Oxygen sensor compensation for mechanically ventilated patient oxygen fractional drift

Abstract

One embodiment includes a respirator system that corrects oxygen sensor measurements, such as measurements derived from an oxygen sensor in a mixing chamber of an indirect calorimeter or oxygen consumption (VO2) monitoring device. In one example, an embodiment determines an inhaled oxygen fraction drift provided by a respirator and corrects a VO2 determination made by the system using a change or rate of change in the inhaled oxygen fraction over time.

Description

Cross-reference to related applications

[0001] This patent application claims priority to U.S. Provisional Application No. 63 / 469,584, filed May 30, 2023, pursuant to 35 USC §119(e), the contents of which are incorporated herein by reference. Technical Field The disclosed topics generally relate to correcting oxygen sensor measurements used to determine oxygen consumption (VO2) with greater accuracy. Some disclosed topics relate to the use of corrections for measured oxygen (e.g., the fraction of inhaled oxygen, FiO2) sensed in the mixing chamber of an indirect calorimetric system, which is included, for example, in a patient ventilation circuit. Background Technology

[0002] Oxygen consumption (VO2) is a clinically important measure in the management of acute patients, such as those requiring mechanical ventilation with a fractional oxygen inhaled (FiO2) higher than ambient (i.e., FiO2 greater than 21%). Oxygen consumption has several clinical applications, including infection detection, nutritional management, and hemodynamic and ventilation management. Furthermore, oxygen consumption measurement is of particular interest in critically ill patients because it is closely related to the transport of oxygen from the lungs to the tissues that need it. Therefore, oxygen consumption monitoring provides important insights into a patient's cardiovascular and metabolic status.

[0003] Oxygen consumption is defined as the difference between the volume of inhaled and exhaled oxygen. The volume of inhaled and exhaled oxygen can be calculated (by direct or indirect measurement) to infer oxygen consumption. Typically, oxygen consumption monitoring equipment includes a mixing chamber for measuring gas concentration, in which inhaled and exhaled gases are sampled. Contained within this mixing chamber are gas measurement sensors (oxygen, nitrogen, and / or carbon dioxide sensors), flow sensors, and sensors for compensating for pressure, temperature, and relative humidity.

[0004] Techniques such as Haldane transformation (nitrogen-based normalization) can calculate oxygen consumption using measurements of inhaled oxygen fraction (FiO2), inhaled carbon dioxide fraction (FiCO2), exhaled oxygen fraction (FeO2), and exhaled carbon dioxide fraction (FeCO2) recorded by a mixing chamber sensor. In some systems, inhaled and exhaled gas concentrations sampled at different times are used to calculate oxygen consumption. Summary of the Invention

[0005] In supplemental oxygen systems, such as patient ventilators used for invasive patient ventilation, oxygen consumption is calculated using inhaled and exhaled gas concentrations sampled at different times. Oxygen consumption calculations using methods such as the Haldane transformation become inaccurate in such systems because this method assumes that gas concentration measurements are simultaneous, which does not account for any variations in the supplied oxygen—a situation not present for both inhalation and exhalation measurements. This temporal discontinuity in gas concentration measurements leads to errors in the determination of oxygen consumption, particularly in the case of supplemental oxygen supply, where oxygen consumption is measured as the fractional oxygen inhaled (FiO2) variably supplied by the ventilator.

[0006] Therefore, the embodiments overcome the problems of time-separated inhaled and exhaled gas concentration measurements, especially in the case of the variability of supplemental oxygen (“FiO2 drift”). By taking these factors into account, the embodiments eliminate the dependence of oxygen consumption measurement accuracy on the stability of FiO2 values.

[0007] In summary, one embodiment provides a ventilator system comprising: a ventilator including a first sensor; one or more mixing chambers; one or more other sensors disposed in the one or more mixing chambers; a collection of one or more processors; and a non-transitory storage medium storing code executable by the collection of one or more processors. In one embodiment, the code includes code for obtaining a first inhaled oxygen fraction (FiO2) value of the breathable gas provided to the patient by the ventilator, measured by the first sensor at a first time, and a second FiO2 value of the breathable gas provided to the patient by the ventilator, measured by the first sensor at a second time. The code also includes code for obtaining a third FiO2 value of the breathable gas provided to the patient by the ventilator, measured by one or more other sensors at a first time, and code for obtaining an exhaled oxygen fraction (FeO2) value of the breathable gas exhaled by the patient, measured by one or more other sensors at a second time.

