Accurate evaluation of the thickness and function of the diaphragm using signals from an ultrasonic and a mechanical ventilator

Abstract

The diaphragm measurement device includes at least one electronic processor programmed to perform a diaphragm measurement method, the diaphragm measurement method including receiving ultrasonic image data of the dimensions of a patient's diaphragm during inhalation and exhalation while the patient is receiving mechanical ventilation therapy using a mechanical ventilator, receiving respiratory data of the patient during inhalation and exhalation while the patient is receiving mechanical ventilation therapy, calculating a diaphragm thickness metric based on the received ultrasonic image data of the patient's diaphragm and the received respiratory data, and displaying an indication of the calculated diaphragm thickness metric on a display device.

Description

Technical Field

[0001] This patent application claims the benefit of U.S. Provisional Patent Application No. 63 / 354,824, filed on June 23, 2022, under 35 U.S.C. § 119, the content of which is incorporated herein by reference.

[0002] The following generally relates to respiratory therapy techniques, mechanical ventilation techniques, ventilator-induced lung injury (VILI) techniques, mechanical ventilation weaning techniques, and related techniques.

Background Art

[0003] Ultrasonography (US) of the diaphragm enables quantification of diaphragm thickness, strain (velocity), and displacement, and using this, quantification of respiratory rate and duration of each contraction is also possible. Diaphragm thickness (expressed as hypertrophy rate) and strain reflect contractile activity and correlate well with diaphragm electrical activity and diaphragm pressure. As a result, thickness and strain can be used as a surrogate for respiratory effort. Uses of diaphragm ultrasonography include assessment of diaphragm function, detection of atrophy, prediction of weaning, and management of mechanical ventilation (MV) settings. Other uses are detection of asynchrony and proportional ventilation (non-invasive neurally adjusted ventilatory assist (NAVA)). The use of diaphragm ultrasonography in mechanical ventilation has attracted attention, and thus, technical problems and use cases are currently being investigated.

[0004] The diaphragm hypertrophy rate (TFdi or TFDI) as measured by ultrasonography (US) is performed by an operator who views the patient and acquires ultrasound images at end-inspiration and end-expiration. The diaphragm hypertrophy rate is determined according to Equation 1 by subtracting the end-expiratory thickness from the end-inspiratory thickness and dividing the difference by the end-expiratory thickness.

Equation

[0005] Several studies have evaluated the correlation between TFdi and respiratory effort. In one study (see, for example, E. Oppersma et al., Functional assessment of the diaphragm by speckle tracking ultrasound during inspiratory loading. J Appl Phys. 2017), the strain of the diaphragm can also be measured in real time at the zone of apposition). For example, in this study, the functional assessment of the diaphragm by speckle tracking ultrasound during inspiratory loading was analyzed. The technique of speckle tracking ultrasound enables the detection and tracking of the strain of the diaphragm over time by analyzing acoustic markers called speckles. These speckles are formed by the interference of ultrasonic waves scattered from physical structures sized corresponding to the wavelength of the ultrasonic waves. Both the strain of the diaphragm and the strain rate of the diaphragm were strongly correlated with the transdiaphragmatic pressure Pdi (strain r 2 = 0.72, strain rate r 2 = 0.80), and the electrical activity of the diaphragm EAdi (strain r 2 = 0.60, strain rate r 2 = 0.66).

[0006] The problem lies in the reliability of diaphragm thickness measurement. Accuracy, repeatability, and reproducibility are limited by the thin shape factor of the diaphragm, the movement of the diaphragm, surrounding structures and tissues, as well as macroscopic deformation, the handling of the device (angle, position, movement), insufficient image quality, and the operator's skill. The variability and uncertainty in TFDI become very high (see, for example, Goligher EC, et al., 2015, “Measuring diaphragm thickness with ultrasound in mechanically ventilated patients: feasibility, reproducibility and validity”. Intensive Care Med. 2015 Apr;41 (4):642-9. doi: 10.1007 / s00134- 015-3687-3. Epub 2015 Feb 19. Erratum in: Intensive Care Med. 2015 Apr;41(4):734. Sebastien- Bolz, Steffen [corrected to Bolz, Steffen-Sebastien], PMID: 25693448; Tuinman PR, etal., 2020, “Respiratory muscle ultrasonography: methodology, basic and advanced principles and clinical applications in ICU and ED patients-a narrative review”. Intensive Care Med. 2020 Apr;46(4):594-605. doi: 10.1007 / s00134-019-05892-8. Epub 2020 Jan 14. PMID: 31938825; PMCID: PMC7103016). For example, Goligher reported a thickness change of 0.3mm ± 0.3mm. In this example, the tolerance (0.6mm) is twice the nominal thickness change (0.3mm). This uncertainty undermines confidence in clinical decisions based on TFDI, such as decisions regarding pressure support, weaning, and extubation (see, for example, Tuinman).

