Innovations in mechanical ventilators

Abstract

A respiratory device of negative pressure type comprising a shell fastened to the user's chest and/or abdomen with minimal dead space, one or more vacuum and compressed air chambers attached to the shell; vacuum generating and compressed air generating sources connected to the vacuum and compressed air chambers respectively, one or more openings on the shell to allow exchange of the air enclosed between shell and user's body, with the vacuum and compressed air chambers; a valve shuttling between the vacuum and compressed air chambers. By having low dead space, pre-generated vacuum and compressed air close to the user, and the use of fast acting valves in some embodiments, the power requirement, weight, and size are reduced, making the device low cost and portable. In some embodiments, the vacuum and compressed air generating sources can be mounted on the shell itself, making the device ambulatory.

Claims

1. A respiratory device comprising: a shell enclosing the front and side parts of the user's chest and/or abdomen; one or more vacuum chambers attached to the shell; one or more compressed air chambers attached to the shell; a vacuum generating source connected to the one or more vacuum chambers; a compressed air generating source connected to the one or more compressed air chambers; one or more openings on the shell to allow exchange of the air which is enclosed between the shell and the user's body, with the one or more vacuum and compressed air chambers; a valve shuttling between the vacuum and compressed air chambers; one or more sensors and one or more electronic control unit attached to the shell to operate the valve, and/or the vacuum and compressed air generating sources, and/or any other electronic component of the device; one or more battery and/or electrical connection to the mains or to an external power source attached to the electronic control unit, to power the sensors and electronic control unit, and/or the vacuum and compressed air generating sources and/or any other power driven component of the device; a sealing mechanism to seal the shell to the user's body; and a shell fastening mechanism to fasten the shell to the user's body.

2. The respiratory device of claim 1, wherein: the vacuum and compressed air generating sources are attached onto the shell in the form of a vacuum pump and compressor, or just a compressor that can also generate vacuum via venturi effect or any other means; and any or all of the components of the device, apart from the shell, could be a detachable separate unit, attachable onto a large number of shell sizes.

3. The respiratory device of claim 1, wherein: the vacuum and compressed air generating sources are external to the shell in the form of external vacuum pump and compressor, or just compressor which also generates vacuum via venturi effect, or vacuum and compressed air outlets of hospital pipelines, or just compressed air outlet of hospital pipelines which also generates vacuum via venturi effect; and wherein these said sources communicate with the vacuum and compression chambers of the shell by means of small diameter pipes (<1 cm) high pressure pipes.

4. The respiratory device of claim 1, wherein the valve is ultra-fast acting, within microseconds of the user's initiation of inhalation effort or within microseconds of command from the electronic control unit.

5. The respiratory device of claim 1, wherein the device auto-starts ventilating the user on fastening the fastening mechanism.

6. The respiratory device of claim 1, further comprising pipes and/or other suitable conveying means to supply warm air from the device to the user's nose, which can also nebulize medicine and/or be humidified and delivered to the user via nasal pipes or mask or helmet.

7. The respiratory device of claim 1, wherein the shell is either made in several sizes and/or is adjustable and/or is customizable, to minimize dead space.

8. The respiratory device of claim 1, wherein the shell and/or the vacuum and compressed air chambers are made lightweight, utilizing thin-walled, structurally supported elements, like double shells supported by fins, or thin shells that are well stiffened with narrowly spaced ribs or lattice structures.

9. The respiratory device of claim 1, wherein: the electronic control unit is connectable to an external programming device like a mobile phone or any other computing device, to customize settings per user, via any suitable wired and/or wireless means, and can even be programmed via the internet; or the electronic control unit is connected to an input device such as a keypad and/or to a display unit or touchscreen, which may be attached to the shell, to program the various settings like respiratory rate, rhythm, pressures, tidal volume, and so on, onto the device as desired.

10. The respiratory device of claim 1, wherein the device can be programmed such as to provide resistance training to the user's respiratory muscles, to improve strength of respiratory muscles, and/or to improve the respiratory rate, rhythm, and volume of the user.

11. The respiratory device of claim 1, wherein the device can also be utilized to generate and provide positive pressure ventilation to the user, via nasal pipes and/or mask and/or helmet and/or endotracheal tube and/or or any other means.