[0008] In one embodiment, the code includes determining the FiO2 change between a first FiO2 value and a second FiO2 value, determining a correction for one or more of a third FiO2 value and an FeO2 value based on the determined FiO2 change, and adjusting one or more of the third FiO2 value and the FeO2 value based on the correction.

[0009] In one embodiment, the system includes code for determining the difference between: (a) a third FiO2 value and an adjusted FeO2 value; (b) an adjusted third FiO2 value and an FeO2 value; or (c) an adjusted third FiO2 value and an adjusted FeO2 value. In one embodiment, the code includes code for determining the patient's oxygen consumption based on the difference.

[0010] In one embodiment, the first time period occurs during a first time interval including patient inhalation, and the second time period occurs during a second time interval including patient exhalation. In one embodiment, the first time period includes a first time sampling window, wherein the first and third FiO2 values ​​are averages over the first time sampling window. In one embodiment, the second time period includes a second time sampling window, wherein the second FiO2 value and the FeO2 value are averages over the second time sampling window.

[0011] In one embodiment, the adjustment code includes code to output a correction value to increase or decrease the third FiO2 value by a magnitude equal to the difference between the first FiO2 value measured at a first time and the second FiO2 value measured at a second time.

[0012] In one embodiment, the determined correction code includes a code identifying the real-time change of a first FiO2 value provided by a first sensor over time. In one embodiment, the real-time change value is derived from a time series of oxygen measurements performed by the first sensor, including oxygen measurements taken at first and second times.

[0013] In one embodiment, the first and second time sampling windows each include multiple respiratory cycles of the patient, and the first and second times are separated by multiple respiratory cycles.

[0014] Another embodiment provides a computer-implemented method for performing actions using one or more processors that execute instructions, comprising: obtaining a first fractional inhaled oxygen concentration (FiO2) value of a breathable gas supplied to a patient by a ventilator, measured by a first sensor at a first time; obtaining a second FiO2 value of the breathable gas supplied to the patient by the ventilator, measured by the first sensor at a second time; obtaining a third fractional FiO2 value of the breathable gas supplied to the patient by the ventilator, measured by one or more other sensors at a first time; obtaining an exhaled fractional oxygen concentration (FeO2) value of a breathable gas exhaled by the patient, measured by one or more other sensors at a second time; determining a FiO2 change between the first FiO2 value and the second FiO2 value; determining a correction for one or more of the third FiO2 value and the FeO2 value using a set of one or more processors based on the determined FiO2 change; and adjusting one or more of the third FiO2 value and the FeO2 value based on the correction.

[0015] In one embodiment, the method includes performing actions on a ventilation system or its components, as described herein.

[0016] Another embodiment provides a computer program product comprising: a non-transitory storage medium storing code executable by a collection of one or more processors, the code including code contained in a ventilator system or a component operatively coupled thereto, as described herein.

[0017] As will become apparent from reading this specification, methods, apparatuses, systems, and products for implementing various embodiments are provided.

[0018] The foregoing is an overview and may therefore contain simplifications, generalizations and omissions of details; therefore, those skilled in the art will understand that the overview is merely illustrative and not intended to be limiting in any way.

[0019] These and other features and characteristics of the exemplary embodiments, as well as the operation and function of the related elements of the structure and their combinations thereof, will become more apparent after considering the following description and appended claims with reference to the accompanying drawings, all of which form part of this specification. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to be construed as limiting the invention. Attached Figure Description

[0020] Figure 1 An example method according to one embodiment is shown.

[0021] Figure 2 An example system according to one embodiment is shown.

[0022] Figure 3 An example oxygen measurement correction according to one embodiment is shown.

