The present system relates to a mechanical insufflation-exsufflation (MI-E) device with enhanced device-patient synchrony during MI-E therapy and, more particularly, to a MI-E device which provides an improved device-patient synchrony during MI-E therapy based on passively timing delivery of mechanical insufflation using breath pacing, and a method of operation thereof.
A major challenge in the delivery of MI-E therapy to patients (e.g., a target patient group), who are either too young or incapable of following commands, is asynchrony between an MI-E device (e.g., a CoughAssist™ MI-E device by the Philips Healthcare) during insufflation and the patient's breathing pattern. This asynchrony may be referred to as device-patient asynchrony. This target patient group may, for example, hold their breath during either the insufflation or the exsufflation phase and/or exhale during the pause phase, which leads to ineffective therapy delivery.
Mechanical insufflation-exsufflation (MI-E) therapy has been described as safe and effective in the pediatric neuromuscular disease (NMD) patient population and is considered to be a critical component of the respiratory support strategy. In spite of this, it remains unclear how MI-E therapy can be optimized when a patient, such as a pediatric patient, is highly agitated and either too young or otherwise unable/unwilling to follow commands due to cognitive limitations, etc.
Effective MI-E therapy requires appropriate settings and is highly dependent on therapy technique. A key barrier to effective MI-E therapy is the inability to obtain adequate lung volume due to agitation and breath holding. Frequently, when pediatric patients are highly agitated and either too young or otherwise unable to follow commands, they may hold their breath during insufflation, they may hold their breath or inhale during exsufflation and/or may exhale during a pause phase, which leads to asynchrony between an MI-E device and the patient's breathing pattern, resulting in ineffective MI-E therapy delivery.
A key barrier to effective MI-E therapy appears to be the inability to obtain adequate lung volume due to: (a) agitation likely induced by the dishabituation to the negative and positive pressure sensation produced by the MI-E therapy; and/or (b) breath holding linked to lack of cooperation with the therapy.
Hence there is a need to overcome the aforementioned barriers, by finding novel ways to effectively deliver mechanically assisted coughs during MI-E therapy for patients including those who are too young or otherwise unable to follow commands. For example, embodiments of the present system address the problem of poor patient-device synchrony during the delivery of MI-E therapy to patients who are too young (i.e., infants) or unable to follow commands. More specifically, embodiments of the present system address the problem of how to synchronize mechanical insufflation with the breathing of a patient to ensure effective MI-E therapy delivery whether or not patient-device synchrony is initially present.
The system(s), device(s), method(s), arrangements(s), interface(s), computer program(s), processes, etc., (hereinafter each of which will be referred to as system, unless the context indicates otherwise), described herein address problems in prior art systems.
In accordance with embodiments of the present system, there is disclosed a mechanical insufflation-exsufflation (MI-E) device. The device may include an air source configured to provide patient airway pressure including positive airway pressure (PAP); a patient interface coupled to the air source and configured to be flow coupled to a user; at least one sensor configured to sense air pressure and flow at the patient interface; and a controller coupled to the air source and the at least one sensor. The controller may be configured to control the air source to deliver at least one mechanically assisted cough (MAC) to the patient in response to at least one of a target breathing flow and a target inhalation time period being sensed by the at least one sensor. When the at least one of a target breathing flow and a target inhalation time period is not sensed by the at least one sensor, the controller may be configured to control the air source to deliver a series of high-level PAP, each in the series of high-level PAP provided over a high-level duration being followed by a low-level PAP provided over a low-level duration, the series of high-level PAP increasing in at least one of a pressure level and the high-level duration from a prior one in the series of high-level PAP. Each in the series of high-level PAP may start in response to a corresponding inhalation trigger. The series of low-level PAP may each have a pressure level that is lower than the pressure level of each of the series of high-level PAP.
The MI-E device may include a force transmitting device (FTD) coupled to the controller. The controller may be configured to control the FTD to apply an abdominal chest thrust that is synchronized to the MAC. The controller may be further be configured to receive flow and pressure information from the at least one sensor and generate corresponding flow and pressure waveforms. The controller may be further configured to produce each in the series of high-level PAP in response to detecting an inhalation trigger (TG) in a form of a change in pressure below ambient in the pressure waveform. The MI-E device may include a CO2 controller coupled to the patient interface that may be configured to control a concentration of CO2 gas at the patient interface.
The controller may be configured to control the air source to deliver the at least one mechanically assisted cough (MAC) to the patient when both of the target breathing flow and the target inhalation time period are sensed by the at least one sensor. The controller may be configured to determine whether the pressure level and the high-level duration of a current one of the series of the high-level PAP has a sensed pressure and a duration greater than, or equal to, a pressure threshold value and a high-level duration threshold value, respectively and may be configured to control the air source to provide a further one of the series of high-level PAP in response to the pressure level and the high-level duration of a current one of the series of steps of the high-level PAP being sensed to have a pressure and a duration that is not greater than, or equal to, the pressure threshold value and the high-level duration threshold value, respectively. The controller may be configured to increase the high-level duration of each of the series of high-level PAP by a predetermined period of time. The controller may be configured to increase the pressure of each of the series of high-level PAP by a predetermined pressure.
In accordance with embodiments of the present system, there is also disclosed a mechanical insufflation-exsufflation (MI-E) device including a controller that may be configured to control an air source to deliver at least one mechanically assisted cough (MAC) to a patient in response to at least one of a target breathing flow and a target inhalation time period being sensed by at least one sensor. When the at least one of a target breathing flow and a target inhalation time period is not sensed by the at least one sensor, the controller may also be configured to control the air source to deliver a series of high-level PAP, each in the series of high-level PAP provided over a high-level duration being followed by a low-level PAP provided over a low-level duration. The series of high-level PAP increasing in pressure level and duration from a prior one in the series of high-level PAP. Each in the series of high-level PAP starting in response to a corresponding inhalation trigger. The series of low-level PAP each having a pressure level that is lower than the pressure level of each of the series of high-level PAP.
