Pressure safety device for bag-valve masks

Abstract

A pressure safety device is used with a bag valve mask (BVM) to prevent overpressure. The BVM includes a bag assembly having a bag connector for removably mating with a mask connector on a patient mask. The pressure safety device has a housing having a bag port, a mask fitting, and a flow path from the bag port to the mask fitting. The bag port is removably connected to the bag connector on the BVM, and the mask fitting is removably connected to the mask connector on the BVM. The pressure safety device includes an automatic flow reduction valve located on the flow path in the housing and obstructs flow when the pressure on the bag connector side of the valve exceeds a maximum threshold.

Description

[0001] Cross-references

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 679,301, filed on June 1, 2018, which is incorporated herein by reference. Background Art

[0003] 1. Field of the Invention The present invention relates generally to medical devices and methods. More particularly, the present invention relates to the field of breathing gas delivery using manual resuscitators.

[0004] Bag valve mask (BVM) resuscitators have long been used to artificially ventilate patients who are unable to breathe on their own, such as patients in cardiac arrest, suffering from respiratory distress, under anesthesia, etc. Conventional BVMs have a compression bag that is manually compressed by the user to pressurize and deliver breathing gases to the patient through a breathing mask worn over the patient's mouth and nose.

[0005] Poor manual technique using a BVM can cause problems. Specifically, overpressurization of the compression bag can increase the pressure and flow rate of the breathing gases beyond optimal levels and can injure the patient in the worst case, and in some cases can compromise safety levels, such as causing air to enter the stomach. Although some solutions have been proposed, such as placing a pressure relief valve in the flow path between the compression bag and the breathing mask, the resulting ventilation is not always effective and does not produce tactile or other feedback to the user to alert them to the need to relieve the pressure they are applying.

[0006] It is therefore an object of the present invention to provide alternative and improved devices and methods for limiting overpressure when using a BVM. Specifically, it is an object of the present invention to limit the delivery of overpressure BVM breathing gas without ventilation. It is another object of the present invention to provide tactile or other feedback to the user when such overpressure occurs. At least some of these objects will be achieved by the present invention described and claimed herein.

[0007] 2. Background Art . U.S. Patent No. 5,557,049 discloses a disposable pressure gauge as an accessory to a BVM to indicate the pressure of the gas being delivered to a patient. U.S. Patent No. 5,722,394 shows a BVM with a high pressure exhaust valve. U.S. Patent No. 5,537,998 discloses a spring loaded piston that senses and exhausts excess air pressure. U.S. Patent No. 4,898,166 discloses a resuscitation bag control device, and U.S. Patent No. 6,792,947 discloses a BVM with flow control. U.S. Patent No. 2015 / 0096559A1 discloses a feedback sensor for a BVM. Summary of the invention

[0008] The present invention can be used to optimize airflow to a patient during manual ventilation using a bag-valve-mask (BVM) resuscitator to maintain proper ventilation and lung perfusion while minimizing air entry into the stomach. Specifically, the present invention controls inspiratory pressure to the patient by blocking airflow from the BVM compression bag when the optimal outflow pressure is exceeded. In addition to protecting the patient, the stiffening of the bag caused by back pressure also provides "tactile feedback" to the user as a teaching or reinforcement indicator of proper manual ventilation technique.

[0009] Thus, the present invention improves safety when performing manual ventilation using a BVM resuscitator and can minimize complications of concurrent surgery such as gastric aspiration, suctioning, aspiration pneumonia, acute respiratory distress syndrome (ARDS), cardiopulmonary injury. The present invention can also reduce human error and variability, improve the quality of patient care, and reduce the cost of providing care to the health system.

[0010] The present invention may be used with any positive pressure air delivery device, impedance threshold attachment device, air filter and / or resuscitation outlet device, such as a mask, endotracheal tube, laryngeal mask airway, mouthpiece, etc. The present invention may also be used to deliver air to any entity other than a patient, such as a lung simulation system, an animal, a cadaver, training equipment, etc.

[0011] In a first aspect, the present invention provides a pressure safety device for use with a bag-valve-mask (BVM). The BVM typically includes a bag assembly having a bag connector for removably mating with a mask connector on a patient mask. The bag assembly will also typically have at least one compression bag that allows a user to manually compress the compression bag to deliver a volume or bolus of air or other breathing gas to the patient through the mask. The BVM may include various other components typical of conventional manual gas resuscitators.

