Cough assistance and measurement system and method

Systems and methods are configured to inexsufflate a subject and provide cough-by-cough feedback during treatment and/or therapy of the subject. Through sensors that are included in the systems, various gas and/or respiratory parameters maybe measured and/or determined in real-time, such as, for example, peak cough flow and/or inspiratory tidal volume.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure pertains to systems and methods for inexsufflating a subject. In particular, the systems and methods described herein measure, display, and/or record the efficacy of individual inexsufflations quantitatively through various gas and/or respiratory parameters, including, for example, peak cough flow and inspiratory tidal volume.

2. Description of the Related Art

Various systems for increasing patient cough flow through (in)exsufflation are known. Conventional (in)exsufflation is generally accomplished using a single (in)exsufflation event including a single exhalation of the subject. A respiratory circuit and/or the subject may positively pressurize the airway of the subject, and then the respiratory circuit and/or the subject may suddenly reverse the pressure and expel all (or substantially all) of this gas. Secretions built up in the airway of the subject over time may thus be expelled with the gas. Control of the operation of conventional systems used for (in)exsufflation may include setting an inspiratory pressure and/or one or more time parameters related to the duration of inhalation and/or exhalation.

Some characteristics of manual inexsufflation by a subject, without the aid of mechanical and/or electronic assistance, may be quantified using a spirometer. For example, a subject may cough into a spirometer such that, e.g., a peak expiratory flow and/or an expiratory tidal volume may be measured. It is noted that the use of a spirometer is limited by various practical limitations, including but not limited to the limitation that some mechanically ventilated patients may not be able to use a spirometer.

SUMMARY OF THE INVENTION

Accordingly, one or more aspects of the present disclosure relate to a system configured to inexsufflate a subject. The system comprises a pressure generator configured to generate a pressurized flow of breathable gas for delivery to an airway of the subject, a subject interface configured to guide the pressurized flow of breathable gas to the airway of the subject; one or more sensors configured to generate one or more output signals conveying information related to one or more parameters, wherein the one or more parameters include one or both of a gas parameter and/or a respiratory parameter; and one or more processors configured to execute computer program modules. The computer program modules comprise a control module configured to control the pressure generator to inexsufflate the subject, and a parameter determination module configured to determine a peak cough flow parameter based on the one or more output signals.

Yet another aspect of the present disclosure relates to a method of inexsufflating a subject. The method comprises generating a pressurized flow of breathable gas for delivery to an airway of the subject; guiding the pressurized flow of breathable gas to the airway of the subject; generating one or more output signals by one or more sensors conveying information related to one or more parameters, wherein the one or more parameters include one or both of a gas parameter and/or a respiratory parameter; controlling the pressurized flow of breathable gas to inexsufflate the subject; and determining a peak cough flow parameter based on the one or more output signals.

Still another aspect of present disclosure relates to a system configured for inexsufflating a subject. The system comprises pressure means for generating a pressurized flow of breathable gas for delivery to an airway of the subject; means for guiding the pressurized flow of breathable gas to the airway of the subject; sensor means for generating one or more output signals conveying information related to one or more parameters, wherein the one or more parameters include one or both of a gas parameter and/or a respiratory parameter; means for controlling the pressure means to inexsufflate the subject; and means for determining a peak cough flow parameter based on the one or more output signals.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1schematically illustrates an exemplary embodiment of a system10to inexsufflate a subject106. Inexsufflation may loosen and/or expel secretions. Unaided inexsufflation may be difficult and/or impossible for a wide range of patients due to a wide range of different medical reasons. The efficacy of an individual inexsufflation (e.g. during an individual respiratory cycle) can be quantified using one or more characteristic parameters, described below. System10measures, displays, and/or records information pertaining to individual inexsufflations, sets of such inexsufflations, individual treatments including one or more of such inexsufflations, sets of such treatments, days including one or more such treatments, and/or other periods of treatment time including one or more such individual inexsufflations.

System10includes one or more of a pressure generator140, a user interface120, a delivery circuit180, electronic storage130, one or more sensors142, one or more processors110, a control module111, a parameter determination module112, an interface module113, a metric storage module114, and/or other components. System10may be dedicated to providing inexsufflations.

In some embodiments, pressure generator140of system10inFIG. 1may be integrated, combined, or connected with a ventilator device or system.