[0023] Figure 4 A diagram of example system components according to one embodiment is shown. Detailed Implementation

[0024] As used herein, the singular forms of “a,” “an,” and “the” include plural references unless the context clearly specifies otherwise. As used herein, the expression “coupled” means that these parts are directly or indirectly (e.g., through one or more intermediate parts or components) connected or operating together, provided a link exists. As used herein, “operably coupled” means that two or more elements are coupled to operate together or communicate unidirectionally or bidirectionally with each other. As used herein, the term “number” should mean an integer of one or more (i.e., a plurality). As used herein, “set” should mean one or more.

[0025] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to provide a thorough understanding of the embodiments. However, those skilled in the art will recognize that various embodiments can be practiced without one or more specific details, or using other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid confusion.

[0026] In contrast to known techniques that rely on the simultaneous measurement of inhaled oxygen fraction (FiO2) and exhaled oxygen fraction (FeO2) (i.e., FiO2 is constant or measured simultaneously with FeO2) to determine oxygen consumption (VO2), the embodiments determine variations in delivered FiO2 and compensate for the measured oxygen concentration to reduce errors in VO2 calculation. The positive effects of the disclosed embodiments on VO2 determination are illustrated in an example from a VO2 monitoring device designed for mechanically ventilated patients. The example VO2 monitoring device includes a mixing chamber that intermittently exchanges air between the inspiratory and expiratory branches of the breathing circuit. The example monitoring device uses the Haldane transformation to calculate VO2. Therefore, the embodiments can be advantageously used to eliminate errors caused by variations in FiO2.

[0027] The description will now turn to the accompanying drawings. The exemplary embodiments shown will be best understood with reference to the drawings. The following description is intended only by way of example and simply illustrates certain exemplary embodiments.

[0028] refer to Figure 1 The examples are used to determine the change of FiO2 over time, for example, by combining Figure 3 The time periods A and B are specified. The benefit of this determination is that it provides a defined FiO2 required to compensate for the variation in inhaled oxygen concentration measured by the mixing chamber.

[0029] In one embodiment, changes in FiO2 are determined, for example, by obtaining baseline measurements from the oxygen sensor of the ventilator. Figure 1 In the example, at a first time, such as during inspiration, a first value of FiO2 is obtained from a first sensor (e.g., an oxygen sensor of a ventilator) as shown in 101. It should be noted that the first value of FiO2 can be an instantaneous value or a point value, or a total or average value over a time period or time window. Similarly, in 102, a second value of FiO2 is obtained from the sensor at a second time, such as during expiration from an oxygen sensor of a ventilator. Like the first value, the second value can be a single value or a point-in-time value or an average value. It should be noted here that although a ventilator oxygen sensor is used as an example, the first sensor can take other forms, such as using a separate oxygen sensor associated with a component of the ventilation system (such as the inspiratory branch of a patient circuit).

[0030] At 103, it is determined whether a change or drift is detected in the FiO2 measurement results between the first and second time points. If FiO2 has changed, the embodiment may determine a correction to FiO2 to provide oxygen consumption values ​​indicated at 104 and 105, respectively. If FiO2 has not changed (no drift exists), the embodiment may continue to determine oxygen consumption without correction.

[0031] Figure 2 An example ventilator system according to one embodiment is shown. Here, a mechanical ventilator 210 is shown, which is operatively coupled to a patient 260 using a patient circuit including an inspiratory branch 220 and an expiratory branch 230. An inspiratory-side mixing chamber 250 and its associated oxygen sensor 250a, and an expiratory-side mixing chamber 240 and its associated oxygen sensor 240a are shown with corresponding sampling lines. Note that a single mixing chamber can be used to switch its sampling between inspiratory and expiratory positions.

[0032] Supplemental FiO2 is delivered to patient 260 via mechanical ventilator 210. One or more mixing chambers 240, 250 of VO2 monitoring device 270 used with ventilator 210 measure the inhaled oxygen concentration (e.g., FiO2 in mixing chamber 250) during time interval A (for inhalation) and the exhaled oxygen concentration (e.g., FeO2 in mixing chamber 240) during time interval B (for exhalation).

