Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
  • A61N1/3601—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation of respiratory organs
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61H—PHYSICAL THERAPY APPARATUS, e.g. DEVICES FOR LOCATING OR STIMULATING REFLEX POINTS IN THE BODY; ARTIFICIAL RESPIRATION; MASSAGE; BATHING DEVICES FOR SPECIAL THERAPEUTIC OR HYGIENIC PURPOSES OR SPECIFIC PARTS OF THE BODY
  • A61H31/00—Artificial respiration by a force applied to the chest; Heart stimulation, e.g. heart massage
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  • A61N1/02—Details
  • A61N1/04—Electrodes
  • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
• • A—HUMAN NECESSITIES
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  • A61N1/02—Details
  • A61N1/04—Electrodes
  • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
  • A61N1/0551—Spinal or peripheral nerve electrodes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
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  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
  • A61N1/36014—External stimulators, e.g. with patch electrodes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
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  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
  • A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
  • A61N1/36053—Implantable neurostimulators for stimulating central or peripheral nerve system adapted for vagal stimulation
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
  • A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
  • A61N1/3606—Implantable neurostimulators for stimulating central or peripheral nerve system adapted for a particular treatment
  • A61N1/3611—Respiration control
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
  • A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
  • A61N1/36128—Control systems
  • A61N1/36135—Control systems using physiological parameters
• • A—HUMAN NECESSITIES
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  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
  • A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
  • A61N1/36128—Control systems
  • A61N1/36135—Control systems using physiological parameters
  • A61N1/36139—Control systems using physiological parameters with automatic adjustment
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N5/00—Radiation therapy
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N7/00—Ultrasound therapy
• • G—PHYSICS
  • G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
  • G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
  • G16H20/00—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance
  • G16H20/40—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61H—PHYSICAL THERAPY APPARATUS, e.g. DEVICES FOR LOCATING OR STIMULATING REFLEX POINTS IN THE BODY; ARTIFICIAL RESPIRATION; MASSAGE; BATHING DEVICES FOR SPECIAL THERAPEUTIC OR HYGIENIC PURPOSES OR SPECIFIC PARTS OF THE BODY
  • A61H2201/00—Characteristics of apparatus not provided for in the preceding codes
  • A61H2201/10—Characteristics of apparatus not provided for in the preceding codes with further special therapeutic means, e.g. electrotherapy, magneto therapy or radiation therapy, chromo therapy, infrared or ultraviolet therapy
  • A61H2201/105—Characteristics of apparatus not provided for in the preceding codes with further special therapeutic means, e.g. electrotherapy, magneto therapy or radiation therapy, chromo therapy, infrared or ultraviolet therapy with means for delivering media, e.g. drugs or cosmetics
  • A61H2201/107—Respiratory gas
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61H—PHYSICAL THERAPY APPARATUS, e.g. DEVICES FOR LOCATING OR STIMULATING REFLEX POINTS IN THE BODY; ARTIFICIAL RESPIRATION; MASSAGE; BATHING DEVICES FOR SPECIAL THERAPEUTIC OR HYGIENIC PURPOSES OR SPECIFIC PARTS OF THE BODY
  • A61H2201/00—Characteristics of apparatus not provided for in the preceding codes
  • A61H2201/12—Driving means
  • A61H2201/1253—Driving means driven by a human being, e.g. hand driven
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61H—PHYSICAL THERAPY APPARATUS, e.g. DEVICES FOR LOCATING OR STIMULATING REFLEX POINTS IN THE BODY; ARTIFICIAL RESPIRATION; MASSAGE; BATHING DEVICES FOR SPECIAL THERAPEUTIC OR HYGIENIC PURPOSES OR SPECIFIC PARTS OF THE BODY
  • A61H2230/00—Measuring physical parameters of the user
  • A61H2230/04—Heartbeat characteristics, e.g. E.G.C., blood pressure modulation
  • A61H2230/045—Heartbeat characteristics, e.g. E.G.C., blood pressure modulation used as a control parameter for the apparatus
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61H—PHYSICAL THERAPY APPARATUS, e.g. DEVICES FOR LOCATING OR STIMULATING REFLEX POINTS IN THE BODY; ARTIFICIAL RESPIRATION; MASSAGE; BATHING DEVICES FOR SPECIAL THERAPEUTIC OR HYGIENIC PURPOSES OR SPECIFIC PARTS OF THE BODY
  • A61H2230/00—Measuring physical parameters of the user
  • A61H2230/20—Blood composition characteristics
  • A61H2230/201—Blood composition characteristics used as a control parameter for the apparatus
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61H—PHYSICAL THERAPY APPARATUS, e.g. DEVICES FOR LOCATING OR STIMULATING REFLEX POINTS IN THE BODY; ARTIFICIAL RESPIRATION; MASSAGE; BATHING DEVICES FOR SPECIAL THERAPEUTIC OR HYGIENIC PURPOSES OR SPECIFIC PARTS OF THE BODY
  • A61H2230/00—Measuring physical parameters of the user
  • A61H2230/40—Respiratory characteristics
  • A61H2230/405—Respiratory characteristics used as a control parameter for the apparatus
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
  • A61M25/0105—Steering means as part of the catheter or advancing means; Markers for positioning
  • A61M2025/0166—Sensors, electrodes or the like for guiding the catheter to a target zone, e.g. image guided or magnetically guided
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N7/00—Ultrasound therapy
  • A61N2007/0004—Applications of ultrasound therapy
  • A61N2007/0021—Neural system treatment
  • A61N2007/0026—Stimulation of nerve tissue

Definitions

• MV may induce Ventilator Induced Lung Injury (VI LI), including, for example, voiutrauma, ateiectrauma, and biotrauma.
