CROSS REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to U.S. Provisional Application Serial No. 63/168,273, filed on March 31, 2021, which is hereby incorporated by reference in its entirety.

FIELD

[0002] The present invention relates to a device for pressure indication. In particular, the invention relates to a device for indicating and regulating an air pressure of a cuff of an airway device.

BACKGROUND

[0003] Regulation of endotracheal tube (ETT) cuff pressure and laryngeal mask (LMA) cuff pressure is the most important part of patient care and preventing ventilator- associated pneumonia.

[0004] The goal of monitoring ETT cuff pressure is to achieve a seal between the trachea and the ETT cuff with a high enough pressure to prevent micro-aspiration of contaminated oropharyngeal content, but low enough to avoid promoting airway (mucosa or cartilage) damage. Keeping the ETT cuff pressure between 20 and 30 cm H20 is recommended.

[0005] However, the manual manometer for routine intermittent ETT pressure measuring and correction cannot avoid under-inflation or over-inflation episodes between measurements. Hence, less than one-fifth of patients have a correct EET pressure during the 8 hours between two manual corrections. Moreover, the cuff pressure is also altered by the airway tone or the patient's position.

[0006] Similarly, in patients provided with an LMA, a high cuff pressure may lead to palsy of the lingual, hypoglossal, and recurrent laryngeal nerves, but with the cuff pressure maintained below 60 cm H20, the airway seal is optimized, and the incidence of a postoperative sore throat is low.

[0007] Numerous attempts have been made in the art to address this problem. One approach focuses on providing an indicator connected with the cuff to provide pressure information continuously.

[0008] U.S. Patent No. 8,033,176 B2 teaches an indicator of the internal pressure of an inflatable cuff. The device includes a bellow and housing with two openings. The inner chamber of bellows is communicated with the atmosphere. The openings of housing are for syringes and cuffs. When the internal pressure of the cuff increases, the bellow will be compressed until the pressure force and the resilience force of the bellow is balanced. The condition of the bellow indicates the pressure value of the cuff. Hence, the device can provide a pressure indication when the cuff pressure is higher than atmospheric pressure. However, the bellow cannot show the negative pressure of the cuff when the cuff is required to be fully deflated.

[0009] US 9,901,693 is another design with a balloon in a hollow ball. Besides monitoring the pressure, the design can also regulate the pressure in a specific range. Specifically, the design uses the flexibility of the balloon to regulate the pressure. The regulating ability is limited because the buffer volume is the concave region of the hollow ball, which is hard to increase further. The dimension of the whole device will become too big if a significant buffer volume is required. Moreover, the balloon size is subjective and hard to be quantitative, increasing the difficulty of realizing the cuff pressure. In other words, the balloon can maintain the pressure fall within 20 to 30 cmH ₂ 0 under certain volume range. Further, '693 patent disclosed that when the volume in the full 2/3 to 3/4 of the range can maintain the pressure within 20 to 30 cmH ₂ 0, which also means that 2/3 of the volume waste cannot be used as buffer. Therefore, the design disclosed by '693 patent has an issue of ineffective use of the internal space of the device, which may cause the whole device to be too large. [0010] Many researches have proven the effectiveness of such pressure indicating devices. For example, Sole ML, Penoyer DA, et. El. found that 30% of cuff pressure will decrease to lower than 20 cmH20 by a continuous monitoring technique, as the results described in Assessment of endotracheal cuff pressure by continuous monitoring: a pilot study, Am. J. Crit. Care, 2009. However, the cuff pressure change is complex, including air leakage through the cuff balloon material and patient position change. Therefore, a better strategy is to automatically control and maintain the pressure within a specific range, besides continuously monitoring the cuff pressure.

[0011] Jerome E. Dauvergne et. El. has completed a study to evaluate the necessity of an automatic regulation system. (Automatic regulation of the endotracheal tube cuff pressure with a portable elastomeric device. A randomized controlled study, SFAR, 2020) The results show only 2.1% of underinflation episodes within the 48h ventilating period while 14.9% of ventilating without automatic regulation. Also, 62.5% of patients with manual correction of cuff pressure have at least one detected episode of underinflation. The value successfully decreased to 17.9% if an automated correction system had been conducted.

[0012] With an eye to further reduce the risk of under or over-inflation of the cuff, a cuff pressure monitoring and regulation device with a compact structure is presented in this invention. Compared to the previous design, the invention has a larger buffer volume to regulate the pressure if the dimension of the device is similar. The indication of the cuff pressure can be quantitative. Moreover, the device can not only provide information when the pressure is positive but provide pressure information when the pressure is negative, which is very important when the cuff is required to be fully deflated before removal.