The controller may be configured to control a force transmitting device (FTD) to apply an abdominal chest thrust that is synchronized to the MAC. The controller may be further configured to receive flow and pressure information from the at least one sensor and generate corresponding flow and pressure waveforms. The controller may be further configured to produce each in the series of high-level PAP in response to detecting an inhalation trigger (TGI) in a form of a change in pressure below ambient in the pressure waveform. The controller may be further configured to control a concentration of CO2 gas available to the patient. The controller may be configured to control the air source to deliver the at least one mechanically assisted cough (MAC) to the patient when both of the target breathing flow and the target inhalation time period are sensed by the at least one sensor.
The controller may be configured to determine whether the pressure level and the high-level duration of a current one of the series of the high-level PAP has a sensed pressure and a duration greater than, or equal to, a pressure threshold value and high-level duration threshold value, respectively. The controller may be configured to control the air source to provide a further one of the series of high-level PAP in response to the pressure level and the high-level duration of a current one of the series of steps of the high-level PAP being sensed to have a pressure and a duration that is not greater than, or equal to, a pressure threshold value and the high-level duration threshold value, respectively. The controller may be configured to increase the duration of each of the series of high-level PAP by a predetermined period of time. The controller may be configured to increase the pressure of each of the series of high-level PAP by a predetermined pressure.
In accordance with embodiments of the present system, there is also disclosed a method of controlling a mechanical insufflation-exsufflation (MI-E) device. The method may include acts of controlling an air source to deliver at least one mechanically assisted cough (MAC) to a patient in response to at least one of a target breathing flow and a target inhalation time period being sensed by at least one sensor, and controlling the air source to deliver a series of high-level PAP, when the at least one of a target breathing flow and a target inhalation time period is not sensed by the at least one sensor. Each in the series of high-level PAP provided over a high-level duration being followed by a low-level PAP provided over a low-level duration. The series of high-level PAP increasing in at least one of a pressure level and a duration from a prior one in the series of high-level PAP. Each in the series of high-level PAP starting in response to a corresponding inhalation trigger. The series of low-level PAP each having a pressure level that is lower than the pressure level of each in the series of high-level PAP. The method, wherein the act of controlling the air source to deliver at least one mechanically assisted cough (MAC) to the patient in response to at least one of the target breathing flow and the target inhalation time period being sensed by the at least one sensor may include an act of at least one of increasing the high-level duration of each of the series of high-level PAP by a predetermined period of time and increasing the pressure of each of the series of high-level PAP by a predetermined pressure.
It should be expressly understood that the drawings are included for illustrative purposes and do not represent the scope of the present system. It is to be understood that the figures may not be drawn to scale. Further, the relation between objects in a figure may not be to scale and may in fact have a reverse relationship as to size. The figures are intended to bring understanding and clarity to the structure of each object shown, and thus, some features may be exaggerated in order to illustrate a specific feature of a structure. In the accompanying drawings, like reference numbers in different drawings may designate identical or similar elements, portions of similar elements and/or elements with similar functionality. The present system is explained in further detail, and by way of example, with reference to the accompanying drawings which show features of various exemplary embodiments that may be combinable and/or severable wherein:
The following are descriptions of illustrative embodiments that when taken in conjunction with the following drawings will demonstrate the above noted features and advantages, as well as further ones. In the following description, for purposes of explanation rather than limitation, illustrative details are set forth such as architecture, interfaces, techniques, element attributes, etc. However, it will be apparent to those of ordinary skill in the art that other embodiments that depart from these details would still be understood to be within the scope of the appended claims. Moreover, for the purpose of clarity, detailed descriptions of well-known devices, circuits, tools, techniques, and methods are omitted so as not to obscure the description of the present system.
The term and/or and formatives thereof should be understood to mean that only one or more of: the recited elements may need to be suitably present (e.g., only one recited element is present, two of the recited elements may be present, etc., up to all of the recited elements may be present) in a system in accordance with the claims recitation and in accordance with one or more embodiments of the present system. In the context of the present embodiments, the terms “about”, “substantially” and “approximately” denote an interval of accuracy that a person skilled in the art will understand to still ensure the technical effect of the feature in question which in some cases may also denote “within engineering tolerances”. The term may indicate a deviation from the indicated numerical value of ±20%, ±15%, ±10%, ±5%, ±1% ±0.5% or ±0.1%.
As used herein, the term patient, patients, or formatives thereof may be interchangeably used with the terms subject, subjects, user, and/or users unless the context indicates otherwise. Further, the term operator of embodiments may be referred to as operator or clinician unless the context indicates otherwise.
As used herein, the term breath pacing is intended to convey a controlled sequence of high and low level positive airway pressure delivered to a patient in response to a patient initiated inhalation that encourages over the sequence for the patient to have an inhalation that satisfies at least one of a target breathing flow, pressure and/or a target inhalation time period.
It should be appreciated that embodiments of the present system may provide enhanced device-patient synchrony during MI-E therapy based upon passive timing delivery of mechanical insufflation using breath pacing which may be ideal for users (e.g., subjects, patients, etc.) who, for example, may be incapable of following instructions and/or may otherwise not follow instructions during the performance of MI-E therapy such as infants, the disabled, and the like.
Methods which provide improved MI-E device synchrony with patient breathing based on passively monitoring flow and pressure waveforms during breathing cycles of patients to trigger the delivery of mechanical insufflation at a time when these patients are not holding their breath will now be described below with reference to
Several examples illustrating when effective MI-E therapy may be provided in contrast with therapy delivery conditions that may provide ineffective therapy delivery in the pediatric NMD patient population are illustrated with reference to
VC=TV+IRV+ERV
In the instance indicated in
Flow and pressure waveforms for MI-E therapy performed on a nine-year-old patient is shown in
In the instance indicated in
Several examples showing patient profiles of pediatric patients that are either too young or otherwise unable to follow commands for any reason (e.g., due to cognitive limitations) are illustrated with reference to
In summary, the preceding figures show that when a patient, such as an infant/child, is too young or unable to follow commands, several problems may be encountered leading to ineffective MI-E therapy in the absence of the system in accordance with the present system. The present system may address problems associated with patients that exhibit one or more problems, thereby providing an opportunity to bring about patient-device synchrony such that effective MI-E therapy may be delivered. Problems that may be detected in accordance with the present system may include one or more of failure to accept insufflation, patient—device asynchrony (e.g., breath holding, patient exhalation during the pause phase), no exhale flow, low Peak Cough Flow (PCF) rates, and/or no or low effective cough volume (ECV).