• Volutrauma is damage from over-distension of the lung parenchyma, which may result from high tidal volume and/or low lung compliance.
• Ateiectrauma may result from recruitment- decruitment of collapsed alveoli during each ventilator cycle, generally a result of low tidal volume (Vt), low pressure, or inadequate levels of Positive End Expiratory Pressure (PEEP).
• Vt low tidal volume
• PEEP Positive End Expiratory Pressure
• Biotrauma is the expression of a local inflammatory process and may be characterized by the release of inflammatory mediators because of over- distending tidal volumes and repetitive opening and closing of unstable lung units.
• MV induced stress and strain in the lungs may result in inflammatory response of the alveoli, recruitment of neutrophils to lung parenchyma, and the production of cytokines. This process may then spread into intravascular circulation systems, and may reach distal organs, such as, for example, the brain.
• the lungs may sense the MV induced mechanical stimuli by mechanoreceptors, and the lung may communicate this information to the brain, via the autonomic nervous system.
• the diaphragm has significant sensory innervations.
• the goals of mechanical ventilation are to provide precise control of the respiratory variables, such as, for example, partial pressure of arterial oxygen (Pa0 2 ) and partial pressure of arterial carbon dioxide (PaCC ⁇ ) control.
• the mechanical ventilator may cyclically pressurize the lungs to provide effective gas exchange, it is important to balance goals with minimizing lung stretch and minimizing lower lung collapse.
• the unique lung volume, lung compliance, and gas exchange requirements for each patient may complicate these goals.
• Decreased tidal volumes may lead to hypercapnia (increased PaCC1 ⁇ 2).
• Hypercapnia may lead to intracranial hypertension.
• Improved systemic oxygenation may reduce brain hypoxic insults.
• excessively high ventilator pressures may lead to systemic inflammatory response, which, in turn, may affect cerebral oxygenation and metabolism, thereby inducing brain injury.
• PEEP may be used to recruit previously collapsed alveoli, improve arterial oxygenation, and reduce elastance of the respiratory system.
• PEEP may be detrimental to gas exchange, decrease cardiac output by reducing aortic blood flow/pressure, and may lead to barotrauma.
• MV can be a life-saving intervention for patients suffering from respiratory failure
• prolonged MV can promote diaphragmatic atrophy and contractile dysfunction (VIDD).
• VIDD diaphragmatic atrophy and contractile dysfunction
• This type of diaphragm injury and the accompanying diaphragm weakness may contribute to difficulty in weaning from MV.
• the majority of patients treated with V are readily liberated from ventilator support upon resolution of respiratory failure or recovery from surgery, but approximately one-third of patients encounter challenges with regaining the ability to breathe spontaneously. The prognosis may be favorable for patients who wean from MV successfully at the first attempt, but is less so for the remaining patients.
• the diaphragm muscle is an important crossroad for information involving the entire body. In addition to serving as the primary respiratory muscle, it has links throughout the body as part of an information network necessary for breathing.
• the diaphragm has significant sensory innervations. Both the phrenic and vagus nerves are part of this network, and each nerve contains both sensory and motor fibers.
• the vagus nerve which innervates the crural region of the diaphragm can directly affect the system of reciprocal tension membranes (e.g. dura), producing a range of relevant symptoms in the body.
• the event of diaphragmatic dysfunction can lead to a cascade of signaling events, which affect the brain and other organs.
• vagus and phrenic nerves innervate the diaphragm muscle
• stimulation of either the vagus or phrenic nerve can affect a signaling cascade in the other.
• the potential implications of the stimuli on the brain, other body organs, and tissues will be discussed further below.
• Both delirium and cognitive dysfunction occur in as many as 87% of the intensive care unit (ICU) patients when they are provided with pulmonary support via invasive MV (Ely EW et ai., "Delirium in mechanically ventilated patients: validity and reliability of the confusion assessment method for the intensive care unit (CAM- ICU)," JA A, 2001). While treatment methods have progressed, delirium and cognitive dysfunction remain a major problem in MV patients.
• Aberrant neuro-signaling may lead to neurological, cellular, and inflammatory processes, which may lead to cognitive impairment during and after treatment with mechanical ventilation.
