NON-INVASIVE CAROTID COOLER BRAIN HYPOTHERMIA MEDICAL DEVICE

Abstract: A carotid cooler medical device with a cooling element configured to remove heat largely from an area substantially proximate the patient's carotid arteries to rapid cool the brain to decrease brain injury is disclosed. The carotid cooler can be configured as a topical carotid cooler and an endotracheal carotid cooler that can be used independently or together. The topical carotid cooler is configured for placement on a patient's neck proximate the patient's carotid arteries and coupling to a cooling source. The topical carotid cooler has a patient's side that carries at least one cooling element that is coupled to the cooling source. The endotracheal cooler is configured for placement in a patient's trachea with the cooling element near the distal end. The cooling element is positionable distal to a patient's oral cavity to cool blood flowing through the patient's carotid arteries. Methods for creating brain hypothermia using the carotid cooler are also disclosed.

Description: NON-INVASIVE CAROTID COOLER BRAIN HYPOTHERMIA MEDICAL DEVICE BACKGROUND OF THE INVENTION This disclosure relates to a medical device and more specifically to a non-invasive medical device used to lower human brain temperature. The medical device industry produces a wide variety of electronic and mechanical devices for treating patient medical conditions. Non-invasive medical devices are used to treat medical conditions without the need for invasive procedures such as insertion of a catheter into a blood vessel. Non-invasive medical devices are particularly suitable for the early responders to a medical condition such as emergency medical technicians and persons having limited training. The early application of a medical device designed to reduce injury to a patient can greatly enhance restoration of an individual to a more healthful condition and a fuller life. One type of non-invasive medical device designed to reduce injury is a brain cooler hypothermic medical device. Cooling the brain can significantly reduce brain injury caused by lack of blood flow to the brain (ischemic) or lack of oxygen to the brain (anoxic). Ischemic and anoxic brain injury can be caused by conditions such as strokes, cardiac arrest, transient ischemia attacks (TIA), brain injury, toxic poisoning, respiratory arrest, suffocation, electrocution, edema, and head trauma. Under ischemic or anoxic conditions, reversible brain damage can start as early as four minutes after the condition has begun and irreversible brain damage can start as early as six minutes after the condition has begun. Lowering brain temperature, hypothermia, slows brain metabolic activity to slow or reduce brain injury. Early hypothermia of the brain in the initial critical minutes after injury can significantly reduce further injury compared with hypothermia of the brain performed once the patient reaches a facility such as a hospital. Previous topical brain cooling medical devices do not efficiently target heat removal from the patient's carotid arteries and can require application of an encircling collar to the patient. The cooling source is typically applied to the entire collar, and the collar is not shaped to apply the cooling source to the close proximity of the patient's carotid arteries. Additionally, the collar may be difficult to apply and risk further injury to patient's with neck and head. Previous endotracheal brain cooling medical devices also do not efficiently target heat removal from the patient's carotid arteries. The cooling source is placed in the patient's oral cavity which is a considerable distance from the patient's carotid arteries. An example of a non-invasive brain cooling medical device is disclosed in U.S. Patent No. 5,916,242 "Apparatus For Rapid Cooling Of The Brain And Method Of Performing Same" issued to Schwartz (June 29, 1999). For the foregoing reasons, there is a need for a non-invasive brain cooling medical device that more efficiently targets the patient's carotid arteries and provides additional improvements. SUMMARY OF THE INVENTION The non-invasive carotid cooler brain hypothermia medical device applies cooling efficiently to carotid arteries to rapid cool the brain to decrease brain injury. In one embodiment, at least one cooling element is configured to remove heat from an area substantially proximate the patient's carotid arteries. The cooling element is carried on a patient side of a topical carotid cooler. The topical carotid cooler is configured for placement on a patient's neck proximate the patient's carotid arteries and is coupled to a cooling source. In another embodiment, the cooling element is carried on an endotracheal carotid cooler. In other embodiments, methods for creating brain hypothermia with a non- invasive carotid cooler are provided. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an environment view of a patient anatomy; FIG. 2 shows another environment view of the patient anatomy; FIG. 3 shows a topical carotid cooler applied to a patient embodiment; FIG.4 shows a brain hypothermia system embodiment; FIG. 5 shows a flow diagram of a method for brain hypothermia embodiment; FIG. 6 shows an endotracheal carotid cooler applied to a patient embodiment; FIG. 7 shows a cross-section view of both a topical carotid cooler and an endotracheal carotid cooler applied to a patient embodiment; and, FIG. 8 shows front view of both a topical carotid cooler and an endotracheal carotid cooler applied to a patient embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show environmental views of a patient; FIG. 3 shows a topical carotid cooler applied to a patient embodiment; and, FIG. 4 shows a brain hypothermia system embodiment. One embodiment of the medical device for non-invasive brain hypothermia comprises a topical carotid cooler, a cooling source, and a cooling element. This medical device embodiment can also include a cooling controller, a