[0007] In addition to the measurement errors described above, another cause of the variation in TFDI is the variation in respiratory effort / work of breathing (WOB) between breaths. This is reflected in the waveforms of the ventilator that change over time. If TFDI is measured and averaged across different breaths without considering the variability of WOB, this clearly contributes to the tolerance error in TFDI.

[0008] A further cause of the variation predicted in medical treatment is the atrophy of the diaphragm induced by the disease, which is likely to increase the "noise-to-signal" ratio.

[0009] Another study (see, for example, O’Hara DN, et al., 2020, “Ultrasonographic modeling of diaphragm function: A novel approach to respiratory assessment”. PLoS ONE 15(3): e0229972. https: / / doi.org / 10.1371 / journal.pone.0229972) measured the diaphragm thickness Tdi at different levels of negative inspiratory force (NIF) using a portable maximum negative inspiratory force (NIF) meter. The NIF meter determines the strength of the respiratory muscles by recording the negative airway pressure generated while the patient attempts to breathe through a mouthpiece equipped with a closed valve. Tdi was measured using an ultrasonic probe during exhalation at NIF = -30 cmH2O, NIF = -60 cmH2O, and maximum NIF. A quadratic function was used to fit the relationship between NIF and Tdi. O’Hara suggested that a statistical function could predict the maximum NIF based on ultrasonic measurements. Summary of the Invention Problems to be Solved by the Invention

[0010] The advantages include, for example, the ability to seal the lips, or the ability to follow the instructions of a respiratory therapist, or to rule out patient factors that might otherwise limit NIF measurement, such as patients with a depressed mental or neurological state.

[0011] The following discloses specific improvements to overcome these and other problems.

Means for Solving the Problems

[0012] In one aspect, a diaphragm measurement device includes at least one electronic processor programmed to perform a diaphragm measurement method, the diaphragm measurement method including receiving ultrasonic image data of the dimensions of the patient's diaphragm during inhalation and exhalation while the patient is receiving mechanical ventilation therapy using a mechanical ventilator, receiving respiratory data of the patient during inhalation and exhalation while the patient is receiving mechanical ventilation therapy, calculating a diaphragm thickness metric based on the received ultrasonic image data of the patient's diaphragm and the received respiratory data, and displaying a representation of the calculated diaphragm thickness metric on a display device.

[0013] In another aspect, a diaphragm measurement method includes using at least one electronic controller to receive ultrasonic imaging data of the dimensions of the patient's diaphragm during inhalation and exhalation while the patient is receiving mechanical ventilation therapy using a mechanical ventilator, receiving respiratory data of the patient during inhalation and exhalation while the patient is receiving mechanical ventilation therapy, calculating a diaphragm thickness metric based on the received ultrasonic image data of the patient's diaphragm and the received respiratory data, and displaying a representation of the calculated diaphragm thickness metric on a display device.

[0014] One advantage is to facilitate the patient's weaning from mechanical ventilation therapy.

[0015] Another advantage is to reduce the allowable error in the estimation of the diaphragm thickness by using the waveform of the ventilation device.

[0016] Another advantage is to determine the respiratory function based on the correlation between the waveform of the ventilation device and the change in the diaphragm thickness.

[0017] Another advantage is to determine the sedation level based on the correlation between the waveform of the ventilation device and the change in the diaphragm thickness.

[0018] A given embodiment may or may not provide any, one, two, more, or all of the advantages described above, and / or may provide other advantages that will become apparent to those skilled in the art upon reading and understanding the present disclosure.

