Patent Application
20080110462
The present disclosure relates generally to oxygen delivery, and more particularly to a system and method for optimizing the delivery of oxygen having a desired level of purity.
Prior oxygen delivery systems have been configured to deliver oxygen at a constant flow rate or in pulses having a fixed duration and/or fixed valve timing based upon a predetermined flow setting.
Constant flow oxygen delivery systems provide output during periods of patient inhalation, exhalation, and therebetween. It is recognized that substantially oxygen-rich fluid provided at times other than during patient inhalation is generally inefficient, and, in some instances, may waste the oxygen-rich fluid. Additionally, due to the constant operation of constant flow oxygen delivery systems, power consumption may be higher than necessary; and if battery-operated, this may result in reduced battery life of the oxygen delivery system.
Previous oxygen delivery systems configured to output fixed-duration and/or fixed-timing pulses of substantially oxygen-rich fluid have been regulated by a flow setting, which may be manually input. Such fixed-duration and/or fixed-timing systems may suffer from shortcomings similar to those of the constant flow oxygen delivery systems. More specifically, the pulses are output at predetermined intervals and/or for a predetermined duration. Thus, the pulses of substantially oxygen-rich fluid may not be delivered during patient inhalation, when the fluid may be optimally received and utilized by the patient. As such, oxygen delivery systems that output fixed-duration and/or fixed-timing pulses also may be relatively inefficient with respect to the amount of oxygen inhaled by the patient as compared to the amount of substantially oxygen-rich fluid generated and output.
As such, it would be desirable to provide an improved system and method for optimizing the delivery of substantially oxygen-rich fluid.
An oxygen delivery system includes a supply fluid containing oxygen. The system further includes first and second sieve beds, each sieve bed in selective fluid communication with the supply fluid and configured to selectively receive the supply fluid during a predetermined supply period. Each of the first and second sieve beds is further configured to separate a substantially oxygen-rich fluid from the supply fluid. A patient conduit having a patient outlet is in alternate selective fluid communication with the first and second sieve beds. The oxygen delivery system includes a breath-detection device in fluid communication with the patient conduit, which breath detection device may be configured to measure a rate of breathing. The breath-detection device is configured to trigger an output, in response to a breath detection, of a predetermined volume of the substantially oxygen-rich fluid alternately from a respective one of the first sieve bed or the second sieve bed, the output having a target flow rate and a flow rate. The oxygen delivery system also includes a device in fluid communication with patient conduit, the device configured to measure the output flow rate at predetermined intervals. The predetermined volume is output via the patient outlet during a respective dynamically adjusted patient oxygen delivery phase. The dynamically adjusted patient oxygen delivery phase is dependent upon the target flow rate, the output flow rate, and/or the breathing rate.
Features and advantages of the present disclosure will become apparent by reference to the following detailed description and drawings, in which like reference numerals correspond to similar, though not necessarily identical components. For the sake of brevity, reference numerals or features having a previously described function may not necessarily be described in connection with other drawings in which they appear.
Embodiment(s) of the oxygen delivery system disclosed herein advantageously provide oxygen to a patient during a dynamically adjusted oxygen delivery phase. A supply fluid is selectively provided alternately to two sieve beds, which are configured to separate a substantially oxygen-rich fluid from the supply fluid. The sieve beds may alternately provide the substantially oxygen-rich fluid to a patient in response to a breath inhalation. As such, embodiment(s) of the hereindescribed oxygen delivery system may provide a patient with a substantially pulse of oxygen of a desired purity, and/or may substantially prevent the delivery of a pulse having a relatively low oxygen level, while optimizing timing to allow synchronization with a patient breathing rate, including a substantially fast breathing rate.
Referring to
As depicted in
Additionally, the first 22 and second 26 supply conduits may be configured with first 30 and second 34 supply valves, respectively. It is to be understood that when one of the first 14 or second 18 purifying systems are receiving the supply fluid, the respective one of the first 30 or second 34 supply valves is in an open position. In an embodiment, the supply valves 30, 34 are configured as two-way supply valves.
The first 30 and second 34 supply valves are configured to direct the supply fluid to a respective one of the first 14 or second 18 purifying systems at a particular time. As such, in an embodiment, when the supply fluid is directed to one of the first 14 or second 18 purifying systems, the supply fluid is prevented from flowing to the other of the second 18 or the first 14 purifying systems. It is contemplated, however, that in addition to the first 30 and second 34 supply valves preventing the supply fluid from flowing to both the first 14 and second 18 purifying systems at the same time, the first 30 and second 34 supply valves may also prevent the supply fluid from flowing to either of the first purifying system 14 or the second purifying system 18 at a particular time, as desired.
