Damage in compensating for respiratory gas flow measurement

Abstract

This disclosure generally relates to systems and methods for delivering therapeutic gases to patients using techniques to compensate for disruptions in respiratory gas flow measurement, such as when respiratory gas flow measurement is unavailable or unreliable. Such techniques include using historical respiratory gas flow rate data, such as moving average flow rate, moving median flow rate, and / or flow waveforms. At least some of these techniques can be used to ensure that interruptions in therapeutic gas delivery are minimized or eliminated.

Description

[0001] This application is a divisional application of Chinese patent application No. 201780008467.2 (filed on January 31, 2017, entitled "Compensation for Damage in Respiratory Gas Flow Measurement").

[0002] Cross-reference to related applications

[0003] This application claims priority to U.S. Provisional Application No. 62 / 290,430, filed February 2, 2016, entitled “COMPENSATING FOR DISRUPTIONS IN FLOW MEASUREMENT”, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0004] This disclosure generally relates to the delivery of therapeutic gases to patients. Background Technology

[0005] Therapeutic gases can be delivered to patients to provide medical benefits. One such therapeutic gas is nitric oxide (NO) gas, which, when inhaled, dilates blood vessels in the lungs, thereby improving blood oxygenation and reducing pulmonary hypertension. For this reason, nitric oxide can be provided as a therapeutic gas in the inhaled breathing gases of patients with pulmonary hypertension.

[0006] Many such patients who can benefit from nitric oxide gas receive breathing gases from a breathing circuit attached to a ventilator (e.g., a constant-flow ventilator, a variable-flow ventilator, a high-frequency ventilator, a bilevel positive airway pressure ventilator, or a BiPAP ventilator). To deliver nitric oxide to a patient receiving breathing gases from a ventilator, nitric oxide can be injected into the breathing gas flowing in the breathing circuit. The inhaled nitric oxide (iNO) is typically delivered at a constant concentration based on the proportional delivery of NO to the breathing gas.

[0007] Despite the many benefits described above, improvements in the delivery of therapeutic gases remain necessary. For example, new technologies are still needed to address, at least in various situations, such as, but not limited to, disruptions in respiratory gas flow systems used to deliver therapeutic gases (such as nitric oxide). Summary of the Invention

[0008] Various aspects of this disclosure relate to therapeutic gas delivery systems (e.g., nitric oxide delivery systems) that utilize new technologies to compensate for errors or disruptions in respiratory gas flow rate measurements. In some instances, the therapeutic gas delivery systems disclosed herein store historical respiratory gas flow rate data (e.g., average respiratory gas flow rate, respiratory gas flow rate waveform, etc.) and can be used when current respiratory gas flow rate data is unavailable or unreliable. Therefore, such exemplary therapeutic gas delivery systems can continue to provide therapeutic gas delivery without any significant interruption to treatment.

[0009] In one example of implementation, a therapeutic gas delivery device is provided, the device comprising: a therapeutic gas injector module configured to be in fluid communication with a breathing circuit attached to a ventilator, the therapeutic gas injector module including a breathing gas inlet, a therapeutic gas inlet, and a combined breathing gas and therapeutic gas outlet for providing a combined flow of breathing gas and therapeutic gas to a patient in need; a first flow sensor configured to sense breathing gas flow rate data; and a controller configured to control the delivery flow rate of the breathing gas based on a first mode, and, upon detection of disruption, to control the delivery flow rate of the breathing gas based on historical breathing gas flow rate data previously sensed by the first flow sensor and stored in a memory.

[0010] The controller may include: a memory configured to store historical flow rate data associated with respiratory gas flow rate data sensed by the first flow sensor; and a detection processor configured to detect disruptions in the sensed respiratory gas flow rate data from the first flow sensor, wherein the first flow sensor is a gas inspiratory flow sensor, and the controller is configured to use a historical respiratory gas flow rate based on a historical average when disruptions are detected, the disruptions being in the form of a malfunction in the operation of the gas inspiratory flow sensor. The historical flow rate data may include one or more of a moving average respiratory gas flow rate, a moving median respiratory gas flow rate, and / or a gas flow rate waveform. The historical flow rate data may be stored over a time period ranging from 10 seconds to 5 minutes. The sensed respiratory gas flow rate may be received from a syringe module. The sensed respiratory gas flow rate may be received from a ventilator. The sensed respiratory gas flow rate data may include first respiratory gas flow rate data and second respiratory gas flow rate data, wherein the first respiratory gas flow rate data is received from the syringe module and the second respiratory gas flow rate data is received from the ventilator. The controller may compare corresponding flow rate data from the first respiratory gas flow rate data with the second respiratory gas flow rate data. The controller can be configured to automatically resume delivery of respiratory gas flow based on the first mode upon detecting and / or inputting that the first flow sensor has been reconnected, replaced, and / or repaired. The controller can also be configured to remove stored flow data points outside the range using at least one of data smoothing and / or low-pass filtering.