As discussed, the present system and method improves MI-E device synchrony with patient breathing based on passively monitoring the flow and pressure waveforms during breathing cycles of the patient to trigger a delivery of a mechanically assisted cough (MAC) at a time when the patient is not holding their breath, such as during an exhalation following a favorable inhalation by the patient.
During act 603, the process may initialize the one or more settings that may be input by an operator in real time or may be obtained from a memory of the system. Such information may be stored in a memory of the system as system information (SI). The settings may, for example, include information related to initialization and/or default settings such as threshold settings, pressure settings, step settings, user settings, etc. These settings may be formed, set, updated, and/or reset by the system and/or operator and stored as a portion of the SI in the memory. Accordingly, the controller may obtain the SI from a memory of the system and/or may render information requesting input by the operator of one or more settings, depending upon system settings. After completing act 603, the process may continue to act 605.
During act 605, the process may obtain sensor information from the one or more sensors of the system, such as pressure sensors, flow sensors, temperature sensors, humidity sensors, gas analysis sensors. Each of these sensors may monitor corresponding parameters, form corresponding information, and provide this information to a breath monitoring unit (BMU) of a controller of the system (e.g., a program portion that may be executed by the controller) for further processing. For example, it is envisioned that the pressure sensors may monitor pressure, ambient pressure, etc., may form corresponding pressure information, and provide this pressure information to the controller for further processing. Similarly, it is envisioned that the flow sensors may monitor fluid flow (e.g., as of respiratory gasses) in one or more locations such as in a line-set (LS) or a patient interface (PI), may form corresponding flow information, and provide this flow information to the controller for further processing.
The gas analysis sensors may be configured to determine a concentration of one or more types of gasses within a sampled airflow such as Carbon dioxide (CO2), Oxygen (O2), etc., form corresponding sensor information (e.g., CO2 concentration in percent) and provide this information to the controller for further processing. The controller may identify each sensor directly or via the sensor information provided by each of the sensors (e.g., which may include information identifying the type of information, and/or sensor which formed it, etc.). The process may obtain the sensor information in real time, and/or on a periodic or non-periodic intervals depending upon system settings. The BMU and/or other portion of the controller may process the sensor information and generate corresponding pressure and/or waveform information (e.g., pressure and waveforms, respectively, for one or more locations throughout the system, e.g., such as within a patient line-set (LS) or other patient interface (PI)). The BMU may monitor flow and pressure waveforms in accordance with embodiments of the present system. The LS may be coupled to the PI and at least some of the flow and/or pressure sensors may provide information related to flow and/or pressure within a gas flow path (GFP) of one or more of the LS and/or PI.
Thus, for the sake of clarity, pressure, flow, and volume may refer to pressure, flow, and volume, respectively, of a gas flow within the GFP of one or more of the LS and/or a PI coupled thereto. The PI may include a one-way or check valve that may help prevent buildup of CO2, which may be passively or actively controlled (e.g., by the controller) through the valves or other systems as described further herein. After competing act 605, the process may continue to act 607.
During act 607, the process may be operative (e.g., programmed) to apply low-level positive airway pressure (PAPLOW) to the patient until the patient initiates a spontaneous breath. Accordingly, the process may be operative to control one or more pumps and/or pressure regulators of the system to provide a pressurized flow of gas (e.g., air) within the GFP. This pressurized flow of gas may have (absent other forces such as a breath of a patient) a positive pressure (e.g., at the PI) which may correspond to a threshold low pressure value (TPLOW). The TPLOW may depend upon system settings, may be operator defined (e.g., 4 cm H2O), may be preset (e.g., as stored in the SI), and/or may be determined by the system (e.g., in real time).
As discussed, a low-level PAP (PAPLOW) is initially delivered as a baseline pressure. The baseline PAP level may be user-defined (e.g., 4-10 cm H2O such as 4 cm H2O) as discussed or may be based on the pressure level that creates a lower inflection point (LIP) in a pressure volume (P-V) curve as will be discussed below (e.g., 8 cm H2O). A PAP value that is set to the LIP may offer additional therapeutic value to a pediatric patient using MI-E therapy. Closing capacity is the volume in the lungs that is associated with small airway and alveolar closing. Closing capacity is the point during expiration when small airways begin to close. This phenomenon may be seen in pediatric patients <6 years of age that have a functional residual capacity (FRC) below closing capacity. FRC is the volume remaining in the lungs after a normal, passive exhalation.
The present system may provide advantages in an embodiment using a dynamic algorithm for determination of the baseline PAP setting using the LIP include: (1) increasing FRC above closing capacity, (2) mitigating small airway and alveolar collapse, (3) ultimately improving lung compliance, (4) aiding in both pressure habituation and breath-pacing to create an optimal MI-E delivery window. By the term dynamic algorithm, it is intended to convey a mathematical optimization method and a computer programming method.
For example, during operation the TPLOW may be based upon a pressure of gas at a detected lower inflection point (LIP) of a pressure volume (P-V) curve as will be discussed below. For example, to determine the value of TPLOW, the process may monitor sensor information relating to a P-V curve for a given patient as set forth in
During act 609, the process may determine whether an inhalation trigger (TGI) is detected. The inhalation trigger is a sensor reading received by the processor that is indicative of the patient starting a spontaneous breath (e.g., a detected change in pressure, flow, etc., within the within the LS, PI, etc.). The inhalation trigger indicates that the patient has initiated a spontaneous breath as may be indicated by a small drop in flow rate and also may be detectable in the flow waveform as previously discussed.