• a vagotomy in subjects receiving MV may mitigate the increase in the levels of the dopamine-synthesizing enzyme and the degree of apoptosis in the hippocampus compared to control animals. This implies that the vagus nerve is sending a signal, related to MV, to cause the dopamine increase.
• Inflammation is a common pathomechanism of acute lung injury and acute brain injury, affecting brain homeostasis.
• the inflammatory cascade following an acute brain injury may adversely affect the lungs, but evidence indicates that the opposite can occur as well. This can occur by means of a complex interaction between the autonomic, neuro-inflammatory, neuroendocrine, and immunologic pathways, which are physiologically programmed to preserve systemic homeostasis, but in certain circumstances may be responsible for harmful effects on remote organs and systems.
• the lungs sense mechanical stimuli via mechanoreceptors, and the information is communicated to the brain via the autonomic nervous system.
• the afferent vagal nerves communicate information from pulmonary stretch receptors to the respiratory center in the brain.
• inflammatory cells and central vagal nucleus in the brain form an inflammatory reflex that may control inflammation and immunity.
• Sensory neurons detect pathogens, damage, or injury via peripheral afferent vagal nerve endings and may then provide feedback to nucleus tractus solitarii (NTS) in the brain stem.
• NTS nucleus tractus solitarii
• the information is processed, and the efferent vagus nerve may transmit integrated information by action potentials to the celiac ganglion and then to other parts of the body.
• the vagus nerve originates from medullar oblongata, which consists of four nuclei: dorsal nucleus, nucleus ambiguous, NTS, and spinal nucleus of trigeminal nerve. Approximately 80% of afferent sensory fibers are contained in the vagus nerve and are responsible for transmission of the information to the NTS. There are numerous afferent vagus nerve endings in the lungs and diaphragm. For example, lung information is transmitted via the afferent arm to NTS, a processing center, which is capable of differentiating types of infection, inflammation, or injury.
• vagus nerve consists of both afferent and efferent fibers with 80% of the afferent impulses originating in the thoracic and abdominal organs.
• the afferent activity is relayed to the NTS, which has projections to the locus coeruieus (LC) which controls the release of norepinephrine (N E) and 5- hydroxytryptamine (5-HT).
• N E activated by VNS may have anti-inflammatory effects and may stimulate the release of 5-HT.
• agonists of 5-HT may reduce the release of glutamate in cerebral ischemia indicating the 5-HT attenuates excitotoxicity by inhibiting glutamate release.
• these afferent nerve pathway effects could contribute to the effectiveness of NVS in brain ischemia.
• the efferent vagal pathway may also induce neuroprotection via the cholinergic antiinflammatory pathway (CAP) which is activated by the central cholinergic system in the brain via the efferent fiber of the vagus nerve.
• CAP cholinergic antiinflammatory pathway
• vagus nerve leading to the activation of the CAP may suppress brain inflammation, leading to neuroprotection in ischemic stroke.
• the efferent vagus nerve stimulation can also inhibit a localized
• the resident macrophages of the central nervous system may secrete molecules that cause neuronal dysfunction, or degeneration. It has further been discovered that stimulation of efferent vagus nerve fibers releases sufficient acetylcholine to mitigate a systemic inflammatory cytokine cascade, as occurs in endotoxic shock, or a localized inflammatory cytokine cascade.
• Vagus nerve stimulation may cause up-reguiation (expression) of a7 nAChR.
• the cellular and molecular mechanism for anti-inflammation may be partly attributable to acetylcholine (Ach), a neurotransmitter mainly released from vagus nerve endings.
• Ach acetylcholine
• Activation of a7 nAChR by Ach on macrophages may suppress the release of pro-inflammatory cytokines in peripheral circulation, thereby preventing tissue damage via the inflammation reflex of the VN.
• the a7 nAChR receptors are commonly expressed in the brain including neurons glia and endothelial ceils. Activation of these receptors may enhance neuronal resistance to ischemic or other types of insults.
• An alternate technique to stimulate neural tissue is temporally interfering stimulation and involves crossing two high frequency electrical signals at the specific brain region to be stimulated. The two signals interfere with each other, resulting in a low frequency signal at the target area. Low frequency signals may provoke neurons to fire, while high frequency signals do not, so the targeted area may be activated while the surrounding tissue is not.
• Embodiments of the present disclosure relate to, among other things, systems, devices, and methods for preventing, moderating, and/or treating brain injury.
• Each of the embodiments disclosed herein may include one or more of the features described in connection with any of the other disclosed embodiments.
• the methods may include obtaining a test result reflecting a condition of a brain in the subject; determining a stimulation parameter based on the test result; and stimulating a nerve based on the stimulation parameter, wherein stimulation of the nerve assists or causes contraction of a respiratory muscle in the subject, in some examples, the nerve may be a phrenic nerve, and the respiratory muscle may be a diaphragm muscle.
• the second nerve may be stimulated by a nerve stimulator.
• the second nerve may be stimulated by an external nerve stimulator.
• the external nerve stimulator may be positioned on a skin area adjacent to a vagus nen/e in the subject.