[0012] The pressure safety device of the present invention will include a housing and an automatic flow reduction valve. The housing will typically have a bag port, a mask accessory, and an interior with a channel configured to define a flow path from the bag port to the mask accessory. The bag port will typically be configured to be detachably connected to a bag connector on a BVM, and the mask accessory will typically be configured to be detachably connected to a mask connector on a BVM. The automatic flow reduction valve is located on or along the flow path in the housing and will be configured to obstruct flow when the pressure or flow rate of the breathing gas passing through the automatic flow reduction valve or the pressure on the bag connector side of the automatic flow reduction valve exceeds a maximum threshold.

[0013] In certain cases, the automatic flow reduction valve can be configured to block flow when the maximum threshold pressure value includes a pressure of 5 mmHg to 20 mmHg, typically 9 mmHg to 15 mmHg. Alternatively or additionally, the automatic flow reduction valve can be configured to block flow when the maximum threshold flow value includes a peak flow rate of 30 l / min to 70 l / min, typically 35 l / min to 50 l / min.

[0014] The automatic flow reducing valve of the present invention will typically have any one of a number of conventional mechanical designs, such as an umbrella valve, a spring-piston valve, etc. Alternatively, the automatic flow reducing valve of the present invention may contain electronic components, including: a pressure sensor, a flow sensor, a microprocessor controller, a power valve, to block or inhibit flow through the BVM according to the principles of the present invention described herein.

[0015] In some cases, the automatic flow reduction valve can be configured to completely block flow, and / or in other cases, the automatic flow reduction valve can be configured to partially block flow. "Partially blocked flow" means that the flow rate will be reduced by at least 50% of the non-restricted value, usually reduced by at least 60% of the non-restricted value, often reduced by at least 75% of the non-restricted value, and often reduced by at least 90% or more of the non-restricted value. In other cases, the automatic flow reduction valve can be adjustable so that it can be set to completely block flow or partially block flow according to the desired use. For example, the spring of the spring-piston valve can have a variable set point or a variable load adjustment to allow the pressure or flow rate set point to be changed when the valve is closed. It should be understood that when the automatic flow reduction valve does not completely block flow, a residual flow path (residual flow path) for delivering respiratory gas to the patient at a reduced pressure and / or flow rate will be retained.

[0016] The pressure safety device of the present invention may also include a one-way valve located in or along the flow path from the bag port to the mask fitting, wherein the one-way valve will be oriented to block or divert the flow of exhaled air from the BVM mask through the mask fitting into the housing. Typically, the housing will be configured with a fenestration or other opening oriented to release the diverted or blocked flow of exhaled air from the one-way valve to the exterior of the housing. The change in flow resistance provided by the fenestration can be used to establish or otherwise control intrapulmonary pressure (PEEP).

[0017] In a second aspect, the present invention provides a method for generally reversibly changing a bag valve mask (BVM) comprising a bag assembly and a bag connector as described above. The method of the present invention for changing a BVM comprises providing a pressure safety device (PSD) having a bag port and a mask fitting, and connecting the bag port and the mask fitting of the PSD to the bag connector and the mask connector of the BVM, respectively. The PSD will be configured to obstruct the flow of breathing gas from the BVM to the patient when the pressure or flow rate of the breathing gas entering the bag port of the PSD exceeds a maximum threshold.

[0018] Certain aspects of the PSD and its use in conjunction with the BVM have been previously described in conjunction with the structure of the PSD.

[0019] In a third aspect, the present invention provides a bag-valve-mask (BVM) assembly comprising a manifold; an attached compression bag for delivering breathing gas to the manifold; and an attached breathing mask for receiving breathing gas from the manifold. In accordance with the principles of the present invention, an automatic flow reduction valve is located in a flow path in the manifold between the compression valve and the breathing mask. The automatic flow reduction valve is configured to block flow when a flow rate or pressure on the compression bag side of the automatic flow reduction valve exceeds a maximum threshold.

