Systems and methods for determining a patient's respiratory effort

Abstract

The present invention relates to a system and method for determining a patient's respiratory effort, the method for determining a patient's respiratory effort and associated patient-ventilator asynchrony comprising: acquiring first impedance data representing a first region of the patient's lungs, the first region including at least a dependent region of the lungs; during applied positive expiratory pressure, optionally acquiring second impedance data representing a second region of the lungs; and comparing the first impedance data with one or more of the second impedance data, a flow rate within the patient's respiratory circuit, a pressure within the respiratory circuit, historical impedance data for the first region, and a stored pattern of impedance data for the first region. A related system for determining a patient's respiratory effort is also disclosed.

Description

[0001] Priority declaration

[0002] This application claims the benefit of the filing date of U.S. Provisional Patent Application Serial No. 62 / 916,929, filed on October 18, 2019, "SYSTEMS AND METHODS FOR DETERMINING A RESPIRATORY EFFORT OF A PATIENT." Technical Field

[0003] Embodiments of the present disclosure are generally related to systems and methods for determining a patient's respiratory effort. More specifically, embodiments of the present disclosure are related to methods for determining a patient's respiratory effort and / or patient-ventilator asynchrony (such as ineffective effort) based at least on impedance data of dependent regions of the lung and / or information derived from the impedance data, and to related devices and systems. Background Art

[0004] Treatment of patients with respiratory failure requires ventilator support. Patients with respiratory failure, such as those with acute respiratory distress syndrome (ARDS), may be subjected to ventilator support and positive end-expiratory pressure (PEEP). Unfortunately, sometimes the patient and the mechanical ventilator may become out of sync. Patient-ventilator asynchrony refers to the poor interaction between the patient and the ventilator. Patient-ventilator asynchrony affects 35%-43% of mechanically ventilated patients and is associated with poor patient outcomes, such as prolonged mechanical ventilation and increased in-hospital mortality. One consequence of patient-ventilator asynchrony is ineffective inspiratory effort (also known as "ineffective effort"), which occurs when the mechanical ventilator cannot recognize the patient's efforts to initiate breathing and the mechanical ventilator does not respond to the patient's breathing attempts. Ineffective inspiratory effort (IEE) during exhalation is defined as (patient) inspiratory effort that cannot trigger the ventilator to deliver a breath, and is the most common type of patient-ventilator asynchrony. The exact event of IEE varies and depends on several factors, such as the specific patient, mechanical ventilation (MV) settings, sedation level, and the patient's state of consciousness.

[0005] Unfortunately, despite the importance of detecting patient effort and the deleterious effects of asynchrony on patient outcomes, it is difficult even for experts to detect patient effort and asynchrony based solely on the ventilator waveform. Typically, patient effort is detected using invasive techniques, such as using an esophageal catheter or measuring the electrical activity of the diaphragm (Eadi measurement) to reduce the incidence of ineffective effort asynchrony. For example, patient effort can be detected using esophageal pressure tracking, esophageal balloons, or neurally adjusted ventilator assist (NAVA). However, both esophageal pressure and NAVA monitoring require positioning of the catheter, which is an invasive and complex procedure. Summary of the invention

[0006] In some embodiments, a method of determining a patient's respiratory effort includes: acquiring first impedance data representing a first region of the patient's lungs, the first region including at least a dependent region of the lungs; comparing the first impedance data with one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the patient's lungs including at least an independent region of the patient's lungs, historical impedance data for the first region, and a stored pattern of impedance data for the first region; and identifying an occurrence of the patient's respiratory effort based on the comparison.

[0007] In an additional embodiment, a system for determining a patient's respiratory effort includes: an electrical impedance tomography system; at least one processor coupled to the electrical impedance tomography system; and at least one non-transitory computer-readable storage medium storing instructions thereon that, when executed by the at least one processor, cause the at least one processor to: acquire first impedance data representing at least one dependent region of the patient's lungs using the electrical impedance tomography system; and compare the first impedance data with one or more of a flow rate within the patient's breathing circuit, a pressure within the breathing circuit, second impedance data representing a second region of the patient's lungs including at least a non-dependent region, historical impedance data of the first region, and a stored pattern of impedance data representing the first region of the lungs to identify the patient's respiratory effort based on the comparison.

[0008] In other embodiments, a system for determining a patient's respiratory effort includes: an electrical impedance tomography system; and a controller, wherein the electrical impedance tomography system is operably coupled to the controller. The controller includes: at least one processor; and at least one non-transitory computer-readable storage medium, the at least one non-transitory computer-readable storage medium storing instructions thereon, the instructions, when executed by the at least one processor, causing the at least one processor to: cause the electrical impedance tomography system to acquire first impedance data of a first region of the patient's lungs, the first region including a dependent region of the lungs; compare the first impedance data with one or more of second impedance data representing a non-dependent region of the patient's lungs, a flow rate within the patient's breathing circuit, a pressure within the breathing circuit, historical impedance data of the first region, and a stored pattern of impedance data of the first region; and identify the patient's respiratory effort based on the comparison. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of a portion of an electrical impedance tomography (EIT) system according to one or more embodiments of the present disclosure, the schematic diagram showing a plurality of electrodes positioned around a region of interest of a patient;

[0010] Figure 2 is a schematic diagram showing a cross-section of a patient's chest along the plane of an electrode according to one or more embodiments of the present disclosure;

[0011] Figure 3 is a schematic block diagram of an EIT system according to an embodiment of the present disclosure;

[0012] Figure 4 is a schematic diagram of a system for identifying a patient's respiratory effort and patient-ventilator asynchrony according to one or more embodiments of the present disclosure;

[0013] Figure 5 is a flow chart of a method of determining a patient's breathing-related effort according to one or more embodiments of the present disclosure;

[0014] Fig. 6A is a graph of flow and airway pressure measured at the airway of a patient and impedance data (ΔZ) of the patient's lung measured at a posterior region and at an anterior region according to an embodiment of the present disclosure;

[0015] Figure 6B is an EIT image showing dependent and independent regions of a patient's lung according to an embodiment of the present disclosure;

[0016] Figure 6C is a graph of flow and airway pressure measured at the airway of a patient and impedance data of the patient's lung measured at a posterior region and at an anterior region according to an embodiment of the present disclosure;

[0017] Fig.6D is a graph of flow and airway pressure measured at the airway of a patient and impedance data of the patient's lung measured at a posterior region and at an anterior region according to an embodiment of the present disclosure; and

[0018] Figure 7 are graphs of flow and airway pressure measured at the airway of a suckling pig and impedance data of the lung measured at the posterior region and at the anterior region, and a graph of the electrical activity of the diaphragm. DETAILED DESCRIPTION

[0019] This provisional patent application is related to Appendix A and Appendix B, each of which is attached to this application and also constitutes a part of this disclosure. The published documents cited in the reference section at the end of Appendix A are hereby incorporated by reference into this document.