Brief Description of the Drawings

[0019] The present disclosure may take the form of various components and arrangements thereof, as well as various steps and arrangements of the steps. The drawings are for the sole purpose of illustrating the preferred embodiments and should not be construed as limiting the present disclosure.

Figure 1

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Mode for Carrying Out the Invention

[0020] Unless otherwise clearly stated in context in the specification, even if not stated as plural, it includes the case where there are a plurality of them. As used herein, the expressions that two or more parts or components are "coupled", "connected", or "engaged" mean that these parts are joined either directly or indirectly, i.e., by any of one or more intermediate parts or components, or operate together as long as they are interlocked. The directional expressions used in the specification, for example, but not limited to, up, down, left, right, top, bottom, front, back, and their derivatives, are related to the orientation of the elements shown in the drawings and do not limit the scope of the claimed invention unless clearly described in this specification. The terms "having" and "including" do not exclude the presence of elements or steps other than those described in this specification and / or recited in the claims. In an apparatus composed of several means, some of these means may be embodied by the same item of hardware.

[0021] Referring to FIG. 1, a diaphragm measuring device 1 is shown. The mechanical ventilator 2 is configured to perform ventilation therapy on an associated patient P. As shown in FIG. 1, the mechanical ventilator 2 includes an outlet 4 connectable to a patient breathing circuit 5 to deliver mechanical ventilation to the patient P. The patient breathing circuit 5 includes, for example, an intake line 6, an optional exhaust line 7 (which is omitted if the ventilator uses a single-limb patient circuit), a connector or port 8 for connecting to an endotracheal tube (ETT) 16, and one or more breathing sensors (not shown), such as, for example, a gas flow meter, a pressure sensor, and / or an end-tidal carbon dioxide (etC2) sensor, which are typical components for a mechanical ventilator. The mechanical ventilator 2 is designed to deliver air, an air-oxygen mixture, or another breathable gas (not shown) to the outlet 4 at a programmed pressure and / or flow rate to ventilate the patient via the ETT. The mechanical ventilator 2 also includes at least one electronic processor or controller 13 (e.g., an electronic processor or a microprocessor), a display device 14, and a non-transitory computer-readable medium 15 storing instructions executable by the electronic controller 13.

[0022] Figure 1 illustrates a patient P with an endotracheal tube (ETT) 16 inserted (the lower part of which is inside the patient P and is thus shown by a phantom line). A connector or port 8 is connected to the ETT 16 to operably connect a mechanical ventilator 2 and deliver breathable air to the patient P via the ETT 16. The mechanical ventilation provided by the mechanical ventilator 2 via the ETT 16 is therapeutic for a wide range of diseases, such as various types of lung diseases, such as emphysema or pneumonia, viral or bacterial infections that affect breathing, such as COVID-19 infection or severe influenza, or cardiovascular diseases in which the patient P receives oxygen-enriched breathable gas.

[0023] Figure 1 also shows a medical imaging device 18 (also referred to as an image acquisition device, an imaging device, etc.). As mainly described herein, the medical imaging device 18 includes an ultrasonic (US) medical imaging device 18. In an exemplary embodiment, a brightness mode (B-mode) ultrasonic image is used to evaluate the thickness metric of the diaphragm. However, other types of ultrasonic images or data, such as motion mode (M-mode) data collected as a single ultrasonic line over a time interval, are conceivable.

[0024] In a more specific example, the medical imaging device 18 includes an ultrasonic (US) patch 20 that can be worn by a patient P (e.g., on the abdomen or chest of the patient P at a position suitable for imaging the patient's diaphragm as shown in FIG. 1). The ultrasonic patch 20 is arranged to acquire ultrasonic image data (i.e., ultrasonic (US) image) 24 of the patient P's diaphragm. For example, the ultrasonic patch 20 is configured to acquire image data of the patient P's diaphragm, and more specifically, to acquire ultrasonic image data related to the thickness of the patient P's diaphragm during inhalation and exhalation while the patient P is receiving mechanical ventilation therapy using the mechanical ventilator 2. The electronic processor 13 controls the ultrasonic imaging device 18 to receive the ultrasonic image data 24 of the patient P's diaphragm from the ultrasonic patch 20. Although only one ultrasonic patch 20 is shown in FIG. 1, it will be understood that any suitable number of patches can be attached to the patient P. The ultrasonic patch 20 enables continuous and automatic acquisition of diaphragm thickness data (Tdi) from the acquired ultrasonic image data 24.

