Gas mixing device and gas delivery system with same

Abstract

A gas mixing device (10) for delivering gas at ambient pressure from a donor reservoir (104) to a recipient, and a gas delivery and conservation system at ambient pressure involving such a gas mixing device (10). A main conduit body (12) has a first port in fluid communication with the donor reservoir (104) and a second port for supplying gas to the recipient through an ambient pressure tube (122). A one-way intake valve (32) between the first and second ports allows gas to be drawn from the reservoir (104) but does not receive gas into the donor reservoir (104) through the second port. An air input hole (18) allows ambient air to mix with the gas drawn from the reservoir (104). The aperture adjustment member (16) is selectively repositioned relative to the air input aperture (18) to adjust the effective size of the aperture and thereby adjust the ratio of ambient air to gas drawn from the reservoir (104).

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 408,655, filed September 21, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates generally to the delivery of gases from a source to a recipient. More particularly, disclosed herein is a gas mixing device for use in a system for delivering oxygen or another gas or mixture of gases to a recipient. The gas mixing device operates to allow direct and rapid control of the inspired oxygen fraction (FiO2) or inspired concentration of other gases delivered to the recipient. [Background technology]

[0003] Normally, the lungs absorb a sufficient supply of oxygen from the air during natural breathing. However, certain conditions can prevent a person from obtaining enough oxygen. As a result, oxygen therapy using an oxygen delivery device is necessary. Patients can receive oxygen therapy from an oxygen source through a tube placed in the patient's nose, through a face mask, or through a tube placed in the patient's tuleikia (windpipe). Oxygen therapy increases the amount of oxygen the lungs can receive and deliver to the blood. Oxygen therapy can be prescribed to patients when their blood oxygen levels are significantly reduced. Low blood oxygen can leave patients feeling short of breath, fatigued, or dizzy, and can be damaging to the patient's body. Oxygen therapy can be needed temporarily or long-term, such as for treatable respiratory conditions. Oxygen sources are often tanks of compressed oxygen gas or liquid.

[0004] Oxygen supplies can be critically needed for hospital patients and others. Meanwhile, in developing countries and while demand is increasing everywhere, oxygen shortages and excessive costs can significantly limit availability and endanger the health and safety of patients in need. For example, during the COVID-19 pandemic, demand for oxygen has left hospitals and other care facilities in dire need of the life-saving gas. A headline from AP Network News on June 24, 2020, sounded the alarm: "Scarce Medical Oxygen Worldwide Leaves Many Gasping for Life." A day later, Reuters noted, "WHO Warns of Oxygen Shortage as COVID Cases Set to Top 10 Mln," stating that the World Health Organization estimates that roughly one million new coronavirus cases are occurring worldwide each week, and the world is experiencing an average of 620,000 m² of oxygen a day. 3 The study estimates that approximately 88,000 large cylinders of oxygen will be needed for COVID-19 patients alone.

[0005] One way supplemental oxygen is delivered to a patient under the teachings of the prior art is via a fluid connection, typically by tubing, between a pressurized source of oxygen, such as an oxygen cylinder or tank, and an output interface, such as a nasal cannula or mask, to provide a high flow of oxygen to the patient. In such systems, oxygen flows continuously, whether the patient is breathing or not. As a result, oxygen flows continuously, even while the patient is exhaling and unable to inhale oxygen. Thus, a huge amount of oxygen is wasted. In fact, more than half of the continuously supplied oxygen is wasted, simply expelled to the environment. During exhalation, the entire supplied oxygen is wasted, and even during inhalation, a portion of the supplied oxygen is often wasted.

[0006] High-flow systems inherently provide an excess oxygen supply to ensure that the patient receives sufficient oxygen throughout the entire respiratory cycle. Concomitantly, it will be appreciated that the ability to conserve oxygen for one patient may be lifesaving for another, particularly in emergency situations such as during epidemics or pandemics associated with respiratory distress, when demand may critically exceed supply. In remote and economically challenged areas, replenishing oxygen supplies can be prohibitively costly or catastrophically impossible. The difficulty of providing sufficient oxygen while minimizing waste is widely understood.

[0007] In a typical nasal cannula configuration, one end of an oxygen delivery tube is connected to an oxygen source, while the other end of the tube splits into two branches that meet to form a loop. Two nasal prongs are positioned along the loop for insertion into the patient's nares. Oxygen flows continuously through the tube and exits through the nasal prongs into the patient's nares. During inspiration, the patient thus breathes oxygen through the prongs along with entrained room air. Room air is drawn in through the space between the nasal prongs and the patient's nostril walls. During expiration, the patient exhales through the space between the nasal prongs and the patient's nostril walls, while oxygen continues to exit into the patient's nares. Much of this oxygen is carried with the exhaled airflow into the surrounding room air.

[0008] In continuous flow systems, the fraction of inspired oxygen (FiO2) provided to the patient is sought to be controlled by increasing or decreasing the flow of oxygen through the oxygen delivery tube. Unfortunately, once the flow rate is set, it only works optimally for the patient's breathing pattern at the time of calibration. Changes to this breathing pattern, such as due to physical exercise, or other changes in circumstances, will affect the FiO2, which in turn will affect the patient's saturation. For example, when a patient takes deep breaths or moves and breathes more frequently as a result of strenuous activity, the patient will inhale a greater volume into their lungs. Because the amount of oxygen provided is fixed but the amount of air is not, more air enters the mixture, becoming more diluted and decreasing the FiO2. Thus, the patient's blood oxygen concentration (SaO2) may decrease along with the decreased FiO2. Active readjustments from the patient or healthcare provider may be required. However, the patient may not have the necessary skills or knowledge to make such adjustments accurately, or the patient may simply be unaware or inattentive to do so. Additionally, medical personnel may be overwhelmed with making continuous adjustments to the oxygen flow, especially in non-medical settings.

[0009] In an attempt to counter the foregoing, pulse oxygen delivery systems have been disclosed to attempt to conserve oxygen by sensing a patient's breathing cycle and delivering short streams, or pulses, of oxygen during inspiration. However, such systems rely on complex electrical circuitry and operation and may not adequately approximate a person's natural breathing. In pulse oxygen delivery, oxygen is "pulsed" to the patient with a single bolus of oxygen administered during the inhalation phase.

[0010] Several important factors come into play in providing a consistent and effective supply of supplemental oxygen to a patient. By way of non-limiting example, FiO2 is affected by oxygen purity, triggering mechanism, pulse dose, pulse duration, pulse flow curve, ventilation volume, and peak inspiratory flow. Known devices do not fully optimize all of these factors. Instead, each manufacturer is forced to make compromises among them.

[0011] Pulse oxygen delivery systems are configured to trigger pulse doses at specific, but non-standard, negative pressures in the inspiratory curve of the respiratory cycle. If the triggering pressure is too low, the pulse dose will be delivered too early in the inspiratory curve when the patient does not have enough negative pressure to inhale the entire amount of delivered oxygen. If the triggering pressure is too high, the pulse will be delivered too late in the inspiratory curve for optimal clinical use. With high sensitivity to negative pressure and the patient's respiratory cycle and volume, a pulse oxygen delivery system would require fairly complex engineering, hardware, and software to respond based on real-time biofeedback as the patient dynamically responds. To be fully responsive, the system needs to respond immediately or near-instantly to what may be called the "shadow effect" to meet the fluctuating demands of daily life, such as when a person transitions from sitting to standing, walking, talking, exercising, and other daily activities. Current systems do not do this satisfactorily. Additionally, it should be noted that current supplemental oxygen systems typically require the patient to remember to adjust flow rate and to do so based on best estimate needs based on varying activity levels or respiratory volume. These and other factors force patients to use pulse oxygen systems that are vulnerable to desaturation, resulting in discomfort and health risks.

[0012] Recognizing the conflicting needs of conserving oxygen while being able to provide sufficient oxygen on demand, the inventors developed an automated system for conserving gases and other substances, U.S. Patent Application Publication No. 17 / 068,718, filed October 12, 2020, which is incorporated herein by reference. The automated conserving system operates to provide sufficient oxygen to a patient on demand while conserving against loss and waste, including during the respiratory phase of exhalation. The automated conserving system minimizes an individual patient's oxygen consumption while meeting patient demand and maximizing the effective supply of oxygen. In doing so, the automated conserving system enables better health outcomes in a cost-effective manner, even during a public health crisis.

[0013] In this system implementation, an expandable and compressible donor reservoir holds a volume of oxygen at ambient pressure. A supply conduit receives oxygen from an oxygen source, and an ambient pressure conduit delivers oxygen from the donor reservoir to a patient through the ambient pressure conduit. An inflation detection system detects when the donor reservoir has been inflated with oxygen to a predetermined inflation state, within a fully inflated state, and when the donor reservoir is below the predetermined state of inflation. When the donor reservoir is inflated to the predetermined inflation state, the valve system closes, preventing oxygen from the oxygen source from flowing into the donor reservoir. When the donor reservoir is below the predetermined inflation state, the valve system opens, allowing oxygen to flow from the oxygen source to automatically replenish the donor reservoir. In this way, oxygen can be continuously held in the reservoir and delivered to the patient on demand through a patient-contact delivery device, such as a nasal cannula or breathing mask, with minimal waste. By providing such an on-demand oxygen supply system at a given location, such as a high flow oxygen supply system, a significant reduction in oxygen demand and waste is realized.