[0033] refer to Figure 3 The illustration shows an example of FiO2 drift correction. It can be noted that the two measurements of FiO2 indicated at 301 and 302 respectively indicate a change of almost 1% in FiO2 (e.g., measured by the oxygen sensor of ventilator 210 as delivered from ventilator 210). The measurements indicated at 301a and 302a represent a change in FiO2 that will be reflected in the measurements in (multiple) mixing chambers 240, 250 between the first sampling time during interval A for inhalation mixing chamber 250 and when mixing chamber 240 begins sampling (for exhalation measurement) of exhaled gas during time interval B. In one embodiment, in Figure 3 The change in delivered FiO2, represented by the "delta" near time interval B, can be determined as a difference in FiO2, for example, the difference between the averages of FiO2 measurements or values ​​for 301 and 302 during times A and B, respectively. Determining this change can guide the correction of embodiments measuring oxygen concentration in mixing chambers(s) 240, 250, for example, correcting the FiO2 value of inhaled oxygen, as indicated by applying the delta to measurement result 301a to produce value 303, thereby helping to increase the reliability of VO2 measurements.

[0034] As an example, the embodiment can correct for FiO2 values ​​to address drift in FiO2 delivered from ventilator 210, thereby increasing the reliability of VO2 measurements. This is important because the concentration of inhaled oxygen varies in many systems delivering supplemental oxygen. Mixing chambers, such as 240 and 250, allow the volume of oxygen flowing through them to be calculated by measuring the oxygen concentration (if chamber 240 is exposed to exhaled gas, the volume of oxygen in exhaled gas is measured; if chamber 250 is exposed to inhaled gas, the volume of oxygen inhaled gas is measured). As described herein, VO2 is calculated as the volume difference between inhaled and exhaled oxygen. However, the mixing chambers(s) in VO2 monitoring device 270 are exposed to both inhaled and exhaled gases at different times during each respiratory cycle. FiO2 variations (emanating from ventilator 210), along with sampling of the mixing chambers for inhaled and exhaled gases at different times, result in a determination of VO2 that is inconsistent with the patient's actual oxygen consumption. One embodiment is designed to correct for changes in delivered FiO2 (Δ FiO2 drift) proportionally to the variation in delivered FiO2 (Δ FiO2 drift). Figure 2 In the example system, the inhaled oxygen concentration is measured by the mixing chamber 250 containing the oxygen sensor 250a, such that the corrected FiO2 of the mixing chamber 250 reflects the actual FiO2 when the mixing chamber 240 samples the exhaled gas (time period B).

[0035] Using an example test bed equipped with a VO2 monitoring device (e.g., monitoring device 270 shown), calibration (using Haldane transformation) was used to verify that VO2 is calculated as the difference between the volume of inhaled oxygen measured during time intervals A and B, respectively, and the volume of exhaled oxygen, as shown in the following equation:

[0036] in: - Expiratory minute ventilation - Inhaled oxygen concentration measured by the mixing chamber during time interval A - : Expiratory oxygen concentration measured by the mixing chamber during time interval B - As described herein, given a FiO2 supplement, the FeO2 measured by mixing chamber 240 involves different values ​​of FiO2, and the calculated VO2 should be corrected for this difference, i.e., for variations due to time variations or FiO2 drift caused by fan 210. Appropriate correction includes subtracting, for example, from the FiO2 measured at time period B in mixing chamber 240. Figure 1The difference was detected at 103. Then, by adjusting the measurement results provided by the mixing chamber 240, VO2 can be calculated using the corrected FiO2 measurement results. In one embodiment, VO2 is therefore determined by: in:

[0037] Figure 3 This correction for FiO2 was visually depicted to address ventilator drift in systems that, for example, use the same or different mixing chambers to measure inhaled and exhaled oxygen at different times. Figure 3 The example provides simulated patient data, and as shown in the figure, it is generated by... Figure 3 The "change" near time interval B in the table represents a change or drift in the FiO2 supplied by the ventilator, which is offset by a change, adjustment, or correction to the FiO2 value indicated at 301a. That is, a change or drift in the supplied FiO2 can be detected by measuring (point or average) FiO2 at times A and B, which in this example represents a negative change or decrease in FiO2 supplied by the ventilator between time A and time B. Therefore, the correction for FiO2 at time A (by...) Figure 3 The change in FiO2 delivered by the ventilator (represented by, for example, 301a) is used to calculate VO2. Therefore, value 303 represents an alternative, synthetic, or analog value of O2 measured in (multiple) mixing chambers (e.g., mixing chamber 240 in time period A), which can be used to correct the VO2 system (and corresponding oxygen sensor measurements) based on simultaneous or constant FiO2 measurements, for example, in patient ventilation systems requiring correction due to the provision of supplemental but varying FiO2. In this respect, it should be noted that although... Figure 3 An example correction of oxygen sensor measurements at time A is shown, but in one embodiment, corrections can be made using one or more oxygen sensor measurements. For example, in one embodiment, corrections to one or more of the FiO2 and FeO2 values ​​can be determined based on determined FiO2 changes. Furthermore, adjustments to one or more of the FiO2 and FeO2 values ​​based on corrections can be applied, as long as changes or drift in the FiO2 value are taken into account.

[0038] Table 1 illustrates the measurement effectiveness of the proposed embodiment in terms of VO2 determination accuracy and compares it with baseline-fact measurements on a test bench consisting of a mechanical ventilator and test lungs modified to accommodate metabolic gases (O2 and CO2). In the test bench, a highly precise mass flow controller delivers constant amounts of O2 and CO2 into the test lungs, resulting in realistic O2 and CO2 exhalation waveforms that indicate O2 production rather than consumption. Although the signs are reversed, the resulting VO2 is a reliable baseline fact against which devices and algorithms used for its measurement can be tested and evaluated. The VO2 determined relative to baseline-fact measurements is significantly improved by correcting for changes in measured oxygen levels given ventilator drift (Δ). Therefore, one embodiment helps correct for VO2 changes in delivered FiO2, resulting in robust VO2 monitoring device performance independent of the need for a stable (constant) oxygen supply.

[0039] Table 1: Test bench error percentage

[0040] The reduced error in VO2 has numerous practical applications. For example, embodiments can provide more accurate VO2 measurements that impact decision support systems. For instance, if VO2 measurements are used to adjust nutritional therapy, an uncorrected VO2 reading could lead to a significant reduction (e.g., halving) in the amount of calories given to the patient compared to their actual needs, resulting in severe malnutrition. In one embodiment, a corrected VO2 measurement would maintain or slightly increase the caloric target without causing malnutrition.

[0041] Implementation examples may include being configured to perform, for example Figure 1 The application program outlined herein, in conjunction with device hardware, allows for the identification or determination of calibrations to the measurement data of oxygen measurement sensors(s). Such embodiments allow the ventilator system to update the determination of VO2 and related outputs, such as indications, warnings, alarms, and communications to the system, healthcare providers, or other users.

[0042] refer to Figure 4 It will be readily understood that certain embodiments can be implemented using a wide variety of devices or combinations of devices and components. Figure 4 The diagram illustrates an example of a computer 400 and its components, which can be used in a device to implement the functions or actions described herein, for example, performing corrections to oxygen sensor measurements to address ventilator drift in the supplemental inhaled oxygen fraction. Furthermore, in one or more embodiments, different... Figure 4 The circuit system shown. Figure 4Examples include certain functional blocks, as shown in the figure, which can be integrated onto a single semiconductor chip to meet specific application requirements.

[0043] One or more processing units are provided, which may include a central processing unit (CPU) 410, one or more graphics processing units (GPUs) and / or microprocessor units (MPUs) including an arithmetic logic unit (ALU) that performs arithmetic and logical operations, a decoder that decodes instructions and provides information to a timing and control unit, and registers for temporary data storage. The CPU 410 may include a single integrated circuit comprising several units, the design and arrangement of which vary depending on the selected architecture.