patient thermometer, a carotid flow sensor, a temperature sensor. The topical carotid cooler is configured for application on a patient's neck proximate the patient's carotid arteries. The topical carotid cooler has a patient side that is placed against the patient's neck when the topical carotid cooler is positioned on the patient. The cooling source is coupled to the topical carotid cooler and can be a wide variety of cooling sources capable of cooling in the range from about 37° Celsius (98.6° Fahrenheit) to about 0° Celsius (32° Fahrenheit). The cooling source can include technologies such as a Peltier device, a cryogenic fluid, ice, salinated ice, cold water, active refrigerant systems, Joule-Thompson cryostat, and the like. The cooling source delivers cooling to the cooling element. The cooling element is at least one cooling element carried on the topical carotid cooler patient side. The cooling element is coupled to the cooling source, and the cooling element is configured to remove heat largely from an area substantially proximate the patient's carotid arteries. The cooling element is positionable over both patient carotid arteries. The cooling element can be at least a first cooling element positionable over one carotid artery and a second cooling element positionable over the other carotid artery. When a first and second cooling element are used, the cooling elements can be positionable laterally to a patient's trachea. The temperature of the cooling element is regulated by the cooling controller. The cooling controller is coupled to the cooling source for regulating the amount of cooling delivered by the cooling element. The cooling controller regulates the cooling source, so the temperature of the cooling element cools blood flowing through the carotid arteries to rapidly reduce brain core temperature down to no lower than about 30.0° Celsius (86.0° F). The cooling controller regulates the cooling source so the temperature of the cooling element is not lower than about minus 2.0° Celsius (35.6° F). The cooling controller is also configured to accept a variety of sensory inputs such as patient temperature, cooling element surface temperature, carotid blood flow, and the like. The cooling controller can use these sensor inputs in its cooling control algorithm to regulate brain temperature to a predetermined value and otherwise regulate cooling. The cooling controller can also use sensor inputs to alert the medical device operator of conditions such as inadequate carotid blood flow. The cooling controller can also include communication capabilities to access telephone, radio, and internet networks as desired. For a patient temperature input to the cooling controller, patient temperature can be measured with a patient therometer. The patient thermometer is coupleable to patient for measuring patient temperature. The thermometer is can be any type of thermometer that measures a patient's temperature that can be correlated to brain temperature such as an infrared thermometer positionable in a patient's ear, bimetallic thermometers, thermistors, resistive temperature devices (RTDs), and the like. An ear thermometer which measures tympanic membrane temperature can be configured similar to a stereo headphone set for ease of application to the patient. The thermometer is coupled to the cooling controller to provide an input of patient temperature correlateable to patient brain temperature. Another sensor that the cooling controller can use for adjusting cooling or identifying conditions to the operator is a carotid flow sensor. The carotid flow sensor is carried on the topical carotid cooler patient side to determine if there is adequate carotid arterial blood flow to the brain. Patient carotid blood flow to the brain is a critical parameter that should be monitored to avoid conditions that could adversely affect blood flow. The carotid flow sensor can use a wide variety of sensors technologies capable of sensing carotid arterial flow such as Doppler ultrasound, Doppler microwave, impedance plethysmography, accelerometry, Doppler laser interferometry, and the like. The carotid flow sensor is coupled to the cooling controller to provide an input of patient carotid blood flow. Another sensor that the cooling controller can use for adjusting cooling or identifying conditions to the operator is a temperature sensor. The temperature sensor is carried on the cooling element in a manner to measure cooling element surface temperature. The temperature sensor provides a cooling element temperature input to a cooling controller. The cooling controller will typically regulate the cooling element to prevent cooling below -2.2° Celsius (28° F) because these temperatures can induce tissue damage due to freezing also known as frostbite. The temperature sensor can be coupled to the cooling controller to assist in regulating cooling. The topical carotid cooler can be used to perform a method for non-invasive brain hypothermia. FIG. 5 shows a flow diagram of a method for non-invasive brain hypothermia embodiment. The medical device embodiment can be used to perform a method of creating brain hypothermia which may be beneficial in cases of stoke, cardiac arrest, transient ischemia attack (TIA), brain injury, toxic poisoning, respiratory arrest, suffocation, edema, head trauma, and the like. The method begins by applying a topical carotid cooler topically to a patient's neck. The topical carotid cooler is operationally positionable on a patient neck without the requirement of circumscribing the patient's neck. After application of the topical carotid cooler, the topical carotid cooler is positioned so that the cooling element is in close proximity to the patient's carotid arteries. Cooling the topical carotid cooler also cools blood flowing through carotid arteries to the patient's brain. Cooling blood destined for the patient's brain in turn cools the patient's brain. The cooled brain reduces tissue metabolism