12. A lightweight, low power respiratory device, weighing less than 2 kg: requiring less than 20 watts power comprising: one or more compressed air chambers; a compressed air generating source connected to the one or more compressed air chambers; a fast acting valve opening the compressed air chamber; one or more sensors and one or more electronic control unit to operate the device; one or more battery and/or electrical connection to the mains or to an external power source attached to the electronic control unit, to power the device; and a pipe from the compressed air chamber conveying compressed air to the user via nasal pipes and/or mask and/or helmet and/or endotracheal tube.

13. The respiratory device of claim 1, wherein the seal comprises an open cell foam, covered with an outer skin, preventing air from within the seal from communicating with the atmosphere, while at the same time allowing movement of air within the seal, allowing a soft, comfortable, yet sturdy seal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

[0041] These and other features, benefits and advantages of the present invention will become apparent by reference to the following text figures, with like reference numbers referring to like structures across the views, wherein:

[0042] FIG. 1 illustrates an outline view of the respiratory device according to one embodiment of the present invention, fastened on a user.

[0043] FIG. 2 illustrates a perspective view of the assembly of the respiratory device according to one embodiment of the present invention.

[0044] FIG. 3 illustrates an outline view of a respiratory device according to one embodiment of the present invention, wherein warm air from the vacuum pump exhaust is used to nebulise medication and/or to humidify air and deliver it to the user's nostrils.

DETAILED DESCRIPTION OF THE INVENTION

[0045] The respiratory device disclosed in the present invention simulates the natural breathing process. To initiate a breath, it creates a negative pressure around the chest cavity either directly (if the ventilator shell is attached to chest) or indirectly (if the ventilator shell is attached to the abdomen, in which case expansion of the abdomen lowers the diaphragm, indirectly leading to negative pressure in the lungs)—leading to air entering into the lungs via the nostrils, to equalize the pressure, and thus causing inspiration. When the pressure is equalized, the device now aids the natural elastic recoil of the lungs by pushing in compressed air around the chest cavity or abdomen—helps expel air from the lungs, thus aiding exhalation.

[0046] FIGS. 1 and 2 illustrate the respiratory device according to one embodiment of the present invention, which is the best mode or preferred embodiment. FIG. 1 shows shell 10 which encloses the front and side parts of the abdomen of the user, with seal 12 that seals the shell 10 and prevents leakage of air between the shell and user's body. The shell is fastened to the body of the user by means of a fastener. Fixed onto the shell 10 is assembly 14 which is attached to the shell 10, which comprises other parts of the device as detailed in FIG. 2. Assembly 14 comprises vacuum chamber 16 and 2 compressed air chambers 18, valve housing 20, vacuum generating source which is a vacuum pump 22 and a compressed air generating source which is a compressor 24, connected to vacuum chamber 16 and compressed air chambers 18 respectively. Valve 26, located inside valve housing 20 communicates with vacuum chamber 16 and with compressed air chamber 18. Valve housing 20 communicates with shell 10 via openings 28 and 30. Also mounted on the shell 10 is electronic control unit 32, with electrical connection 34 and battery 36. Pressure sensors are present in vacuum chamber 16, compressed air chamber 18 and between shell 10 and user's body. Pressure and/or flow regulators 44, 46 are situated between vacuum pump 22 and vacuum chamber 16 and between compressor 24 and compressed air chamber 18 respectively. The device can be programmed via wired and/or wireless connections connected to the electronic control unit 32, which in this embodiment are Wifi module 48 and USB cable 50 respectively. One or more breath sensors are situated in one or more openings in the shell.

[0047] Initiation of the user's inhalation is sensed by the breath sensor. This leads to synchronous opening of the vacuum chamber 16 by the fast acting valve 26. The vacuum chamber 16 has vacuum pre-generated by the vacuum pump 22 and the air inside the shell 10 now enters into the vacuum chamber 16 via openings 28 on the shell 10. This instantly reduces pressure around the user's abdomen, initiating expansion of the abdomen into the negative pressure area. This leads to contraction of the diaphragm and thus the simultaneous expansion of the lungs, initiating inhalation of air via the nostrils into the lungs. This simulates natural respiration, wherein expansion of the lungs by the respiratory muscles causes negative pressure in the lungs, causing atmospheric air to enter the lungs via the nostrils. Since the valve 26 acts within microseconds, and also since there is pre-generated vacuum stored in the vacuum chamber 16 by vacuum pump 22, the vacuum generation is instantaneous. This reduces user respiratory effort, thereby increasing user ease and very importantly, allowing the ailing user's energy resources to be utilized for other vital body functions. This device can be thus advantageously utilized by any critically ill user, even one who does not require respiratory support, to reduce the physical effort of the user.