SUMMARY OF THE DISCLOSURE

[0013] The present disclosure describes a pressure regulator for automatically regulating and indicating an inner pressure of a cuff. The pressure regulator includes a hollow housing with first and second chambers, a valve, first and second openings, an indicator, and a biasing element. Further, a syringe can be coupled with the valve and the first opening to which a cuff can be coupled. The first chamber is in fluid communication with the first opening and the valve, and the second opening is for venting the second chamber to the atmosphere. The indicator was configured within the housing and defined the first and second chambers. The biasing element is configured within the second chamber and engaged the housing and the indicator, respectively, and the arrangement of the indicator and the biasing element are co-axial. In addition, the arrangement being such that a balance between a restoring force from the biasing element and first fluid pressure from the cuff can cause a longitudinal movement of the indicator along the housing to indicate an equilibrium pressure thereby, wherein the restoring force of the biasing element maintains the equilibrium pressure in a range.

[0014] In another embodiment, the housing includes a first portion and a second portion, and the first opening and valve are configured at the first portion. The second opening, indicator, and biasing element are configured in the second portion.

[0015] In another embodiment, the first portion includes a first longitudinal axis, and the second portion comprises a second longitudinal axis, and the first and second longitudinal axes are not parallel.

[0016] In another embodiment, the first portion further includes a second indicator.

[0017] In another embodiment, a partial of the second portion of the housing is received within the first portion of the housing.

[0018] In another embodiment, the housing includes a guiding element connected with the valve and the first chamber.

[0019] The present disclosure also provides another pressure regulator for automatically regulating and indicating an inner pressure of a cuff. The pressure regulator includes longitudinal and hollow housing, deformable element, and biasing elements. Further, the longitudinal and hollow housing includes the first opening to which a cuff can be coupled, valve to which a syringe can be coupled, second opening passed through the first housing, and guiding element. Further, the first chamber is in fluid communication with the first opening and valve through the guiding element. The second opening is for venting the second chamber to the atmosphere. The biasing element engaged with the housing and the deformable element, respectively, and the arrangement of the deformable element and the biasing element are co-axial. In addition, the arrangement being such that a balance between a restoring force from the biasing element and first fluid pressure from the cuff can cause compression or extension of the deformable element to indicate an equilibrium pressure thereby, and the restoring force of the biasing element maintains the equilibrium pressure in a range.

[0020] In another embodiment, the housing comprises a window.

[0021] The present disclosure further provides others pressure regulators for automatically regulating and indicating an inner pressure of a cuff. The pressure regulator includes longitudinal and hollow first housing, second housing configured within the first housing, indicator configured within the first housing and used to define first and second chambers, and biasing element configured within the first housing and engaged the second housing and the indicator, respectively. The longitudinal and hollow first housing includes a first opening to which a cuff can be coupled and a second opening having a valve to which a syringe can be coupled. The second housing includes a third opening passed through the first housing. The first chamber is in fluid communication with the first and second openings, and the third opening is for venting the second chamber to the atmosphere. The arrangement of the indicator and the biasing element are co-axial. In addition, the arrangement being such that a balance between a restoring force from the biasing element and first fluid pressure from the cuff can cause movement of the indicator to indicate an equilibrium pressure thereby, and the restoring force of the biasing element maintains the equilibrium pressure in a range.

[0022] In another embodiment, the indicator comprises a deformable element. [0023] The deformable element is a rubber, membrane, balloon, or bellow in another embodiment.

[0024] In another embodiment, the deformable element is compressed when the first fluid pressure is higher than the restoring force.

[0025] In another embodiment, the deformable element is extended when the first fluid pressure is higher than the restoring force.

[0026] In another embodiment, the volume of the first chamber increases when the first fluid pressure is higher than the restoring force.

[0027] In another embodiment, the volume of the first chamber is decreased when the first fluid pressure is lower than the restoring force.

[0028] In another embodiment, the deformable element deforms, and the spring has the longest longitudinal length when the fluid pressure is under the atmosphere.

[0029] In another embodiment, the housing comprises a fixing element used to anchor the pressure regulator on a tube.

[0030] In another embodiment, the range is 20 to 30 cm H2O.

[0031] In another embodiment, the range is 40 to 60 cm H2O.

[0032] In another embodiment, the biasing element is a spring.

[0033] In another embodiment, a k value of the biasing element is 1.5 to 2.5 / mm.

In another embodiment, when the equilibrium pressure is not in the range, the syringe adjusts the equilibrium pressure to maintain the equilibrium pressure in the range.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a schematic illustration of the cuff having a pressure regulator with a syringe.

