Source: https://patents.google.com/patent/US8251061B2/en
Timestamp: 2019-03-25 02:21:32
Document Index: 481450082

Matched Legal Cases: ['art 840', 'art 840', 'art 840', 'art 840', 'art 840', 'art 990', 'art 990', 'Application No. 08075738', 'Application No. 04784602']

US8251061B2 - Methods and systems for control of gas therapy - Google Patents
Methods and systems for control of gas therapy Download PDF
US8251061B2
US8251061B2 US10/929,306 US92930604A US8251061B2 US 8251061 B2 US8251061 B2 US 8251061B2 US 92930604 A US92930604 A US 92930604A US 8251061 B2 US8251061 B2 US 8251061B2
US10/929,306
US20050061323A1 (en
2003-09-18 Priority to US50475003P priority Critical
2004-08-30 Application filed by Cardiac Pacemakers Inc filed Critical Cardiac Pacemakers Inc
2004-08-30 Assigned to CARDIAC PACEMAKERS, INC. reassignment CARDIAC PACEMAKERS, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HARTLEY, JESSE W., LEE, KENT, NI, QUAN, STAHMANN, JEFFREY E.
2005-03-24 Publication of US20050061323A1 publication Critical patent/US20050061323A1/en
2012-08-28 Publication of US8251061B2 publication Critical patent/US8251061B2/en
Bradycardia is a disorder involving a heartbeat that is abnormally slow, causing insufficient blood supply to the body's tissues. Tachyarrhythmia occurs when the patient's cardiac rhythm is too fast. The excessively rapid cardiac contractions result in diminished blood circulation because the heart has insufficient time to fill with blood before contracting to expel the blood. Ventricular fibrillation is a particularly dangerous form of tachyarrhythmia, and may result in death within minutes if the heart's normal rhythm is not restored. Myocardial ischemia or infarction, caused by a lack of oxygen to heart tissues, promotes fibrillation. Because of the complex interactions between the cardiovascular, pulmonary and other systems, an effective approach to monitoring, diagnosis, and/or treatment of various disorders is needed.
According to further embodiments, a sensor may be configured to detect disordered breathing, and, in response to detecting disordered breathing, gas therapy may be modified (e.g., initiated, modified, terminated) to suppress the disordered breathing. In addition, the type of disordered breathing may be discerned, such as discerning central apnea from obstructive apnea. If, for example, central apnea is detected, small amounts of carbon dioxide may be applied to the patient's air supply (e.g., via a positive airway pressure device) to mitigate the carbon dioxide instability that is leading to central apnea.
Gas therapy, such as oxygen or carbon dioxide therapy, continuous positive airway pressure therapy, or other therapies provided to a patient through the pulmonary system, may mitigate a patient's suffering from a number of respiratory disorders. Some lung diseases, such as emphysema, sarcoidosis, and chronic obstructive pulmonary disorder, reduce lung function to the extent that supplemental oxygen is needed to continue normal bodily functions. For many patients with end stage lung disease, oxygen therapy allows the patients to get the oxygen they need, helps them be more active, and may also prevent heart failure.
In accordance with embodiments of the invention, a system controls gas therapy, such as oxygen or carbon dioxide therapy, using one or more patient-internal sensors, one or more patient-external sensors and/or an implanted device. The gas therapy may be delivered to the patient, and measurement of exhaled gas concentration may be implemented using a respiratory mask, such as a CPAP mask, for example. The one or more sensors may include, for example, a gas saturation sensor or other implanted sensor for determining the patient's blood gas saturation. Other sensors, such as a disordered breathing detector (internal or external) may be used to determine the presence of disordered breathing, and then deliver gas therapy as needed to resolve or treat the disordered breathing. The patient's blood gas saturation may be determined externally, e.g., using pulse oximetry techniques, and/or external sensors positioned on a respiratory mask or nasal cannulae.
One illustrative approach involves sensing the patient's blood gas saturation and controlling the delivery of gas by a patient-external therapy device based on the blood gas saturation. At least one of sensing the blood gas saturation and controlling the delivery of gas is performed at least in part implantably.
Another approach involves sensing the body's need for gas, as manifested, for example, as apnea, hypopnea, hypoxia, hypocapnia, or myocardial ischemia, and then providing appropriate gas therapy to remedy the physiological need. Sensing of the body's need for gas may be effected either internally or externally of the patient.
