with the lead system and stimulator, the controller circuit being configured and arranged to
 using a flow sensor, detect inspiration and expiration of a patient exceeding a set trigger flow, 
 calculate time between the inspirations that exceed the set trigger flow, and 
 control the stimulator circuit for delivering the electrical stimulus via the lead system in response to the time that passes after one of the inspirations exceeding the set trigger flow, and before a subsequent inspiration that exceeds the set trigger flow, exceeding a set time. 
 
 
     
     
       2. A percutaneous electrical phrenic nerve stimulation system comprising:
 a lead system; 
 a stimulator configured to deliver electrical stimulus via the lead system; and 
 a controller circuit in operative communication with the lead system and stimulator, the controller circuit being configured to calculate work of breathing (WOB) for patient breaths detected by a flow sensor based on lung compliance and resistance of the patient, and the controller circuit being configured to:  
 control the stimulator to deliver the electrical stimulus when the WOB is less than a predetermined level; and 
 cease the delivery of electrical stimulation from the stimulator when the WOB meets or exceeds the predetermined level. 
 
     
     
       3. A percutaneous electrical phrenic nerve stimulation system comprising:
 a lead system in electrical communication with a stimulator; 
 a controller circuit in operative communication with the lead system and stimulator; and 
 a GUI in operative communication with the controller circuit,
 the controller circuit being configured to calculate work of breathing (WOB) for patient breaths detected via a flow sensor, including assist breaths and spontaneous breaths based on lung compliance and resistance of the patient, and 
 the stimulator configured to deliver electrical stimulus via the lead system, the controller configured to cease the delivery of electrical stimulation from the stimulator if the assist breath WOB and spontaneous breath WOB are above a desired level of WOB. 
 
 
     
     
       4. The apparatus of  claim 1 , wherein the controller circuit includes:
 a pulse generator configured and arranged to control the stimulator for delivering the electrical stimulus by supplying electrical pulses to the lead system based on the inspiration and expiration and the set time between inspirations; and 
 a processor circuit configured and arranged to provide the set time between inspirations that is used in supplying the electrical pulses from the pulse generator. 
 
     
     
       5. The apparatus of  claim 4 , wherein the processor circuit is configured and arranged to generate an output for communicating characteristics of the sensed inspiration and expiration, and for communicating characteristics of the stimulation. 
     
     
       6. The apparatus of  claim 5 , wherein the output includes a graphical output that displays characteristics of one or more of: the electrical pulses generated by the pulse generator, the sensed inspiration and expiration, and the stimulation. 
     
     
       7. The apparatus of  claim 1 , further including:
 a wye flow sensor configured to sense flow and pressure of the inspiration and expiration; and 
 a user interface having circuitry and configured and arranged to display a graphical output indicating one or more of the detected inspiration and expiration, the set time between inspirations, the set time between inspirations being exceeded, and characteristics of the delivery of the electrical stimulus. 
 
     
     
       8. The apparatus of  claim 7 , wherein the user interface is configured and arranged to generate signals in response to respective user inputs for one or more of setting the time between inspirations, setting characteristics of the electrical stimulus to be delivered, and designating a stimulation breath. 
     
     
       9. The apparatus of  claim 7 , wherein the controller circuit is configured and arranged with the wye flow sensor to detect inspiration based upon wye flow settings exceeding set trigger flow for inspiration, and to detect expiration based upon a set trigger for expiration. 
     
     
       10. The apparatus of  claim 1 , wherein the controller circuit is configured and arranged to calculate work of breathing (WOB) indicative of lung compliance and resistance of a patient, and the controller circuit is configured to control the stimulator circuit for delivering the electrical stimulus via the lead system in response to the WOB being less than a predetermined level. 
     
     
       11. The apparatus of  claim 1 , wherein the controller circuit is configured and arranged to calculate work of breathing (WOB) for assist breaths assisted by a ventilator and spontaneous breaths taken by a patient, as detected by a wye flow sensor, and the controller circuit is configured to control the stimulator circuit to cease the delivery of electrical stimulation if the WOB of one of the assist breaths and the WOB of one of the spontaneous breaths are respectively being-above predetermined levels. 
     