in the brain. By reducing tissue metabolism in the brain, the rate of irreversible brain damage caused by toxic metabolic byproducts can also be reduced. Toxic metabolic byproducts, including neurochemical such as glutamate, are produced by brain tissue from conditions such as stoke, cardiac arrest, transient ischemia attack (TIA), brain injury, toxic poisoning, respiratory arrest, suffocation, edema, head trauma, and the like. Additionally, the cooled brain reduces inflammation and swelling (edema) that often occurs with head trauma. Other embodiments of the carotid cooler include an endotracheal carotid cooler. FIG. 6 shows an endotracheal carotid cooler embodiment applied to a patient; FIG. 7 shows a cross-section view of both a topical carotid cooler and an endotracheal carotid cooler applied to a patient; and, FIG. 8 shows a front view of both a topical carotid cooler and an endotracheal carotid cooler applied to a patient. The endotracheal carotid cooler embodiment of the medical device for non-invasive brain hypothermia comprises an endotracheal carotid cooler, a cooling source, and a cooling element. This medical device embodiment can also include a cooling controller, a patient thermometer, a carotid flow sensor, a temperature sensor, and a positioning balloon. The elements that are common between the previously described topical carotid cooler embodiment and the endotracheal carotid cooler embodiment are generally further described to the extent the common elements differ. The endotracheal carotid cooler is configured for placement in a patient's trachea. The endotracheal carotid cooler forms an air passage having an inner surface, an outer surface, a distal end, and a proximal end. The cooling source is coupled to the endotracheal carotid cooler and serves as a means for removing heat from an area substantially proximate the patient's carotid arteries. At least one conduit extending from the proximal end of the endotracheal carotid cooler couples the cooling source to the cooling element. The cooling element is at least one cooling element and can be more than one cooling element carried on the endotracheal carotid cooler near the distal end. The cooling element is positionable distal to a patient's oral cavity to cool blood flowing through the patient's carotid arteries. The cooling source is regulated by a cooling controller. The cooling controller is coupled to the cooling source for regulating the amount of cooling delivered by the cooling source. The cooling controller is configurable to couple to both the topical carotid cooler embodiment and the endotracheal cooler embodiment to regulate the cooling source either independently or in conjunction with one another. The carotid flow sensor carried on the endotracheal carotid cooler determines if there is adequate carotid arterial blood flow. The carotid flow sensor can be used as an input for adjusting the positioning balloon to ensure adequate blood flow. Once the medical device operator becomes aware that the carotid flow rate is inadequate, the medical device operator can change the position of the topical carotid cooler and endotracheal carotid cooler as necessary to achieve adequate carotid arterial blood flow. The endotracheal carotid cooler can also include a positioning balloon to assist in positioning the cooling element proximate the patient' s carotid arteries. The positioning balloon urges the cooling element toward the patient's carotid arteries upon inflation of the positioning balloon. The positioning balloon will typically have an inflation conduit extending out of the endotracheal tube proximal end. The positioning balloon can be inflated manually by the medical device operator or automatically by the cooling controller. When inflated manually, the medical device operator typically measures the inflation pressure by tactile feel or with an instrument such as a pressure gauge. When inflated automatically, the cooling controller inflates the positioning balloon to a predetermined inflation pressure or an inflation pressure dependent upon a sensed parameter such as the force the endotracheal carotid cooler is exerting near the patient's carotid arteries, or the sensed patient carotid blood flow. The endotracheal carotid cooler can be used to perform a method for non-invasive brain hypothermia. FIG. 5 shows a flow diagram of a method for non-invasive brain hypothermia embodiment. The medical device embodiment can be use to perform a method of creating brain hypothermia. The method begins by inserting the endotracheal carotid cool into the patient's trachea. The endotracheal carotid cooler is positioned distal to the patient's oral cavity at this time. After positioning of the endotracheal carotid cooler such that the cooling element is urged proximate to the patent's carotid arteries, the endotracheal carotid cooler is cooled. Cooling the endotracheal carotid cooler also cools blood flowing through carotid arteries to the patient's brain. Cooling blood destined for the patient's brain, cools the patient's brain. The cooled brain reduces tissue metabolism in the brain. By reducing tissue metabolism in the brain, the rate of irreversible brain damage caused by toxic metabolic byproducts is also reduced. Toxic metabolic byproducts, including neurochemical such as glutamate, are produced by brain tissue from conditions such as stoke, cardiac arrest, transient ischemia attack (TIA), brain injury, toxic poisoning, respiratory arrest, suffocation, edema, head trauma, and the like. Also the cooled patient's brain also appears to reduce inflammation and swelling that often occurs with head trauma. Thus, embodiments of a non-invasive brain hypothermia medical device are disclosed to rapid cool the brain to decrease brain injury. One skilled in the art will appreciate that the present invention can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation, and the present invention is limited only by the claims that follow.