[0020] As with the previous devices and methods described above, the automatic flow reduction valve can be configured to block flow when the maximum threshold pressure value includes a pressure of 5 mmHg to 20 mmHg, typically 9 mmHg to 15 mmHg. Alternatively or additionally, the automatic flow reduction valve can be configured to block flow when the maximum threshold flow value includes a peak flow rate of 30 l / min to 70 l / min, typically 35 l / min to 50 l / min.

[0021] Other features and description of the automatic flow reducing valve of the BVM assembly may be as previously described with respect to the PSD and method for varying the BVM.

[0022] In a fourth aspect of the invention, a method for delivering breathing gas to a patient comprises placing a breathing mask over the mouth and nose of the patient. A compression bag is then compressed to deliver breathing gas to the breathing mask and the patient. If the pressure or flow rate from the breathing gas bag exceeds a maximum value, the flow of breathing gas delivered to the breathing mask is impeded.

[0023] In certain cases of these methods, obstructing the flow of breathing gas into the mask includes placing an automatic flow reduction valve in a flow path between the compression bag and the breathing mask. The automatic flow reduction valve will be configured to obstruct the flow of breathing gas when the flow rate or pressure from the compression bag exceeds a maximum threshold.

[0024] The automatic flow reduction valve may be incorporated directly into the structure of the BVM, or alternatively may be provided as a separate PSD as described above.The specific features of the automatic flow reduction valve may be the same as previously described in the above-described apparatus and method of the present invention.

[0025] Certain embodiments of the present invention are particularly advantageous because the PSD can be removed from the BVM when treating certain conditions where there are obstructive or restrictive conditions that require the use of high pressures to deliver adequate volumes during manual ventilation. However, in other cases, the PSD can be incorporated into the manifold or other structure of the BVM as an integrated component with an override mechanism to allow high pressure ventilation that is not controlled by the PSD component.

[0026] The PSD of the present invention is configured to be handheld, lightweight, portable, durable, and cost-effective to meet the standards for adoption in the Emergency Medical Services (EMS) space. During ventilation, because the device forms a continuous column of air with the lungs, the pressure threshold of the flow choke valve is relative to the patient's intrathoracic pressure and can therefore be personalized to optimize airflow into the lungs while preventing gastric air ingress.

[0027] Incorporation by reference

[0028] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The novel features of the present invention are particularly set forth in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by referring to the following detailed description and the accompanying drawings which set forth illustrative embodiments in which the principles of the present invention are utilized, in which:

[0030] Figure 1A and Figure 1B A conventional bag-valve-mask (BVM) device into which the pressure safety device of the present invention is incorporated is illustrated.

[0031] Figure 2 is an exploded view of a first embodiment of the pressure safety device of the present invention, which has an umbrella valve as an automatic flow reducing valve.

[0032] Figure 3A and Figure 3B yes Figure 2 A cross-sectional view of a pressure safety device, wherein the umbrella valve is Figure 3A is shown in an open configuration and in Figure 3B Shown in a closed configuration.

[0033] Figure 4 is an exploded view of an alternative embodiment of a pressure safety device constructed in accordance with the principles of the present invention and having a spring loaded valve as the automatic flow reducing valve.

[0034] Figure 5 yes Figure 4 sectional view of a pressure safety device of FIG. 1 showing the sealing plate of the spring-loaded valve in an open configuration (solid line) and a closed configuration (dashed line).

[0035] Figure 6 is a detailed view of the sealing plate of a spring loaded valve.

[0036] Fig. 7A and 7B A window in the housing of a pressure safety device is shown for releasing exhaled gas from a patient that is blocked by a one-way valve in the pressure safety device. DETAILED DESCRIPTION

[0037] Figure 1A and Figure 1B A pressure safety device (PSD) 10 constructed in accordance with the principles of the present invention is shown in its intended position within a standard bag-valve-mask (BVM) assembly 50. The BVM 50 includes a compression bag 52, a reservoir bag 54 connected to the compression bag by a reservoir valve 56, a positive end-expiratory pressure (PEEP) valve 58, and a pressure safety valve 60. The compression bag 52, the PEEP valve 58, and the pressure safety valve 60 are all connected to a manifold 62 having a connector port 64 for removably receiving a respiratory mask 70. The respiratory mask 70 typically has an air cushion 72 on one surface for placement over the patient's mouth and nose when in use; and a connector fitting 74 for removably mating with the connector port 64 of the manifold 62. Generally, the connector port 64 on the manifold 62 will be a male connector and the connector fitting 74 on the respiratory mask 70 will be a female fitting, but the present invention can be adapted for use with any pair of removable connectors, including screw connectors, snap connectors, latch connectors, etc.