[0014] However, in light of these developments in systems for delivering oxygen and other gases at ambient pressure as needed, the inventors recognize additional needs and opportunities in delivering gases in terms of format. Chief among these is the ability to exercise direct and rapid control over the ratio of oxygen to entrained air provided in inspiration. While this may additionally or alternatively be accomplished with a nasal cannula or breathing mask, the inventors recognize that it would be advantageous to do so in close proximity to or within the device from which the oxygen or other gas is delivered. The inventors further recognize the need to ensure that exhaled respiratory air is prevented from returning into the delivery device, and particularly from returning into the donor reservoir and mixing with the oxygen or other gas held therein. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] U.S. Patent Application Publication No. 17 / 068,718 Summary of the Invention [Problem to be solved by the invention]

[0016] With the foregoing understanding, the inventors further explain their underlying objective of providing a gas mixing apparatus, particularly adapted for use with gas delivery and conservation systems at ambient pressure.

[0017] A more specific object of embodiments of the present invention is to provide a gas mixing device for an ambient pressure gas delivery and conservation system that allows direct and rapid control of the ratio of oxygen to entrained air provided in inspiration.

[0018] Another object of an embodiment of the present invention is to provide a gas mixing device for a gas delivery and conservation system at ambient pressure that allows control of the ratio of oxygen to entrained air provided in inspiration, either adjacent to or within the device to which the gas is delivered.

[0019] Another specific object of embodiments of the present invention is to provide a gas mixing device for an oxygen delivery and conserving system at ambient pressure that operates to prevent exhaled breath from returning into the oxygen delivery device or into a donor reservoir held within the oxygen delivery device.

[0020] It is yet another object of the present invention, in certain embodiments, to provide a gas mixing device and an ambient pressure oxygen delivery and conservation system using such a gas mixing device that allows for the realization of a "shadow effect," in which oxygen or other gas is automatically provided at the desired saturation level on an as-needed basis with each breath, regardless of breathing frequency, volume, or other factors to quickly and automatically adjust to the patient's breathing pattern.

[0021] Another object of embodiments of the present invention is to provide a gas mixing device and an oxygen delivery and conservation system at ambient pressure using such a gas mixing device that allows a constant fraction of inspired oxygen (FiO2) or other inspired gas concentration to be provided without the need for complex mechanical or software systems.

[0022] An additional object of embodiments of the present invention is to provide a gas mixing device and an oxygen delivery and conserving system at ambient pressure using such a gas mixing device that allows a patient to maintain a desired blood oxygen saturation (SaO2), including during changes in breathing frequency and volume.

[0023] These and other objects and advantages of the present invention will be apparent not only to those who examine this specification and drawings, but also to those who have the opportunity to experience the gas mixing device and ambient pressure oxygen delivery and conserving system, which employ such a gas mixing device in surgery. However, while it is possible, and indeed preferred, to achieve several of the foregoing goals in a single embodiment of the invention, it is understood that not all embodiments seek or are required to achieve each and every possible advantage and feature. Nevertheless, all such embodiments should be considered within the scope of the present invention. [Means for solving the problem]

[0024] To further one or more of the foregoing objects, one embodiment of a gas mixing device is adapted for use with an ambient pressure oxygen delivery and conserving system, which may alternatively be referred to as an ambient pressure gas dispensing and conserving system, involving an ambient pressure tube for providing ambient pressure gas from a donor reservoir to a recipient. The gas mixing device includes a main conduit body with an internal volume, a first port for fluidly connecting to the donor reservoir, and a second port for supplying gas to the recipient. A one-way intake valve is disposed within the main conduit body between the first and second ports. The one-way intake valve operates to allow gas to be drawn from the donor reservoir through the first port, through the second port, and to the recipient. The one-way intake valve also operates to prevent gas from being received into the donor reservoir through the second port and through the first port. For the avoidance of doubt, the foregoing is intended to be binding and means that the one-way intake valve operates to prevent gases, such as exhaled breath, from flowing through the main conduit body and into the donor reservoir. The air input hole is disposed in the main conduit body at an end of the one-way intake valve distal to the first port. The air input hole operates to provide an aperture of an effective size within the interior volume of the main conduit body, which aperture allows ambient air to enter the interior volume of the gas mixing device, such as by inspiration by a recipient. In this manner, ambient air can be drawn into the main conduit body through the air input hole and mixed with gases drawn from the donor reservoir at a ratio of ambient air to gas drawn from the donor reservoir.

[0025] In embodiments of the gas mixing apparatus, a neck connector is engaged with the main conduit body to connect the first port of the main conduit body to the donor reservoir. For example, the neck connector may be matingly engaged with the main conduit body and sealingly received within a neck formed on the donor reservoir.

[0026] Also as disclosed herein, a one-way valve is fitted to the air input port, the one-way valve operative to allow ambient air to be drawn into the interior volume of the main conduit body, but to prevent gas from being exhausted through the air input port.

[0027] According to embodiments of the gas mixing device, the effective size of the aperture provided by the air input port is selectively adjustable. By adjusting the effective size of the aperture provided by the air input port, adjustment of the ratio of ambient air drawn through the air input port to gas drawn from the donor reservoir through the first port can be achieved. For the avoidance of doubt, reference to the effective size of the aperture provided by the air input port is intended to refer to the effective total size of the open passages through the air input port. This includes, but is not necessarily limited to, adjusting the size of the port itself or adjusting the size of the open passages provided through the port. The effective size of the aperture provided by the air input port can be manually selectively adjustable, or the effective size of the aperture can be automatically adjusted.

[0028] In one implementation of the invention, the effective size of the aperture provided by the air input hole can be manually and selectively adjustable by selective repositioning a hole adjustment member selectively engaged with the main conduit body to overlap the air input hole. The hole adjustment member is repositionable relative to the main conduit body to adjust the effective size of the aperture provided by the air input hole into the interior volume of the main conduit body. The effective size of the aperture into the interior volume of the main conduit body can be adjusted in any manner, including, but not limited to, by multiple different apertures in the hole adjustment member, by one or more continuous apertures of varying dimensions so that a portion of the aperture can be aligned with the air input hole, by a hole adjustment member with an adjustable portion that overlaps the air input hole, or in another manner that will be apparent to one of ordinary skill in the art after reading this disclosure. In any such configuration, adjustment of the effective size of the aperture into the interior volume of the main conduit body allows direct and rapid control of the ratio of ambient air to gas drawn from the donor reservoir through the first port.

[0029] For example, the hole adjustment member can have multiple apertures spaced apart from one another to selectively align with the air input holes and adjust the effective size of the aperture provided by the air input holes. The hole adjustment member can have multiple aperture locations spaced apart from one another that establish different effective opening sizes for selectively aligning with the air input holes. Within the aforementioned ranges, the aperture locations can each have a single aperture of a different size, or the aperture locations can have different numbers of apertures of similar or different sizes or shapes that collectively provide different cumulative total open areas.

[0030] In certain embodiments, the hole adjustment member comprises a cylindrical member that is selectively repositionable relative to the main conduit body to overlap the air input hole. The cylindrical member has a plurality of differently sized holes spaced apart to selectively align with the air input hole to adjust the effective size of the aperture provided by the air input hole and thereby provide direct and rapid control over the ratio of air drawn through the air input hole to gas drawn from the donor reservoir. For example, the differently sized apertures in the cylindrical member can be spaced circumferentially around the cylindrical member, spaced longitudinally along the cylindrical member, or otherwise disposed. While other configurations are possible, the differently sized apertures spaced apart around the cylindrical member can vary in size sequentially.

[0031] In an implementation of the present invention, the cylindrical member of the hole adjustment member comprises a portion of an output connector matingly engaged with the main conduit body. In this embodiment, the output connector may further comprise a tubular portion that extends beyond the main conduit body for connection to an ambient pressure conduit to provide gas to a recipient.

[0032] Mechanical engagement arrangements may be carried on at least one of the cylindrical member and the main conduit body to enable the cylindrical member to be positioned and held in a known position relative to the main conduit body, and visual setting indicators may be carried and move with the cylindrical member, and at least one visual setting indicator may be carried on the main conduit body to enable the effective size of the aperture provided by the air input hole to be adjusted in a known manner.

[0033] In an embodiment of the gas mixing device, an injection port is disposed in the main conduit body. The injection port can be connected to a supply source, such as a compressed oxygen source, via high-pressure tubing. The injection port is disposed proximal to the first port and a one-way intake valve, whereby gas received from the supply source is directed into the donor reservoir to replenish and expand the donor reservoir.