     
       12. The apparatus of  claim 1 , wherein the controller circuit is configured and arranged to calculate work of breathing (WOB) for breaths, and the controller circuit is configured to control the stimulator circuit to cease the delivery of electrical stimulation if the WOB exceeds a predetermined level. 
     
     
       13. The apparatus of  claim 1 , wherein the controller circuit is configured and arranged to, in response to detecting a time between inspirations that is shorter than a predetermined time, identify one of the inspirations as a patient-initiated breath and control delivery of the electrical stimulus via the lead system to selectively avoid electrical stimulation when the patient initiates a breath. 
     
     
       14. The apparatus of  claim 13 , wherein the controller circuit is configured and arranged to, in response to identifying the one of the inspirations as a patient-initiated breath, assess a work of breathing (WOB) corresponding to the patient-initiated breath, and to control the delivery of the electrical stimulus by:
 in response to the WOB of the patient-initiated breath being at or exceeding a threshold, prevent delivery of the electrical stimulus, and 
 in response to the WOB of the patient-initiated breath being below the threshold, delivering the electrical stimulus. 
 
     
     
       15. A method comprising:
 detecting inspiration and expiration of a patient exceeding a set trigger flow; 
 calculating time between the inspirations that exceed the set trigger flow; and 
 delivering electrical stimulus to stimulate the patient's diaphragm via a lead system by,
 withholding the electrical stimulus in response to the calculated time not exceeding a set time; and 
 applying the electrical stimulus in response to the time that passes after one of the inspirations that exceeds the set trigger flow, and before a subsequent inspiration that exceeds the set trigger flow, exceeding a set time. 
 
 
     
     
       16. The method of  claim 15 , further including calculating work of breathing (WOB) for detected breaths of patient based on lung compliance and resistance of the patient, wherein delivering the electrical stimulus includes delivering the electrical stimulus to a phrenic nerve of the patient based on the calculated WOB. 
     
     
       17. The method of  claim 15 , further including
 calculating work of breathing (WOB) for detected breaths of patient based on lung compliance and resistance of the patient; and 
 ceasing delivery of the electrical stimulus in response to the calculated WOB meeting or exceeding a predetermined level. 
 
     
     
       18. The method of  claim 15 , further including
 calculating work of breathing (WOB) for assist breaths taken by the patient and assisted by a ventilator, and for spontaneous breaths taken by the patient; and 
 ceasing the delivery of the electrical stimulus in response to the calculated WOB of one of the assist breaths and the calculated WOB of one of the spontaneous breaths respectively being at or above a predetermined level. 
 
     
     
       19. The method of  claim 15 ,
 further including identifying one of the detected inspirations as a patient-initiated breath; and 
 wherein delivering the electrical stimulus includes selectively interrupting delivery of the electrical stimulus in response to detecting the patient-initiated breath. 
 
     
     
       20. The method of  claim 15 , further including, in response to identifying one of the inspirations as a patient-initiated breath, assessing a work of breathing (WOB) corresponding to the patient-initiated breath, and controlling the delivering of the electrical stimulus by:
 in response to the WOB of the patient-initiated breath being at or exceeding a threshold, interrupt the delivering of the electrical stimulus, and 
 in response to the WOB of the patient-initiated breath being below the threshold, facilitating the delivering of the electrical stimulus. 
 
     
     
       21. A percutaneous electrical phrenic nerve stimulation system comprising:
 a lead system in electrical communication with a stimulator;   a controller circuit in operative communication with the lead system and stimulator; and   a graphical user interface (GUI) in operative communication with the controller circuit,   the controller circuit being configured to calculate work of breathing (WOB) for a patient-initiated breath detected via a flow sensor, the patient-initiated breath including one of an assist breath and a spontaneous breath such that the controller is configured to calculate at least one of an assist breath WOB and a spontaneous breath WOB based on lung compliance and resistance of the patient, and   the stimulator configured to deliver electrical stimulation via the lead system, the controller configured to cease the delivery of electrical stimulation from the stimulator if said at least one of the assist breath WOB and spontaneous breath WOB is above a desired level of WOB.   
     