FIG. 1 illustrates a block diagram of a system 150 for providing coordinated cardiac and respiratory therapy in accordance with embodiments of the invention. The system utilizes an xTherapy device 182 to provide respiratory therapy to the patient. A controlled flow of air, oxygen, carbon dioxide or other gas is developed by the xTherapy device 182 and delivered to the patient's airway through tubing and a mask 184, such as a nasal mask.
If a disorder is detected at detection block 504, a determination of one or more possible actions and/or interventions is made at block 506, relative to the detected disorder. For example, detecting a blood oxygen level below a lower threshold may suggest that more oxygen is needed by the patient. A decision is made at block 508, based on the determination from block 506, as to whether therapy initiation or therapy modification is desired to increase the patient's blood oxygen level. For example, if a patient is receiving oxygen therapy, the oxygen level administered to the patient may be increased. In another embodiment, if the patient is sleeping and wearing a CPAP device, the air pressure may be increased. In a further embodiment, the patient may be administered a vasodilating or bronchodilator agent, or have a level of vasodilating or bronchodilator agent therapy modified. Combined therapies may also be performed, such as increasing gas pressure and adding a vasodilating or bronchodilator agent, increasing the heart rate of a patient using a pacemaker and increasing oxygen therapy, or other desired combined therapies.
Arousal and other episodes of breathing disorders may be determined using the impedance signal 600. During non-REM sleep, a normal respiration pattern includes regular, rhythmic inspiration-expiration cycles without substantial interruptions. When the tidal volume (TV) of the patient's respiration, as indicated by the transthoracic impedance signal, falls below a hypopnea threshold, then a hypopnea event is declared. For example, a hypopnea event may be declared if the patient's tidal volume falls below about 50% of a recent average tidal volume or other baseline tidal volume value. If the patient's tidal volume falls further to an apnea threshold, e.g., about 10% of the recent average tidal volume or other baseline value, an apnea event is declared.
According to one embodiment of the present invention, illustrated in FIG. 8, a medical system 800 may include an implantable CRM 810 that cooperates with an xTherapy device 820 to provide coordinated patient monitoring, diagnosis and/or therapy. The CRM 810 may provide a first set of monitoring, diagnostic, and/or therapeutic functions to a patient 855. The CRM 810 may be electrically coupled to a patient's heart 840 through one or more cardiac electrodes 815 terminating in, on, or about the heart 840. The cardiac electrodes 815 may sense cardiac signals produced by the heart 840 and/or provide therapy to one or more heart chambers. For example, the cardiac electrodes 815 may deliver electrical stimulation to one or more heart 840 chambers, and/or to one or multiple sites within the heart 840 chambers. The CRM 810 may directly control delivery of one or more cardiac therapies, such as cardiac pacing, defibrillation, cardioversion, cardiac resynchronization, and/or other cardiac therapies, for example. In addition, the CRM 810 may facilitate the control of the xtherapy device 820. Further, the CRM 810 may perform various monitoring and/or diagnostic functions in relation to the cardiovascular system and/or other physiological systems.
In the example illustrated in FIG. 8, a mechanical respiration therapy device, such as the patient-external respiration therapy device 820, includes a positive airway pressure device that cooperates with the CRM 810. The xTherapy device 820 develops a positive air pressure that is delivered to the patient's airway through a tube system 852 and a mask 854 connected to the xTherapy device 820. Positive airway pressure devices are often used to treat disordered breathing. In one configuration, for example, the positive airway pressure provided by the xTherapy device 820 acts as a pneumatic splint keeping the patient's airway open and reducing the severity and/or number of occurrences of disordered breathing due to airway obstruction.
FIG. 9 is a partial view of an implantable device useful for providing sensing and/or therapy in accordance with embodiments of the invention. In this example, the implantable device comprises a cardiac rhythm management device (CRM) 900 including an implantable pulse generator 905 electrically and physically coupled to an intracardiac lead system 910. Portions of the intracardiac lead system 910 are inserted into the patient's heart 990. The intracardiac lead system 910 includes one or more electrodes configured to sense electrical cardiac activity of the heart, deliver electrical stimulation to the heart, sense the patient's transthoracic impedance, and/or sense other physiological parameters, e,g, cardiac chamber pressure or temperature. Portions of the housing 901 of the pulse generator 905 may optionally serve as a can electrode.