• the second nerve may be stimulated by an implantable nerve stimulator.
• the second nerve may be stimulated by manual, mechanical, electrical, ultrasonic, or electromagnetic energy.
• the test result may be from imaging the brain.
• the test result may comprise a level of an inflammation- or pain-related protein in blood of the subject.
• the methods may further include performing a test that provides the test result.
• stimulating the nerve may include inserting a catheter with one or more electrodes in a blood vessel of the subject, and positioning the one or more electrodes proximate the nerve.
• the methods may further include ventilating the subject with a mechanical ventilator, in such cases, the test result may comprise an effect of ventilation on the brain.
• the methods may further include stimulating a second nerve during at least a portion of a ventilation inspiration period.
• the methods of treating a subject may include stimulating a first nerve with a first stimulator to assist or cause contraction of a respiratory muscle in the subject; and stimulating a second nerve with the first stimulator or a second stimulator to reduce a level of a causing factor of a brain injury.
• the methods may further include stimulating a third nerve with the first stimulator, the second stimulator, or a third stimulator to assist or cause contraction of the respiratory muscle in the subject.
• the causing factor of the brain injury may be inflammation in the brain.
• the first nerve may be a phrenic nerve
• the second nerve may be a vagus nerve.
• the respiratory muscle may be a diaphragm muscle.
• the stimulation of the first nerve may be in synchrony with stimulation of the third nerve.
• the stimulation of the first nerve may be coordinated with stimulation of the second nerve.
• the stimulation the first nerve may be in synchrony with stimulation of the second nerve.
• the methods may further include ventilating the subject with a mechanical ventilator.
• the second nerve may be stimulated during at least a portion of a ventilation inspiration period.
• the stimulation of the second nerve may be performed while the first nerve is not stimulated by the first stimulator.
• the first stimulator may comprise an intravascular catheter having a set of electrodes configured to stimulate a phrenic nerve.
• the second stimulator may comprise an intravascular catheter having a set of electrodes configured to stimulate a vagus nerve.
• the methods for treating a subject may include stimulating a first nerve with a stimulator to assist or cause contraction of a respiratory muscle in the subject; obtaining a test result of a vagus nerve activity in the subject; generating a stimulation parameter based on test result; and stimulating at least one of the first nerve and a second nerve based on the stimulation parameter.
• the second nerve may be a vagus nerve, and stimulating at least one of the first nerve and the second nerve based on the stimulation parameter may include stimulating the second nerve based on the stimulation parameter.
• the first nerve may be a first phrenic nerve, and the second nerve may be a second phrenic nerve.
• the test result may be obtained by testing heart blood flow, testing peripheral blood flow, testing blood pressure, imaging, or assessing inflammation- or pain-related molecules in blood of the subject.
• the disclosure also includes systems.
• the systems may include a processor configured to: receive a test result reflecting a condition of a brain in a subject; and determine a stimulation parameter based on the test result; and a stimulator configured to stimulate a nerve based on the stimulation parameter, wherein stimulation of the nerve assists or causes contraction of a respiratory muscle in the subject.
• the systems may further include a mechanical ventilator.
• the systems may further include one or more switches operatively connected to the processor, the one or more switches being configured to regulate stimulation output to the stimulator.
• the systems may further include a sensor configured to detect a cardiac event, a respiratory event, a catheter location, a blood pressure, or a level of an inflammatory agent.
• the stimulator may be in
• the stimulator may comprise an intravascular catheter having a first set of electrodes configured to stimulate a right phrenic nerve and a second set of electrodes configured to stimulate a left phrenic nerve.
• the stimulator may be configured to affect signaling of a phrenic nerve, signaling of a vagus nerve, or a combination thereof.
• the systems may include an electrode configured to stimulate a first nerve to assist or cause contraction of a respiratory muscle in the subject; and a stimulator configured to stimulate a second nerve to reduce a level of a causing factor of a brain injury.
• the stimulator may comprise an intravascular catheter having one or ore electrodes configured to stimulate a vagus nerve.
• the systems may further include a catheter configured for intravascular insertion, wherein the catheter comprises a first plurality of electrodes and a second plurality of electrodes.
• FIG. 1 illustrates the anatomy of selected nerves, tissues, and blood vessels in a person's neck, brain, lungs, and upper torso.
• FIG. 2 illustrates the anatomy of selected nerves and blood vessels in a person's neck and upper torso, the diaphragm and intercostal respiratory muscles, an exemplary stimulation device (e.g. catheter) placed in one vein, a control unit, a sensor (e.g., motion sensor, airflow sensor, and/or pressure sensor), an exemplary remote control device, a graphical user interface, a pulse generator, and an externa! respiratory support device, according to an exemplary embodiment.
• a stimulation device e.g. catheter
• a sensor e.g., motion sensor, airflow sensor, and/or pressure sensor
• a remote control device e.g., graphical user interface, a pulse generator, and an externa! respiratory support device, according to an exemplary embodiment.
