NEGATIVE AIR PRESSURE DEVICES AND USES THEREOF
20210330908 · 2021-10-28
Inventors
Cpc classification
A61M16/1005
HUMAN NECESSITIES
A61M16/20
HUMAN NECESSITIES
A61M16/208
HUMAN NECESSITIES
A61M16/024
HUMAN NECESSITIES
A61M2207/00
HUMAN NECESSITIES
A61M16/0045
HUMAN NECESSITIES
A61M2205/3375
HUMAN NECESSITIES
A61M2205/3317
HUMAN NECESSITIES
International classification
A61M16/00
HUMAN NECESSITIES
Abstract
Provided herein are negative air pressure devices and uses thereof. In particular, provided herein are negative air pressure devices that modulate CO.sup.2 delivery for use in the treatment of sleep apnea.
Claims
1. A negative air pressure breathing device comprising an air chamber configured to move air via a venturi effect.
2. The device of claim 1, comprising: a transport tube configured to transport air; at least one mixing chamber; at least one gas inlet in operable communication with said mixing chamber; and at least one inlet/outlet in operable communication with said mixing chamber.
3. The device of claim 2, wherein said mixing chamber comprises primary, secondary, and tertiary mixing chambers, wherein said primary mixing chamber is proximal to said transport tube, said secondary mixing chamber is proximal to said primary mixing chamber and distal to said tertiary mixing chamber.
4. The device of claim 1, wherein said device further comprises a face mask in operably communication with said transport tube.
5. The method of claim 1, wherein said transport tube further comprises a nozzle in operable communication with said mixing chamber.
6. The device of claim 1, wherein said transport tube further comprises an adjustment component configured to move said transport tube in closer or further proximity to said mixing chamber.
7. (canceled)
8. The device of claim 1, wherein said inlet further comprises a valve configured to control the cross-sectional area of said inlet.
9-11. (canceled)
12. The device of claim 1, wherein said device comprises two or more inlets and/or outlets.
13. The device of claim 1, wherein said outlet/inlet comprises a valve.
14-15. (canceled)
16. The device of claim 1, wherein said inlet comprises an actuator that controls movement of air through said actuator.
17. The device of claim 1, wherein said device further comprises a secondary flow inlet.
18. The device of claim 17, wherein said secondary flow inlet enters said device tangentially to said mixing chamber.
19. The device of claim 8, wherein said valve is configured to move with the axis of the inlet.
20-21. (canceled)
22. The device of claim 1, wherein said mixing chamber comprises a constrictable region.
23. The device of claim 22, wherein constriction generates negative pressure via the venturi effect.
24-26. (canceled)
27. The device of claim 1, wherein said device further comprises an external source of gas in operable communication with said device.
28. The device of claim 1, wherein said device provides intermittent, periodic, or continuous negative air pressure.
29. The device of claim 1, wherein said device traps CO.sub.2 in said mixing chamber.
30. A system, comprising: a) the device of claim 1; b) at least one sensor selected from the group consisting of a CO.sub.2 sensor, a pressure sensor, a temperature sensor, and an air flow sensor; and c) a processor configured to use an algorithm to control CO.sub.2 levels or airflow provided by said device.
31-32. (canceled)
33. A method of treating sleep apnea in a subject, comprising: applying the device of claim 1 to a subject in need thereof.
34-36. (canceled)
Description
DESCRIPTION OF THE FIGURES
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DETAILLED DESCRIPTION
[0029] Provided herein are negative air pressure devices and uses thereof. In particular, provided herein are negative air pressure devices that modulate CO.sub.2 delivery for use in the treatment of sleep apnea.