[0035] FIGs. 2A and 2B are schematic illustrations of the pressure regulator. Further, FIG. 2A is a side view of the pressure regulator and FIG. 2B is an end view of the pressure regulator. [0036] FIGs. 3A and 3B are schematic illustrations of the pressure regulator. Further, FIG. 3A is an exploded view of a pressure regulator and FIG. 3B is an isometric view of an inner barrel of an end view of a pressure regulator.

[0037] FIGs. 4A to 41 are side cross-sectional views of a pressure regulator to one non limiting illustrated embodiment, and a deformable element is a piston. Further, FIG. 4A is a side cross-sectional view of a pressure regulator, FIG. 4B and 4C are side cross-sectional views of an inside portion of a pressure regulator, FIG.4D, 4E, and 4G-4I are side cross-sectional views of an indicator of a pressure regulator and FIG.4F is side cross-sectional views of a pressure regulator to another non-limiting illustrated embodiment.

[0038] FIGs. 5A to 5C are side cross-sectional views of a pressure regulator to one non limiting illustrated embodiment, and a deformable element is a membrane. Further, FIG. 5A is a side cross-sectional view of a pressure regulator and FIG. 5B and 5C are side cross-sectional views of an inside porbon of a pressure regulator.

[0039] FIGs. 6A to 6C are side cross-sectional views of a pressure regulator to one non limiting illustrated embodiment, and a deformable element is bellow. Further, FIG. 6A is a side cross-sectional view of a pressure regulator and FIG. 6B and 6C are side cross-sectional views of an inside portion of a pressure regulator.

[0040] FIGs. 7 A to 7C are side cross-sectional views of a pressure regulator to one non limiting illustrated embodiment.

[0041] FIGs. 8A to 8C are side cross-sectional views of a pressure regulator to one non limiting illustrated embodiment.

The drawings are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice of the disclosure. Any reference signs in the claims shall not be construed as limiting the scope. Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION

[0042] The making and using of the embodiments of the disclosure are discussed in detail below. It should be appreciated, however, that the embodiments provide many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the embodiments and do not limit the scope of the disclosure.

[0043] Throughout the various views and illustrative embodiments, like reference numerals are used to designate like elements. Reference will now be made in detail to exemplary embodiments illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. The shape and thickness may be exaggerated for clarity and convenience in the drawings. This description will be directed in particular to elements forming part of, or cooperating more directly with, an apparatus in accordance with the present disclosure. It is to be understood that elements not specifically shown or described may take various forms. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be appreciated that the following figures are not drawn to scale; rather, these figures are merely intended for illustration.

[0044] In the drawings, reference numbers are used to designate similar elements throughout the various views, and illustrative embodiments of the present disclosure are shown and described. The figures are not necessarily drawn to scale, and in some instances, the drawings have been exaggerated and/ or simplified in places for illustrative purposes. One ordinary skill in the art will appreciate the many possible applications and variations of the present disclosure based on the following illustrative embodiments.

[0045] Definition

[0046] It will be understood that when an element is referred to as being "on" another element, it can be directly on the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly on" another element, no intervening elements are present.

[0047] It will be understood that singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, relative terms, such as "bottom" and "top," may be used herein to describe one element's relationship to other elements as illustrated in the Figures.

[0048] The term "fluid" refers to a liquid or a gas. In the present disclosure, preferably, "fluid" refers to air. However, the term "fluid" should not be limited to air or liquid only.

[0049] The term "guiding element" refers to the element used to guide the flow of fluid in the pressure regulator, e.g., to guide the flow of fluid (e.g., air) into the first chamber of the pressure regulator after entering from the valve system, or to allow the flow of fluid in the pressure regulator to each opening to maintain pressure balance. More specifically, a guiding element can be a space formed between two walls, a recess on the case, or a separate channel. In a preferable embodiment of the present disclosure, the guiding element is a space between the outer and inner cases.

[0050] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms; such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0051] FIG. 1 discloses an endotracheal tube 4 and a pressure regulating system. Further, the endotracheal tube 4 includes a tube body 41 with two open-ends, a cuff 43, and an adaptor 45. The cuff 43 is configured at a place close to one end of the tube body 41, and the adaptor 45 is configured at an opposite end thereof. Additionally, the pressure regulating system, including pressure regulator 1 and syringe 2, regulates and monitors the pressure inside the cuff 43. More specifically, tube 431 extends from cuff 43, and the tube 431 can connect with pressure regulator 1. Therefore, pressure regulator 1, cuff 43, and tube 431 are fluid communication. A fluid pressure (e.g., air) inside the cuff 43 or the pressure regulator 1 is aligned by the tube 431 balancing each other. Further, when the equilibrium fluid pressure within the cuff 43 is not within the desired range, the pressure regulator 1 can automatically adjust the fluid pressure within the cuff to the desired range. Moreover, when an equilibrium fluid pressure inside the cuff 43 is outside the range where pressure regulator 1 can be automatically adjusted, medical professionals can increase or decrease the equilibrium fluid pressure inside the pressure regulator 1 by means of a syringe to adjust the fluid pressure inside the cuff back to the desired range.