Referring again to
In an embodiment, the first and second sieve beds 14, 18 are configured to separate the fluid by utilizing pressure swing adsorption (PSA). As such, in an embodiment, the supply fluid is air, and the first and second sieve beds 14, 18 are each configured to substantially adsorb at least nitrogen out of the air to substantially separate the oxygen in the air from at least the nitrogen.
As used herein, substantially oxygen-rich fluid is to be understood to include a fluid comprising a majority of breathable oxygen. In an embodiment, the substantially oxygen-rich fluid is a gas. As a non-limiting example, the substantially oxygen-rich fluid is a gas containing from about 70% oxygen by volume to about 100% oxygen by volume. In an alternate embodiment, the substantially oxygen-rich fluid is a gas containing from about 82% oxygen by volume to about 98% oxygen by volume. In yet a further alternate embodiment, the substantially oxygen-rich fluid contains at least about 87% oxygen by volume.
A patient conduit 38 having a patient outlet 42 is in alternate selective fluid communication with the first and second sieve beds 14, 18. As an example, the patient conduit 38 may be formed at least partially from flexible plastic tubing. In an embodiment, the patient conduit 38 is configured substantially in a “Y” shape. As such, the patient conduit 38 may have a first conduit portion 38′ and a second conduit portion 38″, which are in communication with the first sieve bed 14 and second sieve bed 18, respectively, and merge together before reaching the patient outlet 42, as depicted in
As depicted in
Referring yet again to
In an embodiment, the duration of the dynamically adjusted patient oxygen delivery phase is dependent upon at least one of the output target flow rate, the output flow rate, the breathing rate, or combinations thereof. In an alternate embodiment, the duration of the dynamically adjusted patient oxygen delivery phase is dependent upon each of the output target flow rate, the output flow rate (e.g., as detected via flow-sensor feedback), and the breathing rate.
The duration of the dynamically adjusted patient oxygen delivery phase may be calculated, in one embodiment, taking into account the target flow rate. For each equivalent of Liter Per Minute (LPM) of flow of substantially oxygen-rich fluid desired, the system 10, 10′ is configured to deliver a pulse of about 8.5 milliliters (mL). As such, if the system 10, 10′ is set to deliver 2 LPMe of flow, each breath inhalation will trigger a pulse of the substantially oxygen-rich fluid that, when integrated, totals about 17 mL. The pulse size may be further calculated based upon the integration of the actual flow rate (LPM) versus time. This integration is performed by monitoring the output flow rate at predetermined intervals (e.g., every millisecond) and summing the monitored samples. The sum of the samples may be divided by the number of samples monitored per minute to convert the units to Liters. As such, in an embodiment, the pulse size is equal to the total of the sampled flow rates divided by (1000*60).
Since the separating/purifying process (e.g., a PSA process) requires a certain pressure for a fixed sieve bed size and target pulse size, the inlet pressure to the sieve beds 14, 18 is generally increased as breathing rate increases, and decreased as breathing rate decreases. For this reason, in embodiment(s) of the present disclosure, the speed of the motor (not shown) driving the air compressor 28 is advantageously, dynamically changed as needed to achieve the desired peak pressure inside each respective sieve bed 14, 18 to generate the target pulse size.
Following a dynamically adjusted patient oxygen delivery phase from the first 14 or second 18 sieve bed, breath detection may be masked for a predetermined masking time, for example, during the dynamically adjusted oxygen delivery phase and during a predetermined amount of time following the delivery phase. It is understood that such predetermined masking time may be configured to prevent the triggering of another dynamically adjusted patient oxygen delivery phase before sufficient substantially oxygen-rich fluid is available from the other of the second 18 or first 14 sieve bed. As used herein, sufficient substantially oxygen-rich fluid may be a pulse having a desired oxygen content. The predetermined masking time may be very short in duration. As a non-limiting example, the predetermined masking time may be about 500 milliseconds in length. In an embodiment, this masking time may also be dynamically adjusted based on the average breath rate. Further, in order to accommodate a maximum breathing rate of 30 Breaths Per Minute (BPM), a maximum mask time of 2 seconds may be used.
The breath-detection device 54 may include a pressure sensor configured to monitor the pressure of the substantially oxygen-rich fluid. More specifically, the pressure sensor may be configured to measure the pressure of the substantially oxygen-rich fluid in the patient conduit 38, for example, substantially near the patient outlet 42. Further, a system component, such as, for example, the breath-detection device 54 and/or a controller connected to the pressure sensor, may be configured to associate a predetermined drop in pressure of the substantially oxygen-rich fluid with a breath inhalation. A typical pressure drop may be, for example, less than 1 in. H2O.