Claims: What is claimed is: 1. A medical device for non-invasive brain hypothermia, comprising: a topical carotid cooler configured for placement on a patient's neck proximate the patient's carotid arteries, the topical carotid cooler having a patient side; a cooling source coupled to the topical carotid cooler; and, at least one cooling element carried on the topical carotid cooler patient side and coupled to the cooling source, the cooling element configured to remove heat largely from an area substantially proximate the patient's carotid arteries. 2. The medical device as in claim 1 wherein the cooling element is at least a first cooling element positionable over one carotid artery and a second cooling element positionable over the other carotid artery. 3. The medical device as in claim 2 wherein the first cooling element and the second cooling element are positionable on either side of a patient's trachea. 4. The medical device as in claim 1 further comprising a cooling controller coupled to the cooling source for regulating the amount of cooling delivered by the cooling source. 5. The medical device as in claim 4 wherein the cooling controller regulates the cooling source so the temperature of the cooling element cools blood flowing through the carotid arteries to rapidly reduce brain core temperature down to no lower than about 30 degrees Celsius. 6. The medical device as in claim 4 wherein the cooling controller regulates the cooling source so the temperature of the cooling element is not lower than about minus 2 degrees Celsius. 7. The medical device as in claim 1 further comprising a patient thermometer coupleable to the patient for measuring patent temperature. 8. The medical device as in claim 7 wherein the patient thermometer is an infrared thermometer positionable in a patient's ear for measuring the patient's temperature. 9. The medical device as in claim 7 wherein the patient thermometer is coupled to the cooling controller to provide an input of patient temperature to a cooling controller. 10. The medical device as in claim 1, further comprising a carotid flow sensor carried on the topical carotid cooler to sense carotid arterial blood flow. 11. The medical device as in claim 10 wherein the carotid flow sensor is selected from the group comprising: Doppler, ultrasound, impedance plethysmography, and accelerometer. 12. The medical device as in claim 1 wherein the cooling source has a temperature range that includes from about 37 degrees Celsius to about 0 degrees Celsius. 13. The medical device as in claim 1 wherein the cooling source is selected from the group comprising: a Peltier device, a cryogenic fluid, ice, salinated ice, cold water, and a Joule-Thompson cryostat. 14. The medical device as in claim 1, further comprising a temperature sensor carried on the cooling element, the temperature sensor providing a cooling element temperature input to a cooling controller. 15. The medical device as in claim 1 wherein the topical carotid cooler is operationally positionable on a patient without circumscribing the patient's neck. 16. A medical device for non-invasive brain hypothermia, comprising: a topical carotid cooler configured for placement on a patient' s neck proximate the patient's carotid arteries; a cooling source coupled to the topical carotid cooler; and, means for cooling coupled to the cooling source to remove heat from an area substantially proximate the patient's carotid arteries. 17. A method of creating brain hypothermia, comprising: applying a topical carotid cooler to a patient's neck; positioning the topical carotid cooler proximate a patient's carotid arteries; cooling the topical carotid cooler, cooling blood flowing through carotid arteries to the patient's brain; and, cooling the patient' s brain. 18. The method as in claim 17, further comprising, reducing tissue metabolism in the brain. 19. The method as in claim 18, further comprising, reducing the rate of irreversible brain damage caused by toxic metabolic byproducts. 20. The method as in claim 19 wherein toxic metabolic byproducts are produced by brain tissue from the group comprising: damaged brain tissue, ischemic brain tissue, and hypoxic brain tissue. 21. The method as in claim 17, further comprising, reducing inflammation in the brain. 