[0052] Referring to FIGs. 2, FIGs. 2A and 2B are schematic illustrations of a pressure regulator 1. Further, FIG. 2A is a side view of pressure regulator 1, and FIG. 2B is an end view of the pressure regulator 1. Referring to FIG. 2A, the hollow housing (e.g., an outer case 10) has two parts: a first case 11 and a second case 13 (also referred to as the distal and proximal portion, respectively).

[0053] In a preferable embodiment, the first case 11 and the second case 13 are hollow cylinders with an open end and a closed-end, and both the first case 11 and the second case 13 form a whole (i.e., the outer case 10) by docking each other with their open ends. The shape of the first case 11 and the second case 13 in this embodiment is only an example but does not limit the case to a cylinder shape. It is worth knowing that the first case 11 and the second case 13 can be manufactured separately and assembled as a whole or formed as a single unit at the time of manufacture. Moreover, first case 11 has a first opening 111, a window 113, and a fixing element (e.g., hook 115). The pressure regulator 1 can be attached to tube body 41 of the endotracheal tube 4 for convenient use. Both the first opening 111 and the window 113 are configured at the closed end of the first case 11 (also referred to as a distal end 101 of the pressure regulator 1), and the window 113 is configured between the first opening 111 and the first case 11. The first opening 111 is used to couple with tube 431 extended from the cuff 43 in FIG.l.

[0054] The second case 13 has a valve system 131, including a valve (not showing in the figure) and a hole 1311, and a second opening 133. Further, the second opening 133 is configured at the closed end of the second case 13 (also referred to as a proximal end 103 of the pressure regulator 1). Referring to FIG. 2B, the hole 1311 of the valve system 131 is set to the center of the closed end of the second case 13 (i.e., a proximal end 103 of the pressure regulator 1), and the second opening 133 is set close to the hole 1511 on the closed end of the second case 13. Hole 1311 is used to couple with syringe 2 in FIG.l.

[0055] Referring to FIG. 3A, it discloses an exploded view of the pressure regulator 1. As FIG. 2A discloses the outer case 10 of the pressure regulator 1 includes the first case 11 and the second case 13. Further, an indicator 15, a biasing element (e.g., a spring 14), an inner housing (e.g., an inner case 12), and the valve 1315 of the valve system 131 are received within the first case 11 and the second case 13. It is worth knowing that indicator 15 is composed of a sliding element 151 and a piston head 153, and the piston head 153 is configured on the distal end of the sliding element 151. The inner case 12 is also a hollow cylinder with an open end and a closed-end (also referred to as the distal and proximal ends, respectively). A third opening 121 is configured at the closed end (i.e., the proximal end). The position of the third opening 121 is aligned with the second opening 133 on the second case 13. The third opening 121 and the second opening 133 are connected when all components are grouped together. Spring 14 is deposited within the inner case 12, and the two ends of spring 14 are engaged with the sliding element 151 and the inner side of the closed end of the inner case 12, respectively. Since pressure regulator 1 uses spring 14 to drive the movement of indicator 15, it has the advantages of (1) providing stable force, (2) not easy to creep, (3) effective use of internal space and does not occupy space, etc.

[0056] Referring FIG. 3B discloses an isometric view of the inner case 12 of a proximal end view of the inner case 12. It is clear from the figure that the inner case 12 has a cavity 123 configured in the center position of the closed end and several guiding elements (for example, but not limited to grooves 125) configured on the closed- end or the sidewall of the inner case 12. The cavity 123 is used to receive the valve 1315 in the FIG. 3A forms the valve system 131, and cavity 123 is a closed cavity. The grooves 125 are used to guild the fluid from the valve system 131 to a first chamber 105 in the FIG. 4A and vice versa.