Further, the breath-detection device 54 and/or a suitable device connected thereto may be configured to calculate the rate of breathing based upon detected breath inhalations. The breathing rate may be detected based upon the monitoring of the pressure of the substantially oxygen-rich fluid in the patient conduit 38, particularly near the patient outlet 42. An exhalation generally follows each inhalation, and, thus, detection of each inhalation may be associated with a complete breath. As used herein, a rate of breathing may be defined as a number of breaths per minute, wherein one breath includes an inhalation and an exhalation.
The system 10, 10′ may be configured to monitor the inhalations detected by the breath-detection device 54. The system 10, 10′ may further include an alert system 58 configured to emit an alarm if the breath-detection device 54 fails to detect an inhalation within a predetermined amount of time. The alarm may be embodied as an aural alarm, a visual alarm, and/or a tactile alarm. As non-limiting examples, the predetermined amount of time may range from about 15 seconds to about 30 seconds.
The alert system 58 may be in operative communication with the breath-detection device 54 via a wired communication system 62 and/or a wireless communication system 66. As non-limiting examples, the wireless communication system 66 may utilize radio frequency (RF) communication and/or infrared communication.
In an embodiment, if an inhalation is not detected within a predetermined detection time (e.g., if the patient is disconnected from the system 10, 10′), the system 10, 10′ may be configured to enter a suspend mode, which may be configured to reduce power consumption for example, by reducing motor speed in the compressor 28. As non-limiting examples, the predetermined detection time may be five minutes, ten minutes, fifteen minutes, or twenty minutes, etc. When a system 10, 10′ enters suspend mode, substantially oxygen-rich fluid located in the first 14 or second 18 sieve beds may be held therein until a next inhalation is detected.
A device 70 may be in fluid communication with the patient conduit 38 and is configured to measure the output flow rate of the substantially oxygen-rich fluid. In an embodiment, the device 70 is configured to measure the output flow rate at predetermined intervals. Generally, the predetermined intervals may be dependent on various factors, e.g., the capabilities of the microprocessor (not shown) being used, the target accuracy of the measurement, and/or the like. In an example, the predetermined intervals may range from microseconds to about 50 milliseconds. As a non-limiting example, the predetermined intervals may be about every millisecond.
Referring again to
Referring back to
The transmission of the remaining amount/portion thereof of the substantially oxygen-rich fluid from one of the sieve beds 14 to the other of the sieve beds substantially after a dynamically adjusted oxygen delivery phase may be referred to as “counterfilling.” It is to be understood that the remaining amount may be any suitable amount of substantially oxygen-rich fluid remaining in the first 14 or second 18 sieve bed following the delivery of oxygen-rich fluid from the first 14 or second 18 sieve bed to the patient conduit 38. In an embodiment, the at least a portion of the remaining amount is substantially the entire amount of oxygen-rich fluid remaining in the first 14 or second 18 sieve bed; whereas, in an alternate embodiment, it is less than the entirety of the amount of oxygen-rich fluid remaining in the first 14 or second 18 sieve bed after the dynamically adjusted oxygen delivery phase.
In an embodiment, the duration of a counterfill may be dynamically adjusted. As such, a counterfill duration may be calculated for a flow setting and a predetermined breathing rate, e.g., an average breathing rate. As an example, the average breathing rate may be determined by calculating an average of the time duration between the prior five inhalations. In another example, the number of prior inhalations may be larger (for example, ten) or smaller (for example, three), as desired. In an embodiment, the counterfill duration ranges between about 400 milliseconds (mS) and about 800 mS. In an alternate embodiment, the counterfill duration is about 600 mS. A flow valve isolation time may be utilized substantially before and/or after the counterfill duration, as desired.
Counterfilling may be advantageous in that it hastens the availability of substantially oxygen-rich fluid (e.g., air having a desired level of oxygen content) from the respective sieve bed 14, 18 being counterfilled.
Referring again to
Referring yet again to
The first 14 and second 18 sieve beds may purge via the first purge conduit 94 and the second purge conduit 98, respectively. As used herein, “purging” is to be interpreted broadly to include purging substantially all of the oxygen-depleted fluid from the system 10, 10′, as well as purging a portion (i.e., less than all) of the oxygen-depleted fluid.
Referring again to
The first 102 and second 106 purge valves may direct the fluid being purged substantially out of the system 10′ via a muffler 110. The muffler 110 may be configured to reduce noise created by the purging fluid.
The oxygen delivery system 10′ may further include a filtration system 114. The filtration system 114 substantially filters particulate matter from the supply fluid and/or the substantially oxygen-rich fluid, depending upon the location of the filtration system 114 within the system 10′. In an embodiment, the filtration system 114 includes a HEPA filter. The system 10′ may yet further include a pressure relief valve (as depicted), if desired.