• FIG. 3 illustrates the anatomy of selected nerves and blood vessels in a person's neck and upper torso, along with a first exemplary stimulation device (e.g. catheter) placed in a first location (e.g. vein, artery, skin, etc.) and a second exemplary stimulation device (e.g. catheter) placed in a second location (e.g. vein, artery, skin, etc.), in addition to a control unit.
• a first exemplary stimulation device e.g. catheter
• a second exemplary stimulation device e.g. catheter
• FIG. 4A illustrates a ventral view of a pair of exemplary catheters having windows that may align with nerve-stimuiating electrodes within the catheter, with the exemplary catheters inserted in a person's neck and upper torso, according to an exemplary embodiment
• FIG. 4B illustrates a ventral view of a single exemplary catheter with location securement means (e.g. anchor, adhesive, expandable coil/helix, etc.), the catheter having windows that may align with nerve-stimulating electrodes within the catheter, with the exemplary catheter inserted in a person's neck and upper torso, according to an exemplary embodiment.
• location securement means e.g. anchor, adhesive, expandable coil/helix, etc.
• FIG. 5 illustrates a perspective view of an exemplary catheter with conductors and electrodes exposed on an exterior of the catheter and including fluid transport lumens, according to an exemplary embodiment.
• FIG. 8 illustrates an exemplary stimulation catheter with flexible electrical leads, circuits, and electrodes.
• FIG. 7 illustrates the anatomy of selected nerves and blood vessels in a person's neck and upper torso along with an exemplary implanted stimulation device (e.g. catheter and pulse generator), a control button, and a control unit connected via a wireless connection, according to an exemplary embodiment.
• an exemplary implanted stimulation device e.g. catheter and pulse generator
• a control button e.g., a button
• a control unit connected via a wireless connection
• FIG. 8 illustrates the anatomy of respiratory muscles of the torso, a transdermal respiratory muscle stimulation array of electrodes placed upon the skin of the patient over the intercostal muscles, transesophageal stimulation electrodes, and an external respiratory support device, according to an exemplary embodiment.
• FIG. 9 illustrates a block diagram of a nerve stimulation system having an intravascular catheter and a control unit, according to an exemplary embodiment.
• proximal and distal are used herein to refer to the relative positions of the components of an exemplary medical device or insertion device.
• proximal refers to a position relatively closer to the exterior of the body or closer to an operator using the medical device or insertion device.
• distal refers to a position relatively further away from the operator using the medical device or insertion device, or closer to the interior of the body.
• embodiments of this disclosure relate to systems, medical devices, and methods for electrically stimulating a patient's nerves, and preventing, modulating, controlling, or treating injury (e.g., injury of the brain, the lungs, or the diaphragm muscle).
• the injury may be caused or enhanced by mechanical ventilation.
• the term "injury” may refer to an alteration in cellular or molecular integrity, activity, level, robustness, state, or other alteration that is traceable to an event.
• brain injury may be neuronal injury resulting from stress (repetitive stress), inflammation, oxidative stress, disease, pain, stroke, and/or physical injury such as surgery or trauma.
• the methods herein may include stimulating one or more nerves, such as one or more phrenic nerves and/or one or more vagus nerves.
• the methods may include stimulating one or more respiratory muscles (e.g., diaphragm muscle) or a portion thereof by stimulating one or more nerves (e.g., phrenic nerves).
• Stimulation of one or more phrenic nerves may play a role in preventing or treating brain injury (e.g., caused by mechanical ventilation).
• stimulation of phrenic nerves may pace the diaphragm muscle so that the pressure and time required from the mechanical ventilation are reduced.
• the blocking signal may be designed to occur in synchrony with a specific phase (e.g., inspiration) of the mechanically delivered breath to minimize aberrant signaling.
• the blocking signal may be designed such that its intensity is modulated by one or more characteristics of the mechanical ventilation delivered breath (e.g., pressure, flow, tidal volume).
• the vagus-blocking signal may be delivered via transcutaneous electrodes, minimally invasively placed electrodes, transvenous electrodes, subcutaneous electrodes, direct contact electrodes, or other suitable delivery vehicle.
• the stimulation profile envelope of the blocking signal may be tailored to minimize the passage of the aberrant vagus signaling to the brain caused, for example, by the pulmonary stretch pain receptors.
• timing of stimulation of multiple nerves may also be coordinated. For example, stimulation of a second nerve is performed while a first nerve is not stimulated by the one or more electrodes of a first plurality of the electrodes of the catheter.
• stimulating one or more portions of a respiratory muscle e.g., diaphragm muscle
• one proximal window of a first row 72a is located at the same axial position as a window of a second row 72b, but at a different circumferential position around the exterior of the catheter.
• the two rows of proximal windows 72a and 72b may be substantially posterior facing, and at least one proximal window may face, abut or be positioned in the vicinity of the left phrenic nerve.
• the catheter may also include two axialiy extending rows of distal apertures or windows (74a and 74b).
• catheter 12 may further include one or more lumens. Each lumen may extend from a proximal end of catheter 12 to a distal end of catheter 12, or to a location proximate the distal end of catheter 2.