[0057] FIGs. 4A to 41 are side cross-sectional views of the pressure regulator 1, and indicator 15 includes a deformable element (e.g., a piston head 153). Referring FIG. 4 A is a side cross-sectional view of pressure regulator 1. It discloses a relative position of the sliding element 151, the piston head 153, and the inner case 12 inside the outer case 10 of the pressure regulator 1. FIGs. 4A to 4F do not disclose all the elements of pressure regulator 1 to illustrate more clearly the mechanism of the action of the indicator 15 in the outer case 10. Indicator 15 divides the internal space of the outer case 10 into a first chamber 105 and a second chamber 107. In other words, indicator 15 is used to define the first chamber 105 and the second chamber 107. Indicator 15 is received within the inner case 12. The sliding element 151 guilds the indicator 15 to slide along the A-axial direction/ longitudinal direction (i.e., from distal end to proximal end and vice versa) of the pressure regulator 1. The piston head 153 is made of a material with elasticity, such as rubber so that it can form an airtight seal, and therefore the first chamber 105 and the second chamber 107 are not in fluid communication. Further, a gap or space between the outer case 10 and the inner case 12 can be a guiding element, and therefore the first chamber 105, the first opening 111, and the valve system 131 are in fluid communication. Further, the third opening 121 of the inner case 12 passes through the second opening 133 (i.e., a hole) of the outer case 10 and communicates directly with the outside. Therefore, the third opening 121 is for venting the second chamber 107 to the atmosphere.

[0058] FIG.4B and 4C are side cross-sectional views of the inner case 12 and the indicator 15 of the pressure regulator 1 in different statuses. Referring FIG. 4B, the force applied to the indicator 15 from the second chamber 107 is higher than the force from the first chamber 105 so that the indicator 15 is pushed and then moved to the distal end of the inner case 12. Therefore, the second chamber 107 has a maximal volume. Referring FIG. 4C, it discloses a situation opposite to that in FIG. 4B, in which the force from the first chamber 105 (also referred to as the pressure inside the cuff 43 in FIG. 1) applied to the indicator 15 is higher than the force from the second chamber 107 so that the indicator 15 is pushed and then moved to the proximal end of the inner case 12. Therefore, the first chamber 105 has a maximal volume, and a preferable volume is about 5.5 ml.

[0059] Our design has an unexpected result because of providing a buffer space. Please refer to FIG. 4D for the following description. For example, assuming that the original volume of cuff is 6 ml, and the pressure is set to the middle value (e.g., gage pressure is 25 cmFhO). Please refer to the data marked by the diamond and solid line in FIG. 4D. If the cuff does not connect to the pressure regulator, the volume of the cuff must be maintained at 4 to 8 ml (the original volume of cuff ± 2 ml) to maintain the gage pressure within the range of 20 to 30 cmFhO, but the reality is that human body is likely to make the volume change outside the above range due to the contraction or relaxation of the trachea. Please refer to the data marked by the circle and dotted line in FIG. 4D. On the contrary, when the pressure regulator is connected to the cuff, the allowable volume change range is greatly increased, and the cuff pressure can be maintained in the standard range within the interval of 2 to 11 ml (cuff decrease by 4 ml or increase by 5 ml).

[0060] FIG. 4E and 4F are side cross-sectional views of the indicator 15. As previously mentioned, indicator 15 includes the sliding element 151 and the piston head 153. Further, the sliding element 151 has a hole 1511 deposited at its center, and the piston head 153 has a deformable portion 1531 and a ring portion 1533. Therefore, when the atmospheric pressure inside the second chamber 107 is higher than the first chamber 105 and causes indicator 15 to move and engages the distal end 101 of the first case 11 as shown in FIGs. 4A and 4B, the atmospheric pressure will cause the deformable portion 1531 bugle and be detected in window 113 of the first case 11 in FIG.4A. FIG.4G is side cross-sectional views of a pressure regulator 3 to another non-limiting illustrated embodiment. The major components of pressure regulators 1 and 3 are the same, and the only difference between pressure regulators 1 and 3 is the outer case. Specifically, the outer case 10 of the pressure regulators 1 is consists of the first case 11 and the second case 13, and the inner case 12 is receipted within the outer case 10. However, an inner case 32 of the pressure regulators 3 is not completed receipted within the outer case 30. A portion of the inner case 32 of the pressure regulators 3 exposes to the outside directly.