[0011] In another example of the implementation, a method for delivering therapeutic gas to a patient is provided, the method comprising: controlling a flow of respiratory gas to the patient in a first mode via a controller; receiving sensed flow rate data of the respiratory gas flow; storing historical flow rate data associated with the respiratory gas flow rate data received by the sensor in a memory; detecting corruption of the sensed respiratory gas flow rate data from the sensor; and controlling the respiratory gas flow in a temporary mode instead of the first mode via the controller based on the received respiratory gas flow rate data.

[0012] The historical sensed flow rate data may include one or more of moving average respiratory gas flow rate, moving median respiratory gas flow rate, and / or gas flow rate waveforms. Storing the historical flow data may include storing the historical flow rate data over a time period ranging from 10 seconds to 5 minutes. The method may also include returning to the first mode upon detecting an abort of the disruption. Receiving the received flow rate data includes receiving first received flow rate data and second received flow rate data, and detecting the disruption includes detecting the disruption by comparing corresponding flow rate data between two or more sets of received flow rate data.

[0013] In another example of the implementation, an apparatus for delivering nitric oxide and therapeutic gases to a patient is provided, comprising: a controller configured to control the flow of gas to the patient in a first mode and to receive sensed flow rate data; a receiver configured to receive sensed flow rate data of the respiratory gas flow; a memory configured to store received respiratory gas flow rate data associated with previously sensed historical flow data; a detector configured to detect corruption of the received respiratory gas flow rate data from the received respiratory gas flow rate data; and wherein the controller is further configured to retrieve historical flow rate data and control the respiratory gas flow rate in a temporary mode instead of the first mode based on the historical flow rate.

[0014] The historical sensed flow rate data may include one or more of the following: moving average respiratory gas flow rate, moving median respiratory gas flow rate, and / or respiratory gas flow waveform. The historical flow rate data may be stored over a time period ranging from 10 seconds to 5 minutes. The controller may also be configured to return to the first mode upon detecting an abrupt cessation of the disruption. The received sensed flow rate data may include first and second received flow rate data from two or more sensors, and detecting the disruption may include comparing the flow rate data between the two or more received flow rate data.

[0015] Other features and aspects will be apparent from the following detailed description, the accompanying drawings and the claims. Attached Figure Description

[0016] The features and advantages of this specification will be more fully understood by referring to the following detailed description in conjunction with the accompanying drawings, wherein:

[0017] Figure 1 An exemplary nitric oxide delivery system having a flow sensor in a breathing circuit, as described in the exemplary description of this specification, is schematically depicted.

[0018] Figure 2 An exemplary nitric oxide delivery system connected to a ventilator, as illustrated in this specification, is depicted schematically.

[0019] Figure 3 An exemplary nitric oxide delivery system having a flow sensor in a breathing circuit and also connected to a ventilator, as described in the exemplary description of this specification, is schematically depicted.

[0020] Figure 4 An exemplary flowchart schematically depicts a method for compensating for exemplary NO delivery during a disruption in respiratory gas flow measurement; and

[0021] Figure 5schematic depiction Figure 4 The flowchart of the method shown has been modified. Detailed Implementation

[0022] This disclosure generally relates to systems and methods for delivering therapeutic gases to patients (e.g., patients receiving respiratory gases, including therapeutic gases, from a ventilator via a breathing circuit) using previously unknown techniques to compensate for disruptions in respiratory gas flow measurement, such as when respiratory gas flow measurement is unavailable or unreliable. Such techniques may include, but are not limited to, using historical respiratory gas flow rate data, such as moving average flow rate, moving median flow rate, flow integral over a known time period for determining gas volume, and / or flow waveforms, to name just a few. At least some of these techniques can be used to mitigate interruptions in therapeutic gas delivery and / or ensure uninterrupted therapeutic gas delivery. Reducing and / or eliminating interruptions in the delivery of therapeutic gases to patients requiring therapeutic gases can particularly improve patient safety (e.g., reducing and / or eliminating the risk of rebound pulmonary hypertension, reducing and / or eliminating incorrect dosing, etc.).

[0023] The systems and methods described herein can deliver therapeutic gas to a patient from a delivery system connected to an injector module, which in turn can be in fluid communication with a breathing circuit (attached to a ventilator) from which the patient receives breathing gas. These systems and methods may include at least one breathing gas flow sensor capable of measuring the flow rate of the patient's breathing gas in the breathing circuit. Furthermore, the systems and methods described herein can deliver therapeutic gas into the breathing circuit such that the therapeutic gas is turbulently mixed with the patient's breathing gas. Advantageously, the therapeutic gas delivery systems and methods described herein can store past breathing gas flow rate measurements for use in the event of disruption in the breathing gas flow rate measurement.