[0025] The non - transitory computer - readable medium 15 stores instructions executable by the electronic controller 13 to perform the diaphragm measurement method or process 100.

[0026] Referring to FIG. 2 and continuing to refer to FIG. 1, an exemplary embodiment of the diaphragm measurement method 100 is schematically shown as a flowchart. In operation 101, ultrasonic image data 24 of the patient's diaphragm is received during inhalation and exhalation while the patient P is receiving mechanical ventilation therapy using the mechanical ventilator 2. To do so, the electronic controller 13 can control the ultrasonic patch 20 to acquire the ultrasonic image data 24 and receive the ultrasonic image data 24 of the patient P's diaphragm from the ultrasonic patch 20. These images do not necessarily have to be acquired while the patient P is in mechanical ventilation; instead, they may be acquired, for example, before the patient is intubated.

[0027] In operation 102, while the patient is receiving mechanical ventilation therapy using the mechanical ventilator 2, respiratory data of patient P during inhalation and exhalation is received. The respiratory data of patient P can include one or more of the airway pressure in the airway of patient P or the airway flow rate in the airway of patient P, which are measured during the ventilation therapy by the ventilator 2. In some examples, the respiratory data of patient P can include the average airway pressure value or the average airway flow rate value at the end of inhalation and the end of exhalation. In other examples, the respiratory data of patient P can have the maximum airway pressure or the maximum airway flow rate value and the minimum airway pressure or the minimum airway flow rate value at the end of inhalation and the end of exhalation. It will be understood that the operation 101 of acquiring an image and the operation 102 of acquiring respiratory data can be performed in any suitable order or simultaneously.

[0028] In operation 103, based on the received ultrasonic image data 24 of the diaphragm of patient P and the received respiratory data, a diaphragm thickness metric can be calculated. In one example, the diaphragm thickness metric includes a diaphragm hypertrophy rate indicating the thickness of the diaphragm during inhalation relative to the thickness of the diaphragm during exhalation. In another example, the diaphragm thickness metric includes the average thickness of the diaphragm over a plurality of respiratory cycles.

[0029] To calculate the diaphragm thickness metric, the electronic controller 13 is configured to receive a Tdi signal from the ultrasonic image data 24 and a pressure p (or flow rate v) signal from the mechanical ventilator 2. The electronic control device 13 applies a regression analysis to estimate the relationship (e.g., function, model, etc.) between the Tdi signal and the pressure or flow rate data (i.e., Tdi = f(p) or Tdi = f(v)). From this relationship, the electronic controller 13 determines Tdi expiration = f(p expiration )(i.e., the exhalation relationship) and Tdi inspiration = f(p inspiration )(i.e., the inhalation relationship), and then is configured to determine the change in diaphragm thickness ΔTdi and the diaphragm hypertrophy rate TFDI as the diaphragm thickness metric. The input values p inspiration and p expirationis the minimum and maximum recorded airway pressure, or the average airway pressure in inspiration and expiration (e.g., the average of 10 or 100 subsequent cycles).

[0030] Figures 3 and 4 show examples of generating a diaphragm thickness metric. Figure 3 shows an example of determining a change in diaphragm thickness (ΔTdi). The example shown in Figure 3 displays diaphragm thickness data Tdi as a function of the waveform of the ventilator (i.e., the pressure p or flow v depending on which of the respiratory data received in operation 102) for the change in diaphragm thickness ΔTdi. The confidence interval (shown as the shaded bar in Figure 3 and having a 95% value) is shortened for the reasons that (1) more data points are obtained using the ultrasonic patch 20, (2) intermediate data points (the central point shown in Figure 3) are obtained, (3) the inspiration and expiration points are determined more accurately, i.e., from the waveform of the ventilator instead of looking at the patient P or looking at the ultrasonic image data 24, and (4) by taking into account the variation from cycle to cycle, i.e., the variation of the pressure and volume of inspiration and / or expiration between breaths. Figure 4 shows an alternative example, in which two functions (one during inspiration and one during expiration) are adapted.