[0020] The drawings presented herein are not meant to be actual views of any particular material, component, or system, but are merely idealized representations used to describe embodiments of the present disclosure.

[0021] The following description provides specific details, such as material types, dimensions, and processing conditions, in order to provide a thorough description of the embodiments of the present disclosure. However, it will be appreciated by those skilled in the art that the embodiments of the present disclosure may be practiced without adopting these specific details. In fact, the embodiments of the present disclosure may be practiced in conjunction with conventional manufacturing techniques employed in the industry. In addition, the description provided below does not form a complete process flow, device or system, or related methods for determining the respiratory effort of a patient, patient-ventilator asynchrony. Only those process actions and structures necessary for understanding the embodiments of the present disclosure are described in detail below. Additional actions for determining the respiratory effort of a patient or patient-ventilator asynchrony may be performed by conventional techniques. In addition, any drawings attached to the present application are for illustrative purposes only and are therefore not drawn to scale. In addition, common elements between the drawings may retain the same digital identifiers.

[0022] In the following detailed description, reference is made to the accompanying drawings forming a part thereof, in which specific embodiments in which the present disclosure may be practiced are shown by way of illustration. These embodiments are described in sufficient detail to enable those of ordinary skill in the art to practice the present disclosure. However, it should be understood that the detailed description and specific examples, although indicating examples of the embodiments of the present disclosure, are given only in an illustrative and non-limiting manner. According to the present disclosure, various replacements, modifications, additions, rearrangements or combinations thereof may be made within the scope of the present disclosure, and this will become apparent to those of ordinary skill in the art.

[0023] As a matter of practice, the various features shown in the drawings may not be drawn to scale. The drawings presented herein are not meant to be actual views of any particular device (e.g., equipment, system, etc.) or method, but are merely representations for describing various embodiments of the present disclosure. Therefore, for the sake of clarity, the sizes of various features may be arbitrarily enlarged or reduced. In addition, for the sake of clarity, some of the drawings in the drawings may be simplified. Therefore, the drawings may not depict all the components of a given device or all the operations of a particular method.

[0024] The information and signals described herein may be represented using any of a variety of different techniques and skills. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the specification may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof. For the purpose of clear presentation and description, some drawings may show multiple signals as a single signal. It will be appreciated by those of ordinary skill in the art that a signal may represent a bus of signals, wherein the bus may have a variety of bit widths, and the present disclosure may be implemented on any number of data signals including a single data signal.

[0025] The various exemplary logic blocks, modules, and circuits described in conjunction with the embodiments disclosed herein may be implemented or executed using a general-purpose processor, a special-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. When a general-purpose processor executes instructions (e.g., software code) stored on a computer-readable medium, the general-purpose processor may be considered a special-purpose processor. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0026] In addition, it should be noted that the embodiments can be described according to the process that can be depicted as a flow chart, a flow diagram, a structure diagram or a block diagram. Although the flow chart can describe the operation action as a sequential process, many of these actions can be performed in another order, in parallel or substantially simultaneously. In addition, the order of these actions can be rearranged. The process can correspond to a method, a function, a program, a subroutine, a subprogram, etc. In addition, the method disclosed herein can be implemented in hardware, software or both. If implemented in software, these functions can be stored or transmitted on a computer-readable medium as one or more instructions or codes. Computer-readable media includes both computer storage media and communication media, including any medium that facilitates the transmission of a computer program from one place to another.

[0027] As used herein, the singular forms following “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0028] As used herein, the term "may" with respect to a material, structure, feature, or method action indicates that this is intended for use in implementing an embodiment of the present disclosure, and such term is used in preference to the more restrictive term "is" to avoid any implication that other compatible materials, structures, features, and methods that may be used in combination therewith should or must be excluded.

[0029] As used herein, the "dependent" region of the lungs refers to and includes the lower region of the lungs, such as the region of the lungs located near the patient's back (as opposed to the region of the lungs located near the patient's chest). The dependent region of the lungs may include the dorsal region, which may also be referred to as the posterior region of the lungs.

[0030] As used herein, the "non-dependent" region of the lungs refers to and includes the upper region of the lungs, such as the region of the lungs located near the patient's chest. The non-dependent region of the lungs may include the ventral region, which may also be referred to as the anterior region of the lungs.

[0031] As used herein, the term "impedance data" refers to a signal from an electrical impedance tomography system, and also includes information that can be derived from the signal of an electrical impedance tomography system. Non-limiting examples of information that can be derived from the signal of an electrical impedance tomography system include images (EIT images), plethysmographs derived from EIT data, chord compliance, and perfusion.

[0032] It should be understood that any reference to elements herein using names such as "first", "second", etc. does not limit the quantity or order of those elements, unless such restrictions are explicitly stated. On the contrary, these names can be used as a convenient method to distinguish two or more elements or two or more instances of elements in this article. Therefore, the reference to the first element and the second element does not mean that only two elements can be adopted here, or that the first element must precede the second element in some way. In addition, unless otherwise stated, a group of elements may include one or more elements.

[0033] As used herein, the term "substantially" with respect to a given parameter, characteristic, or condition means and includes to the extent that one skilled in the art would understand that the given parameter, characteristic, or condition is met with a small degree of variance (such as within acceptable manufacturing tolerances). For example, a substantially met parameter may be at least about 90% met, at least about 95% met, or even at least about 99% met.

[0034] As used herein, the term "about" used with reference to a given parameter is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with the measurement of the given parameter, as well as variations due to manufacturing tolerances, etc.).