22. A medical device for non-invasive brain hypothermia, comprising: an endotracheal carotid cooler configured for placement in a patient's trachea, the endotracheal carotid cooler forming an air passage having an inner surface, an outer surface, a distal end, and a proximal end; a cooling source coupled to the endotracheal carotid cooler; and, at least one cooling element carried on the endotracheal carotid cooler near the distal end, the cooling element coupleable to the cooling source and positionable distal to a patient's oral cavity to cool blood flowing through the patient's carotid arteries. 23. The medical device as in claim 22, further comprising a positioning balloon to urge the cooling element toward the patient's carotid arteries upon inflation of the positioning balloon. 24. The medical device as in claim 22 wherein the cooling source is coupled to the endotracheal carotid cooler by at least one conduit extending from the proximal end of the endotracheal carotid cooler. 25. The medical device as in claim 22 further comprising a cooling controller coupled to the cooling source for regulating the amount of cooling delivered by the cooling source. 26. The medical device as in claim 25 wherein the cooling controller regulates the cooling source so the temperature of the cooling element cools blood flowing through the carotid arteries to rapidly reduce brain core temperature to no lower than about 30 degrees Celsius. 27. The medical device as in claim 25 wherein the cooling controller regulates the cooling source so the temperature of the cooling element is not lower than minus 2 degrees Celsius. 28. The medical device as in claim 22 further comprising a patient thermometer coupleable to patient for measuring patent temperature. 29. The medical device as in claim 28 wherein the patient thermometer is an infrared thermometer positionable in a patient's ear for measuring the patient's temperature. 30. The medical device as in claim 28 wherein the patient thermometer is coupled to a cooling controller to provide an input of patient temperature to the cooling controller. 31. The medical device as in claim 22, further comprising a carotid flow sensor carried on the endotracheal carotid cooler to determine if there is adequate carotid arterial blood flow. 32. The medical device as in claim 31 wherein the carotid flow sensor is selected from the group comprising: Doppler ultrasound, Doppler microwave, impedance plethysmography, accelerometry, and Doppler laser interferometry. 33. The medical device as in claim 22 wherein the cooling source has a temperature range from about 0 degree Celsius to about 37 degrees Celsius. 34. The medical device as in claim 33 wherein the cooling source is selected from the group comprising: a Peltier device, a cryogenic fluid, ice, salinated ice, cold water, Joule- Thompson cryostat. 35. The medical device as in claim 22, further comprising a temperature sensor carried on the cooling element, the temperature sensor providing a cooling element temperature input to a cooling controller. 36. A medical device for non-invasive brain hypothermia, comprising: an endotracheal carotid cooler configured for placement on a patient's neck proximate the patient's carotid arteries; a cooling source coupled to the endotracheal carotid cooler; and, means for cooling carried on the endotracheal carotid cooler and coupled to the cooling source, the means for cooling positionable distal to a patient's oral cavity to remove heat from an area substantially proximate the patient's carotid arteries. 37. A method of creating brain hypothermia, comprising: inserting an endotracheal carotid cooler into a patient's trachea; positioning an endotracheal carotid cooler distal to the patient's oral cavity; cooling the endotracheal carotid cooler; cooling blood flowing through carotid arteries to the patient's brain; and, cooling the patient's brain. 38. The method as in claim 37, further comprising, reducing tissue metabolism in the brain. 39. The method as in claim 38, further comprising, reducing the rate of irreversible brain damage caused by toxic metabolic byproducts. 40. The method as in claim 39 wherein toxic metabolic byproducts are produced by brain tissue from the group comprising: damaged brain tissue, ischemic brain tissue, and hypoxic brain tissue. 41. The method as in claim 37, further comprising, reducing inflammation in the brain. 42. The method as in claim 37, further comprising, urging the endotracheal carotid cooler toward the patient's carotid arteries.

Inventors: LECKRONE MICHAEL E, LECKRONE, MICHAEL, E.
Applicants: MEDTRONIC INC, MEDTRONIC, INC.
Application year: 2001
Main classification: A61F7
IPC codes: A61F7