[0031] In some embodiments, the regression analysis can be a linear regression analysis that, according to Equation 2, makes the relationship between Tdi and the pressure p (or flow v) a straight line with a slope S. [Equation]

[0032] In some embodiments, the change in diaphragm thickness ΔTdi can be divided by the average thickness during inspiration or expiration (i.e., the diaphragm thickening rate TFDI). The advantage of using TFDI is that the slope becomes less sensitive to the change in average thickness over time due to, for example, atrophy.

[0033] In other embodiments, the logarithm of the thickness can be used to calculate the diaphragm thickness metric because the slope is invariant to changes in the average thickness (i.e., any factor becomes an invariant offset on a logarithmic scale).

[0034] Referring again to FIG. 2, in operation 104, the representation 30 of the calculated diaphragm thickness metric is displayed on the display device 14 of the mechanical ventilator 2. In some examples, when a plurality of ultrasonic patches 20 are attached at different positions on the chest of the patient P, the representation 30 can include a color map showing the distribution of the diaphragm activity.

[0035] In some embodiments, the diaphragm thickness metric is calculated as a ratio of the diaphragm thickness of the diaphragm to one of the airway pressure or airway flow rate in the airway of the patient P. In such embodiments, the ratio of the diaphragm thickness of the diaphragm to one of the airway pressure or airway flow rate in the airway of the patient P has the airway compliance of the patient P.

[0036] The slope S of the linear regression relationship provides insights into the behavior and effectiveness of the diaphragm muscle activity as a function of the MV support of the patient P and the sedation therapy of the patient P. The slope S is displayed as an indication 30 on the display device 14 of the mechanical ventilator 2. This relationship S provides more information than a single TFDI point without further reference or information. The change ΔTdi in the diaphragm thickness reflects the patient's effort ("input"), while the airway pressure and / or airway flow rate reflect the result ("output"). Depending on the level of support, the ratio of this output to the input (i.e., 1 / S) indicates the total "compliance" of the respiratory system of the patient P.

[0037] An example of using the slope S of the linear regression relationship between the diaphragm thickness Tdi and the airway pressure (or flow rate) to inform the patient's respiratory effort and effectiveness is shown in FIGS. 5A and 5B. FIG. 5A shows the patient's effort in different situations. Goligher (2015) mentions that when there is no diaphragm activity, the diaphragm thickness does not change (i.e., a flat line with zero slope). When the pressure support is decreased, the slope should increase. The more the slope increases, the more the patient P is responding to mechanical ventilation therapy. On the condition that the end-tidal CO2 does not increase due to respiratory failure (diaphragm insufficiency), and the CO2 starts to pull the muscles via chemoreceptors and the sedation level remains constant. To monitor the effect of the variation in respiratory rate, additional indicators such as, for example, the power of breathing (POB), POB per liter of air (POB / L), the work of breathing (WOB), and WOB per liter of air (WOB / L) are used as additional inputs. FIG. 5B shows, for example, the alternative of the efficiency of breathing in a spontaneous breathing trial (SBT), and the first curve 1 is more efficient than the second curve 2 (i.e., a larger pressure swing with less effort). In this case, since the vertical and horizontal axes are swapped compared to FIG. 5A, the slope S of the second curve 2 is 1 / S.

[0038] In some embodiments, instead of using the slope S (or the reciprocal 1 / S), the change in slope ΔS when the level of support or sedation changes can be used to provide insights into the behavior and effectiveness of the diaphragm muscle activity as a function of the MV support of the patient P and the sedation therapy of the patient P.