[0035] According to embodiments described herein, a non-invasive technique may be used to determine a patient's respiratory effort. In some embodiments, patient-ventilator asynchrony (such as ineffective effort (IEE; also referred to as "ineffective inspiratory effort")) may be detected by comparing impedance data (e.g., an EIT plethysmograph) of at least one dependent region of the lung to one or more of historical impedance data of at least one dependent region of the lung, impedance data of an independent region of the lung, airway pressure, airway flow, and a stored pattern of impedance data of at least one dependent region. In some embodiments, in response to determining a relative increase in impedance of a dependent region of the lung without a corresponding increase in impedance of an independent region of the lung, an increase in flow rate in the airway, pressure in the airway, historical impedance data of at least one dependent region, or a stored pattern of impedance of at least one dependent region, a patient's respiratory effort (such as patient-ventilator asynchrony) may be detected. Each of the impedance of the dependent region, the impedance data of the independent region, the flow rate in the airway, the pressure in the airway, historical impedance data of at least one dependent region, and a stored pattern of impedance data of at least one dependent region can be determined in a non-invasive manner. In response to detecting patient-ventilator asynchrony, corrective action may be taken, such as adjusting ventilator parameters to reduce the incidence of asynchrony. Related systems and devices for detecting patient-ventilator asynchrony are also disclosed. Thus, a patient's respiratory effort and / or patient-ventilator asynchrony may be detected using a non-invasive method, such as using an EIT system mechanical ventilator.

[0036] Figure 1 1 is a schematic diagram of a portion of an EIT system 100 showing a plurality of electrodes 110 positioned around a region of interest (e.g., a chest) of a patient 105. The electrodes 110 of a conventional EIT system 100 are typically physically held in place by an electrode band 103. The placement of the electrodes 110 is typically transverse to the patient's cranio-caudal axis 104 and substantially parallel to the axis 102. Although the electrodes 110 are positioned Figure 1 105, but the electrodes 110 may be placed around the entire patient 105, depending on the particular region of interest available for measurement or desired for measurement. The electrodes 110 may be coupled to a computing system (not shown) that is configured to control the operation of the electrodes 110 and perform reconstruction of the EIT image.

[0037] Figure 2 1 is a schematic diagram showing a cross section of the chest of a patient 105 along the plane of the electrodes. A voltage may be applied to a pair of electrodes 110 (shown by electrodes with + and - symbols) to inject an excitation current into the patient between the pair of electrodes. Thus, the voltages (e.g., V1, V2, V3, ... V n) may be detected by other electrodes and measured by the EIT system 100. Current injection may be performed according to a circular pattern for a measurement cycle using different electrode pairs to generate the excitation current.

[0038] Figure 3 3 is a schematic block diagram of an EIT system 300 according to one embodiment of the present disclosure. The EIT system 300 may include an electrode belt 310 operably coupled to a data processing system 320. The electrode belt 310 and the data processing system 320 may be coupled together via a wired connection (e.g., a cable) and / or may have a communication module for wirelessly communicating with each other. The data processing system 320 may include a processor 322 operably coupled to an electronic display 324, an input device 326, and a memory device 328. The electronic display 324 may be configured together with the data processing system 320 to form a singular form factor of an EIT device coupled to the electrode belt 310. In some embodiments, the electronic display 324 and the data processing system 320 may be separate units of the EIT device coupled to the electrode belt 310. In yet other embodiments, the EIT system 300 may be integrated within another host system that is configured to perform additional medical measurements and / or procedures, wherein the electrode belt 310 may be coupled to a port of the host system that already has its own input devices, memory devices, and electronic displays. Thus, the host system may have the EIT processing software installed therein. Such software may be built into the host system prior to field use or updated after installation.

[0039] The processor 322 can coordinate communications between various devices and execute instructions stored in the computer-readable medium of the memory device 328 to direct current excitation, data acquisition, data analysis, and / or image reconstruction. As an example, the memory device 328 may include a finite element mesh library used by the processor 322 to model the patient's body in the region of interest in order to perform image reconstruction. In some embodiments, the memory 328 includes historical data of the impedance of the patient's lungs (such as impedance data of the region of interest (e.g., dependent region) and impedance data of other regions of the lungs) and / or a pattern of impedance data of the patient's lungs. The input device 326 may include devices such as a keyboard, a touch screen interface, a computer mouse, a remote control, a mobile device, or other devices configured to receive information, which the processor 322 may use to receive input from an operator of the EIT system 300. Therefore, for a touch screen interface, the electronic display 324 and the input device 326 that receives user input may be integrated into the same device. The electronic display 324 may be configured to receive the data and output an EIT image reconstructed by the processor for viewing by the operator. The processor 322 may also utilize the measured EIT data to generate additional data (e.g., numerical data, graphs, trend information, and other information deemed useful to an operator) either alone or in combination with other non-EIT data from other equipment coupled thereto. Such additional data may be displayed on the electronic display 324.

[0040] As will be appreciated by one of ordinary skill in the art, the EIT system 300 may include components not shown in the figure but may also be included to facilitate communication with the electrode belt 310 and / or current excitation, such as one or more analog-to-digital converters, signal processing circuits, demodulation circuits, power supplies, etc.

[0041] Figure 4 is a schematic diagram of a system for identifying a patient's respiratory effort and patient-ventilator asynchrony. For example, Figure 4 A system 400 is depicted for determining whether a given patient 410 connected to a mechanical ventilator 408 exhibits asynchrony with the mechanical ventilator 408. The system 400 may include a ventilator system 402, an EIT system 404, and a controller 406 for operating the system 400, and in particular, the ventilator system 402, the EIT system 404. The ventilator system 402 and the EIT system 404 may be operably coupled to the controller 406.

[0042] In some embodiments, the ventilator system 402 includes a mechanical ventilator 408 that provides respiratory support or respiratory assistance to a patient 410. For example, the mechanical ventilator 408 can provide a flow of medical gas that can include one or more of air, oxygen, nitrogen, and helium. In some embodiments, the flow of medical gas can also include additives, such as aerosol drugs or anesthetics. The ventilator system 402 can also include a breathing circuit 412, an inspiratory limb 414, a patient limb 416, and a patient connector 418. In some embodiments, the mechanical ventilator 408 can provide a flow of medical gas to the breathing circuit 412 through the inspiratory limb 414, which is connected to the inspiratory port 420 of the mechanical ventilator 408. The medical gas can flow (e.g., travel) through the inspiratory limb 414 and enter the patient limb 416 of the breathing circuit 412. Therefore, the mechanical ventilator 408 can provide medical gas to the patient 410 through the patient connector 418.

[0043] Exhaled gas from the patient 410 may be delivered back to the mechanical ventilator 408 through the patient connector 418 and the patient limb 416. In some embodiments, the exhaled gas may be directed into the expiratory limb 422 of the breathing circuit 412 via one or more valves (e.g., check valves). For example, the ventilator system 402 may also include a plurality of check valves that may be placed at various points along the breathing circuit 412, such as to allow only medical gas to flow in a desired direction along an appropriate path toward or away from the patient 410.

[0044] Additionally, exhaled air may be returned to the mechanical ventilator 408 through an exhalation port 424 of the mechanical ventilator 408 .