[0024] The term “damage” is used herein to encompass any and all types of damage. For example, the term “failure” is sometimes used herein to refer to any type of damage. One exemplary type of damage may occur when a gas sensor becomes disconnected from and / or loses electrical communication with a control module attached to an exemplary nitric oxide delivery system. In the case of multiple sensors, another exemplary type of damage is when one or more sensors provide inaccurate or mismatched readings. Yet another exemplary type of damage may be when readings from a sensor are identified by the controller as deviating from the normal, expected, and / or desired range; this may include, for example, partial or complete termination of received sensor data, i.e., they may be inaccurate. Another exemplary type of damage is when the sensor itself or other components associated with the delivery of the respiratory gas may indicate a failed or disconnected state. Depending in part on the system location of the sensor, it may be subject to some degree of wear (e.g., due to impact from surrounding objects). For example, wear may occur when the sensor is closer to the remote patient end of the gas flow path (e.g., because the sensor is located at a syringe module component, which in turn may be coupled to and / or in fluid communication with the patient's breathing circuit). Many types of damage or malfunction can occur; however, for convenience only, not all types of damage are described herein, but those skilled in the art will understand them. At least some of the systems and methods described herein can be used to prevent interruption of therapeutic gas delivery in the event of damage.

[0025] Reference Figure 1 This specification schematically depicts an exemplary nitric oxide delivery system 100 for delivering therapeutic nitric oxide gas to a patient 108 receiving respiratory gases from a breathing circuit 104 attached to a ventilator 117 via a syringe module 102. It should be understood that any teachings of this specification can be used in any applicable system for delivering therapeutic gases to a patient receiving respiratory gases from a breathing device (e.g., a ventilator, a high-frequency ventilator, a breathing mask, a nasal cannula, etc.). For example, the systems and methods of this specification may use, modify, and / or be based on the delivery system and / or other teachings of U.S. Patent No. 5,558,083 entitled “Nitric Oxide Delivery System,” the contents of which are incorporated herein by reference in their entirety.

[0026] This disclosure sometimes relates to use with a ventilator; however, the systems and methods described herein can be used with any suitable respiratory device that may be attached to a ventilator. Therefore, references to ventilators are merely for ease of description and are in no way intended to be limiting. Therapeutic gases, therapeutic gases turbulently mixed into the breathing circuit, therapeutic gas delivery systems, etc., are sometimes described with reference to nitric oxide gas (NO, iNO, etc.) used for inhaled nitric oxide therapy. It should be understood that other suitable therapeutic gases may be used. Therefore, references to nitric oxide, NO, iNO, etc., are merely for convenience and are in no way intended to be limiting.

[0027] In the exemplary description, an exemplary nitric oxide delivery system (such as nitric oxide delivery system 100) can be used to turbulently mix a therapeutic gas (e.g., nitric oxide, NO, etc.) into the patient's breathing gas in a breathing circuit (attached to a ventilator) as part of the patient's breathing gas. To at least turbulently mix NO into the patient's breathing gas, nitric oxide delivery system 100 may include nitric oxide and / or receive nitric oxide from a nitric oxide source 103 (e.g., a gas cylinder storing NO, an NO generator, etc.) via conduit 105. Additionally, conduit 105 may also be in fluid communication with injector module 102, for example, via therapeutic gas inlet 110. Injector module 102 may also be in fluid communication with the inspiratory branch 121 of the patient breathing circuit 104 attached to a ventilator 117.

[0028] As shown in the figure, the ventilator 117 may include: an inspiratory outlet for delivering respiratory gas to the patient via the inspiratory branch 121 and the "Y"-shaped member 125 of the patient's breathing circuit (e.g., forward flow 133); and an expiratory inlet for receiving the patient's exhaled air via the expiratory branch 127 and the "Y"-shaped member 125 of the patient's breathing circuit. Generally, the "Y"-shaped member may connect the inspiratory branch 121 and the expiratory branch 127, and the delivered respiratory gas and / or the patient's exhaled air may flow through the "Y"-shaped member. Sometimes, for convenience, the delivery and exhalation of respiratory gas are described without mentioning the "Y"-shaped member. This is merely for convenience and is in no way intended to be limiting.

[0029] With the syringe module 102 connected to and / or in fluid communication with the inspiratory branch 121 of the breathing circuit, nitric oxide can be delivered from the nitric oxide delivery system 100 (e.g., NO forward flow 137) to the syringe module 102 via the conduit 105 and / or the therapeutic gas inlet 110. The nitric oxide can then be delivered via the syringe module 102 to the inspiratory branch 121 of a patient breathing circuit attached to a ventilator 117 for delivering breathing gases to a patient 108. In at least some cases, the patient breathing circuit may include only one branch for inspiratory and expiratory flow. For convenience, patient breathing circuits are sometimes described as having separate inspiratory and expiratory branches. This is merely for convenience and is by no means intended to be limiting. For example, this disclosure is sometimes described and / or depicted for use with two-branch (e.g., inspiratory and expiratory branches) patient breathing circuits; however, where applicable, this disclosure can be used with single-branch patient breathing circuits (e.g., inspiratory branch only, combined inspiratory and expiratory branches, etc.). Similarly, this is merely for convenience and by no means a restriction.