[0061] FIGs. 4H-4J are side cross-sectional views of pressure regulator 1 and indicate the action of the indicator 15 and the spring 14 in response to a different status. Please referring to FIGs. 1 and 4H-4J, the first opening 111 of the pressure regulator 1 is connected to cuff 43 through tube 431, and syringe 2 connects with the pressure regulator 1 through the valve system 131. The cuff 43 and the first chamber 105 form a confined space with a certain fluid volume when valve system 131 is closed. In other words, the capacitance (total internal volume) of the cuff 43 and the first chamber 105 is fixed when the valve system 131 is closed. When the trachea (windpipe) compresses the cuff 43 (i.e., the volume of the cuff 43 is decreased), the indicator 15 in the inner case 12 will tend to move toward the proximal end 103 for increasing the volume of the first chamber 105 to maintain the constancy. [0062] FIG. 4H discloses that pressure regulator 1 is under a status, which it has not been connected to the cuff, or connects to the cuff and the equilibrium gage pressure is under 20 cm H2O. Under this condition, indicator 15 moves to the distal end 101 of the pressure regulators 1 by spring 14. More specifically, the restoring force of the spring 14 drives it back from the compressed length to the original length, thus causing a consequent movement of the indicator 15 to which it is connected. In a preferable embodiment, the k value of the spring 14 is about 1.9 g/ mm.

[0063] Referring now to FIG. 41, the pressure regulator 1 is connected to the cuff placed inside a patient's trachea (windpipe). As previously mentioned, when the pressure regulators 1 and cuff are connected by tube 431, the pressures inside the first chamber 105 and the cuff 43 will be in balance because of the connection. In other words, when the patient's trachea squeezes the inflated cuff 43 (i.e., decreasing the volume) and increases the pressure therein, it will force the indicator 15 tends to move to a direction close to the proximal end 103 to increase the volume of the first chamber 105 for maintaining the same total volume (i.e., the same balance pressure). In a preferable embodiment, the first case 11 and the inner case 12 are made of translucent or transparent material. Therefore, the position of indicator 15 relative to the inner case 32 can be used to indicate the pressure inside the cuff 43. Moreover, indicator 15 is subjected to the fluid pressure from the first chamber 105 and the return force, which is the exact opposite of the fluid pressure from the spring 14. Specifically, the return force of the spring 14 applied to indicator 15 can be used to adjust the volume of the first chamber 105 by moving the indicator 15 to adjust further the balance pressure inside the cuff 43 and the first chamber 105. FIG. 4H disclosed the equilibrium gage pressure inside the first chamber 105, or the cuff 43 is about 30 cmFhO and therefore, the first chamber 105 has a maximal volume.

[0064] Under normal circumstances, the pressure of the cuff may be influenced by several reasons including the position change of the patient, change of the muscle or tissue rigidity and operating of the ventilator. As FIG. 4H and 41 show, the pressure regulator 1 can act as a pressure buffer when the cuff pressure fluctuated. When the pressure decreased, the spring 14 will push the indicator 15 to decrease the total volume of the first chamber 105 and cuff. The decrease of the volume can increase the pressure again. Therefore, the pressure can be maintained within a specific value. In other words, the cuff pressure is controlled by the spring 14. The scenario is similar when the pressure inside the cuff is increased. Specifically, the spring 14 in the pressure regulator 1 is in the "pre-load" state, so there is no volume waste at all, and all the volume can be used as a buffer for adjusting pressure changes.

[0065] FIG. 4J discloses a status of pressure regulators 1 when medical professionals try to remove the endotracheal tube 4 from the patient's trachea. Therefore, the professional medical needs to confirm that cuff 43 is thoroughly compressed to prevent cuff 43 from harming the patient's windpipe or causing discomfort during the removal process. For the purpose of making the cuff 43 thoroughly compressed, the medical professional could use syringe 2 to extract fluids from cuff 43 and the first chamber 105 to reduce their volume (i.e., decreasing the balance pressure inside the cuff 43 and the first chamber 105). In a preferable embodiment, when cuff 43 is thoroughly compressed, the equilibrium gage pressure inside the cuff 43 and the first chamber 105 is £0 atm. Further, when the balance gage pressure is £ 0 atm, the atmospheric pressure will pass through the hole 1511 of the sliding element 151, deform the deformable portion 1531 of the piston head 153, and cause the deformable portion 1531 to appear in window 113 of the first case 11. Thus, whether the deformable portion 1531 is displayed in window 113 can be used as an indication or sign to help the medical professional identify whether the endotracheal tube 4 can be removed from the patient's trachea. Additionally, the loading range of the spring 14 is about 70 to 100g.