Accordingly, when the inhalation trigger (TGI) is detected, the process may continue to act 611. However, when the inhalation trigger (TGI) is not detected, the process may repeat act 609 and may continue to apply PAPLOW to the LS. For example, the process (e.g., through operation of a suitably programmed processor) may determine that the inhalation trigger (TGI) is detected (e.g., detection of a spontaneous breath by the patient) by using one or more methods in accordance with settings of the system. For example, in one method the process may detect the inhalation trigger (TGI) in response to sensing a drop in pressure and/or sensing negative pressure within the GFP which may occur in response to a spontaneous breath of the patient.
Referring to
Upon detecting the inhalation trigger (TGI) (e.g., indicative of the start of an inhalation), the process may also start an inhalation timer which may count a current inhalation time (TI) which corresponds to a total inhalation time during which the patient inhales (e.g., spontaneously) for the current cycle.
Flow and pressure waveform will now be discussed with reference to
Referring to
Thus, once an inhalation trigger is detected, embodiments of the present system may deliver an increase in positive airway pressure until the patient terminates their breath (e.g., end of inhalation/insufflation] as determined by a flow decay and zero flow crossing at point 3. The present system will synchronize an increase in the baseline PAP level until the patient terminates their breath as for example determined by a flow cycle threshold (peak flow decay or zero flow crossing). The pressure increase, which is graphically illustrated in
In accordance with embodiments of the present system, the inhalation trigger (TGI) may be detected in response to detection of a spontaneous breath such as through detection of a negative pressure waveform and/or a change in flow characteristics (e.g., see point 1 of
Referring back to
Referring back to
With regard to the pressure threshold value (PAPHIGH), depending upon system settings, this value may be a preset value set by a user or system (e.g., 35 cm H2O, etc.) or may be based on an arbitrary pressure below the upper inflection point (UIP) on the Pressure-Volume curve (e.g., see,
With regard to the inhalation time threshold value (ITT), depending upon system settings this value of ITT may be a preset value set by a user or system (e.g., 1 second, etc.), may be derived from a longest insufflation time, for example, as determined by a zero-flow crossing during the breath pacing phase, and/or may be based upon a calculated inspiratory time constant (TCI) of the respiratory system. For example, a measurement of dynamic compliance and airways resistance may be utilized for performing the inhalation time constant calculation: TCI=CDYN×RAW×3 (95% of inspiratory capacity) to ensure adequate lung filling and alveolar equilibration time. Airways resistance or RAW may be determined by a modified forced oscillation technique pressure application during an ideal measurement window. For example, airway resistance may be determined by a forced oscillation technique (i.e., PAP value oscillated according to a set Hz). Compliance may be determined by dividing the tidal volume by the plateau pressure minus PEEP. Settings for the maximum pressure threshold value (PAPHIGH) and the inhalation time threshold value (ITT) may be stored in the SI for later use.
During act 617, the process may extend the current insufflation time (TI) (e.g., which is an inhalation time during which PAPHIGH is applied) by a current period ΔTI as may be set by the system and/or user (e.g., see, ΔTI,
The process may also increment the period ΔTI by some other desired value such that with each inhalation, the period of insufflation ΔTI may increase. Thus, a next value of ΔTI may equal the current value of ΔTI plus (+) a given or variable increase. Thus, with each successive inhalation, the process may extend the total inhalation time (TI) during which PAPHIGH is applied by a current value of ΔTI. Thus, during each successive inhalation, PAPHIGH may be applied for an increasing period of time when compared with the time period of a previous inhalation as shown in
A transient inspiratory hold when achieved, may be used to calculate a static lung compliance CSTAT value which may in turn be used to replace a CDYN value in an inhale time constant calculation to improve accuracy when acts 607, 609, 611, 613, 615, 617, 619 are repeated following act 619 as described, otherwise a quasi-static (inhale flow <10 L/sec) lung compliance estimate may be used to determine CDYN as noted in the description of act 615 above.
Thereafter, the process may continue to act 619. During act 619, the process may increase the value of TPHIGH by a threshold value such as a ΔPI (e.g., see,
In accordance with embodiments of the present system, acts 607 through 619 may form a portion of a breath pacing phase and may be repeated for each breath with patient-initiated, device-modulated increases (after the first breath of the sequence) in inhale pressure (TPHIGH) and/or insufflation time for each breath (e.g., see, points 45, 6, for first through third breaths (Br1 through Br3, shown in
Acts 621 through 627 may be similar to acts 607 through 613, respectively, though occur following detection of thresholds during act 615. Accordingly, only a brief description of these acts will be provided for the sake of clarity and reference will be made to acts 607 through 613 for further detail.
During act 621, the process may be operative to apply low-level positive airway pressure (PAPLOW). At this time, pressure and inhalation period thresholds for the delivery of an optimized MAC window (e.g., see, point 8,
After completing act 621, the process may continue to act 623. During act 623, the process may determine whether an inhalation trigger (TGI) is detected. Accordingly, when the inhalation trigger (TGI) is detected, the process may continue to act 625. However, when the inhalation trigger (TGI) is not detected, the process may repeat act 623 and may continue to apply PAPLOW to the LS.
During act 625, the process may be operative to apply high-level positive airway pressure (PAPHIGH) to the LS, for example at the same pressure as the previous inhalation as the threshold high pressure value (TPHIGH) may not have been increased for the current inhalation. After completing act 625, the process may continue to act 627 where it may determine whether a termination trigger (TGTER) is detected. Accordingly, when the termination trigger (TGTER) is detected, the process may continue to act 629. However, when the termination trigger (TGTER) is not detected, the process may repeat act 627 and may continue to apply the PAPHIGH to the LS.