[0034] A manifestation of the present invention can alternatively be characterized as a gas delivery system for providing gas to an individual. The gas delivery system, which can be a gas delivery or dispensing system at ambient pressure, has a donor reservoir adapted to hold gas. The donor reservoir has a fully expanded state. A supply valve is disposed in fluid communication with the donor reservoir. The supply valve has an open state when gas is allowed to flow into the donor reservoir and a closed state when gas is disabled from flowing into the donor reservoir. An expansion detection system operates to detect when the donor reservoir has expanded to within a predetermined range relative to the fully expanded state. The expansion detection system detects a first state when the donor reservoir has expanded to within a predetermined range, such as at or within a range less than the fully expanded state, relative to the fully expanded state. The expansion detection system also detects a second state when the donor reservoir has expanded to less than the predetermined range relative to the fully expanded state. The inflation detection system operates to actuate the supply valve to an open state to inflate the donor reservoir when the donor reservoir is inflated to less than a predetermined range relative to a fully inflated state. The gas mixing device has an air input port that operates to provide an aperture of an effective size within the interior volume of the main conduit body to allow ambient air to enter the interior volume of the gas mixing device. In this configuration, ambient air can be drawn into the main conduit body through the air input port and mixed with the gas drawn from the donor reservoir at a ratio of ambient air to gas drawn from the donor reservoir.

[0035] In the practice of the invention disclosed herein, the donor reservoir has an outer wall, an interior volume for holding an amount of oxygen or other gas, and at least one hole for allowing gas to pass into and out of the interior volume. The donor reservoir can include a shell of a flexible material, such as a foil shell. A supply conduit is adapted to receive oxygen from an oxygen source. The supply conduit has a first end for supplying oxygen to the donor reservoir and a second end for fluid connection to the oxygen source. An ambient pressure conduit is adapted to supply oxygen from the donor reservoir along a fluid pathway to a recipient, such as through a nasal cannula or a breathing mask. The ambient pressure conduit has a first end in fluid communication with the donor reservoir, such as through a connector, to receive oxygen from the donor reservoir, and a second end for fluid connection to the recipient.

[0036] In certain embodiments, the expansion detection system comprises an electromechanical system. For example, the expansion detection system can include a switch disposed to be actuated by an outer wall of the donor reservoir when the donor reservoir is inflated with oxygen to a predetermined expansion state. The switch can be biased toward the donor reservoir by gravity, a resilient, compressible member, or other effective method. The switch can be considered to have an activated state, in which the switch is disposed at or beyond an inward position relative to the interior volume of the donor reservoir, and an inactivated state, in which the switch is actuated outward by the outer wall of the donor reservoir when the amount of oxygen in the donor reservoir reaches a predetermined expansion state. The valve system operates to prevent oxygen from flowing into the donor reservoir from the oxygen source when the switch is in the inactivated state and to allow oxygen to flow into the donor reservoir from the oxygen source when the switch is in the activated state.

[0037] In a detailed specification of the system, the switch includes a float switch. For example, the float switch may have a contact structure with an expandable and contractible collar relative to a central post. The collar may then carry a magnet, and the central post may carry electrical contacts that are electrically contacted by the proximity of the magnet when the switch is in an actuated state.

[0038] According to an implementation of the system, the valve system can take the form of a solenoid valve in electrical communication with an expansion detection system. When the donor reservoir is in a first state, the solenoid valve can be induced by the expansion detection system to a closed state to prevent oxygen from flowing from the oxygen source into the donor reservoir. When the donor reservoir is in a second state, the solenoid valve can be induced by the expansion detection system to an open state to allow oxygen from the oxygen source to flow into the donor reservoir.

[0039] In certain embodiments, the donor reservoir is disposed within a housing. This housing may include the main housing of the system, a sub-housing within the main housing, or other types of housings. In other implementations, the donor reservoir may be disposed without a housing. When a housing is provided, the expansion detection system may include an electromechanical system with a switch. The switch is supported by the housing and is disposed to be actuated by the outer wall of the donor reservoir when the donor reservoir is expanded with oxygen to a predetermined expansion state. In alternative implementations of the invention, the expansion detection system includes a non-contact detection system. For example, the expansion detection system may take the form of an optical detection system. In certain embodiments, all or a portion of the housing may be transparent, thereby allowing visual recognition of the expansion state of the donor reservoir, which may provide further assurance to the user that the system is in proper operation.

[0040] A recipient delivery device, such as a nasal cannula, a patient breathing mask, or another recipient delivery device, is coupled to the second end of the ambient pressure conduit. The nasal cannula is configured to allow direct exhaust of breath through the cannula and to prevent the exhausted breath from returning into the connected ambient pressure conduit. As taught herein, the nasal cannula allows for direct and rapid control of the ratio of oxygen to entrained air inhaled through the nasal cannula during inspiration.

[0041] It should be appreciated that the foregoing has outlined broadly the more important objects and features of the present invention in order to better understand the detailed description that follows, and to provide a better understanding of the inventors' contributions to the art. Before describing any particular embodiment or aspect thereof in detail, it should be made clear that the following structural details and illustrations of the inventive concept are merely illustrative of the many possible manifestations of the invention. [Brief explanation of the drawings]

[0042] [Figure 1] 1 is a schematic diagram of an oxygen delivery and conserving system in accordance with the present invention. [Figure 2] FIG. 2 is a front perspective view of a housing portion of an oxygen delivery and conserving system taught herein. [Figure 3] FIG. 1 is a rear perspective view of a housing portion of an oxygen delivery and conserving system. [Figure 4] 1 is a side cross-sectional view of an oxygen delivery and conserving system according to the present invention. [Figure 5] FIG. 1 is a rear perspective view of the oxygen delivery and conserving system with the top, bottom, and side walls of the housing removed. [Figure 6] 1 is a schematic diagram of an oxygen delivery and conserving system in operation during a series of breathing cycles. [Figure 7] FIG. 1 is a perspective view of a gas mixing device for a gas delivery and conservation system at ambient pressure as disclosed herein. [Figure 8]FIG. 8 is a front view of the gas mixing device of FIG. 7. [Figure 9] FIG. 8 is a top view of the gas mixing device of FIG. 7. [Figure 10] FIG. 8 is an exploded perspective view of the gas mixing device of FIG. 7. [Figure 11] FIG. 8 is an alternative exploded perspective view of the gas mixing device of FIG. 7. [Figure 12] FIG. 2 is an exploded side view of an alternative gas mixing apparatus according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] The gas mixing apparatus and associated ambient pressure gas delivery and conservation system are the subject of a wide variety of embodiments, but certain preferred embodiments of the broader invention are described below and illustrated in the accompanying drawings to ensure that those skilled in the art will understand the invention and be able to practice, where appropriate, the invention disclosed herein.

[0044] To understand and appreciate the utility and operation of the gas mixing apparatus disclosed herein, reference will first be made to an oxygen delivery and conserving system 100 designed to function therewith. Reference is made to the schematic diagram of FIG. 1 and the representation of delivery, dispensing, and conserving system 100 in FIGS. 2-5, where the gas mixing apparatus is generally designated 10. Here, the illustrated oxygen delivery and conserving system 100, which may also alternatively be referred to as a gas dispensing and conserving system 100, provides an on-demand oxygen supply at ambient pressure to a recipient. In the illustrated example, oxygen is delivered from a donor reservoir 104 to the recipient through a nasal cannula 158; it should be understood that other gas delivery mechanisms, including, by way of non-limiting example, a respiratory mask, are within the scope of the present invention, except as expressly limited by the claims.

[0045] In accordance with the practice of the present invention, donor reservoir 104 holds oxygen at ambient pressure and is continuously and automatically supplied with oxygen from oxygen source 106, such as a tank of compressed oxygen gas or liquid oxygen. Because donor reservoir 104 holds oxygen at ambient pressure and because donor reservoir 104 is automatically replenished, a large and ample supply of oxygen is constantly available for patient inspiration. Concomitantly, because oxygen is drawn from reservoir 104 solely through inspiration, oxygen loss during patient expiration is virtually eliminated. In this manner, the oxygen supply is conserved without compromising its effectiveness for each individual recipient.

[0046] The donor reservoir 104 in this embodiment comprises an expandable and compressible shell, bladder, or other expandable and compressible body disposed within the housing 102. The housing 102 may be a primary housing or a secondary housing within a larger structure. However, the donor reservoir 104 need not necessarily be within the housing 102 within the scope of the present invention. The housing 102 in the depicted embodiment defines a boundary surrounding the reservoir 104 such that, when the reservoir 104 is expanded, the shell of the reservoir 104 presses toward one or more of the boundaries defined by the housing 102. In this depicted non-limiting example, the housing 102 has a bottom defining a lower boundary of the reservoir 104, a top defining an upper boundary of the reservoir 104, and a distal end defining a longitudinal boundary of the reservoir 104.

[0047] As shown in FIGS. 4 and 5 , the housing 102 in this example is elongated and defines a generally cubic interior volume, and the reservoir 104 has a corresponding elongated, generally cubic shape. Other shapes and combinations of shapes are readily possible and within the scope of the present invention unless expressly excluded by the claims. In a specific implementation of the present invention, the lower wall portion of the shell of the reservoir 104 is adhered or otherwise secured to the housing 102 at one or more locations, such as by adhesive strips 148 as shown in FIG. 4 or any other method. In this example, the reservoir 104 has four elongated side walls that are joined to form a rectangular cross-section when expanded. The first end wall is formed by and joined with four triangular portions extending from the first ends of the side walls. Similarly, the second end wall is formed by and joined with four triangular portions extending from the second ends of the side walls. The edges of the walls are sealingly joined to define a cubic reservoir 104. The reservoir 104 is thus sealed except for an inlet hole at a first end of the reservoir 104.