• lumens may contain or be fluidly connected to sensors, such as blood gas sensors, electrical sensors, motion sensors, flow sensors, or pressure sensors, in some examples, catheter 12 may include three lumens (not shown) that may connect with extension lumens 38, 40, 42 that extend proximally from hub 36. Any lumens within catheter 12 may terminate in one or more distal ports 52, 50, 48 either at the distal end of catheter 12 or in a sidewail of catheter 12.
• the lumens may be used to transport fluid to and from the patient, such as to deliver medications or withdraw blood or other bodily fluids, remove C02, infuse oxygen, etc. in other examples, these lumens may be used to hold a guidewire, stiffening wire, optical fiber camera, sensors, or other medical devices.
• FIG. 5 illustrates an optical fiber camera 46 inserted into lumen 38, extending through a corresponding internal lumen, and exiting from distal port 48.
• the electrodes 34 may be configured to sense physiological information from a patient, such as properties of blood, nerve activities, ECG, or electrical impedance.
• a hub 36 may be connected to the proximal end of catheter 12.
• Hub 36 may include a conductive surface and can act as a reference electrode during monopolar stimulation or sensing.
• hub 36 may be sutured on a patient's skin.
• hub 36 may be used as an ECG or other reference electrode.
• the windows may be covered by a material that allows electrical signals to pass through.
• This medical system includes a vv'ireless connection from control unit 14' to catheters 2 and a wireless connection from a push button or buttons to the control unit 14'.
• control unit 14' is implanted in the patient, along with catheter 12.
• System 10 may further include remote controller 18 and a programmer 98 that communicates with control unit 14' wirelessiy.
• each of programmer 98, control unit 14', and remote controller 16 may include a wireless transceiver 92, 94, 96, respectively, so that each of the three components can communicate wirelessiy with each other.
• Control unit 14' may include all of the electronics, software, and functioning logic necessary to perform the functions described herein. Implanting control unit 14' as shown in FIG. 7 may allow catheter 12 to function as a permanent breathing pacemaker.
• control unit 14 or 14' may test the electrodes and electrode combinations to determine which combinations (e.g., bipolar, tripoiar, quadrupolar, multipolar) of electrodes most effectively stimulate the targeted nerve, e.g., the right phrenic nerve, left phrenic nerve, and/or vagus nerve.
• combinations e.g., bipolar, tripoiar, quadrupolar, multipolar
• control unit may be programmed and/or activated to (a) select a first stimulation group of electrodes from the electrode assemblies to stimulate the left phrenic nerve, (b) select a second stimulation group of electrodes from the electrode assemblies to stimulate the right phrenic nerve, (c) select a third stimulation group of electrodes from the electrode assemblies to stimulate the vagus nerve (d) select a first stimulation current for the first stimulation group of electrodes to stimulate the left phrenic nerve, (e) select a second stimulation current for the second stimulation group of electrodes to stimulate the right phrenic nerve, and (f) select a third stimulation current for the third stimulation group of electrodes to stimulate the vagus nerve.
• the selection of electrodes and current levels may be pre-programmed or input based on the patient's
• control unit may test different electrode groups and current levels and monitor the patient's response to determine the electrode pairs and current levels.
• the diaphragm muscles may contract and generate negative pressure in the thoracic cavity.
• the lungs then expand to draw in a volume of air.
• This contraction of diaphragm muscles can be sensed manually by palpation or by placing a hand on the thoracic cavity, as shown in FIG. 2.
• the breathing activity can be sensed by placing an airflow or airway pressure sensor in the breathing circuit or placing sensors 16, such as acceierometers or a gyroscope, on the surface of the skin at the thoracic region, as shown in FIG. 2.
• Sensors 18 can be hard wired to control unit 18 or can be connected using wireless transmitters and receivers.
• Electrodes 48 can also be used to stimulate the nerves, such as, for example, at least one of vagus nerves, phrenic nerves, sympathetic ganglia, or the esophageal sphincter.
• system 200 of FIG. 8 can include a catheter with electrodes and/or sensors, as described in the FIG. 2.
• system 200 can stimulate one or both phrenic nerves to activate the diaphragm muscles, along with stimulating the intercostal muscles (as illustrated via electrodes 44), to create a negative pressure in the thoracic cavity or a compressive force to the chest cavity.
• the system may receive feedback by sensing the phrenic or vagus activity from one of the electrodes on the intravascular catheter (if used) or transesophageal tube 48. Feedback from nerve activity may be used to determine the stimulation parameters required to sustain proper ventilation and whether adjustments to the stimulation parameters are needed.
• the system can also receive feedback from any other suitable sensor to determine the appropriate stimulation parameters.
• One or more of each of the following sensors may be included in either system 100 or system 200: an airflow sensor, an airway pressure sensor, an acceierometer, a gyroscope, a blood gas sensor, or a sensor to detect an inflammatory agent.
• system 100 or system 200 may include a sensor to detect an inflammatory agent.