     
       22. The system of  claim 21 , wherein the controller circuit is configured to calculate the work of breathing during a single breath. 
     
     
       23. The system of  claim 21 , wherein the controller circuit is configured to calculate the work of breathing for each patient-initiated breath and each ventilator-initiated breath. 
     
     
       24. The system of  claim 21 , wherein the GUI is configured to output a user alert in response to said at least one of the assist breath WOB and spontaneous breath WOB being below the desired level of WOB. 
     
     
       25. The system of  claim 24 , wherein the patient-initiated breath is the spontaneous breath, and the spontaneous breath is a patient breath during mechanical ventilation that is both initiated and terminated by the patient. 
     
     
       26. The system of  claim 24 , wherein said the patient-initiated breath is the assist breath, and the assist breath is a patient breath during mechanical ventilation that is initiated by the patient and terminated by mechanical ventilation. 
     
     
       27. The system of  claim 21 , wherein the lead system includes first and second leads shaped to reside traverse to first and second phrenic nerves, respectively, each of the first and second leads being connectable to the stimulator via a corresponding lead cable. 
     
     
       28. The system of  claim 27 , wherein each of the first and second leads includes at least four electrodes so that a selected electrode pair of the at least four electrodes are configured to capture a respective one of the first and second phrenic nerves. 
     
     
       29. The system of  claim 28 , wherein the selected electrode pair comprises two electrodes of the at least four electrodes that, when activated, stimulate the respective one of the first and second phrenic nerves to provide a particular WOB level. 
     
     
       30. The system of  claim 28 , wherein each of the first and second leads are percutaneously insertable in a neck of the patient. 
     
     
       31. The system of  claim 28 , wherein the flow sensor comprises a wye sensor in operative communication with the controller circuit and configured to sense flow and pressure of inspiration and expiration during each breath, and wherein the GUI configured and arranged to display a graphical output indicating one or more of the sensed flow and pressure of inspiration and expiration, a time between inspirations, and characteristics of the delivery of the electrical stimulation. 
     
     
       32. The system of  claim 31 , wherein the wye sensor is electrically connectable to the controller circuit via a cable. 
     
     
       33. The system of  claim 28 , wherein the GUI includes a touch screen display device that displays user input fields to receive stimulation settings for the selected electrode pair of each of the first and second leads. 
     
     
       34. The system of  claim 21 , wherein the GUI includes a touch screen display device that displays user input fields to receive mechanical ventilator settings and input values for the lung compliance and resistance for the patient. 
     
     
       35. The system of  claim 21 , wherein the GUI includes a touch screen display device includes a stimulation indicator that activates during application of the electrical stimulation via the lead system. 
     
     
       36. The system of  claim 21 , wherein the GUI is configured to output a user alert in response to the unstimulated work of breathing being greater than the unstimulated WOB stop limit. 
     
     
       37. The system of  claim 21 , wherein the GUI includes a user-selectable setting that causes the stimulator to deliver electrical stimulation via the lead system during mandatory breaths only. 
     
     
       38. A percutaneous electrical phrenic nerve stimulation system comprising:
 a lead system in electrical communication with a stimulator and configured to stimulate at least one of first and second phrenic nerves during selected breaths of a patient;   a controller circuit in operative communication with the lead system and stimulator, the controller circuit being configured to calculate an unstimulated work of breathing detected via a flow sensor during an unstimulated breath of a patient; and   a graphical user interface (GUI) in operative communication with the controller circuit, the GUI including a user setting indicative of an unstimulated WOB stop limit,   wherein the stimulator is configured to deliver electrical stimulation via the lead system, and the controller configured to cease the delivery of the electrical stimulation during unstimulated breaths after identifying that the unstimulated work of breathing is greater than the unstimulated WOB stop limit.