[0038] Thus far, the BVM 50 is entirely conventional and is ready for use once the connector port 64 of the manifold 62 has been inserted directly into the connector fitting 74 of the respiratory mask 70. Typically, at least the respiratory mask 70 will be disposable and stored in sterile packaging prior to use.

[0039] In an exemplary embodiment, the PSD of the present invention is intended for use with a standard BVM, such as the BVM 50 just described. Although the PSD may be constructed in a variety of ways, the primary components will include an "automatic flow reduction valve," such as a choke valve, to prevent excessive flow and / or pressure from being delivered to the breathing mask 70. The PSD 10 may also include a one-way valve that prevents the patient's exhaled breath from returning to the BVM, typically redirecting the exhaled flow outward through an opening in the PSD.

[0040] The "automatic flow reducing valve" or "AFRD" of the present invention may take any of a variety of forms. Although the AFRD is typically a dome-shaped flap valve or a spring-loaded shut-off valve as described below, the AFRD may be any type of pressure-responsive or flow-responsive valve that can be positioned along the inspiratory flow path of a patient and that reduces or stops the flow of breathing gas from a compression bag to the patient when the flow or pressure exceeds a maximum threshold.

[0041] Refer again Figure 1A and Figure 1B , a conventional bag-valve-mask assembly (BVM) includes a compression bag 52, an air storage bag 54, an air storage valve 56, a PEEP valve 58, a pressure safety valve 60, and an oxygen tube 61. The compression bag 52, the pressure safety valve 60, and the PEEP valve 58 are all connected to a manifold 62, which has a connection port 64 at its lower end. Specifically, the compression bag 52 is configured to deliver breathing gas from the oxygen tube 61 through the manifold 62 and discharge from the connector port 64.

[0042] In a conventional BVM, a respiratory mask 70 having an air cushion 72 on its lower surface and a connector fitting 74 on its upper surface will be directly connected to the manifold 62. Specifically, the connector port 64 is typically a male fitting that fits into the female connector fitting 74 so that breathing gases flow directly from the manifold into the respiratory mask 70. The BVM can then be used by placing the air cushion 72 over the patient's nose and mouth and manually squeezing the compression bag 52 to deliver breathing gases to the patient.

[0043] However, in accordance with the present invention, a pressure safety device (PSD) may be provided for insertion between the connector port 64 of the BVM 50 and the connector fitting 74 of the respiratory mask 70. As described in more detail below, the pressure safety device may take a variety of specific forms, but will be designed and constructed to limit over-pressurization and / or escape of breathing gases from the compression bag 52 to the patient.

[0044] In a first embodiment, if Figure 2As shown, PSD 10 includes a housing 12 having a bag port 14 and a base 16. An umbrella valve 18 is provided as an automatic flow reducing valve and includes a deformable seal 20, generally in the form of a conical seal that can evert to block or reduce flow as described below.

[0045] The umbrella valve 18 is mounted on a support plate 26 having a plurality of flow openings or passages 28 formed therethrough. The dagger-type anchors 22 are mounted in holes 32 in the support plate 26 to properly position the deformable seal 20 so that when the seal is in an unstressed, undeformed configuration, the conical periphery of the seal is deflected upwardly away from the support plate 26. However, when excessive pressure or respiratory flow occurs on the upstream side of the deformable seal (the side closer to the bag port), the conical periphery of the seal 20 will close downwardly over the flow openings or passages 28.

[0046] The support plate 26 is mounted in a one-way valve fitting 34 having a duckbill valve 36 aligned to receive the outflow of breathing gas from the flow opening 28 in the support plate 26. The duckbill valve is oriented so that breathing gas flowing from the bag port 14 (which flows through the open umbrella valve 18) will open the duckbill and flow freely therein. However, the exhalation flow from the patient will close the duckbill valve 36 and prevent the patient's exhalation from being transmitted back to the BVM.