During act 629, the process may begin an exsufflation wherein it may apply a mechanically assisted cough (MAC) to the LS. Accordingly, the process may be operative to control one or more pumps and/or pressure regulators of the system to provide a vacuum (e.g., negative pressure) within the GFP suitable for the MAC. This is illustrated with reference to
During act 631 the process may evaluate the MAC for effectiveness (ECV or PCF) based on the acquired flow and pressure waveforms, before the process repeats starting at act 607 i.e., returns to the breath pacing phase until the next optimal MAC window is identified. The MAC optimal window may be determined as the combination of meeting the inhale time threshold and inhale pressure thresholds. For example: the patient's breath may be synchronized (no asynchrony, patient accepting the positive pressure) to the inhale pressure threshold of 40 cm H2O or more for an inhale time duration threshold of 1.5 seconds or more. The system may return to breath pacing for a minimum of one patient-triggered breath to evaluate for the presence of MACOW for determining whether a subsequent MAC may be delivered.
In accordance with embodiments of the present system, a MAC may be introduced without or following breath pacing as described with reference to
In accordance with an embodiment, synchronized delivery of M I-E volume mode may be performed with patient breathing. In this embodiment, once the patient inhale effort is detected (e.g., trigger event), the present system may deliver a constant flow rate until the volume reaches the pre-determined inhale volume. The flow rate may be adjusted to optimize the inhale time or the patient comfort. The volume step may be determined by the clinician (e.g. 200 ml increment), as a percentage of the user-defined volume target (e.g. Vti_max=2 L, volume step=10% or 200 ml), or as a percentage ideal body weight or other PFT parameters (i.e., VC, TLC, etc.) (e.g. 15 kg ped patient with 6 ml/kg target tidal volume, 90 ml volume increment).
Thereafter, the present system may extend the inhale time to a preset inhale time. Alternatively, the inhale time may be adjusted automatically to achieve the target volume. For example, a static compliance and resistance calculation may be made as the plateau pressure and zero flow is reached during each inhale cycle.
For example, C_stat=Target Volume/(Peak inhale pressure−PEEP)
Res_stst=(Peak inhale pressure−PEEP)/flow rate.
As before, the acts may be repeated with patient-initiated, device modulated increases in inhale volume and inhale time. Thereafter, the MACOW may be determined by reaching one or both of a volume and time target value. For example, the volume threshold value may be user defined or may be equal to UIP. The UIP may be identified through a single breath when the target volume is sufficiently large enough to reach the true UIP.
As before, when the target volume and/or target time are achieved, a MAC may thereafter be provided to the patient.
In some embodiments, the process may render information on a user interface of the system, such as to provide information to an operator of a current operating state of the system, such as whether the system is pacing breaths and/or delivering MACs. It is further envisioned that the process may end at any time if desired.
Accordingly, the process in accordance with embodiments of the present system, may provide for improved device-patient synchrony during MI-E therapy using breath pacing.
Embodiments of the present system may be provided with a patient interface including a one-way check valve that may provide for the venting of carbon dioxide from the GFP during use thus enhancing patient safety. This may reduce or entirely prevent issues due to build-up of carbon dioxide in the GFP during the breath pacing acts which may last multiple breathing cycles (e.g., 4-10 breath cycles) in some embodiments.
In an embodiment, flushing of CO2 build up in the MI-E circuit may be accomplished with transient negative pressure delivery synchronized with the patient's own breath termination. The frequency, duration, and negative pressure level (e.g., −3 cm H2O for 0.5 seconds) may be applied during synchronized, transient negative pressure applications and may be determined by the number and length of the patient-initiated breaths between MI-E applications For example, a bench model may be setup to see how many breaths at a given tidal volume result in a high CO2 build up in a 6-foot breathing circuit. Conversely, a negative pressure model may then be constructed to determine what negative pressure needs to be delivered and for how long to safely flush the CO2 build-up. For example, a low negative pressure setting of −3 to −5 cm H2O for a short period of time (e.g., (0.1-0.3 sec)) may be sufficient to flush CO2 build up.
It is envisioned that some embodiments may be fitted with a carbon dioxide exhaust line which may be flow coupled to the GFP to introduce a low-level negative pressure, e.g. −3 cm H2O which may be triggered by an exhalation by the patient. A low-level negative pressure application has been shown to be an effective CO2 flushing methodology in bench tests.
In yet another embodiment, a compensation port (e.g., a leak port, an exhalation port, a passive valve, an actively controlled valve, etc.) may be flow coupled to the MI-E circuit to reduce or entirely eliminate CO2 buildup (beyond ambient levels) within the MI-E circuit by venting CO2 and introducing fresh air. The controller may include a leak/pressure compensation algorithm to compensate for pressure leaks and/or other changes in pressure, flow etc., which may actively control one or more portions of the system such as the compensation port to reduce or eliminate CO2 buildup within flow circuits of the system such as within the patient interface, etc., while having little or no impact upon pressure delivery. For example, the controller may control the pressure compensation valve to exhaust CO2 from the patient interface.
Synchronized Abdominal Chest Thrust
In some embodiments, after the patient accepts the positive pressure, insufflated breath successfully, MI-E therapy may be enhanced by providing a synchronized abdominal chest thrust (e.g., to the chest of the patient) under the control of the controller. This may be beneficial in cases where it is determined that the patient produces low peak cough flow (PCF) rate or low effective cough volume (ECV). Accordingly, the process may identify the low PCF or low ECV. The setting for low PCF could be a clinician determined threshold or preset, for example <160 lpm. Effective cough volume could also be set by the clinician, or the threshold automatically determined as a percentage of the inhaled tidal volume. For example, if the VT were 1 liter and the ECV threshold was set at 50%, then any ECV less than 500 mL would be considered a suboptimal mechanically assisted cough. In accordance with embodiments, the system may generate an indication(s) and may render the indication(s) on a rendering device of the system such that an operator of the system may be informed that a synchronized abdominal chest thrust will be applied and/or is suggested (e.g., for the operator to apply including suggested timing) to enhance therapy. This synchronized abdominal chest thrust may be performed by the system during an optional window that may occur prior to, following or during a time when the MAC is performed or may a force transmitting device (FTD) action may be provided in place of or together with a MAC For example, a synchronized abdominal thrust or chest thrust may be be synchronized to the start of exsufflation with the presence of patient exhaled flow to be effective.