[0030] In an exemplary embodiment, to regulate the flow rate of nitric oxide through conduit 105 to syringe module 102 and subsequently to patient 108 receiving respiratory gas from a patient breathing circuit, nitric oxide delivery system 100 may include one or more control valves 109 (e.g., proportional valves, dual-state valves, etc.). For example, with control valve 109 open, nitric oxide can be delivered to patient 108 by flowing in a positive direction (e.g., NO forward flow 137) through conduit 105 to syringe module 102 and subsequently to patient 108.

[0031] In at least some cases, the nitric oxide delivery system 100 may include one or more NO flow sensors 115 that can measure the flow rate of the therapeutic gas (e.g., the flow rate through control valve 109, the flow rate through conduit 105, etc.). The flow sensor 115 may be located upstream or downstream of control valve 109 and / or conduit 105, thereby enabling the measurement of the flow rate of the therapeutic gas entering syringe module 102 through therapeutic gas inlet 110 and then reaching patient 108.

[0032] Furthermore, in at least some cases, the syringe module 102 may include one or more respiratory gas flow sensors 119 that can measure the flow rate of at least the patient's respiratory gas (e.g., forward flow 133) passing through the syringe module 102 and thus reaching the patient 108. In some implementations, a sensor (not shown) may be present to sense the expiratory flow rate. Although shown as being located at the syringe module 102, the respiratory gas flow sensor 119 may be placed at other locations on the inspiratory branch 121, such as upstream of the syringe module 102 and / or in fluid communication with the breathing circuit. Moreover, as Figure 2 As shown, instead of receiving flow rate data from the respiratory gas flow sensor 119, in at least some cases, the nitric oxide delivery system 100 can receive flow rate data directly from the ventilator 117, which indicates the flow rate of respiratory gas from the ventilator 117. Furthermore, in at least some cases, flow rate data is provided by both the respiratory gas flow sensor 119 and the ventilator 117, such as... Figure 3 As shown.

[0033] Nitric oxide gas streams can be turbulently mixed with respiratory gas streams in a proportional manner (also known as a ratiometric) to provide a desired concentration of NO in the combined respiratory and therapeutic gases. For example, nitric oxide delivery system 100 can confirm the presence of a desired concentration of NO in the combined respiratory and therapeutic gases by using a known NO concentration from NO source 103; confirm the amount of respiratory gas flow in the patient circuit using gas flow rate data from respiratory gas flow sensor 119; and confirm the amount of therapeutic gas flow in the catheter 105 flowing to syringe module 102 (and further to patient 108) using gas flow rate data from NO flow sensor 115.

[0034] To deliver at least a desired set dose of therapeutic gas to a patient and / or to a sample dose of therapeutic gas, the therapeutic gas delivery system 100 may include a system controller 111, which may include one or more processors and a memory 112. The system controller may be, for example, a computer system, a single-board computer, one or more application-specific integrated circuits (ASICs), or a combination thereof. The processor may be coupled to the memory and may be one or more readily available memories, such as random access memory (RAM), read-only memory (ROM), flash memory, compact disc / optical disk storage, hard disk, or any other form of local or remote digital storage device. Supporting circuitry may be conventionally coupled to the processor to support the processor, sensors, valves, sampling systems, delivery systems, user input devices, displays, syringe modules, breathing equipment, etc. This circuitry may include cache memory, power supplies, clock circuits, input / output circuits, analog-to-digital converters and / or digital-to-analog converters, subsystems, power controllers, signal conditioners, etc. The processor and / or memory may communicate with the sensors, valves, sampling systems, delivery systems, user input devices, displays, syringe modules, breathing equipment, etc. Reciprocating communication with the system controller can be achieved through a communication path, which can be wired or wireless, and where appropriate hardware, firmware, and / or software can be configured to interconnect components and / or provide electrical communication via the communication path.

[0035] The clock circuit can be internal to the system controller and / or provide time measurement relative to an initial start (e.g., at startup). The system may include a real-time clock (RTC) that provides the actual time and can be synchronized with a time recording source (e.g., a network). Memory 112 can be configured to receive and store values ​​used for calculations and / or comparisons with other values, such as values ​​from sensors, pumps, valves, etc.

[0036] Memory 112 may store a set of machine-executable instructions (or algorithms) that, when executed by a processor, cause the sampling system and / or delivery system to perform various methods and operations. For example, a nitric oxide delivery system may deliver a desired set dose of therapeutic gas (e.g., desired NO concentration, desired NO PPM, etc.) to a patient requiring therapeutic gas. To this end, the delivery system may receive and / or determine the desired set dose of therapeutic gas to be delivered to the patient, for example, the set dose may be input by a user. The delivery system may measure the flow rate in the inspiratory branch of the patient's breathing circuit and may monitor the inspiratory flow rate or changes in the inspiratory flow rate while delivering the NO-containing therapeutic gas to the patient. The system may also vary the amount (e.g., volume or mass) of therapeutic gas delivered in subsequent inspiratory flows.