[0048] Additionally, the valve 26 could also open the vacuum chamber 16 based on preset timing programmed on the electronic control unit 32.

[0049] The vacuum chamber 16 could be sized to evacuate the entire tidal volume (volume of air taken in and expired per breath, which is 7 ml/kg of body weight) at once, or it could be smaller and the vacuum generated in it could be regulated by the pressure and/or flow regulator 44 to continuously evacuate the air enclosed between the shell 10 and the user's body over 1-2 seconds, such that the desired tidal volume is evacuated over this period of 1-2 seconds or in any desired time. The latter mode is preferred as it needs a smaller chamber and causes smoother, non-jerky expansion of abdomen and chest.

[0050] Pressure sensor inside vacuum chamber 16 and pressure sensor between the user's body and shell 10 provide feedback control to the vacuum pump 22 and the pressure and/or flow regulator 44 that is regulating the pressure and/or controlling the flow, to maintain appropriate vacuum in the vacuum chamber 16 to efficiently evacuate the air between the shell 10 and the user's body, such that the desired tidal volume is evacuated per breath.

[0051] In another embodiment, the vacuum pump 22 and compressor 24 could be directly motor controlled based on feedback from the sensors.

[0052] Once the desired tidal volume is evacuated, the further evacuation of the air between shell 10 and the user's body is stopped, inhalation may be held for desired time if any, and then the valve 26 shuts the vacuum chamber 16, simultaneously opening compressed air chamber 18. Air from compressed air chambers 18 enters the gap between shell 10 and the user's body via opening 30 on the shell 10. This air actively pushes the abdomen, aiding the natural deflation of the abdomen that would happen during exhalation due to elastic spring recoil of the lungs. This is especially helpful in people with chronic lung diseases like asthma and chronic bronchitis, who have trouble exhaling completely. The amount and pressure of compressed air in compressed air chamber 18 is regulated by the pressure and/or flow regulator 46 based on feedback from pressure sensor between the user's body and the shell 10, and the pressure sensor in compressed air chamber 18.

[0053] All the sensors, the regulators 44, 46, the vacuum pump 22 and the compressor 24 are controlled by electronic control unit 32, which coordinates the action of all the components, to achieve the desired pressures, flow rates, tidal volumes, breath rates and respiratory rhythms. Some of these settings can be pre-programmed onto the control unit 32, while others could be programmed later at any time, via wifi module 48 or USB cable 50, which would connect to a suitable computing device or mobile phone. In other embodiments the same can be done via any other suitable wired or wireless means and even via the internet. This allows for a much lighter and economical device. In yet another embodiment, the respiratory device can have a keypad and LCD, or a touchscreen, or any other suitable input and/or display device attached to it, to directly program the device.

[0054] In other embodiments, other sensors such as temperature sensor, oxygen saturation sensor, and so on could also be used to further fine-tune the ventilator support given to the user, by altering the tidal volumes, rate or rhythm as needed.

[0055] The user data gathered from the sensors could be stored on the device or transmitted to any external device. All of the aforesaid are powered by battery 36 and can also be powered by the mains via electrical connection 34. The battery 36 is ideally one or more mobile phone batteries, which are readily available, chargeable and replaceable. The user can be completely mobile with the said embodiment, running on lightweight battery when the user is mobile, and charging the one or more batteries via electrical connection 34 when resting. Electrical connection 34 could also directly power the device.

[0056] Soft seal 12 between the shell 10 and the user's body, prevents leakage of air. The said seal 12 in the preferred embodiment is an open cell soft foam with a skin on the outside, preventing air from the seal from communicating with the atmosphere, while allowing movement of air within the seal, making it a very soft and comfortable and yet sturdy seal.

[0057] The shell 10 can be fabricated in several sizes and can even be custom-made. Further, the shells can be slightly flexible, allowing the ready sizes to be further adjusted, thus allowing the shell to closely fit the body of all users. This minimizes the dead space between the shell and the user's abdomen to around 1-2 liters, preferably around 1 liter.