[0044] Computer 400 also includes a memory controller 440, such as a direct memory access (DMA) controller, to transfer data between memory 450 and hardware peripherals. Memory controller 440 includes a memory management unit (MMU) for handling cache control, memory protection, and virtual memory. Computer 400 may include protocols for using various communication protocols (e.g., I...). 2 A controller that communicates with (such as USB, etc.).

[0045] Memory 450 may include various memory types, volatile and non-volatile, such as read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), flash memory, and cache memory. Memory 450 may include embedded programs, code, and downloaded software, such as oxygen drift compensation program 450a, which provides, for example, in conjunction with... Figure 1 The encoding method is shown and described. By way of example and not limitation, memory 450 may also include operating system, applications, other program modules, code, and program data that can be downloaded, updated, or modified via a remote device.

[0046] The system bus allows communication between the various components of computer 400. It may include I / O interfaces 430 and radio frequency (RF) devices 420, such as Wi-Fi and telecommunications radios, to allow computer 400 to send and receive data to and from remote devices using wireless mechanisms. Note that a data exchange interface for wired data exchange may also be utilized. Computer 400 can operate in a networked or distributed environment using logical connections to one or more other remote computers or devices 470, such as ventilators, mixing chambers, oxygen sensors, or combinations thereof. Logical connections may include networks, such as local area networks (LANs) or wide area networks (WANs), but may also include other networks / buses. For example, computer 400 may communicate data with peripheral devices 460 (e.g., oxygen sensors).

[0047] Therefore, the computer 400 can execute program instructions or code configured to acquire, store, and analyze oxygen sensor data and perform other functions of the embodiments, such as in conjunction with... Figure 1 As described, users can interface with computer 400 (e.g., input commands and information) via input devices that can be connected to I / O interface 430. Display 480 or other types of output devices can be connected to or integrated with computer 400, for example, via an interface selected from I / O interface 430.

[0048] It should be noted that the various functions described herein can be implemented using instructions or code stored in memory (e.g., memory 450), which are then transferred to and executed by a processor (e.g., CPU 410). Computer 400 includes one or more storage devices that persistently store programs and other data. The storage devices used herein are non-transitory computer-readable storage media. Some examples of non-transitory storage devices or computer-readable storage media include, but are not limited to, storage devices integrated with computer 400, such as memory 450, hard disks or solid-state drives, and removable storage devices, such as optical discs or memory sticks.

[0049] Program code stored in a memory or storage device may be transmitted using any suitable transmission medium, including but not limited to wireless, wired, fiber optic cable, RF, or any suitable combination thereof.

[0050] The program code used to perform the operations according to the various embodiments can be written in any combination of one or more programming languages. The program code can be executed entirely on a single device, partially on a single device, as a standalone software package, partially on a single device, partially on another device, or entirely on another device. In one embodiment, the program code can be stored in a non-transitory medium and executed by a processor to implement the function or action specified herein. In some cases, the devices referenced herein can be connected via any type of connection or network connection, including a local area network (LAN) or a wide area network (WAN), or via other devices (e.g., through the Internet provided by an Internet service provider), via a wireless connection, or via a hardwired connection (e.g., via USB).

[0051] Therefore, one example embodiment provides a ventilator system comprising: a ventilator (210) including a first sensor, such as an oxygen sensor for the ventilator. The system includes one or more mixing chambers (240, 240') wherein one or more other sensors are disposed in the one or more mixing chambers, such as one or more oxygen sensors associated with the one or more mixing chambers. The system includes a collection of one or more processors (410); and a non-transitory storage medium (450) storing code (450a) executable by the one or more processors.

[0052] In one embodiment, the code includes code to obtain a first fractional FiO2 value of the breathable gas supplied to the patient by the ventilator, measured by a first sensor at a first time. In one embodiment, the code obtains a second FiO2 value of the breathable gas supplied to the patient by the ventilator, measured by the first sensor at a second time, and the code obtains a third fractional FiO2 value of the breathable gas supplied to the patient by the ventilator, measured by one or more other sensors at a first time. In one embodiment, the system obtains an exhaled fractional FiO2 value of the breathable gas exhaled by the patient, measured by one or more other sensors at a second time.