[0045] In some embodiments, the exhalation port 424 may include a controllable flow valve that can be adjusted to regulate the pressure within the breathing circuit 412. Adjusting the flow valve can generate a back pressure that is applied to the patient 410 during exhalation to generate positive end-expiratory pressure ventilation. Thus, the system 400 may include any conventional system for providing PEEP therapy to the patient 410. In addition, other systems and configurations recognized by those of ordinary skill in the art fall within the scope of the present disclosure.

[0046] The ventilator system 402 may also include one or more gas monitoring sensors 426. In some embodiments, the one or more gas monitoring sensors 426 may be disposed within the patient connection 418 of the breathing circuit 412. In alternative embodiments, the one or more gas monitoring sensors 426 may be fluidly connected to the breathing circuit 412 or any other component of the ventilator system 402. In some embodiments, the gas monitoring sensors 426 may include one or more of a pressure sensor, a flow sensor, and a gas concentration sensor. As described in further detail below, the controller 406 and the mechanical ventilator 408 may utilize the one or more gas monitoring sensors 426 to monitor and ultimately control the operation of the mechanical ventilator 408 and provide information (e.g., feedback to a user (e.g., a clinician)). In some embodiments, the one or more gas sensors 426 may include any conventional gas sensor.

[0047] The EIT system 404 may include the Figures 1 to 3 Any EIT system described, and can be operated according to any of the above embodiments. In some embodiments, EIT system 404 may include any conventional EIT system. In addition, as described above, EIT system 404 can be operably coupled to controller 406, and can provide information about the measurement performed by EIT system 404 to controller 406. In some embodiments, EIT system 404 can be completely independent of ventilator system 402, and can determine that PEEP changes during manipulation by corresponding pressure sensors operably coupled to EIT system 404. In one or more embodiments, EIT system 404 may also have a corresponding electronic display and input device separated from the display and / or input device of ventilator system 402. In addition, the electronic display and input device of EIT system 404 can be used to input (e.g., manually input) information about PEEP and / or other ventilation parameters.

[0048] The controller 406 may include a processor 428 coupled to a memory 430 and an input / output component 432. The processor 428 may include a microprocessor, a field programmable gate array, and / or other suitable logic devices. The processor 428 may execute instructions stored in a computer-readable medium of the memory device 430 to direct current excitation, data acquisition, data analysis, image reconstruction, and / or determination of patient-ventilator asynchrony. The memory 430 may include volatile and / or non-volatile media (e.g., ROM, RAM, disk storage media, optical storage media, flash memory devices, and / or other suitable storage media) and / or other types of computer-readable storage media (e.g., non-transitory computer-readable storage media) configured to store data. The memory 430 may store algorithms and / or instructions to be executed by the processor 428 for operating the ventilator system 402 and the EIT system 404. For example, the controller 406 may include the instructions described above with respect to Figure 3 The data processing system 320 described above. In some embodiments, the processor 428 is operably coupled to send data to a computing device, such as a server or a personal computer, that is operably coupled (e.g., via the Internet) to the controller 406. The input / output component 432 may include a display, a touch screen, a keyboard, a mouse, and / or other suitable types of input / output devices configured to accept input from an operator and provide output to the operator. In some embodiments, the memory 430 may include historical data of the impedance of the patient's lungs (such as impedance data for a region of interest (e.g., a dependent region) and impedance data for other regions of the lungs).

[0049] Still reference Figure 4 , system 400 can utilize ventilator system 402 to apply ventilation support, and can be configured to determine the patient's respiratory effort and the presence of patient-ventilator asynchrony (such as ineffective effort). In some embodiments, system 400 is configured to provide a level of PEEP to the patient based on the determined respiratory effort and / or patient-ventilator asynchrony. PEEP increases the baseline pressure within the patient's respiratory system so that the patient's natural exhalation maintains a higher airway pressure than breathing without PEEP therapy. Conventional PEEP pressures range from 0 to 40 cm H2O, but higher PEEP pressures can also be used.

[0050] In some embodiments, the EIT system 300, 404, and / or system 400 may be used to determine ineffective efforts. Figure 55 is a simplified flow chart illustrating a method 500 for determining a patient's breathing-related effort. The method 500 may include placing a plurality of electrodes of an EIT system (e.g., EIT system 100) around a patient's chest; an action 504 includes applying a current between electrodes of the plurality of electrodes; an action 506 includes determining impedance data of at least a first region of the patient's lung using electrodes of the plurality of electrodes; an action 508 includes obtaining one or both of a gas flow rate within a patient's breathing circuit and a pressure within the patient's breathing circuit; an action 510 includes comparing the impedance data of the first region with one or more of historical impedance data of the first region, a stored pattern of impedance data of the first region, impedance data of at least a second region of the patient's lung, a gas flow rate in the breathing circuit, and a pressure within the patient's breathing circuit to determine the patient's breathing effort and / or whether patient-ventilator asynchrony has occurred; an action 512 includes, in response to determining that a patient's breathing effort has occurred, optionally determining whether the patient's breathing effort follows a breathing cycle to identify ineffective effort asynchrony; and an action 514 includes providing one or more corrective actions to a mechanical ventilator in communication with the patient.

[0051] Act 502 includes placing a plurality of electrodes of the EIT system around the patient's chest. In some embodiments, act 502 includes operably connecting the patient to a mechanical ventilator. In some embodiments, the EIT system includes any of the EIT systems described above (EIT system 100, EIT system 300, EIT system 404), and the patient is connected to (in communication with) a mechanical ventilator (such as Figure 4 408). However, the present disclosure is not limited thereto, and the patient may be connected to a mechanical ventilator.

[0052] Action 504 includes applying a current between electrodes in the plurality of electrodes. In some embodiments, a voltage is sequentially applied between a pair of electrodes to inject an excitation current into the patient between the pair of electrodes, and the voltage can be measured with other electrodes of the EIT system. Current injection can be performed for a measurement cycle according to a circular pattern using different electrode pairs to generate the excitation current, as described above with reference to Figure 2 In some embodiments, action 504 occurs simultaneously with providing mechanical ventilation to the patient (such as via PEEP therapy). However, the present disclosure is not limited thereto, and action 504 may occur without providing mechanical ventilation to the patient.