• FIG. 9 illustrates a block diagram of the various components of system.
• the electrodes, hub, and lumens may be part of catheter described herein.
• the catheter may have any number of electrodes and any number of lumens. Five lumens are illustrated in FIG. 9, but in different examples, the catheter may include one, two, three, four, or more than five lumens, in one example, the catheter may have three lumens (e.g., extension lumens and corresponding interna! lumens), which each may hold one or more of a guidewire or optical fiber camera or may be used for fluid delivery or blood sample extraction.
• three lumens e.g., extension lumens and corresponding interna! lumens
• the electrodes may be further configured to sense physiological information from a patient, such as nerve activity, ECG, or electrical impedance, as will be described further below.
• physiological information such as nerve activity, ECG, or electrical impedance, as will be described further below.
• one or more of electrodes may be electronically coupled to a signal acquisition module.
• the signal acquisition module may receive signals from electrodes.
• the signal acquisition module may further be coupled to one or more sensors configured to gather physiological information from a patient.
• the system may include one or more of a blood gas sensor or a pressure sensor. These sensors may be located in lumens of the catheter, outside of the patient in fluid communication with a lumen, on an outer surface of the catheter, or in any other suitable location.
• the blood gas sensor may be housed in or fluidly connected to a lumen, while the pressure sensor may be housed in or fluidly connected to another lumen.
• the blood gas sensor may measure the amount of G 2 or CO 2 in the patient's blood.
• the pressure sensor may measure the central venous pressure (CVP) of the patient.
• CVP central venous pressure
• the signal acquisition module may transmit the signals received from one or more of electrodes, the blood gas sensor, and/or the pressure sensor to the appropriate processing/filtering module of the system. For example, signals from the pressure sensor may be transmitted to a central venous pressure signal
• signals from the blood gas sensor may be transmitted to a blood gas signal processing/filtering module for processing and filtering to determine blood gas levels.
• Signals from electrodes when they are used for sensing, may be sent to a nerve signal processing/filtering module, an ECG signal processing/filtering module, or an impedance signal processing/filtering module, as appropriate.
• Signals from electrodes or other sensors may be sent to an amplification module, if necessary, to amplify the signals prior to being sent to the appropriate processing/filtering module.
• the systems and methods described herein may prevent, modulate, control, or treat brain injury while pacing the diaphragm.
• the brain injury may be caused by mechanical ventilation.
• the systems and methods may perform tests on a brain function and/or a status of vagus nerve stimulation. Based on the results of the tests, one or more phrenic nerves and/or vagus nerves may be stimulated.
• Stimulation of the nerves may reduce inflammation in the brain.
• one or more nerves e.g., vagus
• catheter 12 may be positioned in the vasculature to extend adjacent or across the left and right phrenic nerves 28, 28.
• Appropriate distal and proximal electrode pairs may be selected to cause a contraction of the respiratory muscle, e.g., both the left and right hemi-diaphragm muscles.
• the operator e.g., physician or patient
• the pulse width can be modulated between stimulation pulses in the stimulation pulse train, in some cases, the pulse amplitude can be modulated between stimulation pulses in the stimulation pulse train.
• the operator may provide a therapy set of 10 stimulation pulse trains, in some examples, each of the stimulation pulse trains may be timed to coincide with a breath delivered by a mechanical ventilator or the patient's spontaneous breath.
• the system can communicate directly with a mechanical ventilator, or other external respiratory support system (e.g., external respiratory support 88), to coordinate the therapy delivery with the support provided by the external device.
• sensors detecting activity from diaphragm muscles, nerves e.g.
• phrenic nerves, vagus nerves, etc. or other patient monitors or respiratory support devices can be used to trigger stimulation and/or breath delivery from a mechanical ventilator.
• the systems described herein may be operably connected (e.g., hardwired, wireless, etc.) to receive a signal from the mechanical ventilator indicating the initiation of a breath to the patient, and the systems can synchronize the delivery of the stimulation pulse train to coordinate with a desired phase of the breath.
• an operator may set the stimulation parameters and ask the patient to activate their breathing muscles. The operator may then coordinate the trigger of electrical stimulation with the patient efforts to provide maximum exercise of the muscles.
• external respiratory support 88 can be reduced or even eliminated during a portion of or all of the delivery of a stimulation set or stimulation session.
• 10 stimulations pulse trains are provided.
• the pulse trains can be timed to 10 sequential breaths, or the operator may skip one or more breaths to allow the patient to rest periodically between stimulations.
• the patient may be allowed to rest for a period of time, for example 30 seconds to 5 minutes.
• the operator can initiate a second set, for example 10 breaths, again followed by a resting period.
• the operator can deliver several sets, e.g., 4 sets, that each includes 10 stimulations. Each stimulation may cause a muscle contraction, for a total of 40 muscle contractions over a 1- to 15-minute period.
• the desired number of stimulations for a session may be delivered in a single set, if needed.