[0037] In another example, the sampling system can determine the concentration of a target gas (e.g., NO) delivered to the patient. For this purpose, a sampling pump can be operated and / or a gas sampling valve (e.g., a three-way valve, etc.) can be opened to obtain a gas sample from the inspiratory branch of the patient's breathing circuit. The gas sample may include a mixture of air and therapeutic gas (e.g., NO) delivered to the patient. The gas sample may be exposed to a gas sensor (e.g., a catalytic electrochemical gas sensor) to obtain gas flow rate data indicating the concentration of the target gas (e.g., NO, nitrogen dioxide, oxygen) delivered to the patient. The concentration of the target gas can be communicated to the user. The machine-executable instructions may also include instructions for any other methods described herein.

[0038] Additionally, to at least ensure accurate administration of the therapeutic gas, the nitric oxide delivery system 100 may include a user input device / display 113, which may include a display and a keyboard and / or buttons, or may be a touchscreen device. The user input device / display 113 may receive desired settings from the user, such as the patient's prescription (in mg / kg ideal weight, mg / kg / hr, mg / kg / breath, mL / breath, cylinder concentration, delivery concentration, duration, etc.), the patient's age, height, sex, weight, etc. In at least some cases, the user input device / display 113 may be used, for example, with a gas sampling system 129 to confirm patient administration and / or gas measurement, which may receive a sample of the gas delivered to the patient 108 via a sample line 131. The gas sampling system 129 may include a number of sensors, such as, but not limited to, nitric oxide gas sensors, nitrogen dioxide gas sensors, and / or oxygen gas sensors, to name just a few, which may be used to at least display relevant information (e.g., gas concentration, etc.) on the user input device / display 113 and / or provide alerts to the user. Therefore, the nitric oxide delivery system 100 may operate in a first mode, in which a gas stream is delivered based on desired settings and / or parameters.

[0039] Figure 1 An example is shown where system controller 111 is configured to receive sensing data from sensor 119 located at syringe module 102 via communication path C1. Figure 1-3 The components shown disclose similar components with similar reference numerals. Therefore, for clarity and brevity, reference is primarily made herein. Figure 1 Described Figure 1-3 Common components.

[0040] While the above can be advantageously used to deliver therapeutic gases to patients receiving respiratory gases from a patient breathing circuit attached to a ventilator, mixing NO turbulence into the patient's respiratory gas as part of the patient's respiratory gas may fail if respiratory gas flow information is unavailable and / or unreliable.

[0041] In an exemplary embodiment, at least the syringe module 102 may be exposed to wear. For example, as Figure 1 As shown, syringe module 102 is exposed to wear because it is a component external to the main delivery system 100 and is coupled to the inspiratory branch of the breathing circuit. Syringe module 102 can also be exposed to sterilization and / or disinfection processes, which add additional wear. Syringe module 102 may also be easily dropped, dragged, or placed in the wrong part of the breathing circuit (e.g., downstream of the humidifier or on the expiratory side of the circuit), which may cause additional wear. In summary, syringe module 102 and the sensors therein (e.g., respiratory gas flow sensor 119, etc.) may be more prone to failure / damage than other components in the system (e.g., at least due to the wear described above).

[0042] For nitric oxide delivery systems that communicate directly with a ventilator (e.g., serial communication, USB communication, Ethernet communication, wireless communication, etc.), the ventilator can provide inspiratory flow information in place of a respiratory gas flow sensor in the breathing circuit, or in addition to such a sensor. However, disruptions may occur during the transmission of flow rate data from the ventilator to the nitric oxide delivery system. In at least some implementations, the systems and methods of this disclosure can detect differences between any one or more of a plurality of sensors, as further described herein. That is, flow sensing can originate from any one or more of the sensors described herein.

[0043] In exemplary embodiments, this disclosure overcomes at least some of the problems described herein by advantageously generating, implementing, and / or utilizing a history of respiratory gas flow rate data (e.g., ventilator inspiratory flow information) stored within the nitric oxide delivery system 100 (such as in memory 112). In exemplary embodiments, such historical flow rate data may include one or more of a moving average respiratory gas flow rate or a moving median respiratory gas flow rate over a specific time period (such as the past 5, 10, 15, 20, 30, or 45 seconds; the past 1, 2, 5, 10, 15, 20, 30, 45, or 60 minutes; or since the start of the current treatment). In at least some implementations, the respiratory gas flow rate history over the past minute (i.e., 60 seconds) is calculated.

[0044] Furthermore, in exemplary embodiments, instead of the moving average flow rate or moving median flow rate and / or in addition to said moving average flow rate or moving median flow rate, in some descriptions, the nitric oxide delivery system stores information related to the respiratory gas flow waveform. Similar to the moving average respiratory gas flow rate or moving median respiratory gas flow rate, flow waveform information over a certain time period (such as the past 5 seconds, 10 seconds, 15 seconds, 20 seconds, 30 seconds, or 45 seconds; the past 1 minute, 2 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 45 minutes, or 60 minutes, or since the start of the current treatment) can be stored. In exemplary embodiments, the waveform itself can be processed into segments or time-stamped data points. In at least some implementations, because data immediately preceding the time of detected disruption may be unreliable, this disclosure can look for a “window” of data whose time ends at a predetermined increment before the time of detected disruption and begins at a predetermined time period before the start of the window. For example, data can be selected from data chosen by any range (e.g., a window that starts 35 seconds before destruction detection and ends 5 seconds before destruction detection).

