Breathing therapy device and method

#The invention relates to a device and method for detection, diagnosis and treatment of breathing disorders and to the management of pulmonary or cardiac rhythms, heart failure and other cardiac and/or respiratory related conditions.

#Diaphragm stimulation has been used to provide breathing in patients unable to breath on their own. Diaphragm stimulation has also been proposed to treat sleep apnea. However, these uses of diaphragm stimulation have not provided optimal breathing responses or control of breathing.

#Accordingly it would be desirable to provide improved diaphragm stimulation.

#FIG. 1 is an exemplary respiratory waveform with an identified stimulation phase in accordance with the invention.

#FIG. 2 is a flow showing a baseline establishment in accordance with the invention.

#FIG. 3 is a flow chart showing identification of delivery boundaries in accordance with the invention.

#In accordance with the invention a diaphragm stimulation device as shown in FIG. 12 is used. The diaphragm stimulation device 1200 electrically stimulates the diaphragm 1290 with an electrical signal supplied from a signal source 1260 to at least one electrode 1220 on an implantable unit 1210. The electrode may also sense EMG of the diaphragm which may include respiration parameters. The sensed EMG is communicated to a processor 1280 of a control unit 1240. The control unit also includes an input/output device 1250 for coupling to external communications device. The input/output device 1250 may be used to communicate to or from the device 1210 or the processor 1280 to or from a programmer, user or provider (e.g. via telemetry, wireless communications or other user/provider/programmer interface). The implantable unit 1210 also includes a motion sensor 1230 that senses the motion of the diaphragm 1290 to determine respiration parameters or responses to stimulation. The motion sensor 1230 may also be used to sense patient activity levels. The sensed signals are communicated to a processor 1280 that stores and uses the motion and EMG signals, as described herein, to control breathing. In addition to stimulation of the diaphragm the phrenic nerve may be stimulated to control breathing.

#Referring to FIG. 1 an intrinsic breathing waveform 100 is illustrated. The waveform 100 has a total respiratory interval length 105 that comprises an inspiration period 110, followed by an exhalation period 120 and ending in a rest period 130. The respiratory interval 105 begins at the beginning 101 of the inspiration period 110 and ends at the end 160 of the rest period 130 which is the beginning of the next respiratory cycle. In accordance with the invention as described below a time period is identified for stimulating a diaphragm and/or phrenic nerve to elicit a breathing response where the stimulation is believed to capture or take over breathing control and/or inhibit breathing driven by a subject's innate respiratory drive. The stimulation period 170 is identified by an earliest acceptable stimulation boundary 140 and a latest acceptable stimulation boundary 150.

#In general the stimulation period 170 falls within the rest period 130. The earliest stimulation boundary 140 may be selected on a patient by patient basis and is the earliest time at which the innate respiratory drive is captured by a particular stimulation. The stimulation boundary may be determined, e.g., on a patient by patient basis by optimizing stimulation response prior to implanting the device. Accordingly stimulation is provided and observed at different times near the beginning of the rest period to identify when the respiratory drive is captured for a particular stimulation waveform. In general, it is believed that such earliest stimulation boundary 140 is after the end of the exhalation period 120 and at or near the beginning of the rest cycle 130. As an alternative to optimizing on a patient by patient basis an earliest time may be selected for example as the end of the exhalation period 120 or a given time after the end of the exhalation cycle. It may also be selected as a predetermined fraction of the respiratory interval or its various components based on a baseline respiratory interval or interval component.