[0039] Parameters S, 1 / S, and ΔS are displayed as indication 30 on display device 14 of mechanical ventilator 2 and are used, for example, to distinguish between active and passive breathing to induce sedation therapy, to indicate and monitor the level of sedation, to determine the optimal level of pressure support in the setting of PSV or K in PAV / PAV+ (where K is the percentage of unload), to determine the readiness for weaning prior to a spontaneous breathing trial (SBT), to monitor lung function in case of, for example, lung disease (i.e., when the MV setting is constant, the steeper the slope S, the lower the flow rate), to monitor the strength of the patient P's neuromuscular drive, to detect phrenic nerve disorder or injury (e.g., by placing sensors on both sides of the chest and intentionally paralyzing the left and right nerves sequentially one by one) (in both situations, the diaphragm should move the same, and if not, one of the nerves is damaged), to determine whether the variation in slope between breaths is used as an indicator of asynchrony, etc., to provide clinical decision-making support. Parameter S or (1 / S) is suitable for monitoring CPAP home therapy when the patient breathes spontaneously and the ventilator keeps the pressure approximately constant (i.e., S = ΔTdi / Δv).

[0040] When patient P breathes spontaneously, the "compliance" of the respiratory system (which part of the muscle work is converted into airflow) can be measured. By monitoring and displaying this ratio over time, it is possible to see how the patient's "breathing movement" is performed and developed over time.

[0041] In some embodiments, the MV setting is constant. In other embodiments, while measuring the trend of Tdi or TFDI, the pressure and flow rate settings can be changed, or a controlled breathing method can be performed. This provides additional information regarding the state of patient P and the treatment effect. For example, a strong response of the diaphragm muscle to a change in pressure support or sedation state indicates that the muscle is in good condition and the treatment is in a sensitive range (i.e., there is no over-treatment).

[0042] Referring back to FIG. 2, in some embodiments, at operation 105, the mechanical ventilator 2 is controlled to adjust one or more parameters of the mechanical ventilation therapy delivered to the patient based on the calculated diaphragm thickness metric. For example, the slope of effort S and / or the maximum effort can be used to induce a respiratory muscle training program for the patient P. This program can be run multiple times a day to restore and improve respiratory muscle strength. For example, the clinical team can select the maximum gradient that the patient can tolerate and the period. The mechanical ventilator 2 can automatically change the support to increase / decrease the respiratory activity as required by the clinical team. As a safety feature, the mechanical ventilator 2 can monitor the respiratory rate, end-tidal CO2, SpO2, and other parameters to decide to switch to backup mode and interrupt the training program.

[0043] In any operation 106, the responsiveness index (RI) of the patient P can be calculated as the ratio of the change in the compliance of the patient's airway to the change in one or more mechanical ventilation settings of the mechanical ventilator 2. In some examples, the mechanical ventilator 2 is controlled to adjust one or more parameters of the mechanical ventilation therapy delivered to the patient P based on the calculated responsiveness index. In other examples, the representation 30 further includes a representation of the calculated RI and can be displayed on the display device 14.

[0044] Knowledge of respiratory muscle activity from diaphragm ultrasound or the like, and adjustment of the support of the mechanical ventilator 2 can monitor the patient's responsiveness to such changes (i.e., changes in the slope S of respiratory muscle activity). This is according to RI = ΔS / Δ support which is the change in the slope of respiratory muscle activity divided by the change in support (pressure support ventilation PSV, proportional assist ventilation PAV, here the same PAV+, pressure-controlled volume ventilation PRVC, etc.), where Δ supportrepresents a change in the level of support in response to a change in pressure p or a change in volume / flow rate v. RI is used to derive a sedation strategy by controlling an open-loop or closed-loop solution, i.e., a sedation device configured to provide a sedative to patient P. The electronic controller 13 can ensure its safe operation by using additional inputs such as end-tidal CO2, blood gas analysis, minute ventilation, and ventilator settings.

[0045] For an anesthesiologist, RI is potentially used to quantify the sedation level. Generally, this sedation level is measured using the Ramsay Sedation Scale, which is a qualitative scale. It divides the patient's sedation level into six categories from severe excitement to deep coma. Typically, a clinician observes the patient's response to commands (commands) or tactile and auditory stimuli. Quantitative scales are difficult to interpret, and the automatic measurement of RI can facilitate the use and application of sedation scoring in mechanical ventilation therapy.

[0046] In some embodiments, a medical professional may wish to check the state of patient P. This can be achieved by pressing and / or holding a button on the mechanical ventilator 2 to check the slope S or the change in slope ΔS periodically (e.g., every 12 hours) displayed on the display device 14. Pressing the button causes the support to disappear for a few minutes. This allows RI to be shown.