[0045] In some implementations, more advanced signal processing techniques can be used to modify and / or analyze historical respiratory gas flow rate data. For example, smoothing and / or low-pass filtering, digital finite impulse response (FIR) filters, and / or digital infinite impulse response (IOR) filters can be used to remove out-of-range flow rate data points.

[0046] Figure 2 An example is shown where system controller 111 is configured to receive sensing data from sensors located in or at said ventilator 117 via communication path C2. As previously described, Figure 1-3 The components shown disclose similar components with similar reference numerals. Therefore, for clarity and brevity, reference is primarily made herein. Figure 1 Described Figure 1-3 Common components.

[0047] Figure 3An example with two sensors is shown, wherein system controller 111 is configured to receive sensing data via both pathways C1 and C2. When system controller 111 receives data from more than one sensor device, it can independently monitor each data stream as necessary to detect whether any data stream indicates damage to a single corresponding sensor, and / or system controller 111 can compare two data streams as part of a process for detecting damage in one or more of the sensing data. As further described in various parts of this disclosure, regardless of whether information is received from ventilator 117 and / or flow sensor 119, system controller 111 can leave a first mode (which may be referred to as normal mode) upon detecting damage and may operate in a temporary backup mode (which may also be described as limp mode) until the damage ends, at which point system controller 111 can return to its normal mode.

[0048] Damage detection can be performed via controller 111, which may include or be attached to a detection processor configured to detect damage to sensing flow rate measurements from any or all associated sensors. In some implementations, the detection processor may monitor flow rate data and determine when the flow rate data changes in a manner indicative of damage, such as termination or variation of the data, or digital data error checks. In at least some cases, the detection process may receive and / or detect indications that a sensor has been disconnected, such as in the event of a complete or partial disconnection or removal of the injection module from the system. Upon detection of damage, the nitric oxide delivery system utilizes historical respiratory gas flow data for current delivery of therapeutic gas in the event of damage or other errors in respiratory gas flow measurement. For example, in the event of damage in respiratory gas flow measurement, the nitric oxide delivery system may switch to setting the NO dose delivery based on historical respiratory gas flow data (e.g., proportionally to historical respiratory gas flow data). In some descriptions, this switch may occur automatically without user intervention.

[0049] For nitric oxide delivery systems that have both a respiratory gas flow sensor and communicate directly with the ventilator (e.g., ... Figure 3 As shown, if one flow data source unexpectedly becomes unavailable, the system can seamlessly switch to another flow data source. If both data sources are corrupted or there are discrepancies between the respiratory gas flow information from the two sources, the nitric oxide delivery system can switch to delivery using historical flow rate data as described above. If there are only two data sources (e.g., a NO concentration sensor and an IM flow sensor), corruption detection can be used based on these two data sources, such as when data loss occurs or the flow sensor reads out of range.

[0050] Once the respiratory gas flow information malfunction / damage is cleared (e.g., once the syringe module sensor or the entire syringe module has been repaired or replaced and / or communication with the ventilator has been restored; and / or the ventilator sensor has been replaced or repaired), the nitric oxide delivery system can seamlessly resume normal proportional NO delivery using the current respiratory gas flow rate data provided by the respiratory gas flow sensor and / or from the ventilator to set the dose.

[0051] Furthermore, in some implementations, upon detecting corruption in the respiratory gas flow information, an alarm (auditory alarm, visual alarm, etc.) indicating the corruption can be provided to the user. For example, a message can appear on the user interface display, signaling that the respiratory gas flow sensor has been corrupted or communication with the ventilator has been disrupted. Alternatively, in such a situation, a message, indicator, or alarm can be provided to the user indicating that corruption has been detected and / or that the NO was not delivered based on historical data.

[0052] Figure 4 A flowchart illustrating an exemplary method for compensating for disruptions in respiratory gas flow measurement is provided. It should be understood that in some implementations, one or more sensors, as described herein, may also sense or measure flow characteristics other than flow rate alone.

[0053] At process 410, the respiratory gas flow rate is controlled in normal mode and provided based on preset, desired, input, or otherwise desired input settings. In some implementations, the normal mode setting can be input by the operator at the user input device / display 113 and controlled by the controller 111.

[0054] At process 420, flow rate data is sensed by one or more sensors in the system. In some implementations, the sensors may include sensor 119 located at the injector module and / or a sensor in the ventilator 117, or may be located at other locations throughout the gas breathing circuit.