[0066] As above mention, it is clear that the present disclosure is more effective than the prior art because it has the spring 14 and is more effective than expected. More specifically, the present pressure regulator 1 contains spring 14. It can detect whether the pressure value inside cuff 43 is within the target range and go further to automatically adjust the pressure inside cuff 43 so that it falls within the target range. FIGs. 5A to 5C discloses a preferred embodiment of the pressure regulator 5. FIG. 5A is a side cross-sectional view of the pressure regulator 5 and discloses all the features. As FIG. 5A disclosed that pressure regulator 5 is mainly composed of an outer case having a first case 51 and a second case 53, an inner case 52, a sliding element 551, a spring 54, and a membrane 553 (or balloon). The pressure regulator 5 is similar to pressure regulator 1, the first case 51 has a first opening 511 and a hook 515, and the second case 53 has a valve system 531 and a second opening 533. It is worth knowing that the difference between the two is that the pressure regulator 5 does not have the piston head but a membrane 553, and there is also no configuration window between the first case 51 and the first opening 511. However, the pressure regulator 5 has a window configuration in another embodiment. In a preferable embodiment, the membrane 553 is a balloon made of PVC, PU or similar material, and it has the feature of thin thickness. In preferrable embodiments, the membrane, balloon, or bellow in the present disclosure is made of a relatively inelastic material, so that the equivalent spring force effect can be ignored while the membrane is deformed and expanded, making it easier to design (one less factor to consider). In addition, the membrane gradually regains its shape from a flattened state as it inflates, but the entire membrane is not deformed and expanded like a normal balloon.

[0067] The membrane 553 is configured inside the first case 51, and the perimeter of the membrane 553 is tightly connected to the open end 521 (i.e., the distal end) of the inner case 52 (which can be achieved by using glue or any other means of forming a tight connection). As a result, pressure regulator 5 may offer more precise adjustment capability than pressure regulator 1, depending on the material chosen for the membrane 553. More specifically, the membrane 553 itself is made of a material that can compress (i.e., adjusting the volume of the first chamber 505). Therefore, the combination of spring 54 and membrane 553 can provide better modulation.

[0068] FIGs. 5B and 5C are also side cross-sectional views but only disclose partial elements for illustrating how pressure regulator 5 works like FIG. 4F, the pressure regulator 5 is under a normal status, which it has not been connected to the endotracheal tube 4 in FIG. 1, the absolute pressure inside the first chamber 505 is about 1 atm. Please referring to FIG. 5C, the pressure regulator 5 now is connected to a cuff placed inside a patient's trachea (windpipe). Further, the fluid from the cuff will cause the membrane 553 to expand to increase the volume of the first chamber 505. When the fluid pressure inside the first chamber 505 is balanced with the contraction force of the membrane 553 and the force applied to the sliding element 551 by the restoring force of the spring 54, the movement of the sliding element 551 will stop. The position of the sliding element 551 relatives to the inner case 52 represents the equilibrium pressure inside the cuff and the first chamber 505. Additionally, if a medical professional wants to adjust (e.g., reduce) the expansion volume of the cuff 43, he can adjust (e.g., increase) the volume of the first chamber 505 by the syringe 2. For example, injecting the fluid (i.e., air) inside syringe 2 into the first chamber 505.

[0069] FIGs. 6A to 6C disclose another embodiment of the pressure regulator 6. FIG. 6A is a side cross-sectional view of pressure regulator 6 and discloses all the features thereof. FIG. 6B and 6C are side cross-sectional views of the inner portion of the pressure regulator 6 and disclose the movement of the sliding element 651. As FIG. 6A disclosed that pressure regulator 6 is mainly composed of an outer case (without inner case) having a first case 61 and a second case 63, an indicator 65 having a sliding element 651 and a bellow 653, and a spring 64. The components of pressure regulator 6 are similar to those of pressure regulator 5. For example, the first case 61 has a first opening 611 and a hook 615, and the second case 63 has a valve system 631 and a second opening 633. It is worth knowing that the difference between the two is that the pressure regulator 6 does not have an inner case, and the two ends of the bellow 653 connect the sliding element 651 and the base 6311 of the valve system 631, respectively. Therefore, the sliding element 651 slides along. The sliding element 651 and the bellow 653 form a chamber 607, and the second opening 633 is for venting the second chamber 607 to the atmosphere. The material of bellow 653 can be made of silicone, PVC (Polyvinylchloride), PU (Polyurethane) or other flexible materials that can be compressed and deformed, and it has the feature of thin thickness.

[0070] Please referring FIG. 6B and 6C, the sliding element 651 guilds the indicator 65 to slide along the outer case's longitudinal direction (i.e., from distal end to proximal end and vice versa). The first case 61 is made of translucent or transparent material in a preferred embodiment. Therefore, the position of indicator 65 relatives to the first case 61 can be used to indicate the pressure inside the cuff 43. Moreover, when the pressure of chamber 607 is higher than chamber 605, the bellow 653 will be inflated, implying the cuff is flat and under negative pressure.