[0058] Further in several embodiments, the shell 10 and the chambers 16, 18 are preferably made of thin walls that could be double walls with supporting fins or single walls supported by narrowly spaced ribbed structure, allowing for greater strength at lighter weight than the plain thick shells of the prior art that were needed to withstand the pressure and vacuum generated. This also makes the shells slightly flexible, allowing for a better, more comfortable fit with less dead space and reduced leakage.

[0059] The shell 10 is fastened to the user's body by means of an adjustable fastener. In the preferred embodiment, the respiratory device is configured to auto-start on locking the fastener, thus allowing immediate respiratory support which could be life-saving in many cases. The respiratory device in this case would auto-start with a default minimum respiratory breaths and tidal volume suitable for the said shell size. The respiratory device could then be set appropriately for the user at any later time.

[0060] Normal respiratory effort requires 2.5 watts of energy expenditure by a person. The smallest portable respirators have a power requirement of 50-100 watts. Whereas the present invention allows a much smaller vacuum pump 22, and compressor 24, and much lower power requirement, in the range of 5-20 watts, preferably 5-10 watts. This is achieved by using several methods.

[0061] Firstly, by having vacuum and compressed air chambers 16, 18 respectively attached to the shell 10. Their function is to pre-generate sufficient vacuum and compressed air to instantly evacuate and compress respectively on opening of valve 26. By having pre-stored vacuum and compressed air attached to the shell 10, the efficiency of the vacuum generation and compressed air generation is greatly improved, allowing for the use of low power, lightweight and small sized pumps, to provide desired vacuum and compression quickly, thus also allowing the vacuum and compressed air sources, vacuum pump 22 and compressor 24 respectively, to be mounted on the shell 10, compared to prior art.

[0062] This fast vacuum generation is aided by the fast acting valve 26, which also reduces the power required by the vacuum pump 22, as this instantaneous action requires much less negative pressure to be generated to allow inhalation of desired volume of air into the lungs.

[0063] Further, the dead space between the shell 10 and the user's body and also between the shell 10 and the vacuum pump 22 is greatly reduced. Prior art respiratory devices have very high dead space between the user's body and the shell, to accommodate for various patient sizes, and further dead space in the large bore tube used to connect the shell to the vacuum pump. Their vacuum pump too is large and heavy, to enable it to quickly evacuate this large dead space, to generate the desired negative pressure and cannot be mounted on the shell, thus making the prior art devices non-ambulatory.

[0064] Whereas in the present invention, the shell 10 is fabricated in several sizes to accommodate different users and is further slightly flexible and adjustable, thus minimizing the dead space between the shell and the user's abdomen. Also, there is no wide bore tube to be evacuated between the vacuum pump 22 and the shell 10. This reduces the power requirement of the vacuum pump 22, as it has to evacuate less air from this dead space to create enough negative pressure to start expansion of the lungs, and allows for a smaller size of vacuum pump 22 and compressor 24.

[0065] The entire respiratory device described above is lightweight and ideally weighs less than 1.5 kgs.

[0066] In another embodiment of the present invention, the vacuum and compressed air generating sources 22 and 24 respectively are external to the shell 10, and are connected to it by means of two small diameter (<1 cm) pipes. The said external sources could be external vacuum and compressor pumps or external vacuum and compressed air outlets respectively, of hospital lines. By having low dead space between the shell 10 and the user's body and by having compressed air chamber and vacuum chambers on the shell 10, the pipes connecting to these external sources can be of small diameter—less than 1 cm, ideally 5 mm, and preferably capable of withstanding 60 psi compressed air and 75% vacuum. Using such high pressure and vacuum, as are standard in hospital lines, further allows narrow bore tubes to generate the required pressure and vacuum, reducing dead space between the vacuum and compressed air sources, and the vacuum and compressed air chambers respectively. This embodiment is suitable in hospitals where compressed air and vacuum outlets are already available, reducing the cost of the device. Even in smaller nursing homes, such vacuum and compressed air lines can be specially installed, allowing for servicing of many users simultaneously on these respiratory devices, at a cheaper cost than that of a single conventional respirator. Such external sources could also provide a lightweight, cheaper, low power requiring ventilator support to bedridden users. Pressure and/or flow regulators on the pipes would have to be set to allow the desired vacuum or pressure in the vacuum and compressed air chamber respectively. Further, contrary to prior art devices, which are connected by wide bore tubes to vacuum pumps, this embodiment is still instantly acting due to pre-stored vacuum and compressed air in the vacuum and compressed air chambers, respectively, and can work with very narrow bore tubes, less than 1 cm, ideally around 5 mm.