[0055] At process 430, the controller processes sensed flow rate data from one or more sensors. In some implementations, the sensors may include sensor 119 located at the injector module and / or sensors in the ventilator 117, or may be located at other locations throughout the gas breathing circuit. Figure 1-3 In this context, communication between the sensor and the controller can be illustrated, for example, by dotted lines C1 and C2. Examples of communication include all those described herein, and each can include, for example, a hardwired connection and / or a wireless communication connection.

[0056] At process 440, historical flow rate data is stored in memory over a certain time period. In one implementation example, historical flow rate data is stored over a time period ranging from 10 seconds to 5 minutes, or the respiratory rate over 1 minute is calculated. Respiratory cycles can also be identified and averaged "respiratory flow curves" can be generated. Figure 1-3 In this context, communication between the sensor and the memory can be illustrated, for example, by dotted lines C1 and C2. Examples of communication include all those described herein, and each can include, for example, hardwired connections and / or wireless communication connections. The controller and memory can be arranged in any order and can be housed within a single module.

[0057] At process 450, controller 111 checks or detects whether a sensor malfunction (also referred to as a fault) condition is detected by analyzing the received flow rate data. The analysis of the received flow rate data (analog or digital) can be performed by controller 111. If no malfunction is detected, the system continues normal operation. Malfunction can be a complete lack of data or other fault conditions, or it can be any data variation indicating data irregularity or system failure. For example, malfunction can be any of the malfunctions described herein or others, and in some implementations, other malfunctions include disconnection of the syringe module, lack of matching data determined between the two sensors, unexpected flow rate data readings, etc. Examples of unexpected flow rate data readings could be 10 ms of data loss, out-of-range flow rate readings, or 10 seconds of mismatched flow rate readings.

[0058] At process 460, when disruption is detected at process 450, controller 111 retrieves historical flow rate data from memory 112. The controller and memory can be arranged in any order and can be housed in a single module. In some implementations, the historical flow rate data can be a selected time window, as described herein, which can be a fixed time window of historical data spanning a time window preceding the detected disruption. In some implementations, the time window can end immediately before the detected disruption time, or it can end some time before the detected disruption time. For example, the reference disruption time can be a 1-minute moving average flow rate calculated up to 10 seconds before a point of signal loss, out-of-range signaling, or signal inconsistency.

[0059] At process 470, flow control is performed based on historical flow rate data. In some implementations, controller 111 uses historical flow rate data from memory 112 as its operating parameters to provide a second mode, which may be referred to as a historical proportional gas delivery backup mode and / or a syringe failure temporary backup mode. As described herein, the temporary backup mode provides continuous operation of the entire system, allowing controller 111 to continue supplying and controlling gas even after some disruption to the normal sensing of the gas flow rate has been detected.

[0060] At process 480, if the user indicates or the controller determines that the disruption no longer occurs and / or has been cleared (e.g., due to user-instructed sensor replacement or maintenance and / or the system detects sensor repair or replacement), the system returns to normal mode using initial settings from normal mode (e.g., parameters entered at process 410). As an example, disruption can be considered cleared after determining that the volumetric flow rate is within 20% of the historical average when using CRC messages to establish digital communication signals. In the case of analog signals, disruption can be considered cleared when the flow rate is within the expected ADC count limit reported for flow rate or temperature.

[0061] Figure 5 It is similar to Figure 4 The flowchart has similar reference figures but shows a variation of the implementation. Figure 5 In implementation 500, at process 480, if no damage is detected being cleared, then at process 470, the flow rate is controlled based on historical flow rate data.

[0062] The description herein utilizes the term gas flow rate data (e.g., volumetric flow rate, mass flow rate, etc.). However, in some implementations, this term may also refer to additional or other information besides flow rate, such as any information related to the delivery of therapeutic gases, such as measurements of gas ratios, gas concentrations, etc. The system may also track historical NO flow rate readings from NO flow sensor or historical NO flow rate commands from control systems.

[0063] In some implementations, the user can adjust the dosage of the therapeutic gas when the system is in standby mode. Historical data can be referenced to calculate the expected NO flow rate for the new set dosage. When in standby mode, the historical average flow rate in use can be displayed on an information display screen associated with the device. A GUI or other control interface can be provided, for example, to allow the user to change various settings of the ventilator or other components while in standby mode. Furthermore, instead of using historical flow rate measurements, or in addition to using historical flow rate measurements, the controller can utilize a record of flow rates from historical commands (or input controls) in memory.

[0064] The foregoing detailed description is presented to enable those skilled in the art to make and use the disclosed subject matter. Specific terminology has been set forth for purposes of explanation to provide a thorough understanding. However, it will be apparent to those skilled in the art that such specific details are not required to practice the disclosed subject matter. Descriptions of specific applications are provided only as representative examples. Various modifications to the disclosed implementations will be apparent to those skilled in the art, and the general principles defined herein can be applied to other implementations and applications without departing from the scope of this disclosure. The order of operations described herein is merely illustrative, and the order of operations is not limited to that described herein but can be changed, as will be apparent to those skilled in the art, with the exception of operations that must be performed in a specific order. Furthermore, descriptions of functions and constructions well known to those skilled in the art may be omitted for clarity and brevity. This disclosure is not intended to be limited to the implementations shown, but rather to conform to the widest possible scope consistent with the principles and features disclosed herein.