[0047] This disclosure has been described with reference to preferred embodiments. Others may come up with modifications and variations upon reading and understanding the foregoing detailed description. The exemplary embodiments are intended to be construed as including all such modifications and variations insofar as they fall within the scope of the appended claims or their equivalents.

Claims

1. A diaphragm measurement device having at least one electronic processor programmed to perform a diaphragm measurement method, the diaphragm measurement method comprising: Receiving ultrasonic image data of the dimensions of the patient's diaphragm during inhalation and exhalation while the patient is undergoing mechanical ventilation therapy using a mechanical ventilator; Receiving respiratory data of the patient during inhalation and exhalation while the patient is undergoing mechanical ventilation therapy; Calculating a diaphragm thickness metric based on the received ultrasonic image data of the patient's diaphragm and the received respiratory data; and Displaying an indication of the calculated diaphragm thickness metric on a display device A diaphragm measurement device comprising.

2. The diaphragm measurement device according to claim 1, wherein the diaphragm thickness metric includes a diaphragm hypertrophy rate indicating the thickness of the diaphragm during inhalation relative to the thickness of the diaphragm during exhalation.

3. The diaphragm measurement device according to claim 1, wherein the diaphragm thickness metric includes an average diaphragm thickness over a plurality of respiratory cycles.

4. The diaphragm measurement device according to claim 1, further comprising an ultrasonic imaging device including an ultrasonic patch attached to a part of the patient, the at least one electronic processor controlling the ultrasonic imaging device to receive ultrasonic image data of the patient's diaphragm from the ultrasonic patch.

5. The diaphragm measurement device according to claim 1, wherein the patient's respiratory data has one of the airway pressure or airway flow rate within the patient's airway, and the at least one electronic processor is further programmed to calculate the diaphragm thickness metric based on the airway pressure or airway flow rate.

6. The diaphragm measurement device according to claim 5, wherein the respiratory data has an average airway pressure value or average airway flow rate value at the end of inhalation and the end of exhalation.

7. The diaphragm measurement device according to claim 5, wherein the respiratory data has a maximum airway pressure value or maximum airway flow rate value and a minimum airway pressure value or minimum airway flow rate value at the end of inhalation and the end of exhalation.

8. The diaphragm measurement device according to claim 1, wherein the at least one electronic processor is further programmed to calculate the diaphragm thickness metric as a ratio of the diaphragm thickness of the diaphragm to the airway pressure within the patient's airway.

9. The diaphragm measuring device according to claim 1, wherein the at least one electronic processor is further programmed to calculate the thickness metric of the diaphragm as a ratio of the diaphragm thickness of the diaphragm to the airway flow rate in the airway of the patient.

10. The diaphragm measuring device according to claim 9, wherein the at least one electronic processor is further programmed to calculate a responsiveness index of the patient as a ratio of a change in compliance of the patient's airway to a change in settings of one or more mechanical ventilators of an associated mechanical ventilator.

11. The diaphragm measuring device according to claim 10, wherein the at least one electronic processor is further programmed to control an associated mechanical ventilator to adjust one or more parameters of the mechanical ventilation therapy delivered to the patient based on the calculated responsiveness index.

12. The diaphragm measuring device according to claim 11, wherein the at least one electronic processor is further programmed to display an indication of the calculated responsiveness index on the display device.

13. The diaphragm measuring device according to claim 1, wherein the at least one electronic controller is configured to control an associated mechanical ventilator to adjust one or more parameters of the mechanical ventilation therapy delivered to the patient based on the calculated thickness metric of the diaphragm.

14. The diaphragm measuring device according to claim 1, further comprising a mechanical ventilator configured to deliver mechanical ventilation therapy to the patient.

15. Using at least one electronic controller, receiving ultrasonic image data of dimensions of the patient's diaphragm during inhalation and exhalation while the patient is receiving mechanical ventilation therapy using a mechanical ventilator; receiving respiratory data of the patient during inhalation and exhalation while the patient is receiving mechanical ventilation therapy; calculating a thickness metric of the diaphragm based on the received ultrasonic image data of the patient's diaphragm and the received respiratory data; and displaying an indication of the calculated thickness metric of the diaphragm on a display device A diaphragm measurement method comprising:

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