[0048] The shell of the reservoir 104 is formed of a flexible, substantially gas-impermeable material. One of ordinary skill in the art will recognize many such materials. Each is within the scope of the present invention unless expressly excluded by the claims. The shell of the reservoir 104 can be formed of a flexible polymeric material, with or without a lining layer. The material defining the reservoir 104 can be composed of a foil formed from one or more layers of polymeric material, for example, with an aluminum lining. The reservoir 104 can have one or more flexible walls, rigid walls, compressible walls, collapsible walls, expandable walls, thin walls, or other combinations of walls capable of retaining a volume of gas therein. Other configurations of the reservoir 104 are possible and within the scope of the present invention.

[0049] Preferably, as is possible with the lightweight, flexible foil construction of reservoir 104, once expanded, reservoir 104, whether due to its own structural integrity or otherwise, tends to substantially maintain its expanded shape and configuration even when vented to ambient pressure, such as by fluid connection through ambient pressure tubing 122 to recipient 158, such as a nasal cannula 158, a breathing mask, or another mechanism for delivering oxygen to the recipient. Because system 100 is designed to provide oxygen on demand during natural inspiration by the patient, ambient pressure tubing 122 has a large inner diameter to reduce any resistance to patient inspiration to nearly zero. As taught herein, once expanded, reservoir 104 in preferred embodiments does not collapse significantly on itself due to the weight of its walls. When filled with oxygen, reservoir 104 temporarily stores a compartmentalized amount of oxygen at ambient pressure, waiting to be drawn from by the recipient.

[0050] 1 , fluid connector 118, which may be considered a T-connector, has a first longitudinal port in fluid communication with donor reservoir 104, such as through tubular connector 128 secured and sealed within an aperture in the neck of reservoir 104. Fluid connector 118 has a second longitudinal port, which is in fluid communication with ambient pressure tubing 122, with output connector 116 in fluid communication with the recipient through tubing 122, such as through nasal cannula 158, a breathing mask, or another gas delivery mechanism. Finally, fluid connector 118 has a third lateral port between the first and second openings that is in fluid communication with oxygen source 106, in this case through flow-restricting connector 115. The first, second, and third ports are in fluid communication with each other within fluid connector 118. Fluid communication from source 106 to connector 118 may be through, for example, high pressure tubing 108 from oxygen source 106 to an oxygen connector 110 secured to housing 102, and through high pressure tubing 152 from oxygen connector 110 to supply valve 112. Pressure sensor 126 is interposed, such as by being fluidly sandwiched along high pressure tubing 152, to detect the gas pressure entering supply valve 112.

[0051] Supply valve 112, in this example comprising an electromechanical solenoid valve 112, has an open state and a closed state. Valve 112 is fluidly interposed between pressurized oxygen source 106 and reservoir 104. When supply valve 112 is in the open state, oxygen can be transferred from oxygen source 106 through tubing 108, through valve 112, through connector 118 or gas mixing device 10 as disclosed herein, and into reservoir 104. When valve 112 is in the closed state, the passage of oxygen between oxygen source 106 and reservoir 104 is prevented.

[0052] In the embodiment of FIG. 1 , a one-way intake valve 124 is interposed between the reservoir 104 and the recipient, such as by being fluidly connected directly to a second port of the fluid connector 118 or by using an interposed gas filter 120. In FIG. 1 , the fluid connector 118 has its first port fluidly connected to the neck of the reservoir 104. The one-way intake valve 124 operates to allow gas to flow from the donor reservoir 104 through the ambient pressure tubing 122 to the recipient, such as through a nasal cannula 158 or a breathing mask, but prevents gas from flowing back from the recipient into the donor reservoir 104. The gas filter 120 is fluidly interposed between the recipient and the donor reservoir 104.

[0053] The amount of gas, in this example, oxygen, in the donor reservoir 104 is maintained at substantially ambient pressure. Ambient pressure can be defined as the pressure of the air surrounding the donor reservoir 104. Substantially ambient pressure can be understood to be equal to or within slightly different ranges of ambient pressure. For example, substantially ambient pressure can be interpreted as within 5% of ambient pressure. When the recipient is in the inspiratory phase of breathing, oxygen will be drawn from the donor reservoir 104 through the ambient pressure tube 122, thereby drawing from and tending to reduce the amount of oxygen in the donor reservoir 104. Due to the compressible nature of the donor reservoir 104, the reservoir 104 will tend to contract. When contracted, the donor reservoir 104 is automatically refilled with oxygen, or possibly with another gas. In this embodiment, expansion of the donor reservoir 104 is initiated by an expansion detection system. The inflation detection system detects when the donor reservoir 104 is not fully inflated and actuates the supply valve 112 to an open state to inflate the donor reservoir 104 while avoiding pressurization of the reservoir 104 so that the oxygen in the reservoir 104 remains at substantially ambient pressure.

[0054] The expansion detection system has a first state in which supplemental oxygen is not supplied to the donor reservoir 104 and a second state in which supplemental oxygen is supplied to the donor reservoir 104. The first state can be a state in which the donor reservoir 104 is inflated with oxygen to a predetermined expansion state, and the second state can be a state in which the donor reservoir 104 is inflated with oxygen to less than the predetermined expansion state. The expansion detection system operates to detect when the donor reservoir 104 reaches the predetermined expansion state. The predetermined expansion state can be detected when the donor reservoir 104 reaches a predetermined size or other expansion state of any dimension or combination of dimensions. In embodiments of the present invention, the donor reservoir 104 can be considered to have a fully inflated state, and the expansion detection system detects when the donor reservoir 104 has expanded to the fully inflated state or to within a predetermined range of the fully inflated state. By way of example and not limitation, the inflation detection system can detect when the donor reservoir 104 is inflated with oxygen above a threshold inflation level, which may be below a fully inflated state.

[0055] Upon reviewing the present invention, one skilled in the art will recognize multiple mechanisms that would operate as an inflation detection system for detecting that the donor reservoir 104 has been inflated to a predetermined inflation state. Each such mechanism is within the scope of the present invention unless expressly limited by the claims. The inflation detection mechanism can include mechanical systems, electrical systems, electromagnetic systems, optical systems, electromechanical systems, sound-activated systems, motion sensors, optical sensors, and any other type of system effective for detecting that the donor reservoir 104 has been inflated to a predetermined inflation state. Note again that the predetermined inflation state can be reached while the oxygen in the donor reservoir 104 is at substantially ambient pressure.

[0056] 1-5, the expansion detection system takes the form of a non-contact system 156, which may be an optical detection system 156. The detection system 156 may be, for example, a laser detection system, a camera system, an infrared expansion detection system, or any other effective non-contact detection system 156. In certain embodiments, the non-contact detection system 156 may be formed using an emitter, such as a laser or other emitter, held on one side of the reservoir 104 and an optical receiver disposed on the opposite side of the reservoir 104.

[0057] With such a configuration, the expansion state of the donor reservoir 104 can be sensed in a non-contact manner, such as by expanding the donor reservoir 104 to a state that prevents light communication from the light emitter to the light receiver. The reservoir 104 then exhibits a predetermined reflectivity or other non-contact method. In another embodiment, the detection system 156 includes one or more proximity sensors that operate to detect the proximity of a localized opposing surface of the donor reservoir 104. For example, as shown in FIGS. 4 and 5 , the series of proximity sensors forming the expansion detection system 156 are supported within the housing 102, in this example, by an electronics casing 155 secured within the housing 102 above the donor reservoir 104. The electronics casing 155 supports an electronic control system 157, which includes electronic circuitry for holding the electronic memory storage system's software, one or more computer processors for processing the software, and other electronic circuitry and wiring necessary for the operation of the system 100.

[0058] In this manner, the expansion detection system 156 can detect the expansion state of the donor reservoir 104, possibly at multiple locations along the donor reservoir 104. The expansion detection system 156 can detect when the donor reservoir 104 has filled to a predetermined expansion state. The predetermined state of expansion can be detected based on a sensed position of a wall of the donor reservoir 104, such as by detecting the proximity of the wall of the donor reservoir 104 to a proximity sensor of the expansion detection system 156, or based on a sensed expansion of the donor reservoir 104 interrupting optical communication between the light emitter and the light receiver.

[0059] Based on the expansion state of the donor reservoir 104, as detected by the expansion detection system 156, the flow switch 114 operates to actuate the valve 112 between an on state, which allows oxygen to flow from the oxygen source 106 to the donor reservoir 104, and an off state, in which this flow is prevented. More specifically, when the expansion detection system 156 detects that the donor reservoir 104 is below a predetermined state of expansion, based on inward contraction of the walls of the donor reservoir 104, the flow switch 114 actuates the valve 112 to the on state, allowing oxygen to flow from the oxygen source 106 to fill the donor reservoir 104. When the donor reservoir 104 reaches a predetermined state of expansion based on the detected wall expansion of the donor reservoir 104, as also detected by the expansion detection system 156, the flow switch 114 actuates the valve 112 to the OFF state to prevent further flow of oxygen beyond the predetermined state of expansion, thereby preventing pressurization of the donor reservoir 104 and preventing oxygen or other gases from venting from the system 100. Thus, when the flow switch 114 is in an activated state, it may be considered to be in an ON state, and the donor reservoir 104 is detected to be below the predetermined state of expansion. When the flow switch 114 is in a deactivated state, it may be considered to be in an OFF state, and the donor reservoir 104 is detected to have reached the predetermined state of expansion based on detection by the expansion detection system 156 of the expansion of the donor reservoir 104.