[0065] It will be apparent to those skilled in the art that various modifications and alterations can be made to the methods and systems described herein without departing from the spirit and scope of this specification. Therefore, this specification is intended to include such modifications and alterations within the scope of the appended claims and their equivalents.

[0066] It should be understood that any of the described steps can be rearranged, separated, and / or combined without departing from the scope of the invention. For convenience, the steps are sometimes presented sequentially. This is merely for convenience and is by no means intended to be limiting. Furthermore, it should be understood that any of the elements and / or embodiments of the invention described can be rearranged, separated, and / or combined without departing from the scope of the invention. For convenience, various elements are sometimes described separately. This is merely for convenience and is by no means intended to be limiting.

[0067] The separation of the various system components in the above examples should not be construed as requiring such separation in all examples, and it should be understood that the described components and systems can generally be integrated together and packaged as monoliths into multiple systems and / or multiple components. It should be understood that various modifications can be made herein, and the subject matter disclosed herein may be implemented in various forms and instances, and the teachings can be applied to a wide range of applications, only some of which are described herein. Unless otherwise stated, all measurements, values, grades, locations, quantities, sizes, and other specifications set forth in this specification (including in the following claims) are approximate and not exact. They are intended to have a reasonable range consistent with their associated function and with custom in the art to which they pertain.

[0068] Although the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It will be apparent to those skilled in the art that various modifications and alterations can be made to the methods and apparatus of the invention without departing from the spirit and scope thereof. Therefore, the invention is intended to include such modifications and alterations within the scope of the appended claims and their equivalents.

Claims

1. A nitric oxide gas delivery apparatus for use with a ventilator, the apparatus comprising: a syringe module configured to be placed in fluid communication with a breathing circuit attached to the ventilator, the syringe module comprising: a breathing gas flow inlet; a nitric oxide (NO) flow inlet; and a combined breathing gas and NO flow outlet operable to provide a combined flow of breathing gas and NO to a patient in need thereof; a breathing gas flow sensor configured to sense a breathing gas flow rate; one or more NO flow sensors operable to measure NO flow; and a controller including: a memory for tracking and storing historical flow rate data; and a processor for calculating a historical average flow rate from the historical flow rate data in a first mode, and detecting a disruption in breathing gas flow rate data from the breathing gas flow sensor, wherein upon detecting the disruption in the breathing gas flow rate data, the controller operates in a backup mode to control the delivery flow rate of the NO based on the historical average flow rate.

2. The apparatus of claim 1, wherein the controller operating in the backup mode controls the delivery flow rate of the NO at the historical average flow rate.

3. The apparatus of claim 1, wherein the historical average flow rate is referenced to calculate a required NO flow rate for a new set dose.

4. The apparatus of claim 1, further comprising a user input, wherein a record in the user input controls the delivery flow rate of the NO when the controller operates in the backup mode.

5. The apparatus of claim 1, further comprising a display, wherein the historical average flow rate is displayed on the display when the controller operates in the backup mode.

6. The apparatus of claim 1, further comprising a control valve for regulating the NO flow through a conduit to the syringe module.

7. The apparatus of claim 6, wherein the one or more NO flow sensors are located upstream of the control valve and / or the conduit, and wherein the one or more NO flow sensors are operable to measure the NO flow through the NO flow inlet into the syringe module.

8. The apparatus of claim 6, wherein the one or more NO flow sensors are located downstream of the control valve and / or the conduit, and wherein the one or more NO flow sensors are operable to measure the NO flow through the NO flow inlet into the syringe module.

9. The apparatus of claim 1, wherein the controller is operable to automatically return to the first mode upon detecting that the disruption has ended and / or that the breathing gas flow sensor has been one of reconnected, replaced, and / or serviced.

10. The apparatus of claim 1, wherein the controller is configured to automatically resume delivery of NO flow based on the first mode upon detecting that the disruption has ended and / or that the breathing gas flow sensor has been one of reconnected, replaced, and / or serviced.

11. The apparatus of claim 1, wherein the historical flow rate data is stored from a period of time from 10 seconds to 5 minutes.

12. The apparatus of claim 1, wherein sensed respiratory gas flow rate data is received from the syringe module and / or the ventilator.

13. The apparatus of claim 1, wherein sensed respiratory gas flow rate data includes first respiratory gas flow rate data and second respiratory gas flow rate data, wherein the first respiratory gas flow rate data is received from the syringe module and / or the second respiratory gas flow rate data is received from the ventilator.

14. The apparatus of claim 13, wherein the controller compares respective flow rate data from the first respiratory gas flow rate data and the second respiratory gas flow rate data.

15. The apparatus of claim 1, wherein the controller is further operable to remove stored flow data points that are out of range with at least one of data smoothing and / or low pass filtering.

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