For example, embodiments illustrating synchronized abdominal chest thrust during exsufflation following successful insufflation will now be discussed with reference to
Mechanical chest or abdominal thrusts may be desirable where the patient is not able to cooperate with a synchronized cough effort during the exsufflation phase. Chest and abdominal thrusts may be employed to improve peak cough flow rates (PCFs) rates during MI-E therapy. Increasing the PCFs as well as the effective cough volume (ECV) during the exsufflation phase of MI-E therapy delivery is achieved by triggering automated abdominal and/or chest thrusts that are synchronized with the start of the exsufflation phase following the end of the insufflation phase (e.g., see, point 8,
The automated chest or abdominal thrust may be a viable means of raising the PCFs/ECV in patients that are unable to cooperate, follow commands and/or respond to breath pacing adequately. An increase in PCFs/ECV would improve airway clearance for this therapeutic modality.
Accordingly, in embodiments of the present system a force transmitting device (FTD) such as a belt, wrap, a vest, etc., may be worn by the patient around the patient's chest and may be activated by a controller of the system such as at the initiation of the MAC or other time in accordance with embodiments of the present system. The FTD may be coupled to a controller of the system and may include one or more bladders, an electro-active polymer (EAP) actuator, a mechanically operated tensioning device, etc., that may be operated by the controller to increase pressure at one or more times as may be determined by the controller to transfer a force effective to perform a chest or abdominal thrust upon the patient. The FTD may include one or more actuators and/or one or more sensors, such as force sensors, that may sense a force subject thereupon, form corresponding sensor information, and provide this sensor information to a controller of the system for further processing, such as to determine a force applied to the abdomen or chest of the patient. Indication of the forces may be rendered by the controller on a rendering device of the system.
In yet other embodiments, the FTD 1102 may include bands formed from an EAP polymer or polymers which may expand or contract under the control of the controller to generate a force. These bands may be coupled to an actuator which, in conjunction with the system controller, may control an electrical voltage applied to the bands to cause them to expand and/or contract under the control of the controller. Accordingly, the FTD 1102 may be operative, under the control of the controller and/or operator, to selectively generate desired forces so as to provide for an automated or manual chest or abdominal thrust as may be desired. The rear pan view of the vest 1101 may be similar to that shown in
Mode Saliency to Operator
It is envisioned that some embodiments of the present system may provide or otherwise render salient audio-visual indication(s) of the particular mode of operation in which the system is in, i.e., breath pacing, mechanical insufflation, or exsufflation. Such an indication may provide the operator with useful information of an operating mode of the system which may ensure not only that device operation is safe but also that MI-E therapy is effectively delivered without interruption. Since it may take several breathing cycles (e.g., 4-10 breath cycles) before the pressure and inhale time thresholds are attained to allow mechanical insufflation, the operator may be uncertain when the MAC has been delivered, which may lead to unexpected interruption or termination of therapy when, for example, the operator may prematurely decide to terminate operation of the system. Accordingly, it is envisioned that embodiments of the present system may be operative to detect an operating state of the system and whether there are any errors, whether the system has completed therapy successfully, etc., and render on a rendering device of the system an indicator of such. For example, during therapy the system may render an indication, such as one or more solid colored light(s) to indicate to the operator to continue providing therapy (e.g., therapy continuing). When the therapy has been completed and may be terminated, the system may render a solid light to indicate when to terminate therapy (e.g., such as at the end of therapy). It is also envisioned that the system may render information indicating therapy status such as a solid green light (e.g., emitted by a light-emitting diode (LED)) which may indicate for the duration of the therapy that the therapy is going well. When sufficient and successful therapy has been provided, it is envisioned that the system may detect this and render an indication of such using lighting, for example, a blinking green light (e.g., a green LED) to alert the operator that the therapy was successful and may be terminated. When, for example, it is detected that the therapy is not going well, the system may detect this and render an indicator of such displaying, for example, a continuous red LED light, followed by a blinking red LED light and error tone in case this situation persists for more than 2 cycles. In other embodiments status indicators may be rendered on a display screen of the system such as a touchscreen display for interaction with a user.
Actively Synchronized Delivery of Mechanical Insufflation with Patient Breathing
It is also envisioned that embodiments of the present system may include enhanced device-patient synchronization. This may be beneficial in situations in which breath pacing approach may be unsuccessful due to extreme patient agitation and/or persistent or erratic breath holding. Accordingly, embodiments of the present system may include methods which may actively trigger a patient breath (i.e., initiate inspiration) hold which can then be used to support synchronized delivery of MI-E therapy.
A reflex known as the Hering-Breuer deflation reflex (aka the excito-inspiratory reflex) may serve to shorten exhalation when the lung is deflated and may be initiated by embodiments of the present system. For example, this reflex may be initiated either by stimulation of stretch receptors or stimulation of proprioceptors activated by lung deflation. This reflex may also be triggered using, for example, chest compressions as described by S. Hannam, D. M. Ingram, S. Rabe-Hesketh, and A. D. Milnerin Characterisation of the Hering-Breuer deflation reflex in the human neonate. Respir Physiol 2001; 124(1):51-64, incorporated herein as if set out in its entirety. Chest compressions may be provided using any suitable FTD such as the FTD 1102 operating in accordance with embodiments of the present system. For example, any suitable FTD such as the FTD 1102 or the like, may be selectively activated by a controller of the system to trigger a patient breath through the application of the automatic application of chest compressions/thrusts. The FTD may include any suitable device such as a vest or wrap that may be activated using any suitable activation method or methods as described with reference to the FTD 1120. Accordingly, the FTD may be selectively operative to deliver abdominal and/or chest thrusts during exsufflation. In this case mechanical insufflation will be synchronized with the chest compressions/thrusts as presented in the sequence of acts depicted in
It is envisioned that the force applied during the chest compressions/thrusts may be gradually increased in steps until conditions are met for insufflation such as described above regarding an increasing in fixed steps as described above, without exceeding a maximum safe force. The SI may include information related to maximum force to be applied to the patient by one or more of size, age, etc. The process may then obtain this information to determine a maximum safe force to be applied and may obtain sensory feedback from one or more force sensors of the system to determine that the applied force (as sensed) does not exceed the maximum safe force for the patient. For example, two-finger and two-thumb chest compression during neonatal resuscitation suggests that peak chest compression forces in the range 35-50 N may be safe for infants as described by Dellimore K., Heunis S., Gohier F., et al., in Development Of A Diagnostic Glove For Measurement Of Chest Compression Force And Depth During Neonatal CPR published in Proc 35th Annual International IEEE EMBS Conference of the IEEE Engineering in Medicine and Biology Society, Osaka, Japan, 2013:350-353. Incorporated herein as if set out in entirety. This approach may be applied in combination with the breath pacing approach described above with reference to the embodiments of the present system (e.g., see embodiment of
This process repeats with a chest thrust/compression-initiated, device modulated increases in inhale pressure and time (e.g., see, point 5), until the pressure and inhale time thresholds are met (e.g., see, point 6′). The next synchronized breath may be utilized to introduce a single, mechanically assisted cough (e.g., see, point 7 and following).