[0047] The PSD 10 also includes a bottom plate 38 having a plurality of apertures 40 formed in an annular ring around its periphery. The apertures 40 may be any type of passage that allows the exhaled airflow blocked by the duckbill valve 36 to flow downwardly and outwardly out of the housing 12 through the apertures. Figure 2 As shown, a mask fitting 44 is formed on the bottom of the base plate to provide a connection to a respiratory mask 70.

[0048] Now refer to Figure 3A and Figure 3B , shows the PSD 10 with the conical periphery of the deformable seal 20 of the umbrella valve 18 in its open, upwardly disposed configuration. In this configuration, air flow 46 entering the bag port 14 travels under the deformable seal 20 and through the flow opening 28 in the support plate 26, as indicated by the flow path arrows 48.

[0049] Conversely, when the incoming air flow 46 exceeds a maximum threshold of flow velocity and / or pressure above the deformable seal 20, such as Figure 3B As shown, the seal will depress downward to close the flow opening 28 and stop (or reduce) the delivery of breathing gas to the patient. Partial obstruction may be achieved, for example, by perforating the deformable seal 20 so as to allow residual flow through even when the seal is closed.

[0050] Now refer to Figures 4 to 6 , a second PSD embodiment 80 having a spring loaded valve as the automatic flow reducing valve is illustrated. The housing 14, the check valve 34 and the bottom plate 38 of the PSD 80 may all be the same as previously described with respect to the PSD 10. However, the automatic flow reducing valve will be a spring loaded valve 86 having a support plate 88 having guide posts 90. A sealing plate 94 having a guide groove 102 is slidably received on the guide posts 90, and a spring 92 is placed between the guide posts, the lower end of the spring 92 being received on the support surface 99 of the support plate 88, and the upper end being received in a groove 100 formed in the lower surface of the sealing plate 94.

[0051] like Figure 5 As best shown, in the unrestrained configuration, spring 92 holds sealing plate 94 just above flow opening 95 in support plate 88 so that breathing gas can flow from compression bag 52, into bag port 14, and out through mask fitting 44. However, when the pressure and / or flow rate of incoming breathing gas flow 46 exceeds a maximum threshold, sealing plate 94 will move downward to Figure 5 The position shown by the dashed line in the middle is used to close opening 95 and inhibit or completely block the flow of breathing gas.

[0052] like Fig. 7A and Figure 7B As shown, when the patient exhales, the pressure of the exhaled gas attempting to flow back through the connector port 64 will close the duckbill valve 36, causing the exhaled gas to flow radially outward through the window hole 40 formed in the bottom plate 38 and then flow downward, as shown in FIG. Fig. 7A 40. In this way, the exhaled gas is not forced back into the BVM, thereby preventing contamination. The fenestrations 40 can be varied to cause changes in pressure within the lungs during and after exhalation, known as positive end-expiratory pressure or PEEP. An increase in the size and / or number of fenestrations 30 will reduce resistance and reduce PEEP. Similarly, a decrease in the size and / or number of fenestrations 40 will increase resistance to exhalation and increase PEEP. High PEEP helps keep the airway open in conditions such as chronic obstructive pulmonary disease (COPD), where the airway tends to collapse after exhalation.

[0053] A standard BVM incorporating the PSD of the present invention may be used as follows. The user holds the mask 70 with one hand, placing the air cushion 72 over the patient's nose and mouth to obtain a tight seal and prevent air leakage. The user's other hand continuously squeezes and releases the compression bag 52 of the BVM 50 to pump air from the air reservoir bag 54 through the air reservoir valve 56 to the mask 70 and into the patient's lungs. If the flow rate or pressure delivered by the compression bag exceeds the maximum threshold limit defined elsewhere herein, the AFRD 18 or 86 of the PSD 10 will reduce or stop the flow of breathing gases to the patient to reduce the risk of injury.