[0060] In another non-limiting embodiment, the expansion detection system comprises an electromechanical system for detecting when the donor reservoir 104 has filled to a predetermined expanded state. Such a detection system (not shown in this embodiment) can have a contact structure disposed to contact, be contacted by, be moved by, or be actuated by the donor reservoir 104 when the donor reservoir 104 reaches the expanded state. The location and structure of the contact structure can vary within the scope of the present invention. For example, the contact structure can be disposed from or through the distal end wall of the housing 102 and protrude into the interior volume of the housing 102, such that the contact structure can protrude toward and engage the distal end of the reservoir 104. In other embodiments, the contact structure is disposed to protrude from or through the top wall of the housing 102 into the interior volume of the housing 102 and engage an intermediate portion of the reservoir 104. The contact structure may be held by a support structure, for example, secured to the top wall or another upper portion of the housing 102.

[0061] The contact structure is positioned to be moved by the donor reservoir 104 as it expands toward the expanded state. The contact structure can be, for example, pushed, pivoted, rotated, or otherwise actuated by the donor reservoir 104, and more particularly, by the expansion of the donor reservoir 104. The contact structure can operate as, or as a component of, the flow switch 114 or by actuating the flow switch 114. When the contact structure is actuated by the expansion of the donor reservoir 104, the flow switch 114 operates to operate the valve 112 between an on state that allows oxygen to flow from the oxygen source 106 into the reservoir 104 to replenish and fill the reservoir 104, and an off state that prevents oxygen from flowing from the oxygen source 106 into the reservoir 104. The contact member can be biased toward donor reservoir 104 by a spring force under gravity, by resiliency, or by other biasing methods, or a combination thereof.

[0062] 1-5, donor reservoir 104 is disposed within housing 102. Additionally or alternatively, donor reservoir 104 can be disposed within a sub-housing, which in turn can be disposed within housing 102 or located independently. Furthermore, donor reservoir 104 can be disposed without a housing or enclosure, in which case contact structure and, optionally, flow switch 114 are retained by a surrounding band, rigid arm, or other retaining structure, etc., to contact or otherwise sense or engage donor reservoir 104. Contact structure and flow switch 114 can be retained together, optionally as a unit, or as separate locations.

[0063] When the oxygen content of the donor reservoir 104 drops below a predetermined expansion state, thereby distorting or moving the outer wall inward, the contact structure is permitted to move inward toward the donor reservoir 104. The flow switch 114 has an activated state, which is considered an on state, when the contact structure is fully moved, such as by expanding, pivoting, or other movement in an inward direction toward the interior volume of the donor reservoir 104. The flow switch 114 has a deactivated state, which is considered an off state, when the contact structure is moved, such as by contracting, pivoting, or other movement in an outward direction away from the donor reservoir 104. The contact structure is moved outward to adjust the flow switch 114 to the deactivated state, which is an off state, when the oxygen content of the donor reservoir 104 reaches a predetermined expansion state and the outer wall of the donor reservoir 104 is forced outward by the expansion of the donor reservoir 104. For example, if the contact structure is a push switch, expansion of donor reservoir 104 will push the outer wall or shell of donor reservoir 104 outward, depressing the contact structure and flow switch 114 into a deactivated state.

[0064] Using the respective inflation detection systems, the donor reservoir 104 can be inflated to or within a given maximum volume range of the donor reservoir 104 without over-inflating or over-pressuring. Thus, oxygen in the donor reservoir 104 is prevented from exceeding approximately ambient pressure. However, as may be required by the claims, embodiments of the present invention may calibrate the flow switch 114 and valve 112 to induce deactivation at some other predetermined inflation or pressure condition, including pressure or inflation conditions that potentially exceed ambient pressure or are significantly below the maximum capacity of the donor reservoir 104. The flow switch 114 and valve 112 can be electrical, mechanical, electromechanical, or otherwise configured and constructed.

[0065] In an embodiment of oxygen dispensing and conserving system 100, supply valve 112 may comprise a solenoid valve, which is in electrical communication with flow switch 114, such as through electrical wiring in an electrical circuit. Illustratively, electrical control system 157, which may include electrical circuitry, electronic memory, wiring, system software maintained and operated by the electrical circuitry and electronic memory, and other electrical control and connection elements, cooperates with the inflation detection system to induce solenoid supply valve 112 to an open state, allowing oxygen to flow from source 106 when flow switch 114 is in an activated state. The electrical control system may receive power from a power source. The power source may be an alternating current source through power supply connection 130, a direct current source such as a battery power source, or other power source. The flow of power from the power source may be controlled by power switch 132. The solenoid valve 112 is induced to a closed state by an inflation detection system and an electrical control system to prevent oxygen from flowing from the source 106 into the reservoir 104 when the flow switch 114 is in a deactivated state. Each of the components referenced herein may be further combined or separated within the scope of the present invention.

[0066] Even when valve 112 is in an open state, the flow rate, flow pressure, or both flow pressure and flow rate from source 106 to donor reservoir 104 is limited by flow-restricting connector 115. Flow-restricting connector 115 can limit the flow rate of oxygen from source 106 to donor reservoir 104 to a predetermined rate, such as less than 1 liter / minute or any other rate. Flow-restricting connector 115 can comprise a small-diameter tubing connector, such as a connector having an inner diameter of 0.02 mm or other dimensions that are reduced compared to other conduit connections in the fluid system. Thus, sudden pressure changes in donor reservoir 104 can be prevented by opening valve 112.

[0067] Referring to FIG. 6 , system 100 is shown in operation during a series of breathing cycles, providing an on-demand supply to a recipient, such as through a mask or cannula 158 worn by a patient in need. In operation, inspiration by the patient draws oxygen at ambient pressure from donor reservoir 104, thereby tending to deflate reservoir 104. When reservoir 104 falls below a predetermined inflation state, oxygen is released and reservoir 104 automatically fills to the predetermined inflation state. Thus, a continually replenishing amount of oxygen at ambient pressure is available in reservoir 104, which is drawn through ambient pressure tube 122 during the natural inspiration phase of the breathing cycle. When the recipient is not engaged in inspiration, oxygen is not drawn from reservoir 104 and tends not to be released from reservoir 104. When the amount of oxygen in reservoir 104 falls below the predetermined inflation state, an inflation detection system detects this and triggers valve 112 to an open state. Oxygen flow is then enabled from the oxygen source 106, causing the donor reservoir 104 to fill with oxygen until a predetermined inflation state is reached. Once the predetermined inflation state is reached, an inflation detection system detects this and actuates the valve 112 to a closed state, preventing further delivery of oxygen from the source 106 to the donor reservoir 104 until another inspiratory phase of the breathing cycle draws an amount of oxygen from the reservoir 104. In this manner, the donor reservoir 104 is automatically oxygenated while automatically preventing pressurization of oxygen within the reservoir 104. Supplemental oxygen is safely and efficiently delivered to the patient at ambient pressure with an on-demand volume displacement system, allowing oxygen transfer during the entire inspiratory phase of the breathing cycle while preventing wasteful release of oxygen to the atmosphere, including during the expiratory phase.

[0068] In this manner, the donor reservoir 104 automatically receives supplemental oxygen from the pressurized source 106 through the high-pressure tubing 108 and through the supply valve 112. Automatically filling the reservoir 104 ensures that the donor reservoir 104 always has a supply of oxygen available for the next inspiratory phase of the breathing cycle, while ensuring that the oxygen in the reservoir 104 does not exceed ambient pressure. When the donor reservoir 104 is visually exposed through a partially or fully transparent housing 102 or through an observation aperture or window in the housing 102, the observer is provided with visual confirmation of the inflation state of the donor reservoir 104. For example, as shown in FIG. 3 , the housing 102 of the depicted embodiment has a translucent rear wall portion 105, which allows the inflation state of the donor reservoir 104 to be confirmed. This may be a useful amenity in confirming proper operation, given the quiet operation of the oxygen dispensing and conserving system 100 at ambient pressure. Additionally, system 100 includes an electronic status indicator 125, as shown in FIG. 2, to confirm the inflation status of donor reservoir 104. Electronic status indicator 125 may comprise, for example, a series of lights or another visual electronic indicator of the fill level of donor reservoir 104. System 100 can therefore provide a consistent delivery of supplemental oxygen to the recipient because donor reservoir 104 and system 100 generally match the patient's physiological ventilation based on the storage and replenishment of oxygen in donor reservoir 104 at ambient pressure and automatic termination of oxygen delivery when donor reservoir 104 reaches a predetermined inflation state.

[0069] Within the scope of the present invention, system 100 can measure, record, and analyze oxygen flow and patient breathing characteristics, including through the use of electrical control system 157 and, potentially or alternatively, through data processing by remote data communication and wireless communication. As shown in FIG. 3 , a data port 135, such as a USB port or other data port, allows wired communication to and from electrical control system 157 and overall system 100. Through wired or wireless communication using data port 135 or wireless communication protocols, system software can be updated and modified, system 100 can be programmed to meet specific requirements, and acquired data, such as data regarding system operation, user respiration, and other aspects, can be downloaded for use and analysis.