[0030] The devices described herein are based, in part, on the Bernoulli principle, Venturi effect, and mass and energy transfer equations. Common realizations of these concepts in other systems are (a) ejectors, (b) injectors, (c) air jets, (d) educators, (e) jet pumps, (f) carburetors, (g) cyclonic separators etc. The Bernoulli theorem teaches us that the energy of flowing fluid (for small height differences) remains constant, but this energy can take a form of either kinetic energy or potential energy (in the pure form of pressure for horizontal flow). In order words, if a fluid accelerates its pressure will drop and vice-versa, while the total energy remains unchanged. For air flowing in a tube, the changes in pressure and velocity can be made to occur by narrowing or widening the tube or sections of the tube. For example, one can decrease the pressure and thus increase the velocity of a fluid by creating a reduction in the cross-section area (a throat). The cross-section area of the tube or of the constraint can have any shape, e.g. circular or rectangular. The same effect of changing pressure and kinetic energy can be created using nozzles. Because of the increase in the velocity, the pressure of the moving fluid becomes lower than of any surrounding fluids, which cause the latter to flow toward the area of lower pressure similarly the way air flows into vacuum.
[0031] The Bernoulli principle and the Venturi effect show that regions where a fluid has a higher velocity causes a negative pressure. In other words, an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy. In the present disclosure, these principals are used to create a region of low pressure that can be used to control the mixing between atmospheric air and either exhaled air and/or other gases such as CO.sub.2 or O.sub.2. Because the devices described herein allow for control of the lower pressure, one can control both the intensity and the direction of the secondary gas and thus the mixing of the gas. Thus, contamination of the non-disposable parts is avoided. Moreover, there is no need to use valves to control the amount of CO.sub.2 inside the mixing chamber, however one can still use them if desired. Also, in some embodiments, the tube throat is constrained by an exterior actuator without putting it in direct contact with the exhaled air. In some embodiments, a valve, diaphragm, needle of any other means is used to reduce the cross-section in the tube both/either at the exit/exits and/or in the inlets (primary or secondary). More or less cross-section area provides a more or less differential pressure and hence more or less mixing. Again, this avoids contamination since the air only travels from the outside (atmospheric) to the inside of the mixing chambers if there is a constraint in the tube.
[0032] The devices described herein do not need to be rigid and can be constructed of any type of appropriate fiber or other material, e.g., paper, cardboard, plastic, metal or alloy (e.g., stainless steel), and ceramic. Because the devices can be constructed of an absorbing material, the device can control excess moisture (a common complain of CPAP users) and be disposable so cleaning is not needed (another common complain of CPAP users) and inexpensive to manufacture. Because the pressures involved are small (typically less than 20 mmHg), the mask and/or nasal pillows do not need to be very tight to avoid leaks, which are a source of complaint among users of PAP machines.
[0033] In some embodiments of the device, the venturis are asymmetrical because in most of the applications a fluid can be adequately mixed in only one direction. However, in the devices described herein, they can be symmetrical, so the atmospheric air is mixed inside of the device in both the inhale and exhale phases in a similar fashion. Another advantage of the devices of the present disclosure is that they do not require a fan or blower to create the negative pressure but rather uses the kinetic energy of the inspired and/or expired air from the user to create the differential pressure. Thus, no third source of energy is necessary.
[0034] Further provided herein is a computer-controlled algorithm to control the amount of CO.sub.2 based on one or more parameters (e.g., concentration of CO.sub.2 in the device or mask, detection of apneic event, etc.). The apneic event can be detected by changes or lack of variation of flow, pressure, gas concentration, temperature, humidity, electrical resistivity, sound and/or electromagnetic changes inside or outside of the chamber and/or the mask. Alternatively, or in combination, it can be detected by pulse oximetry, chest movement strain gage attached to the device or patient, chest movement image, and/or video. However, it is preferable not to be in contact with the interior of the primary or secondary chambers to avoid contamination and hence the need of cleaning.
[0035] In some embodiments, the devices described herein treat sleep apnea by delivering amounts of CO.sub.2 either generated by patients during the exhale phase of the respiration or by an external gas reservoir or by concentrating the natural occurred CO.sub.2 in the atmosphere. In some embodiments, the amount of CO.sub.2 delivered to the patient is controlled based on the measurements of the individuals' respiratory instability, e.g., hypoapnea or apnea events.