[0054] The apparatus and methods of the present invention may be used in conjunction with other resuscitator features, such as the rhythm indicators described in U.S. Pat. No. 10,098,809 and U.S. Patent Publication No. 2003 / 0192547, the entire contents of which are incorporated herein by reference. The apparatus and methods of the present invention may also be used in conjunction with devices for managing intrathoracic pressure, such as the impedance threshold devices (ITDs) described in U.S. Pat. Nos. 6,604,523, 6,986,349, 7,195,012, and 7,204,251, the entire contents of which are incorporated herein by reference. The apparatus and methods of the present invention may be used in conjunction with electronic sensors located internally or externally to the apparatus to record the pressure, volume, frequency, delivery pressure, etc. of manual ventilation.

[0055] Although preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that these embodiments are provided by way of example only. Without departing from the present invention, those skilled in the art will now expect many variations, changes and replacements. It should be understood that the various alternatives of the embodiments of the present invention described herein may be used to implement the present invention. It is intended to limit the scope of the present invention by the appended claims, and thus encompass methods and structures and equivalents thereof within the scope of these claims.

Claims

1. A pressure safety device for use with a bag-valve mask (BVM), the BVM comprising a bag assembly having a bag connector for removably mating with a mask connector on a patient mask, the pressure safety device comprising: a housing having a bag port, a mask fitting, and a flow path from the bag port to the mask fitting, wherein the bag port is configured to removably connect to the bag connector on the BVM and the mask fitting is configured to removably connect to the mask connector on the BVM; as well as an automatic flow reducing valve located on the flow path in the housing and configured to block flow when the pressure or flow rate on the bag connector side of the automatic flow reducing valve exceeds a maximum threshold, wherein the automatic flow reducing valve comprises a deformable seal having an open position and a closed position, the deformable seal being configured to deform in response to the pressure or flow exceeding the maximum threshold value so as to completely block the flow path; wherein the deformable seal is in an unstressed configuration in the open position and in a stressed configuration in the closed position; as well as The deformable seal comprises a conical periphery configured to evert from the unstressed configuration to the stressed configuration in response to the pressure or flow exceeding the maximum threshold.

2. A pressure safety device as described in claim 1, wherein the automatic flow reduction valve is configured to block flow when the maximum threshold is a pressure of 5mmHg to 20mmHg.

3. A pressure safety device as described in claim 1, wherein the automatic flow reduction valve is configured to block flow when the maximum threshold includes a peak flow rate of 30 l / min to 70 l / min.

4. The pressure safety device of claim 1, wherein the automatic flow reducing valve comprises an umbrella valve.

5. The pressure safety device of claim 1, wherein the automatic flow reducing valve is configured to allow residual bypass flow.

6. The pressure safety device of claim 1 further comprising a one-way valve in the flow path, the one-way valve being oriented to divert an exhaled flow from the mask fitting.

7. A pressure safety device as described in claim 6, wherein the housing has a window hole, the window hole is oriented to allow bypass exhalation flow to pass from the one-way valve to the exterior of the housing.

8. A bag-valve mask (BVM) assembly, comprising: Manifold; a compression bag attached to deliver breathing gas to the manifold; a breathing mask attached to receive the breathing gas from the manifold; as well as an automatic flow reduction valve located in a flow path in the manifold between the compression bag and the breathing mask, the automatic flow reduction valve being configured to block flow when a flow rate or pressure on the compression bag side of the automatic flow reduction valve exceeds a maximum threshold, wherein the automatic flow reducing valve comprises a deformable seal having an open position and a closed position, the deformable seal being configured to deform in response to the pressure or flow exceeding the maximum threshold value so as to completely block the flow path; wherein the deformable seal is in an unstressed configuration in the open position and in a stressed configuration in the closed position; as well as The deformable seal comprises a conical periphery configured to evert from the unstressed configuration to the stressed configuration in response to the pressure or flow exceeding the maximum threshold.

9. The BVM assembly of claim 8, wherein the automatic flow reducing valve is configured to block flow when the maximum threshold is a pressure of 5 mmHg to 20 mmHg.

10. The BVM assembly of claim 8, wherein the automatic flow reducing valve is configured to block flow when the maximum threshold comprises a peak flow rate of 30 l / min to 70 l / min.

11. The BVM assembly of claim 8, wherein the automatic flow reducing valve comprises an umbrella valve.

12. The BVM assembly of claim 8, wherein the automatic flow reduction valve is configured to allow residual bypass flow.

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