[0070] To facilitate such data acquisition and analysis, a volumetric flow meter may be connected to the oxygen source 106. Additionally or alternatively, one or more flow meters may be retained within the housing 102 along the path of gas flow through the system 100. For example, a flow meter may be disposed to meter oxygen passing through the valve 112. The valve 112 may incorporate a flow meter or may have a separate flow meter disposed therein. A flow meter may also or alternatively be disposed between the reservoir 104 and the ambient pressure tubing 122. By measuring the amount of oxygen delivered to the recipient by the system 100 over a given period of time, determinations, measurements, and analyses may be made for each inspiration and expiration cycle or multiple cycles. For example, the amount of oxygen inhaled by the patient and, additionally or alternatively, the amount of oxygen remaining in the oxygen source 106 may be determined. Through software operating on or in communication with electronic memory and electrical systems, direct integration, wireless communication, or a combination thereof, the system 100 may collect, process, and analyze data based on use of the system 100.

[0071] While a tank of compressed gas is often depicted and referred to herein as the oxygen source 106, other oxygen sources 106 are possible and within the scope of the present invention. By another non-limiting example, the system 100 can provide oxygen to a patient as needed using oxygen supplied by an oxygen concentrator. An oxygen concentrator takes in air and removes nitrogen from it, leaving an oxygen-enriched gas for patients requiring medical oxygen. The typical flow of this compressed oxygen is 1-5 liters per minute. High-end oxygen concentrators can deliver up to 50 liters per minute, but they require more electricity and more maintenance.

[0072] If the oxygen source 106 is an oxygen concentrator, the system 100 can be installed between the oxygen concentrator and the oxygen delivery device, so that as oxygen leaves the concentrator, it enters a large reservoir 104, where it remains at ambient pressure until the patient inhales. As the patient breathes and draws oxygen from the reservoir 104, the reservoir 104 begins to deplete, and a supply valve 112 from the oxygen concentrator as the oxygen source 106 opens, replenishing the reservoir 104 with compressed oxygen from the oxygen concentrator. When the patient exhales, there is no flow between the reservoir 104 and the patient. During the patient's exhalation phase, rather than wasting the oxygen flowing from the concentrator, the flow is utilized to refill the reservoir 104. Once the reservoir 104 is filled, the supply valve 112 stops the flow of oxygen from the oxygen source 106. This cycle can be repeated with each breath. In this way, oxygen not taken in by the patient during inspiration is stored without loss.

[0073] As taught herein, oxygen from the donor reservoir 104 can be made available for inhalation by a recipient through a breathing mask, a nasal cannula 158 as shown in FIG. 1, or another delivery device. In the nasal cannula 158, first and second straps extend in opposite directions from a central portion of the nasal cannula 158 to either side, and buckles are held at the distal ends of the straps. The nasal cannula 158 can be held against the wearer's head by the straps and buckles, possibly in combination with additional fastening mechanisms such as another strap, a cloth tape, or some other fastening method. First and second nasal prongs extend parallel from the central portion of the nasal cannula 158 and are received within the patient's nares. The nasal cannula 158 has gas-receiving apertures for fluidly engaging the ambient pressure tubing 122 of the oxygen dispensing and conserving system 100.

[0074] The ambient pressure gas dispensing and conserving system 100 thus disclosed operates to provide an adequate supply of oxygen or other gas as needed, without the waste associated with constant flow systems, and without the inherently complex mechanics of pulse delivery systems and the difficulty such systems have in tracking natural fluctuations in breathing frequency and volume due to physical activity and other factors. However, as noted above, there is a further need in oxygen delivery systems to mix air with the delivered oxygen to achieve a desired FiO2 oxygen concentration. Prior art systems have been limited in their ability to respond quickly and perform in a consistent manner, particularly during fluctuations, e.g., during ventilation and inspiration.

[0075] In the embodiment of the gas dispensing and conserving system depicted in Figures 2-5, ambient air can be selectively mixed with oxygen drawn from the donor reservoir 104 at a constant level, regardless of ventilation rate, inspiration rate, and other factors, through operation of a gas mixing apparatus, generally designated 10. Here, the gas mixing apparatus 10 operates as a fluid connector. The gas mixing apparatus 10 operates to receive oxygen supplied from an oxygen source through a flow-restricting connector 115, allows oxygen flow to and from the donor 104, and provides an output connector for delivering the mixed air and oxygen to the recipient through ambient pressure tubing 122.

[0076] Gas mixing apparatus 10 is depicted incorporated within gas dispensing and conserving system 100, for example, in FIG. 4 . Gas mixing apparatus 10 is depicted separate from the remainder of dispensing and conserving system 100 in FIGS. 7-12 , where gas mixing apparatus 10 can be seen mounted to main conduit body 12. In this non-limiting example, main conduit body 12 is tubular. A first end of main conduit body 12 defines a first port, which is disposed in fluid communication with donor reservoir 104. In the depicted embodiment, connection between conduit body 12 and donor reservoir 104 is established through tubular neck connector 14 of gas mixing apparatus 10, which is sealingly received in a neck aperture of donor reservoir 104. Neck connector 14 is matingly engaged at the first end of conduit body 12. Gas mixing device 10 has an output connector 16 disposed at a second end of conduit body 12. Output connector 16 establishes a second port for supplying gas to a recipient, such as through ambient pressure tubing 122 as shown in FIG.

[0077] 12, the one-way intake valve 32 is disposed within the main conduit body 12 between a first port of the conduit body 12 that communicates with the reservoir 104 and a second port of the conduit body 12 that communicates with the output connector 16. The one-way intake valve 32 operates to allow gas to be drawn from the reservoir 104 through the first port of the conduit body 12 and to allow gas to be provided to a recipient through the second port of the conduit body 12, while preventing gas from entering the reservoir 104 from the second port of the conduit body 12 through the ambient pressure tube 122 or the like during exhalation through the first port of the conduit body 12.

[0078] Oxygen, or possibly another gas, or combination of gases, is injected from its source into gas mixing device 10 through injection port 30. For example, as shown in FIG. 4, oxygen can be delivered from the oxygen source to injection port 30 through a supply conduit 115, such as a flow-restricting connector 115. Injection port 30 is disposed proximal to one-way intake valve 32 relative to donor reservoir 104, thereby directing gas injected through injection port 30 to act as a refill supply for donor reservoir 104 rather than immediately discharging it through a second port in conduit body 12 and through output connector 16 to the recipient. As shown in FIGS. 8 and 10, compartment panel 22 is longitudinally received within main conduit body 12 and disposed adjacent to injection port 30, further directing gas injected through injection port 30 into donor reservoir 104.

[0079] The air input port 18 is disposed distal to the one-way intake valve 32 relative to the donor reservoir 104 and, therefore, proximal to the output connector 16 relative to the one-way intake valve 32, thereby allowing ambient air to enter the gas mixing device 10 while preventing air from entering the donor reservoir 104. The one-way air input valve 20 is fitted to the air input port 18 with a vent cap 28 retained thereon. The donor reservoir 104 can thus be replenished with oxygen, or possibly another gas, through the injection port 30 and the supply conduit 115. Oxygen, or other gas, held within the donor reservoir 104 can be withdrawn therefrom through the output connector 16 during inspiration, while ambient air is selectively mixed in through the air input port 18. During expiration, exhaled breath is prevented from entering the donor reservoir 104 by the one-way intake valve 32.

[0080] Thus, when the air input port 18 is open, air is drawn in through the air input port 18 and mixed with and entrained in the gas drawn from the donor reservoir 104 by operation of the gas mixing device 10. The ratio of ambient air drawn in through the air input port 18 to the gas drawn from the reservoir 104 will depend on factors including the effective size of the aperture through the air input port 18 and the effective size of this aperture relative to the aperture defined by the neck connector 14 in the donor reservoir 104.

[0081] In accordance with the present invention, the effective size of the aperture provided by air input hole 18 is selectively adjustable, thereby enabling adjustment of the ratio of ambient air drawn through air input hole 18 to the mixture of gas drawn from reservoir 104. Upon review of this disclosure, those skilled in the art will recognize multiple mechanisms for selectively adjusting the effective size of the aperture provided by air input hole 18. Each is within the scope of the present invention unless expressly excluded by the claims.

[0082] In the embodiment of gas mixing device 10 depicted in FIGS. 4 and 7-12, for example, adjustment of the effective aperture provided by air input hole 18 is provided by a rotary adjustment dial formed by output connector 16 associated with main conduit body 12. More specifically, output connector 16 has a cylindrical proximal portion that is matingly received within main conduit body 12 and overlaps air input hole 18. Output connector 16 has a cylindrical distal portion for matingly engaging ambient pressure tubing 122. The cylindrical proximal portion of output connector 16 has a plurality of differently sized apertures 24 circumferentially spaced therearound. While various arrangements are certainly possible, the apertures 24 in the proximal portion of output connector 16 in the depicted example vary in size along a continuum from a largest-sized aperture 24 to a smallest-sized aperture 24.