[0053] Act 506 includes determining impedance data for a first region of a lung of the patient using electrodes from the plurality of electrodes. In some embodiments, act 506 also includes determining impedance data for at least a second region of a lung of the patient. In some embodiments, determining impedance data for at least the second region of the patient is performed substantially simultaneously with determining impedance data for the first region of the lung of the patient using electrodes from the plurality of electrodes. In some such embodiments, voltage data (corresponding to impedance data) for the first region and at least the second region is measured simultaneously.

[0054] In some embodiments, the first region of the patient's lungs includes a dependent (e.g., dorsal, posterior) region of the patient's lungs. The dependent region can include a portion of the lungs that is near the patient's back. In other words, the dependent region includes a portion of the lungs that is closer to the floor when the patient is prone and face up.

[0055] In some embodiments, the first region includes at least one dependent region. In some embodiments, the first region includes only dependent regions of the patient's lungs. However, the disclosure is not limited thereto, and in other embodiments, the first region includes dependent regions and non-dependent regions of the patient's lungs. The first region may be referred to herein as an "ineffective effort region of interest" (IEROI).

[0056] At least one second region may include at least one region of the patient's lung that is different from the first region. In some embodiments, at least one second region includes a non-dependent (e.g., ventral, anterior) region of the patient's lung. The non-dependent region may include a portion of the patient's lung that is close to the patient's chest (and away from the back). In other words, the non-dependent region includes a portion of the lung that is located away from the floor when the patient is prone and face-up. In some embodiments, at least the second region does not contain (does not include) a dependent region of the lung and does not include an IEROI.

[0057] Fig. 6A is a graph of flow and airway pressure measured at a patient's airway and impedance data (ΔZ) of a patient's lung measured at posterior and anterior regions according to an embodiment of the present disclosure. Fig. 6A 6, graph 602 represents an EIT plethysmograph of a first region of the lung, which may include a dependent region of the lung and include an IEROI. Graph 604 represents an EIT plethysmograph of a second region of the lung over the same time period as the EIT plethysmograph of the first region of the lung. Graph 606 represents gas flow within a patient breathing circuit, and graph 608 represents pressure within a patient breathing circuit over the same time period. Gas monitoring sensors (e.g., gas monitoring sensors 426 ( Figure 4 )), ventilator (e.g., mechanical ventilator 408 ( Figure 4)) or both to measure the gas flow and pressure within the patient breathing circuit. Each of the EIT plethysmograph of the first region (first impedance data), the EIT plethysmograph of at least the second region (second impedance data), the flow rate, and the pressure within the patient breathing circuit may be measured substantially simultaneously, such as Fig. 6A As shown, the x-axis represents the time of each measurement.

[0058] The EIT plethysmograph of the first region and the EIT plethysmograph of the at least second region may be obtained simultaneously during ventilator support and PEEP therapy (such as during ascending and descending PEEP steps for alveolar recruitment and / or lung recruitment), as described in U.S. Patent Application Publication No. 2019 / 0246949, the entire disclosure of which is hereby incorporated by reference herein. The EIT plethysmograph of the first region and the EIT plethysmograph of the at least second region may represent the sum of the base impedances of the pixels of the EIT images of the corresponding first region and at least the second region of the lung within the EIT image. For example, with reference to Figure 6B , shows an EIT image showing dependent and independent areas of a patient's lungs. Figure 6B The lower half of may represent the dependent region of the lung, and the upper half may represent the independent region of the lung. The plethysmograph may represent the sum of impedances in a certain region of interest, and may also be derived from pixel values ​​determined after applying an image reconstruction algorithm to the impedance data.

[0059] Reference again Figure 5 and Fig. 6A , act 506 includes measuring impedance data within the first region. In some embodiments, act 506 also includes measuring impedance data within a second region of the lung over time. In some embodiments, the measured impedance data is represented as a relative change in impedance of the respective first and second regions of the lung (such as, relative to a reference baseline impedance in each of the first and second regions). In some embodiments, the reference baseline represents an average value of the voltage set acquired during an initial duration of the EIT system.

[0060] Return to reference Figure 5 , action 508 includes obtaining one or both of a gas flow rate within the patient breathing circuit and a pressure within the patient breathing circuit. In some embodiments, obtaining the gas flow rate and pressure within the patient breathing circuit includes measuring the gas flow rate and pressure. In other embodiments, the gas flow rate and pressure are obtained by a ventilator, which can control the gas flow rate and pressure. In some embodiments, a gas monitoring sensor (such as gas monitoring sensor 426 ( Figure 4)) to measure the gas flow within the patient's breathing circuit. The gas monitoring sensor may be placed anywhere within the patient's breathing circuit. The pressure within the patient's breathing circuit may be measured using a gas monitoring sensor, which may include the same gas monitoring sensor as the gas monitoring sensor that measures the gas flow or a different gas monitoring sensor. In some embodiments, a ventilator (such as a mechanical ventilator 408 ( Figure 4 )) to measure one or both of the gas flow or pressure within the patient's breathing circuit.

[0061] Action 510 may include comparing the impedance data for the first region to one or more of historical impedance data for the first region, a stored pattern of impedance data for the first region, impedance data for the second region, gas flow in the patient breathing circuit, and pressure within the patient breathing circuit to determine the patient's respiratory effort and / or whether patient-ventilator asynchrony has occurred. For example, referring back to Fig. 6A , first impedance data for a first region of the lungs (graph 602) may be compared to one or more of impedance data for a second region of the lungs (graph 604), a flow rate within the breathing circuit (graph 606), and a pressure within the breathing circuit (graph 608). Fig. 6A The shaded area 610 of represents the time range in which ineffective effort asynchrony occurs. During the time period in the shaded area 610, the impedance in the first area (dependent area) shows an increase, as indicated by arrow 601, while the impedance in the second area (independent area) does not increase accordingly, as indicated by graph 604, the flow does not increase, as indicated by arrow 605, and the airway pressure does not increase, as indicated by arrow 607. In other words, the impedance in the second area does not show the same corresponding increase as the impedance in the first area. In addition, during the same time period, the flow and pressure in the airway do not show changes, as occurs during a normal breathing cycle. Therefore, the breathing effort of the patient and patient-ventilator asynchrony (e.g., ineffective effort) can be determined by comparing the impedance data of the first area with one or more of the impedance data of at least the second area, the flow rate in the airway, and the pressure in the airway. In additional embodiments, patient-ventilator asynchrony can be determined based on the impedance of the first area and the historical value of the impedance of the first area, the storage mode of the impedance data of the first area, or the comparison of the two. In some embodiments, patient-ventilator asynchrony may be determined based on a comparison of the impedance of the first region to the impedance of the first region during a previous normal breathing cycle or a wasted effort cycle.