[0053] In one embodiment, the system determines the FiO2 change between a first FiO2 value and a second FiO2 value, determines a correction for one or more of a third FiO2 value and an FeO2 value based on the determined FiO2 change, and adjusts one or more of the third FiO2 value and the FeO2 value based on the correction.

[0054] In one embodiment, the system determines the difference between: (a) the third FiO2 value and the adjusted FeO2 value; (b) the adjusted third FiO2 value and the FeO2 value; or (c) the adjusted third FiO2 value and the adjusted FeO2 value to determine VO2.

[0055] In one embodiment, the first time (e.g., Figure 3 Time A) occurs during the first time period, which includes the patient's inhalation, while the second time (e.g., Figure 3 Time B) occurs during a second time period, including the patient's exhalation. The first time period may include a first time sampling window, wherein the first and third FiO2 values ​​are averages over the first time sampling window. In one embodiment, the first time period includes a second time sampling window, wherein the second FiO2 value and the FeO2 value are averages over the second time sampling window.

[0056] In one embodiment, the first and second time sampling windows each include multiple respiratory cycles of the patient, wherein the first and second times are separated by multiple respiratory cycles, for example, as... Figure 3 As shown.

[0057] In one embodiment, the system adjusts by outputting a correction value to increase or decrease the third FiO2 value by an amount equal to the difference between the first FiO2 value measured at a first time and the second FiO2 value measured at a second time.

[0058] In one embodiment, the correction includes a correction for the real-time change in a first FiO2 value provided by a first sensor over time. The real-time change value can be derived from a time series of oxygen measurements taken by the first sensor, including oxygen measurements taken at first and second times. In one embodiment, the ventilator or a component thereof can be characterized, for example, by periodically determining FiO2 drift and associating predetermined FiO2 drift values ​​with the ventilator or a component thereof for correcting or adjusting values ​​used in relation to determining oxygen consumption, such as inspired oxygen fraction measurements, as described herein.

[0059] In the claims, any reference numerals placed between parentheses should not be construed as limiting the claims. The words “comprising” or “including” do not exclude the presence of elements or steps other than those listed in the claims. In a device claim that enumerates several means, several of these means may be implemented by the same hardware. The words “a” or “an” preceding an element do not exclude the presence of a plurality of such elements. In any device claim that enumerates several means, several of these means may be implemented by the same hardware. The fact that certain elements are enumerated in mutually different dependent claims does not mean that these elements cannot be used in combination. The word “about” or similar relative terms applied to numbers include ordinary (conventional) rounding of numbers with a fixed base (e.g., 5 or 10).

[0060] Although the invention has been described in detail based on embodiments currently considered to be most practical and preferred for illustrative purposes, it should be understood that such details are for that purpose only, and the invention is not limited to the disclosed embodiments, but rather is intended to cover modifications and equivalent arrangements within the spirit and scope of the appended claims. For example, it should be understood that the invention contemplates that, to the extent possible, one or more features of any embodiment may be combined with one or more features of any other embodiment.

Claims

1. A ventilator system, comprising: A ventilator, including the first sensor; One or more mixing chambers; One or more other sensors are disposed in the one or more mixing chambers; A collection of one or more processors; as well as A non-transitory storage medium storing code executable by the set of one or more processors, the code comprising: A code is obtained for the first inhaled oxygen concentration fraction (FiO2) value of the breathable gas provided to the patient by the ventilator, as measured by the first sensor at the first moment; A code is obtained to obtain the second FiO2 value of the breathable gas provided to the patient by the ventilator, as measured by the first sensor at a second time. A code is obtained for the third fractional FiO2 value of the breathable gas supplied to the patient by the ventilator, as measured by one or more other sensors at the first time. A code for obtaining the exhaled oxygen fraction (FeO2) value of the breathable gas exhaled by the patient, as measured by the one or more other sensors at the second time; Code for determining the FiO2 change between the first FiO2 value and the second FiO2 value; Based on the determined FiO2 change, a code is used to determine the correction for one or more of the third FiO2 value and the FeO2 value; and The code that adjusts one or more of the third FiO2 value and the FeO2 value based on the correction.