[0083] The apertures 24 are disposed within the output connector 16 and are longitudinally aligned with the air input holes 18. Thus, selective rotation of the output connector 16 relative to the main conduit body 12 can circumferentially align a selected aperture 24 with the air input hole 18. In this manner, when the largest aperture 24 of the output connector 16 is selectively aligned with the air input hole 18, a maximum or highest proportion of air is drawn through the hole 18 to mix with the gas drawn from the donor reservoir 104. When the smallest aperture 24 is selectively aligned with the air input hole 18, a minimum proportion of air is drawn through the hole 18 to mix with the gas drawn from the donor reservoir 104, and the intermediate apertures 24 allow a ratio of air drawn through the hole 18 between the minimum and maximum ratios. The output connector 16 also has a circumferential portion for aligning with the air input hole 18, which does not have an aperture 24, thereby preventing air from being drawn through the hole 18 and mixing with the gas drawn from the donor reservoir 104. In this configuration, the air does not mix with the gas drawn from the donor reservoir 104. In this configuration, the output connector 16 may alternatively be referred to as a hole adjustment member.

[0084] The gas mixing device 10 has multiple FiO2 settings and effective mechanical engagement formations 26 and 34 held by the output connector 16 and main conduit body 12, allowing the output connector, which acts as a bore adjustment member, to be disposed and held in a known rotational orientation relative to the main conduit body 12. In this embodiment, the output connector 16 has multiple engagement formations 26 with rectangular protrusions that project radially outward from a surface and are spaced circumferentially around the output connector 16. The main conduit body 12 has multiple receiving notches that form engagement formations 34 that are spaced circumferentially around the inner surface at the second end of the main conduit body 12. The spacing of the protruding engagement features 26 on the output connector 16 matches the spacing of the receiving engagement features 34, allowing the output connector 16 to be rotationally and selectively positioned relative to the main conduit body 12 to provide direct and rapid control over the size of the aperture 24 in the output connector 16 that aligns with the bore 18 in the main conduit body 12, thereby providing direct and rapid control over the effective size of the air input aperture provided through the bore 18 to allow air to be drawn in and mixed with the gas stream provided to the recipient. In this manner, selective positioning of the output connector 16 relative to the main conduit body 12 provides direct control over the inspired fraction of oxygen (FiO2), or inspired concentration of other gases, delivered to the recipient.

[0085] Additionally, as perhaps best seen in Figure 9, visual FiO2 setting indicators 36 and 38 are disposed on the output connector 16 and main conduit body 12 to provide a visual indication of the aperture setting of the output connector 16 relative to the main conduit body 12. In the non-limiting example depicted in Figure 9, the main conduit body 12 has a setting indicator 38 with an arrow, while the output connector 16 has a plurality of setting indicators 36 with numeric indicators, such as 0, 1, 2, and 3, spaced circumferentially therearound to indicate the relative size of the aperture 24 or the lack of an aperture 24 aligned with the vacant input hole 18 when the FiO2 setting indicator 36 of the output connector 16 is aligned with the setting indicator 38 of the main conduit body 12. In this manner, the effective size of the opening provided through the air input hole 18 can be adjusted in a known manner to provide rapid control over the mixing of ambient air with inspired oxygen.

[0086] Through use of the oxygen dispensing and conserving system 100 and gas mixing device 10, the patient can draw supplemental oxygen from the donor reservoir 104 through a breathing mask, through a nasal cannula 158 as disclosed herein, or through another delivery device. Alternative recipient delivery devices may include, for example, a laryngeal mask airway (LMA), an endotracheal tube, a tracheostomy, a ventilator, a CPAP machine connector, an ambu bag, or a delivery device for recreationally delivered oxygen.

[0087] The on-demand supply of naturally inspired oxygen provided by the donor reservoir 104 using the present system 100 and gas mixing device 10 overcomes many of the drawbacks and limitations presented by prior art systems. For example, many prior art systems rely on the patient's peak inspiratory flow rate (PIFR) to achieve a prescribed inspired oxygen concentration. For example, using a nasal cannula at a low continuous flow rate can be helpful when the patient requires a low inspired oxygen concentration, but this practice limits the patient's oxygen to only that low inspired oxygen concentration. If the patient's oxygen demand were to increase significantly, the inspiratory effort to force more air into the lungs, which is governed by tidal volume, inspiration "speed," and respiratory rate, would cause the PIFR to exceed the flow rate at which oxygen or oxygen / air mixture is supplied by the delivery device. This means that during the PIFR, more or less room air will be mixed in, causing the resulting FiO2 to vary unpredictably. On the other hand, using a non-rebreathing face mask with very high oxygen rates (10-15 L / min) can provide reliable delivery of oxygen at the prescribed concentration, but while less dependent on PIFR, a large amount of oxygen is wasted in the environment as oxygen continues to flow even during exhalation.

[0088] In a significant advance, the oxygen dispensing and conserving system 100 disclosed herein can passively allow the transfer of oxygen or another gas from a reservoir 104 at ambient pressure by making the gas available to the recipient in a manner that meets the exact volume and amount required by the recipient. The pressure drop due to inhalation is used to transfer volume from the reservoir 104. No additional pressure, such as opening a pressure check valve, is required to initiate flow, which may be required when the chamber or reservoir contains oxygen at a pressure higher than ambient pressure.

[0089] Furthermore, when gas mixing device 10 is utilized, direct and rapid control is provided over the ratio of oxygen to entrained air delivered during inspiration. Using such a gas mixing device 10, an ambient pressure oxygen dispensing and conserving system 100 allows for the realization of a "shadow effect," where oxygen or another gas is delivered at a desired saturation level on an as-needed basis, breath by breath, regardless of breathing frequency, volume, or other factors. System 100 rapidly and automatically adjusts to the patient's breathing pattern. By effectively sizing the openings provided for drawing air into gas mixing device 10, a constant inspired oxygen fraction (FiO2) or inspired concentration of other gases is delivered to the recipient without the need for complex mechanical or software systems. As a result, the recipient can maintain a desired blood oxygen concentration (SaO2), even during changes in breathing frequency and volume. Because dispensing and conserving system 100 is passive to the ventilation the patient receives, the patient's own breathing effectively controls the amount of oxygen delivered at any given time. Without the need for complex mechanisms or software and without repeated adjustments, the patient will automatically breathe approximately the same inspired gas concentration regardless of respiratory volume or breathing frequency.

[0090] As used herein, reference to a singular item should be understood to include a plural number of items, and vice versa, unless expressly stated otherwise or apparent from the context. Unless expressly stated otherwise or apparent from the context, grammatical conjunctions are intended to represent any and all disjunctive and conjunctive combinations of joined clauses, sentences, words, and the like. Thus, for example, the term "or" should generally be understood to mean "and / or." The recitation of ranges of values ​​herein is not intended to be limiting and, unless otherwise indicated herein, instead refers individually to any and all values ​​falling within the range, and each individual value within such range is incorporated herein as if it were individually recited herein. The terms "about," "approximately," and the like, when used in conjunction with numerical values, should be construed to indicate a variation that would be understood by one of ordinary skill in the art to operate to meet the intended purpose. Similarly, approximation terms such as "approximately" or "substantially," when used to refer to physical characteristics, should be understood to contemplate a range of variation that can be understood by one skilled in the art to operate to fulfill a corresponding use, function, or purpose. Any and all examples or exemplary terms "such as" provided herein are intended merely to better illustrate the embodiments and do not impose limitations on the scope of the embodiments. Terms in this specification should not be construed to indicate any undefined elements that are essential to implementing the embodiments. In this description, terms such as "first," "second," "top," "bottom," "upper," and "lower" are terms of convenience and should not be construed as limiting terms.

[0091] It will be appreciated that, given the specific details and embodiments of the present invention for the gas mixing device 10 and the ambient pressure oxygen delivery and conserving system 100 disclosed and operating therewith, those skilled in the art may make numerous modifications and additions thereto without departing from the spirit or scope of the present invention. This is particularly true when keeping in mind that the presently preferred embodiments are merely examples of the broad invention disclosed herein. Thus, while keeping in mind the main features of the present invention, it will be apparent that embodiments incorporating those main features may be created, and that not all features included in the preferred embodiments may be incorporated.

[0092] Accordingly, the following claims are intended to define the scope of protection afforded this invention. The claims are intended to include equivalent structures without departing from the spirit and scope of the present invention. It should be further noted that the following claims may, at times, represent or be construed to represent an element as a means for performing a particular function without reciting the structure or material. As required by law, any such claims shall be construed to cover not only the corresponding structure and materials explicitly described herein, but also their legally recognizable equivalents.

Claims

1. 1. A gas mixing device (10) for use with an ambient pressure gas delivery and conservation system (100) involving ambient pressure tubing (122) for providing ambient pressure gas from a donor reservoir (104) to a recipient, comprising: a main conduit body (12) with an internal volume, a first port for disposing in fluid communication with the donor reservoir (104), and a second port for supplying gas to a recipient; a one-way intake valve (32) disposed within the main conduit body (12) between the first and second ports, the one-way intake valve (32) operative to allow gas to be drawn from the donor reservoir (104) through the first port, through the second port, and to a recipient, and operative to prevent gas from being received into the donor reservoir (104) through the second port, through the first port; an air input hole (18) in the main conduit body (12) distal to the one-way intake valve (32) relative to the first port, the air input hole (18) operative to provide an aperture of an effective size within the interior volume of the main conduit body (12) to allow ambient air to entrain into the interior volume of the gas mixing device (10); and Ambient air can be drawn into the main conduit body (12) through the air input hole (18) and mixed with the gas drawn from the donor reservoir (104) in a ratio of ambient air to gas drawn from the donor reservoir (104); A gas mixing device (10) characterized by:

2. 2. The gas mixing apparatus (10) of claim 1, further comprising a neck connector (14) engaged with the main conduit body (12) for connecting the first port of the main conduit body (12) to the donor reservoir (104).