[0062] Act 512 may include, in response to determining that a patient respiratory effort has occurred, optionally determining whether the patient's respiratory effort follows the respiratory cycle to identify ineffective effort asynchrony.

[0063] Action 514 includes providing one or more corrective actions to a mechanical ventilator in communication with the patient in response to identifying ineffective effort asynchrony. In some embodiments, the one or more corrective actions include: changing ventilator parameters such as PEEP, I:E (inspiratory: expiratory, also known as ventilation ratio) relationship, respiratory rate, and trigger settings; and providing an indication of patient-ventilator asynchrony (such as on input / output component 432 ( Figure 4 )).

[0064] Figure 6C 61 is a graph of flow and airway pressure measured at a patient's airway and impedance data of a patient's lung measured at a posterior region and at an anterior region according to an embodiment of the present disclosure. The graph shows each of a gas flow rate within a patient's breathing circuit to the patient, a pressure within the patient's breathing circuit, an EIT plethysmograph measured over time in a first region of the lung, and an EIT plethysmograph measured over time in at least a second region of the lung during ineffective effort asynchrony in the same time frame. Graph 612 represents the EIT plethysmograph of a first region of the lung, which may include a dependent region of the lung and include an IEROI; graph 614 represents the EIT plethysmograph of a second region of the lung within the same time period as the EIT plethysmograph of the first region of the lung; graph 616 represents the gas flow within the patient's breathing circuit; and graph 618 represents the pressure within the patient's breathing circuit.

[0065] The patient's ineffective breathing effort occurs during the time period corresponding to the shaded area 620. Arrow 611 indicates a slight increase in impedance within the first region without a corresponding increase in impedance within at least the second region. The second region shows a decrease in impedance after the shaded area 620, indicating that the air content in at least the second region has decreased. Arrows 615 and 617 indicate that the flow or pressure does not increase at a time corresponding to the slight increase in impedance within the first region (arrow 611), thereby confirming that the change (increase) in impedance within the first region is in response to the patient's effort, which does not cause a triggering of the ventilation cycle, thereby indicating patient-ventilator asynchrony (ineffective effort). In other words, the change (increase) in impedance within the first region is in response to the patient's breathing effort, and such breathing effort does not trigger a ventilator cycle, as indicated by the flow and pressure curves, resulting in patient-ventilator asynchrony.

[0066] Fig.6D is a graph of flow and airway pressure measured at the patient's airway and impedance data of the patient's lung measured at the posterior region and at the anterior region according to an embodiment of the present disclosure. Fig.6D6, graph 622 represents the pressure within the patient's breathing circuit, graph 624 represents the gas flow within the patient's breathing circuit, graph 626 represents the volume of gas introduced into the patient's breathing circuit via the ventilator, and graph 628 is an EIT plethysmograph of the dependent region of the patient's lungs. A reverse trigger (also called "reverse trigger"; a type of asynchrony that occurs when the patient exerts effort after the ventilator begins breathing) occurs at the time indicated by line 621. In response to the reverse trigger, the impedance within the dependent region of the patient's lungs exhibits a positive excursion only during the second ventilation cycle corresponding to line 623, and the volume graph 626 indicates breath stacking. The positive excursion of impedance at time 623 shows the relationship between diaphragmatic contraction and impedance within the dependent region. At time 625, the impedance within the dependent region decreases in response to the assist cycle via the ventilator starting at time 623, indicating that a reverse trigger has occurred and that there is patient-ventilator asynchrony. At time 625, the patient does not respond to the ventilation provided by the mechanical ventilator.

[0067] Thus, a patient's respiratory effort, patient-ventilator asynchrony, or both may be detected (identified) by comparing impedance data from at least one dependent region of the patient's lungs to one or more historical values ​​of impedance data for at least one dependent region of the lungs, a stored pattern of impedance data for the dependent region of the lungs, concurrent impedance data for a second region of the patient's lungs (at least a portion of which includes an independent region of the lungs), concurrent gas flow in the patient's airway, and concurrent pressure within the airway. Without being bound by any particular theory, it is believed that by analyzing the impedance of the dependent region of the lungs, patient-ventilator asynchrony may be detected because the dependent region of the lungs is more responsive to activity of the diaphragm than the independent region of the lungs. Thus, a patient's respiratory effort (which utilizes the diaphragm) may be monitored via impedance activity of the dependent region of the lungs.

[0068] In some embodiments, a relative increase in impedance within a dependency region without a corresponding increase in impedance within a second region, an increase in gas flow within the airway, or an increase in pressure within the airway may indicate patient-ventilator asynchrony, such as ineffective effort. Advantageously, patient-ventilator asynchrony may be detected via non-invasive means, such as using EIT by applying a voltage to the patient's chest. In addition, patient-ventilator asynchrony may be detected during use of a mechanical ventilator and an EIT system, and no additional equipment or invasive catheters are required. In contrast, conventional methods of determining patient-ventilator asynchrony include, for example, esophageal pressure tracking (which requires an esophageal balloon) or neurally adjusted ventilator assist (NAVA), both of which require positioning of the catheter and are invasive techniques.

[0069] Example

[0070] The detection of ineffective effort based on impedance data of dependent regions of the lung or image data derived from impedance data (EIT) was validated using diaphragm electrical activity (Edi) monitoring in suckling pigs. Figure 7 is a graph of flow and airway pressure measured at the airway of a piglet and impedance data of the lung measured at the posterior region and at the anterior region, and a graph of the electrical activity of the diaphragm. Ineffective effort is indicated in the shaded area 702 of the graph.

[0071] The animal's respiratory effort can be observed by an increase in diaphragm electrical activity (indicated at arrow 704) accompanied by a slight increase in impedance of the dependent region of the lung (indicated at arrow 706) when there is no increase in airway pressure and no flow through the airway. Thus, at times when there is no flow in the airway or when there is no increase in flow or pressure, a slight increase in impedance of the dependent region can indicate ineffective effort asynchrony.

[0072] Additional non-limiting exemplary embodiments of the present disclosure are set forth below.

[0073] Embodiment 1: A method for determining a patient's respiratory effort, the method comprising: obtaining first impedance data representing a first region of the patient's lungs, the first region including at least a dependent region of the lungs; comparing the first impedance data with one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the patient's lungs including at least a non-dependent region of the patient's lungs, historical impedance data for the first region, and a stored pattern of impedance data for the first region; and identifying the occurrence of the patient's respiratory effort based on the comparison.