[0071] The embodiments disclosed in FIGs. 1 to 6, in which the sliding element, indicator, biasing element, valve system, outer case, or inner case are arranged in co-axial, i.e., the longitudinal axis (A-axis) above each element is arranged overlapping. Further, the direction of movement of the indicator, the biasing element, or the deformable element is also along the A-axis. The benefit of such an arrangement is that the space inside the pressure regulator can be efficiently utilized to minimize the size of the pressure regulator. Further, manufacturing costs can be reduced because of the significantly smaller size. It will not interfere with the use of other medical equipment when used by a user and will provide optimal efficiency. The present disclosure also provides embodiments in which all openings and valve systems are configured together, and the biasing element, indicator, and the outer case are still arranged in co-axial. As FIGs. 7 to 8 disclose, the valve system's longitudinal axis (i.e., B-axis) and the first opening is not parallel with the longitudinal axis (i.e., A-axis) of the indicator, the biasing element, or the outer case. Specifically, the A-axis and B-axis cross vertically.

[0072] FIGs. 7 A to 7C disclose another embodiment of the pressure regulator 7 and discloses all the features. FIG. 7B and 7C further disclose the movement of the sliding element 751 and the deformable portion 7531 of the piston head 753. Please refereeing to FIG. 7 A, the design feature of pressure regulator 7 is that venting elements (e.g., a first opening 711 and a valve system 731) are grouped in one place, and the pressure detecting and regulating system (e.g., an outer case 70 and all its internal components) is configured in another place as the previous description. Specifically, the first opening 711 and the valve system 731 are configured at a distal end 701 of the outer case 70. A window 713 is further configured between the first opening 711 and the valve system 731. The first opening 711 is used to connect to the cuff and the valve system 731 is used to connect with a syringe. It is worth knowing that the pressure regulator 7 only has a single layer of the case (i.e., the outer case 70). The design and the arrangement of the indicator 75 (the piston head 753 and sliding element 751) and the biasing element 74 inside the outer case 70 are similar to that in the pressure regulator 1 (see FIG. 4H to 4J).

[0073] Please referring to FIG. 7 A and 7B, detailed description of the action of the indicator 75 is clearly illustrated in FIGS. 4H and 41. Briefly, when the pressure in the cuff decreases, the indicator 75 moves toward the distal end 701 of the outer case 70, while when the pressure in the cuff increases, it drives the indicator 75 in the opposite direction (i.e., to the proximal end 703). Referring now to FIG. 7C, an illustration of the pressure regulator 7 when the endotracheal tube is removed from a patient's trachea is described. As the previous description in FIG. 4J, the user needs to confirm that the cuff is thoroughly compressed when removing the endotracheal tube from the patient's trachea. Therefore, for the purpose of making the cuff thoroughly compressed, the medical professional could use the syringe to extract air from the cuff and the first chamber 705 to reduce their volume (i.e., decreasing the equilibrium pressure). In a preferable embodiment, when the cuff is thoroughly compressed, the equilibrium gage pressure inside the cuff and the first chamber 705 is £ 0 atm. Further, when the balance gage pressure is ₌ 0 atm, the atmospheric pressure will deform the deformable portion 7531 of the piston head 753 and cause the deformable portion 7531 to appear in window 713. Thus, it can help the medical professional identify whether the endotracheal tube can be removed from the patient's trachea.

[0074] FIGs. 8A to 8C illustrate an alternative embodiment of the pressure regulator 7. As FIGs. 7 A and 8A disclosed that the major difference between the two pressure regulators is that pressure regulator 8 further includes a second indicator 817 formed by a second valve 8171 and the piston head 853 without a deformable portion. The method of using pressure regulator 8 to detect and adjust the pressure or volume size of the cuff is similar to that disclosed in the previous FIGs. 4 and 7. Referring to FIGs. 8A and 8B, changes in the equilibrium pressures in the cuff and the first chamber 805 cause the indicator 85 to move in the outer case 80. The position of the indicator 85 relatives to the outer case 80 represents the equilibrium pressures. Further, the second valve 8171 will maintain in the second indicator 817, when the equilibrium absolute pressure is ³1 atm. Referring now to FIGs. 8C, the equilibrium pressures inside the first chamber 805 of the pressure regulator 8 is £ 1 atm (preferably the gage pressure is £ 0 atm) for compressing the cuff as the previous description of FIG. 41. Because the pressure inside pressure regulator 8 is smaller than the atmospheric pressure, a portion of the second valve 8171 will be pushed into and displayed in window 813. Therefore, whether the second valve 8171 is displayed in window 813 can be used as a signal to help the medical professional identify whether the endotracheal tube can be removed from the patient's trachea.