Embodiments of the present system may be applied in domestic and clinical settings to deliver a more optimal and effective MI-E therapy to patients who are too young or unable to follow commands, such as infants or individuals who have learning disabilities than conventional systems. This therapy is specifically relevant to patients with neuromuscular disorders such as spinal muscular atrophy, Duchenne muscular dystrophy, polymyositis, hereditary spinal ataxia, and the like. It should also be appreciated that the present system may be utilized to provide automated MI-E therapy to patients who are cooperative in that the system may make the determination (e.g., automatically) of when conditions and/or timing are optimal or not. In this way, even a patient that exhibits satisfactory patient-system synchrony, may benefit by the proper timing and delivery of MI-E therapy without needing intervention from a clinician.
Further, embodiments of the present system may provide systems that are operative to trigger mechanical insufflation based on breath pacing and are operative to overcome problems such as those that may be caused by breath holding or dishabituation to the negative and positive pressure sensation that may be produced by the MI-E therapy.
The US 1338 may include any suitable user station such as a smart phone or the like that may be configured to communicate with other portions of the system 1300 such as the controller 1310 via any suitable communication method or methods such as via the network 1340.
The controller 1310 may include one or more logic devices such as a microprocessor (P) 1312 and may control the overall operation of the system 1300. A more detailed description of the controller 1310 may be given below. It would be appreciated that in some embodiments the controller 950 may include digital and/or analog control circuitry.
For example, one or more portions of the present system such as the controller 1310 may be operationally coupled to the memory 1322, the user interface (UI) 1318 including a rendering device such as the display 1320, the sensors 1314, and the user input interface 1316, the actuators 1324, the FTD 1326, the air supply 1328, the line set 1332, the patient interface 1334, the CO2 control 1336, the network 1340, and the US 1338.
The memory 1322 may be any type of device for storing application data as well as other data related to the described operation such as the SI, patient information, etc. The application data and other data may be received by the controller 1310 for configuring (e.g., programming) the controller 1310 to perform operation acts in accordance with the present system. The controller 1310 so configured becomes a special purpose machine particularly suited for performing in accordance with embodiments of the present system. For example, the controller 1310 may be configured to perform or coordinate/calculate/determine as described with
In accordance with the present system, the controller 1310 may render content, such as still or video information, on a rendering device of the system such as on the display 1320 of the UI 1318. This information may include information related to operating parameters, instructions, timing, feedback, and/or other information related to an operation of the system or portions thereof. For example, the controller 1310 may receive sensor information from one or more of: the sensors 1314 and compare airflow information related to current airflow, pressure, gas composition (e.g., O2, CO2 percentages, etc.), force (e.g., chest force, etc.) through one or more portions of the system (e.g., such as through the CO2 control 1336, the line set 1332, the patient interface 1334, and/or the air supply 1328) with threshold airflow information, threshold pressure information, threshold gas composition information, and/or threshold force information, respectively, and control the system accordingly. In this way, the controller 1310 may determine whether the valves, pumps, actuators, etc., is/are operating outside of operating parameters and may render results of this determination for the convenience of a user. The controller 1310 may include a breath monitoring unit which may monitor the breathing of the patient by acquiring flow and pressure information (e.g., flow and pressure signals) from the sensors. The controller 1310 may then process the acquired flow and pressure signals to regulate inhale pressure, inhale time, and/or delivery of mechanical insufflation by the system.
The sensors 1314 may be situated at one or more portions of the system and may sense related parameters, form corresponding sensor information, and provide this sensor information to the controller 1310 for further processing. For example, the sensors 1314 may include sensors such as flow, pressure, force, gas analysis, etc., which may form corresponding sensor information (e.g., gas flow, gas pressure, etc.) and provide this information to the controller 1310 for further analysis. The sensors 1314 may distributed throughout the system.
The user input interface 1316 may include a keyboard, a mouse, a trackball, or other device, such as a touch-sensitive display, which may be stand alone or part of a system, such as part of a MAC device, a laptop, a personal digital assistant (PDA), a mobile phone (e.g., a smart phone), a smart watch, an e-reader, a monitor, a smart or dumb terminal or other device for communicating with the controller 1310 via any operable link such as a wired and/or wireless communication link. The user input interface 1316 may be operable for interacting with the controller 1310 including enabling interaction within a UI 1318 as described herein. Clearly the controller 1310, the sensors 1314, the user input interface 1316, the user interface (UI) 1318, the memory 1322, the actuators 1334, the FTD 1326, the air supply 1328, the line set (e.g., a patient line set) 1332, the patient interface 1334, the CO2 control 1336, the network 1340, and the optional a user station (US) 1338 may all or partly be a portion of a computer system or other device such as MAC device, etc.
The UI may be operative to provide audio/visual feedback to the operator of the present system and may inform the operator of operating parameters, operating states, etc. For example, the UI may render information indicative of when a mechanically assisted cough has been successfully delivered.