Referring now to
The method 200 also includes delivering, to a patient conduit 38 in alternate selective fluid communication with the first purifying system 14 and the second purifying system 18, an output (in response to a breath inhalation) of the substantially oxygen-rich fluid from the first purifying system 14 or the second purifying system 18 during a dynamically adjusted oxygen delivery phase, as depicted at reference numeral 204. The method 200 further includes purging the substantially oxygen-depleted fluid from the other of the second purifying system 18 or the first purifying system 14 substantially during the predetermined supply period and the dynamically adjusted oxygen delivery phase, as depicted at reference numeral 206.
The method 200 further includes selectively supplying, during the predetermined supply period, the supply fluid from the other of the second purifying system 18 or the first purifying system 14, and delivering, to the patient conduit 42, another output of the substantially oxygen-rich fluid from the other of the second purifying system 18 or the first purifying system 14. The substantially oxygen-rich fluid may be output during another dynamically adjusted oxygen delivery phase in response to another breath inhalation.
Further, the method 200 includes purging the substantially oxygen-depleted fluid from the first purifying system 14 or the second purifying system 18 substantially during the other predetermined supply period and the other dynamically adjusted oxygen delivery phase.
Yet further, the method 200 may include transmitting, from the respective purifying system 14, 18, at least a portion of a remaining amount of the substantially oxygen-rich fluid to the other respective purifying system 18, 14. The remaining amount may be transmitted after the respective dynamically adjusted oxygen delivery phase.
An example embodiment of a method 300 of delivering a substantially oxygen-rich fluid from an oxygen delivery system 10 having first (A) 14 and second (B) 18 purifying systems is depicted in the state diagram of
The system 10 monitors for an inhalation, as depicted at reference numeral 304. If an inhalation is not detected within the predetermined detection time, the system 10 enters suspend mode, as depicted at reference numeral 306. If an inhalation is detected within the predetermined detection time, an output of the substantially oxygen-rich fluid is selectively delivered from the first purifying system (A) 14 to a patient conduit 38, as depicted at reference numeral 308. The output is delivered during a dynamically adjusted oxygen delivery phase, as depicted at reference numeral 310.
While the first purifying system (A) 14 receives and separates the supply fluid, and delivers the substantially oxygen-rich fluid, the second purifying system (B) 18 is configured to substantially purge the substantially oxygen-depleted fluid therein. Next, a predetermined remaining amount of the substantially oxygen-rich fluid is transmitted (counterfilled) from the first purifying system (A) 14 to the second purifying system (B) 18, as depicted at reference numeral 312. The duration of the counterfill may be dynamically calculated (as described hereinabove), as depicted at reference numeral 314.
Next, the supply fluid is supplied to the second purifying system (B) 18 and separated into a substantially oxygen-rich fluid and a substantially oxygen-depleted fluid, as depicted at reference numeral 316. The system 10 monitors for another inhalation, as depicted at reference numeral 318. If an inhalation is not detected within the predetermined detection time, the system 10 enters suspend mode, as depicted at reference numeral 320. If an inhalation is detected within the predetermined detection time, an output of the substantially oxygen-rich fluid is selectively delivered from the second purifying system (B) to the patient conduit 38, as depicted at reference numeral 322. The output is delivered during a dynamically adjusted oxygen delivery phase, as depicted at reference numeral 324.
While the second purifying system 18 receives and separates the supply fluid, and delivers the substantially oxygen-rich fluid, the first purifying system 14 is configured to substantially purge the substantially oxygen-depleted fluid remaining therein. Next, at least a portion of a remaining amount of the substantially oxygen-rich fluid is transmitted (counterfilled) from the second purifying system (B) 18 to the first purifying system (A) 14, as depicted at reference numeral 326. The duration of the counterfill may be dynamically calculated (as described hereinabove), as depicted at reference numeral 328. The method 300 repeats, as desired.
It is to be understood that the terms “connect/connected/connection” and/or the like are broadly defined herein to encompass a variety of divergent connected arrangements and assembly techniques. These arrangements and techniques include, but are not limited to (1) the direct communication between one component and another component with no intervening components therebetween; and (2) the communication of one component and another component with one or more components therebetween, provided that the one component being “connected to” the other component is somehow in operative communication with the other component (notwithstanding the presence of one or more additional components therebetween). Additionally, two components may be permanently, semi-permanently, or releasably engaged with and/or connected to one another.
While several embodiments have been described in detail, it will be apparent to those skilled in the art that the disclosed embodiments may be modified. Therefore, the foregoing description is to be considered exemplary rather than limiting.