• the patient may then be permitted to rest (e.g., for one or more hours), and in some cases at least 3 hours, and potentially as long as 24 or 48 hours before beginning another therapy session. In some instances, two to three, or more, therapy sessions are delivered each day. Regardless, the number of stimulations provided to the respiratory muscles may be a small fraction of the breaths required by the patient each day. In the previously-described example of 40 stimulations/day, the number of stimulations delivered is approximately less than 0.2% or about 0.2% of the breaths taken by or delivered to the patient per day.
• the stimulation parameters may be kept the same from one stimulation that causes muscle contraction to the next stimulation, from one therapy set to the next therapy set, from one session to the next session, or from one day to the next day.
• one of the parameters such as the stimulation amplitude, the stimulation frequency, the stimulation hold time, or the resistance of the breathing circuit, may be increased or decreased between two stimulations that cause muscle contractions, between two sets, between two sessions, or between two days.
• the factors to consider while changing parameters may be patient tolerance, unintended stimulation of other structures, fatigue, or a desire for increased strength.
• stimulation signals may be delivered over a total period of time of approximately 2 hours or less, during one or more therapy sessions during that total of 2 hours or less, during a 24-hour period. In another example, stimulation signals may be delivered over a total period of time of 5 hours or less during a 24-hour period. [00143] In other examples of therapy sessions, stimulation signals may be delivered to contract one or more respiratory muscles for no more than: 20% of the breaths taken by or delivered to the patient in a 24-hour period; 10% of the breaths taken by or delivered to the patient in a 24-hour period; 2% of the breaths taken by or delivered to the patient in a 24-hour period; or 0.2% of the breaths taken by or delivered to the patient in a 24-hour period.
• a brief stimulation therapy session lasting approximately 3 to 10 minutes may be delivered 12 to 24 times over a 24-hour period; 8 to 12 times over a 24-hour period; or once in a 24-hour period.
• therapy sessions may be administered until the patient no longer requires external respiratory support; or up to 48 hours after the time at which the patient no longer requires, or is no longer receiving, external respiratory support.
• Various examples of the subject disclosure may be implemented soon after the patient begins using external respiratory support (e.g., mechanical ventilation) to help reduce the loss of strength and or endurance of a respiratory muscle.
• external respiratory support e.g., mechanical ventilation
• Various examples of this disclosure can be used to help reduce the level of injury to a patient's lungs, heart, brain and/or other organs of the body, it is contemplated that a stimulation with every breath, or alternatively a majority of breaths, may provide a desired level of protection.
• the systems described herein can be programmed to vary the profile of the stimulation pulse trains from time to time. For example, every tenth stimulation pulse train can be programmed to be longer than the others to produce a deeper or longer breath (e.g., sigh breath). In this case, the duration of the stimulation pulse train between two adjacent pulse trains will vary. [00148] In some examples, therapy may be continued and steps related to activating the stimulator and ceasing activation of the stimulator may be repeated until MIP reaches a pre-determined value.
• steps of any therapy treatment described herein may be carried out with respect to more than one nerve and more than one respiratory muscle.
• Stimulations of multiple nerves (and one or more respiratory muscles) may be synchronized so that the patient's muscle or muscles are stimulated at the same time.
• two or more combinations of selected electrodes may be activated at the same time during a therapy session. For example, if the first set of electrodes emits electrical signals up to 100 times, the second set of electrodes may emit electrical signals up to 100 times, with each emission of the second set corresponding to an emission of the first set of electrodes.
• the first and second sets of electrodes may be used to stimulate the left and right phrenic nerves to cause synchronized contractions of the left and right hemi-diaphragms.
• the first set may be used to stimulate the diaphragm
• the second set may be used to stimulate the intercostal muscles. The diaphragm and the intercostal muscles may be stimulated
• the diaphragm and the intercostal muscles may be stimulated out of phase.
• the diaphragm may be stimulated simultaneously with the external intercostal muscles.
• the diaphragm and the internal intercostal muscles may be stimulated out of phase. Both stimulations may occur at the same time in the patient breath cycle.
• the patient's nerves/muscles may be stimulated during an inspiratory period of the patient's ventilator or other external respiratory support.
• a closed-loop automated example of the system of this disclosure can be designed to deliver a stimulation to a respiratory muscle at a specific duty cycle such as 1 stimulation for every X breaths, where X could range from 10 to 1000.
• This approach may provide for periodic muscle stimulation with a predetermined number of resting breaths in between.
• X may be as small as 1 and as large as 10,000 in various examples.
• the stimulators described herein may include one or more of: nerve stimulation electrodes, endotracheal electrodes, endoesophageal electrodes, intravascular electrodes, transcutaneous electrodes, intracutaneous electrodes, electromagnetic beam electrodes, balloon-type electrodes, basket-type electrodes, umbrella-type electrodes, tape-type electrodes, suction-type electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes, patch electrodes, cuff electrodes, dip electrodes, needle electrodes, or probe electrodes.
• the stimulation energy may be delivered by an energy form that includes at least one of mechanical, electrical, ultrasonic, photonic, or

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• 2018
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