The lead system 910 of the CRM 500 may incorporate one or more transthoracic impedance sensors that may be used to acquire the patient's respiration waveform, or other respiration-related information. The transthoracic impedance sensor may include, for example, one or more intracardiac electrodes 941, 942, 951-955, 963 positioned in one or more chambers of the heart 990. The intracardiac electrodes 941, 942, 951-955, 963 may be coupled to impedance drive/sense circuitry positioned within the housing of the pulse generator 905.
FIG. 10 is a diagram illustrating a subcutaneous implantable medical device 1000 that may be used for gas therapy systems incorporating an implantable component in accordance with embodiments of the present invention. The device 1000 illustrated in FIG. 10 is an implantable transthoracic cardiac sensing and/or stimulation (ITCS) device that may be implanted under the skin in the chest region of a patient. The ITCS device may, for example, be implanted subcutaneously such that all or selected elements of the device are positioned on the patient's front, back, side, or other body locations suitable for sensing cardiac activity and delivering cardiac stimulation therapy. It is understood that elements of the ITCS device may be located at several different body locations, such as in the chest, abdominal, or subclavian region with electrode elements respectively positioned at different regions near, around, in, or on the heart.
The impedance electrodes 1195 sense the patient's transthoracic impedance. The transthoracic impedance may be used to calculate various parameters associated with respiration. Impedance driver circuitry (not shown) induces a current that flows through the blood between the impedance drive electrode and a can electrode on the housing 1101 of the CRM 1100. The voltage at an impedance sense electrode relative to the can electrode changes as the transthoracic impedance changes. The voltage signal developed between the impedance sense electrode and the can electrode is detected by the impedance sense amplifier and is delivered to the sleep detector circuitry 1120 for further processing. The impedance electrodes 1195 may also be used in conjunction with the DB detector 1105. As discussed previously, arousal and other episodes of breathing disorders (e.g., hypopnea, apnea) may be determined using an impedance signal developed by the impedance electrodes 1195.
controlling delivery of a gas therapy delivered by a gas therapy delivery unit to a patient's pulmonary system, the gas therapy involving delivery of a first gas;
adapting the gas therapy by modifying delivery of a second gas, different from the first gas, to treat the detected disorder,
wherein at least one of sensing the blood gas concentration and adapting the gas therapy is performed at least in part implantably by a cardiac rhythm management device having a therapy controller, and wherein the therapy controller is wirelessly coupled to the gas therapy delivery unit.
discerning the type of disordered breathing comprises discerning central apnea from obstructive apnea.
7. The method of claim 6, wherein adapting the gas therapy comprises applying the carbon dioxide to the patient's system through a positive airway pressure device if the disordered breathing type is central apnea.
adapting the gas therapy comprises initiating introduction of oxygen to the patient's pulmonary system to treat the hypoxemia.
the detected disorder comprises ischemia and
the adapted gas therapy is delivered to treat the ischemia.
a gas therapy delivery unit coupled to the therapy controller and configured to deliver the adapted gas therapy to the patient's pulmonary system; and
means for delivering the adapted gas therapy to a patient by delivering a gas to the patient's pulmonary system,
wherein at least one of the sensing means and the adapting means comprises an implantable component, and wherein the means for controlling the gas therapy is wirelessly coupled to the means for delivering the adapted gas therapy.
US10/929,306 2003-09-18 2004-08-30 Methods and systems for control of gas therapy Active 2027-12-28 US8251061B2 (en)
US50475003P true 2003-09-18 2003-09-18
US10/929,306 US8251061B2 (en) 2003-09-18 2004-08-30 Methods and systems for control of gas therapy
US20050061323A1 US20050061323A1 (en) 2005-03-24
US8251061B2 true US8251061B2 (en) 2012-08-28
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US10/929,306 Active 2027-12-28 US8251061B2 (en) 2003-09-18 2004-08-30 Methods and systems for control of gas therapy
US (1) US8251061B2 (en)
WO2019006096A1 (en) * 2017-06-28 2019-01-03 Mayo Foundation For Medical Education And Research Methods and materials for treating hypocapnia
2004-08-30 US US10/929,306 patent/US8251061B2/en active Active
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US20050061323A1 (en) 2005-03-24
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:LEE, KENT;HARTLEY, JESSE W.;STAHMANN, JEFFREY E.;AND OTHERS;REEL/FRAME:015753/0546