[0074] Embodiment 2: A method according to embodiment 1, wherein acquiring first impedance data representing a first region of the lung of the patient includes acquiring the first impedance data of a dependent region only of the lung.

[0075] Embodiment 3: The method of embodiment 1 or embodiment 2, wherein acquiring first impedance data representing a first region of the patient's lungs includes acquiring the first impedance data while the patient is in operable communication with a ventilator.

[0076] Embodiment 4: The method of any one of Embodiments 1 to 3, wherein comparing the first impedance data comprises comparing the first impedance data with the historical impedance data of the first region.

[0077] Embodiment 5: A method according to any one of embodiments 1 to 4, wherein comparing the first impedance data with one or more of the flow rate within the patient's breathing circuit, the pressure within the breathing circuit, second impedance data representing a second region of the patient's lungs including at least a non-dependent region of the patient's lungs, historical impedance data for the first region, and a stored pattern of impedance data for the first region includes comparing the first impedance data with each of the second impedance data, the flow rate, and the pressure within the same time period.

[0078] Embodiment 6: A method according to any of embodiments 1 to 5, wherein comparing the impedance data with one or more of a flow rate within the patient's breathing circuit, a pressure within the breathing circuit, second impedance data representing a second region of the patient's lungs including at least a non-dependent region of the patient's lungs, historical impedance data for the first region, and a stored pattern of impedance data for the first region includes determining ineffective effort by the patient.

[0079] Embodiment 7: A method according to any one of Embodiments 1 to 6, wherein acquiring first impedance data representing a first region of the lung of the patient includes acquiring the first impedance data representing a dependent region and an independent region of the lung.

[0080] Embodiment 8: The method of any one of Embodiments 1 to 7, wherein acquiring first impedance data representative of a first region of the lung of the patient comprises acquiring an EIT plethysmograph of the first region of the lung.

[0081] Embodiment 9: A method according to any one of embodiments 1 to 8, further comprising determining asynchrony between the patient and the ventilator in response to measuring an increase in the first impedance without increasing the pressure or the flow rate within the breathing circuit.

[0082] Embodiment 10: The method of any one of Embodiments 1 to 9, further comprising determining asynchrony between the patient and the ventilator in response to measuring an increase in the first impedance without a corresponding increase in the second impedance.

[0083] Embodiment 11: A method according to any one of embodiments 1 to 10, wherein comparing the first impedance data with one or more of a flow rate within the patient's breathing circuit, a pressure within the breathing circuit, second impedance data representing a second region of the patient's lungs including at least a non-dependent region of the patient's lungs, historical impedance data for the first region, and a stored pattern of impedance data for the first region includes determining a reverse trigger event.

[0084] Embodiment 12: A system for determining a patient's respiratory effort, the system comprising: an electrical impedance tomography system; at least one processor, the at least one processor coupled to the electrical impedance tomography system; and at least one non-transitory computer-readable storage medium, the at least one non-transitory computer-readable storage medium storing instructions thereon, the instructions, when executed by the at least one processor, causing the at least one processor to: acquire first impedance data representing at least one dependent region of a patient's lungs using the electrical impedance tomography system; and compare the first impedance data with one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the patient's lungs including at least a non-dependent region, historical impedance data of the first region, and a stored pattern of impedance data representing the first region of the lungs, to identify the patient's respiratory effort based on the comparison.

[0085] Embodiment 13: According to the system of embodiment 12, the system also includes at least one gas monitoring sensor, which is operably coupled to the system, and the at least one gas monitoring sensor is configured to measure one or both of the pressure and the flow rate within the breathing circuit.

[0086] Embodiment 14: The system of embodiment 12 or embodiment 13, wherein comparing the first impedance data with one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the lungs of the patient including at least a non-dependent region, historical impedance data for the first region, and a stored pattern of impedance data representing the first region of the lungs to identify the patient's breathing effort includes determining asynchrony between the patient and a ventilator in response to measuring an increase in the first impedance without a corresponding increase in one or more of the second impedance, the flow rate, and the pressure within the breathing circuit.

[0087] Embodiment 15: The system of any one of Embodiments 12 to 14, wherein the instructions are further configured to cause the at least one processor to initiate a breathing cycle in response to identifying an asynchrony between the patient and a ventilator.

[0088] Embodiment 16: A system according to any of embodiments 12 to 15, wherein comparing the first impedance data with one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the lung of the patient including at least a non-dependent region, historical impedance data for the first region, and a stored pattern of impedance data representing the first region of the lung includes comparing the first impedance data with the second impedance data in response to determining an increase in the first impedance without a corresponding increase in one or both of the pressure and the flow rate in the breathing circuit.

[0089] Embodiment 17: A system according to any one of embodiments 12 to 16, wherein acquiring first impedance data representing at least one dependent region of a patient's lung using the electrical impedance tomography system includes acquiring the first impedance data of only the dependent region of the lung.

[0090] Embodiment 18: A system according to any of embodiments 12 to 17, wherein comparing the first impedance data with one or more of a flow rate within the patient's breathing circuit, a pressure within the breathing circuit, second impedance data representing a second region of the patient's lungs including at least a non-dependent region, historical impedance data for the first region, and a stored pattern of impedance data representing the first region of the lungs comprises comparing the first impedance data with each of the flow rate within the breathing circuit, the pressure within the breathing circuit, the second impedance data, and the historical impedance data for the first region.

[0091] Embodiment 19: A system for determining a patient's respiratory effort, the system comprising: an electrical impedance tomography system; and a controller, wherein the electrical impedance tomography system is operably coupled to the controller, the controller comprising: at least one processor; and at least one non-transitory computer-readable storage medium, the at least one non-transitory computer-readable storage medium storing instructions thereon, the instructions, when executed by the at least one processor, causing the at least one processor to: cause the electrical impedance tomography system to acquire first impedance data of a first region of the patient's lungs, the first region comprising a dependent region of the lungs; compare the first impedance data with one or more of second impedance data representing a non-dependent region of the patient's lungs, a flow rate within the patient's breathing circuit, a pressure within the breathing circuit, historical impedance data of the first region, and a stored pattern of impedance data of the first region; and identify the patient's respiratory effort based on the comparison.

[0092] Embodiment 20: According to the system of embodiment 19, the system also includes a ventilator that communicates with the patient and is operably coupled to the controller, and the ventilator is configured to provide a breathing cycle to the patient in response to identifying the breathing effort of the patient.

[0093] Although the embodiments of the present disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the present disclosure is not limited to the specific forms disclosed. On the contrary, the present disclosure encompasses all modifications, variations, combinations and alternative forms that fall within the scope of the present disclosure, as defined by the following appended claims and their legal equivalents.