[0067] In other embodiments of the present invention, the compressor performs both functions, compressing air into compressed air chamber and evacuating the vacuum chamber via venturi principle.

[0068] In other embodiments of the present invention, some or all parts of the assembly 14, are together on a separate piece attachable to the shell 10, allowing this separate piece to be used with different sized shells. Providing a large number of shells of different sizes makes it easy for users of different body sizes to obtain a shell that has minimum dead space in the preferred 1-2 liters range. Hospitals, schools, railways, etc. would have to stock up a large number of devices which would be costly. The shell 10 in this invention is preferably lightweight and economical, so that it can even be disposable. So by having some or all of the components of the assembly 14, which are most of the cost of the device, on a single separate unit, several shells can be used with one or a few such units and the cost drops drastically, since all shells are not being used at a time. This is also useful in case of growing children, who only need to change the shell 10 as they grow.

[0069] Another application of the device is in training the respiratory muscles of the user. This could be used even in individuals without respiratory illnesses, for various benefits. Resistance training could be provided by this device to the user's respiratory muscles, by suitably programming the said device such that the number of breaths are reduced, and the respiratory rhythm is improved. The device would not permit rapid, shallow, irregular breathing, for example, by applying appropriate resistance to the user's inhalation effort, or by helping the user perform a deep exhalation. Respiratory muscles undergoing such training, would be thus trained similar to resistance training of muscles of the arms or rest of the body.

[0070] Such muscles would require less energy for respiration, diverting that vital energy to other areas of the body, critical for both athletes and patients with chronic respiratory disease. It is also found that slower, deeper breaths are very calming and useful in reducing stress, and very healing in stress-caused illnesses like hypertension etc. As the ancient Sanskrit proverb states “For breath is life. If you breathe well, you will live long on earth.” In fact, as stated by Dr. Arthur C. Guyton, MD, in “The Textbook on Medical Physiology”, “All chronic pain, suffering and diseases are caused by a lack of oxygen at the cell level.”

[0071] The present invention is thus very vital to city populations who suffer from the above in large numbers. Being portable, non-invasive, easy to use, safe and economical, it could be an important health promoting and disease preventive device.

[0072] Embodiments of this device could also be used to provide positive pressure ventilation. At certain times, e.g. during thoracic or abdominal or back surgeries, it is not possible to use this device in its negative pressure mode. In such and other similar occasions, this same device can also be used as a positive pressure device. The compressed air source 24 would filled in compressed air in the compressed air chamber 18 and the fast acting valve 26 and the pressure and/or flow regulator 46 would help pump air at the desired positive pressure into the user's lungs. During such use, the shell 10 need not be fixed to the user's chest and/or abdomen, and could be lying close to the user.

[0073] Other embodiments could utilize the compressed air chamber 18, the fast acting valve 26, and a compressed air source 24, with required sensors, control electronics, nasal pipe and/or mask and/or helmet and/or endotracheal tube etc. to provide positive pressure ventilation to the user, eliminating the vacuum chamber 16, vacuum generating source 22 and shell 10. This device could be strapped onto the patient by any suitable means, or placed close to the patient. This embodiment also has the advantage of fast acting valve 26 and pre-stored compressed air and thus would require less power, is lighter weight, and economical compared to conventional positive pressure ventilators.

[0074] FIG. 3 illustrates an outline view of a respiratory device according to one embodiment of the present invention, wherein warm air from the vacuum exhaust is used to nebulise medication and/or humidify air and deliver it to the user's nostrils. Many users requiring respiratory support often require medication to be delivered to them in nebulized form. In one embodiment, as illustrated in FIG. 3, the warm exhaust air from the vacuum pump 22 is conveyed by pipe 52 to the user's nostrils directly, as illustrated in the figure, or alternatively via a nasal mask or helmet. En-route to the nose, the pipe 52 narrows while passing over medication and/or humidifier tank 54. Air passing through this narrowing, draws up the liquid medication and/or water via venturi effect and mixes with it—creating a fine mist of the medication and/or humidified air, which travels via the pipe 52 to the user's nostrils. This can be regulated by the regulator 56 on the pipe 52 and used as and when required. The rest of the time, the vacuum pump 22 exhausts out to the atmosphere via outlet 58.

[0075] In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the present invention as set forth in the various embodiments discussed above and the claims that follow. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements as described herein.