2. The system according to claim 1, wherein the code includes: The code that determines the difference between the following two: (a) the third FiO2 value and the adjusted FeO2 value; (b) the adjusted third FiO2 value and the FeO2 value; or (c) the adjusted third FiO2 value and the adjusted FeO2 value.

3. The system of claim 2, wherein the code includes code for determining the patient's oxygen consumption based on the difference.

4. The system of claim 1, wherein the first time occurs during a first time period including inhalation by the patient, and the second time occurs during a second time period including exhalation by the patient.

5. The system according to claim 4, wherein the first time includes a first time sampling window, wherein the first FiO2 value and the third FiO2 value are average values ​​over the first time sampling window.

6. The system of claim 4, wherein the second time includes a second time sampling window, wherein the second FiO2 value and the FeO2 value are average values ​​over the second time sampling window.

7. The system of claim 1, wherein the adjusting code includes code that outputs a correction value to increase or decrease the third FiO2 value by an amount equal to the difference between the first FiO2 value measured at the first time and the second FiO2 value measured at the second time.

8. The system of claim 1, wherein the code determining the correction includes code identifying the real-time change of the first FiO2 value provided by the first sensor over time.

9. The system of claim 8, wherein the real-time change value is derived from a time series of oxygen measurement results performed by the first sensor, the oxygen measurement results including oxygen measurement results performed at the first time and the second time.

10. The system of claim 5, wherein the first time sampling window and the second time sampling window each include multiple respiratory cycles of the patient, and wherein the first time and the second time are separated by multiple respiratory cycles.

11. A computer-implemented method using one or more processors, said one or more processors executing instructions to perform an action, comprising: Obtain the first fractional inhaled oxygen concentration (FiO2) value of the breathable gas supplied to the patient by the ventilator, as measured by the first sensor at the first moment; Obtain the second FiO2 value of the breathable gas supplied to the patient by the ventilator, as measured by the first sensor at a second time. Obtain the third fractional FiO2 value of the breathable gas supplied to the patient by the ventilator, as measured by one or more other sensors at the first time. The exhaled oxygen fraction (FeO2) value of the breathable gas exhaled by the patient, as measured by the one or more other sensors at the second time, is obtained. Determine the FiO2 change between the first FiO2 value and the second FiO2 value. Based on the determined FiO2 change, a set of one or more processors is used to determine a correction for one or more of the third FiO2 value and the FeO2 value; and The third FiO2 value and the FeO2 value are adjusted based on the correction.

12. The method of claim 11, further comprising: Determine the difference between: (a) the third FiO2 value and the adjusted FeO2 value; (b) the adjusted third FiO2 value and the FeO2 value; or (c) the adjusted FiO2 value and the adjusted FeO2 value.

13. The method of claim 12, wherein the patient's oxygen consumption is determined based on the difference.

14. The method of claim 1, wherein the first time occurs during a first time period including inhalation by the patient, and the second time occurs during a second time period including exhalation by the patient.

15. A computer program product comprising: A non-transitory storage medium storing code executable by a set of one or more processors, the code comprising: Obtain a code for the first inhaled oxygen fraction (FiO2) value of the breathable gas provided to the patient by the ventilator, as measured by the first sensor at the first moment; A code is obtained to obtain the second FiO2 value of the breathable gas provided to the patient by the ventilator, as measured by the first sensor at a second time. A code is obtained for the third fractional FiO2 value of the breathable gas provided to the patient by the ventilator, as measured by one or more other sensors at the first time. A code that obtains the exhaled oxygen fraction (FeO2) value of the breathable gas exhaled by the patient, as measured by the one or more other sensors at the second time. Code for determining the FiO2 change between the first FiO2 value and the second FiO2 value. Based on the determined FiO2 change, a code is used to determine the correction for one or more of the third FiO2 value and the FeO2 value; and The code that adjusts one or more of the third FiO2 value and the FeO2 value based on the correction.

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