Claims

1. A method for determining a patient's respiratory effort, the method comprising: acquiring first impedance data representative of a first region of a lung of a patient, the first region including at least a dependent region of the lung, comparing an increase or decrease in the first impedance data with an increase or decrease in one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the lungs of the patient including at least a non-dependent region of the lungs of the patient, historical impedance data for the first region, and a stored pattern of impedance data for the first region; and identifying the occurrence of a breathing effort of the patient and determining whether the breathing effort of the patient is ineffective based on the comparison. 2 . The method of claim 1 , wherein acquiring first impedance data representative of a first region of the lung of the patient comprises acquiring the first impedance data for a region-only dependent region of the lung. 3 . The method of claim 1 , wherein acquiring first impedance data representative of a first region of the patient's lung comprises acquiring the first impedance data while the patient is in operable communication with a ventilator. 4 . The method of claim 1 , wherein comparing the first impedance data comprises comparing the first impedance data to the historical impedance data for the first region.

5. The method of claim 1 , wherein comparing the increase or decrease in the first impedance data to an increase or decrease in one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the lung of the patient including at least a non-dependent region of the lung of the patient, historical impedance data for the first region, and a stored pattern of impedance data for the first region comprises comparing the first impedance data to each of the second impedance data, the flow rate, and the pressure over a same time period.

6. The method of claim 1 , wherein comparing the increase or decrease in the impedance data to an increase or decrease in one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the lung of the patient including at least a non-dependent region of the lung of the patient, historical impedance data for the first region, and a stored pattern of impedance data for the first region comprises determining ineffective effort by the patient.

7. The method of claim 1, wherein acquiring first impedance data representative of a first region of the lung of the patient comprises acquiring the first impedance data representative of a dependent region and an independent region of the lung.

8. The method of claim 1, wherein acquiring first impedance data representative of a first region of the lung of the patient comprises acquiring an EIT plethysmograph of the first region of the lung.

9. The method of claim 1, further comprising determining asynchrony between the patient and a ventilator in response to measuring an increase in the first impedance without an increase in the pressure or the flow rate within the breathing circuit.

10. The method of claim 1, further comprising determining asynchrony between the patient and a ventilator in response to measuring an increase in the first impedance without a corresponding increase in the second impedance.

11. The method of claim 1 , wherein comparing the increase or decrease in the first impedance data to an increase or decrease in one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the lung of the patient including at least a non-dependent region of the lung of the patient, historical impedance data for the first region, and a stored pattern of impedance data for the first region comprises determining a reverse trigger event.

12. A system for determining a patient's respiratory effort, the system comprising: Electrical impedance tomography system; at least one processor coupled to the electrical impedance tomography system, and at least one non-transitory computer-readable storage medium storing thereon instructions that, when executed by the at least one processor, cause the at least one processor to: acquiring, using the electrical impedance tomography system, first impedance data representing a first region of a lung of a patient, the first region including at least one dependent region of the lung of the patient; receiving a flow rate from within a breathing circuit of the patient and a pressure from within the breathing circuit; as well as An increase or decrease in the first impedance data is compared with an increase or decrease in one or more of the flow rate within the breathing circuit of the patient, the pressure within the breathing circuit, second impedance data representing a second region of the lungs of the patient including at least a non-dependent region, historical impedance data for the first region, and a stored pattern of impedance data representing the first region of the lungs to identify the patient's breathing effort based on the comparison and determine whether the patient's breathing effort is ineffective.

13. The system of claim 12, further comprising at least one gas monitoring sensor operably coupled to the system, the at least one gas monitoring sensor being configured to measure one or both of the pressure and the flow rate within the breathing circuit.

14. The system of claim 12, wherein comparing an increase or decrease in the first impedance data to an increase or decrease in one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the lung of the patient including at least a non-dependent region, historical impedance data for the first region, and a stored pattern of impedance data representing the first region of the lung to identify a breathing effort of the patient comprises determining asynchrony between the patient and a ventilator in response to measuring an increase in the first impedance without a corresponding increase in one or more of the second impedance, the flow rate, and the pressure within the breathing circuit.

15. The system of claim 12, wherein the instructions are further configured to cause the at least one processor to send a command to initiate a breathing cycle in response to identifying an asynchrony between the patient and a ventilator.

16. The system of claim 12, wherein comparing the increase or decrease in the first impedance data to the increase or decrease in one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the lung of the patient including at least a non-dependent region, historical impedance data for the first region, and a stored pattern of impedance data representing the first region of the lung comprises comparing the first impedance data to the second impedance data in response to determining an increase in the first impedance without a corresponding increase in one or both of the pressure and the flow rate in the breathing circuit.

17. The system of claim 12, wherein acquiring, using the electrical impedance tomography system, first impedance data representative of at least one dependent region of a patient's lung comprises acquiring the first impedance data for only a dependent region of the lung.

18. The system of claim 12, wherein comparing the increase or decrease in the first impedance data to the increase or decrease in one or more of a flow rate within a breathing circuit of the patient, a pressure within the breathing circuit, second impedance data representing a second region of the lung of the patient including at least a non-dependent region, historical impedance data for the first region, and a stored pattern of impedance data representing the first region of the lung comprises comparing the first impedance data to each of the flow rate within the breathing circuit, the pressure within the breathing circuit, the second impedance data, and the historical impedance data for the first region.

19. A system for determining a patient's respiratory effort, the system comprising: Electrical impedance tomography system; and a controller, wherein the electrical impedance tomography system is operably coupled to the controller, the controller comprising: at least one processor; and at least one non-transitory computer-readable storage medium storing thereon instructions that, when executed by the at least one processor, cause the at least one processor to: cause the electrical impedance tomography system to acquire first impedance data for a first region of a lung of the patient, the first region comprising a dependent region of the lung; receive a flow rate from within a breathing circuit of the patient and a pressure from within the breathing circuit; comparing an increase or decrease in the first impedance data with an increase or decrease in one or more of second impedance data representing a non-dependent region of the lungs of the patient, the flow rate within the breathing circuit of the patient, the pressure within the breathing circuit, historical impedance data for the first region, and a stored pattern of impedance data for the first region; and identifying the patient's breathing effort based on the comparison and determining whether the patient's breathing effort is ineffective.

20. The system of claim 19, further comprising a ventilator in communication with the patient and operably coupled to the controller, the ventilator configured to provide a breathing cycle to the patient in response to identifying the breathing effort of the patient.

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