[0036] Accordingly, provided herein are Variable Negative Air Pressure device (VNAP) or Constantly Negative Air Pressure (CNAP) devices for use in treating sleep apnea. While the present devices are exemplified with controlling the amount of CO.sub.2 delivered to the patients during the respiratory cycle in order to stabilize their respiration, the present disclosure is not limited to CO.sub.2 regulation. In some embodiments, the device is used to control the amount of any other gases exhaled by the patient such as, for example, O.sub.2, N.sub.2, etc. Exemplary devices are described herein.
[0037] In some embodiments, the VNAP or CNAP comprises at least one (e.g., all three) modules: (1) a chamber comprise a venturi, air injector, air ejector or educator based on the Bernoulli principle to vary the mixing between the fresh/atmosperic air and CO.sub.2 by using one or more actuators; (2) one or more sensors to detect apnea or hypoapnea; and (3) a control mechanism for delivering the required amount of CO.sub.2 used to stabilize the patients' respiration.
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[0044] The present disclosure is not limited to a particular location of inlet 8. In
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[0061] The present disclosure is not limited to particular sizes of devices. In some embodiments, the effective cross-section area of the device is larger than the cross-section area of a cylinder of 10 mm in diameter in order to avoid extra resistance to normal respiration. However, any specific cross-section area can be used given another path for the flow of gases to occur. For example, the mixing chamber can have a diameter of 0 mm if the transport tube and inlet have effective diameters in combination of at least 15 mm. In this case, all the flow occurs from the inlet and transport tube with minimal addition of excess CO.sub.2 or other gas/gases.
[0062] Further provided herein are systems comprising the devices described herein, a CO.sub.2 sensor, and a processor and algorithm that controls CO.sub.2 delivery by the device based on feedback from the CO.sub.2 sensor and/or the patient. In some embodiments, systems include a controller (e.g., controlled by the processor) that controls function of the device in order to modulate CO.sub.2 levels and/or airflow through the device.
[0063] The present disclosure is not limited to particular CO.sub.2 sensors. In some embodiments, commercially available CO.sub.2 sensors are utilized (e.g., available from Kele, Memphis, Tenn. or any number of other commercial suppliers). In some embodiments, the CO.sub.2 sensor is located in a suitable location or locations of the device in order measure the level of CO.sub.2 in the mixing chamber (e.g., including but not limited to, internal to the mixing chamber or external with access via an inlet or valve).
[0064] In some embodiments, systems include components to detect apnea in a patient. The apneic event may be an apnea or a hypopnea, or the apneic event may be the absence of normal respiration (e.g., the temporary cessation of breathing) or a hypopnea (e.g., abnormally slow or shallow breathing). For example, one or more sensors are provided in the airstream that measure the flow rate of each breath of the wearer and may sense the slowing or cessation of breathing or a reduction in airflow. The sensor may also be a pulse oximeter, a thermal sensor, an optical sensor, or the like, or combinations of the foregoing, as well as combinations of any of the sensors described herein. Accordingly, apneas may be detected, for example by pulse oximetry, or a thermal flow sensor (such as hot wire anemometer), or an optical sensor (such as that detects movement of a drag sensor), or a flow sensor (such as a pneumotachometer).
[0065] In some embodiments, when apnea is detected, the controller controls the levels of CO.sub.2 or the negative pressure in the device (e.g., by adjusting one or more valves, blowers, etc.) in order to treat the apnea. In some embodiments, the sensor is configured to take readings at regular intervals (e.g., every microsecond, millisecond, second, minute, or longer intervals). The algorithm and processor then determine if apnea or hypoapnea is present and directs the controller to adjust the device accordingly.
[0066] In some embodiments, the controller further controls valves present in a mask as shown in
[0067] As described herein, the present disclosure provides methods of treating apnea using the devices and systems described herein. The devices and systems are suitable for treatment of any type of apnea (e.g., obstructive, central or mixed sleep apnea).
[0068] All publications, patents, patent applications and accession numbers mentioned in the above specification are herein incorporated by reference in their entirety. Although the disclosure has been described in connection with specific embodiments, it should be understood that the disclosure as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications and variations of the described compositions and methods of the disclosure will be apparent to those of ordinary skill in the art and are intended to be within the scope of the following claims.