The methods of the present system are particularly suited to be carried out by a computer software program, such program containing modules corresponding to one or more of: the individual acts or acts described and/or envisioned by the present system. Such program may of course be embodied in a computer-readable medium, such as an integrated chip, a peripheral device or memory, such as the memory 1332 or other memory coupled to the controller 1310.
The program and/or program portions contained in the memory 1322 may configure the controller 1310 to implement the methods, operational acts, and functions disclosed herein. The memories may be distributed, for example between the clients and/or servers, or local, and the controller 1310, where additional processors may be provided, may also be distributed or may be singular. The memories may be implemented as electrical, magnetic or optical memory, or any combination of these or other types of storage devices. Moreover, the term “memory” should be construed broadly enough to encompass any information able to be read from or written to an address in an addressable space accessible by the controller 1310 (e.g., by the P 1312). With this definition, information accessible through a network such as the network 1340 is still within the memory, for instance, because the controller 1310 may retrieve the information from the network 1340 for operation in accordance with embodiments of the present system.
The controller 1310 is operable for providing control signals and/or performing operations in response to input signals from the user input device 1316 as well as in response to other devices of a network, such as the sensors 1314 and executing instructions stored in the memory 1322. The P 1312 may include one or more of: a microprocessor, an application-specific and/or general-use integrated circuit(s), a logic device, etc. Further, the P 1312 may be a dedicated processor for performing in accordance with the present system and/or may be a general-purpose processor wherein only one of many functions operates for performing in accordance with the present system. The P 1312 may operate utilizing a program portion, multiple program segments, and/or may be a hardware device utilizing a dedicated or multi-purpose integrated circuit.
The actuators 1324 may, under control of the controller 1310, control one or more valves, pumps, motors, and/or the FTD 1326. For example, the actuators 1324 may include one or more valve actuators that may control the pressure and/or flow of a fluid such as air used by the system such as in the line set 1332.
The CO2 control may include one or more ports (e.g., balance valves, etc.) or valves (e.g., active and/or passive) that may be operative to control the buildup of CO2 in one or more portions of the system such as in one or more of the line-set 1332 and the patient interface 1334.
The FTD 1326 may include any suitable device such as a vest or wrap that may be activated using any suitable activation method or methods as described with reference to the FTD 1120. Accordingly, the FTD may be selectively operative to deliver abdominal and/or chest thrusts to the patient during one or more operating stages such as during exsufflation.
The air supply 1328 may include one or more fans and/or pumps 1330 that may be configured to supply a flow of air suitable for performing PAP therapy in accordance with embodiments of the present system.
The line set 1332 may couple the patient interface 1334 to the air supply 1328 and may include any suitable air flow path or paths such as may be provided by one or more tubes, hoses, or the like. The line set 1332 may further include one or more sensors, filters, and/or valves.
The patient interface 1334 may include any suitable patient interface such as a mask, a trach, and/or mouthpiece configured to be coupled to the line set 1332. When coupled together, the patient interface 1334 and the line set 1332 may form one or more of a mask circuit, a trachea circuit, and/or a mouthpiece circuit. The patient interface 1334 may form a non-invasive patient interface. The patient interface 1334 may include a one-way check valve operative to reduce or entirely prevent the build-up of CO2 in the flow portions of the systems such as the patient interface 1334. This valve may be a part of or independent from the CO2 control 1336.
The CO2 control 1336 may be coupled to one or more of the air supply 1328, the line set 1332, and the patient interface 1334 and may be configured to control the buildup of CO2 gas within one or more of the of the air supply 1328, the line set 1332, and the patient interface 1334. The CO2 control 1336 may be passive (e.g., a one-way valve permitting the outflow of exhaled gasses from the patient interface 1334) or may be actively controlled by the controller 1310 in accordance with embodiments of the present system.
The controller 1310 may be operable to control one or more ventilation devices and/or other devices as described. Similarly, the controller 1310 may be operable to control peripheral devices operating for example with a PAP device, pressure, humidification, flow, force, and heating circuits operating in accordance with embodiments of the present system.
Accordingly, embodiments of the present system may provide a system to monitor the state of the ventilator and/or provide a user interface for the user to control settings and/or parameters of the ventilator using a local and/or remote communication. A wireless communication link such as a Bluetooth™ or Wi-Fi™ link between portions of the ventilator and the rendering device 138 and the system may enable rendering of system parameters on a UI of the rendering device 138 which may also provide an entry area in which a user may change parameters such as ventilator settings, parameters, etc., of the system. Additionally, this link may be configured to link two or more PAP and/or MAC systems using a two-way connection. With this connection, battery system parameters may be rendered and/or airflow rates, pressure, temperature, humidity, gas analysis, etc., may be displayed and/or adjusted by the user. Parameters such as temperature, pressures, voltages, battery charge, specific oxygen (SpO2), carbon dioxide (CO2), humidity, force, current operating state, etc., may be determined and rendered on a rendering device of the system such as on the display 1320 of the system for the convenience of the user. Through the UI 1318, the user may interact to select and/or change parameters in accordance with embodiments of the present system.
Further variations of the present system would readily occur to a person of ordinary skill in the art and are encompassed by the following claims.
Embodiments of the present system may also be operative with continuous positive airway pressure (CPAP)/bilevel positive airway pressure (BiPAP) devices and other positive airway pressure devices operating in accordance embodiments of the present system.
Finally, the above discussion is intended to be merely illustrative of the present system and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. Thus, while the present system has been described with reference to exemplary embodiments, it should also be appreciated that numerous modifications and alternative embodiments may be devised by those having ordinary skill in the art including using features that are described with regard to a given embodiment with other envisioned embodiments without departing from the broader and intended spirit and scope of the present system as set forth in the claims that follow. In addition, any section headings included herein are intended to facilitate a review but are not intended to limit the scope of the present system. In addition, the specification and drawings are to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.
In interpreting the appended claims, it should be understood that:
This patent application claims the priority benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 63/273,191, filed on Oct. 29, 2021, the contents of which are herein incorporated by reference.
Number | Date | Country | |
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63273191 | Oct 2021 | US |