3. 2. The gas mixing device (10) of claim 1, further comprising a one-way valve (20) fitted to the air input port (18), the one-way valve (20) fitted to the air input port (18) allowing ambient air to be drawn into the interior volume of the main conduit body (12) but preventing gas from being exhausted through the air input port (18).

4. 2. The gas mixing device (10) of claim 1, wherein the effective size of the aperture provided by the air input hole (18) is selectively adjustable, thereby making it possible to adjust the ratio of ambient air drawn through the air input hole (18) to gas drawn from the donor reservoir (104) through the first port.

5. 5. The gas mixing device (10) of claim 4, wherein the effective size of the aperture provided by the air input hole (18) is manually selectively adjustable.

6. 6. The gas mixing apparatus of claim 5, further comprising a hole adjustment member selectively engaged with the main conduit body to overlap the air input hole, the hole adjustment member being repositionable relative to the main conduit body to adjust the effective size of the aperture provided by the air input hole into the interior volume of the main conduit body, providing direct and immediate control over the ratio of ambient air to gas drawn from the donor reservoir through the first port.

7. 7. The gas mixing device of claim 6, wherein the hole adjustment member has a plurality of apertures spaced apart from one another for selective alignment with the air input hole to adjust the effective size of the aperture provided by the air input hole and provide direct and immediate control over the ratio of ambient air to gas drawn from the donor reservoir through the first port.

8. 8. The gas mixing device of claim 7, wherein the hole adjustment member has a plurality of spaced aperture positions that establish various effective opening sizes for selective alignment with the air input hole to adjust the effective size of the aperture provided by the air input hole and provide direct and immediate control over the ratio of ambient air to gas drawn from the donor reservoir through the first port.

9. 7. The gas mixing apparatus (10) of claim 6, wherein the hole adjustment member (16) comprises a cylindrical member (16) that is selectively repositionable relative to the main conduit body (12) to overlap the air input hole (18).

10. 10. The gas mixing device (10) of claim 9, wherein the cylindrical member (16) has a plurality of differently sized holes (24) spaced apart to be selectively aligned with the air input hole (18) to adjust the effective size of the aperture provided by the air input hole (18) and to provide direct and immediate control over the ratio of air drawn through the air input hole (18) to gas drawn from the donor reservoir (104).

11. 11. The gas mixing apparatus (10) of claim 10, wherein the apertures (24) of various sizes in the cylindrical member (16) are spaced circumferentially around the cylindrical member (16).

12. 12. The gas mixing apparatus (10) of claim 11, wherein the apertures (24) of various sizes spaced about the cylindrical member (16) are sequentially varied in size.

13. 11. The gas mixing apparatus (10) of claim 10, wherein the cylindrical member (16) comprises a portion of an output connector (16) matingly engaged with the main conduit body (12), the output connector (16) further comprising a tubular portion that extends beyond the main conduit body (12) for connection to the ambient pressure tube (122) to provide gas to a recipient.

14. 14. The gas mixing apparatus (10) of claim 13, further comprising a mechanical engagement feature (26, 34) carried by at least one of the cylindrical member (16) and the main conduit body (12), which enables the cylindrical member (16) to be disposed and held in a known position relative to the main conduit body (12).

15. 15. The gas mixing apparatus (10) of claim 14, further comprising visual setting indicators (36, 38) carried by and moving with the cylindrical member (16), and at least one visual setting indicator (36, 38) carried by the main conduit body (12) to enable the effective size of the aperture provided by the air input hole (18) to be adjusted in a known manner.

16. 2. The gas mixing apparatus (10) of claim 1, further comprising an injection port (30) in the main conduit body (12) for receiving gas from a supply source (106), the injection port (30) being disposed proximal to the one-way intake valve (32) relative to the first port.

17. A gas delivery system (100) for providing gas to an individual, said gas delivery system (100) comprising: a donor reservoir (104) adapted to hold a gas and having a fully expanded state; a supply valve (112) fluidly associated with the donor reservoir (104), the supply valve having an open state that allows gas to flow into the donor reservoir (104) and a closed state that disables gas from flowing into the donor reservoir (104); an expansion detection system (156) operative to detect expansion of the donor reservoir (104) to within a predetermined range of a fully expanded state, the expansion detection system (156) operative to detect a first state in which the donor reservoir (104) is expanded to within the predetermined range of a fully expanded state and a second state in which the donor reservoir (104) is expanded to less than the predetermined range of a fully expanded state, and to actuate the supply valve (112) to an open state when the donor reservoir (104) is expanded to less than the predetermined range of a fully expanded state; a gas mixing device (10) comprising a main conduit body (12) with an internal volume, a first port for disposing in fluid communication with the donor reservoir (104), and a second port for supplying gas to a recipient; a gas mixing device (10) disposed within the main conduit body (12) between the first port and the second port, operative to allow gas to be drawn from the donor reservoir (104) through the first port, past the second port to a recipient, and gas to be drawn through the second port, past the first port to the donor reservoir; a one-way intake valve (32) operative to prevent air from being received into a reservoir (104); and an air input hole (18) in the main conduit body (12) distal to the one-way intake valve (32) relative to the first port, the air input hole (18) operative to provide an aperture of an effective size within an interior volume of the main conduit body (12) and to allow ambient air to enter the interior volume of the gas mixing apparatus (10); and Ambient air can be drawn into the main conduit body (12) through the air input hole (18) and mixed with the gas drawn from the donor reservoir (104) in a ratio of ambient air to gas drawn from the donor reservoir (104); A gas delivery system (100) comprising:

18. 18. The gas delivery system (100) of claim 17, wherein the gas delivery system (100) comprises a gas dispensing system (100) at ambient pressure, the donor reservoir (104) is adapted to hold gas at substantially ambient pressure, and the inflation detection system (156) operates the supply valve (112) to inflate the donor reservoir (104) without pressurization.

19. 18. The gas delivery system (100) of claim 17, wherein the gas mixing device (10) further comprises a one-way valve (20) fitted to the air input port (18), the one-way valve (20) fitted to the air input port (18) allowing ambient air to be drawn into the interior volume of the main conduit body (12) but preventing gas from being exhausted through the air input port (18).

20. 18. The gas delivery system (100) of claim 17, wherein the effective size of the aperture provided by the air input port (18) of the gas mixing device (10) is selectively adjustable, thereby making it possible to adjust the ratio of ambient air drawn through the air input port (18) to gas drawn from the donor reservoir (104) through the first port.

21. 21. The gas delivery system of claim 20, further comprising a hole adjustment member selectively engaged with the main conduit body to overlap the air input hole, the hole adjustment member being repositionable relative to the main conduit body to adjust the effective size of the aperture provided by the air input hole into the interior volume of the main conduit body, providing direct and immediate control over the ratio of ambient air to gas drawn from the donor reservoir through the first port.

22. 22. The gas delivery system (100) of claim 21, wherein the hole adjustment member (16) has a plurality of apertures (24) spaced apart from one another for selective alignment with the air input hole (18), adjusting the effective size of the aperture provided by the air input hole (18) and providing direct and immediate control over the ratio of ambient air to gas drawn from the donor reservoir (104) through the first port.

23. 23. The gas delivery system (100) of claim 22, wherein the hole adjustment member (16) has a plurality of aperture positions (24) spaced apart from one another that establish various effective opening sizes to be selectively aligned with the air input hole (18), adjusting the effective size of the aperture provided by the air input hole (18) and providing direct and immediate control over the ratio of ambient air to gas drawn from the donor reservoir (104) through the first port.

24. 22. The gas delivery system (100) of claim 21, wherein the hole adjustment member (16) comprises a cylindrical member that is selectively repositionable relative to the main conduit body (12) to overlap the air input hole (18).

25. 25. The gas delivery system (100) of claim 24, wherein the cylindrical member (16) has a plurality of differently sized holes (24) spaced apart to be selectively aligned with the air input hole (18) to adjust the effective size of the aperture provided by the air input hole (18) and to provide direct and immediate control over the ratio of air drawn through the air input hole (18) to gas drawn from the donor reservoir (104).

26. 25. The gas delivery system (100) of claim 24, wherein the cylindrical member (16) comprises a portion of an output connector (16) matingly engaged with the main conduit body (12), the output connector (16) further comprising a tubular portion that extends beyond the main conduit body (12) for connection to an ambient pressure tube (122) to provide gas to a recipient.

27. 27. The gas delivery system (100) of claim 26, wherein the gas delivery system (100) comprises a mechanical engagement arrangement (26, 34) carried on at least one of the cylindrical member (16) and the main conduit body (12) to enable the cylindrical member (16) to be disposed and held in a known position relative to the main conduit body (12).

28. 18. The gas delivery system (100) of claim 17, further comprising an injection port (30) in the main conduit body (12) of the gas mixing device (10) for receiving gas from a supply source (106), the injection port (30) being disposed proximal to the one-way intake valve (32) relative to the first port.

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