Pressure generator140is configured to provide a pressurized flow of breathable gas for fluid communication with the airway of subject106, e.g. via delivery circuit180. The direction of the fluid communication may be selectively controlled. Pressure generator140may be configured to adjust one or more of pressure levels, flow, humidity, velocity, acceleration, and/or other parameters of the pressurized flow of breathable gas.

Delivery circuit180is configured to selectively control the direction and/or flow of breathable gas to and/or from the airway of subject106. Delivery circuit180may sometimes be referred to as subject interface180. Delivery circuit180may be configured to operate in one or more of a first mode, a second mode, a third mode, and/or in other modes. One or more modes may correspond to one or more respiratory phases of a breathing cycle. In the first mode, delivery circuit180is closed such that substantially no gas is communicated with the airway of subject106therethrough. In the second mode delivery circuit180is opened to permit gas to be exhausted from the airway of subject106through delivery circuit180, e.g. to ambient atmosphere. In the third mode delivery circuit180is opened to permit gas to be delivered to the airway of subject106through delivery circuit180.

In some implementations, delivery circuit180may include one or more of a valve and/or another pressure regulating device. In one embodiment delivery circuit180may include multiple valves in series and/or in parallel. Examples of suitable valves and/or other pressure regulating devices include a plug valve, a ball valve, a check valve, a butterfly valve, a solenoid, and/or other pressure regulating devices. Pressure regulating devices may be controlled hydraulically, pneumatically, via an electric motor and/or another mode of control configured to open and/or close a valve and/or other pressure control device.

Delivery circuit180may include a conduit182and/or a subject interface appliance184. Conduit182may include a flexible length of hose, or other conduit, either in single-limb or dual-limb configuration that places subject interface appliance184in fluid communication with pressure generator140. Conduit182forms a flow path through which the pressurized flow of breathable gas (e.g. air) is communicated between subject interface appliance184and pressure generator140.

Subject interface appliance184of system10inFIG. 1is configured to deliver the pressurized flow of breathable gas to the airway of subject106. As such, subject interface appliance184may include any appliance suitable for this function. In some embodiments, subject interface appliance184is configured to engage the airway of subject106without an intervening appliance. In this embodiment, subject interface appliance184may include one or more of an endrotracheal tube, a nasal cannula, a tracheotomy tube, a nasal mask, a nasal/oral mask, a full-face mask, a total facemask, and/or other interface appliances that communicate a flow of gas with an airway of a subject. In some embodiments, pressure generator140is a dedicated ventilation device and subject interface appliance184is configured to be removably coupled with another interface appliance being used to deliver respiratory therapy to subject106. For example, subject interface appliance184may be configured to engage with and/or be inserted into an endrotracheal tube, a tracheotomy portal, and/or other interface appliances. The present disclosure is not limited to these examples, and contemplates delivery of the pressurized flow of breathable gas to subject106using any subject interface.

Electronic storage130of system10inFIG. 1comprises electronic storage media that electronically stores information. The electronic storage media of electronic storage130may include one or both of system storage that is provided integrally (i.e., substantially non-removable) with system10and/or removable storage that is removably connectable to system10via, for example, a port (e.g., a USB port, a FireWire port, etc.), a slot (e.g., an SD card slot, etc.), or a drive (e.g., a disk drive, etc.). Electronic storage130may include one or more of optically readable storage media (e.g., optical disks, etc.), magnetically readable storage media (e.g., magnetic tape, magnetic hard drive, floppy drive, etc.), electrical charge-based storage media (e.g., EPROM, EEPROM, RAM, etc.), solid-state storage media (e.g., flash drive, etc.), and/or other electronically readable storage media. Electronic storage130may store software algorithms, information determined by processor110, information received via user interface120, and/or other information that enables system10to function properly. For example, electronic storage130may record or store information pertaining to individual inexsufflations and/or treatments that include one or more inexsufflations (as discussed elsewhere herein), and/or other information. Electronic storage130may be a separate component within system10, or electronic storage130may be provided integrally with one or more other components of system10(e.g., processor110).

User interface120of system10inFIG. 1is configured to provide an interface between system10and a user (e.g., user108, subject106, a caregiver, a therapy decision-maker, etc.) through which the user can provide information to and receive information from system10. This enables data, results, and/or instructions and any other communicable items, collectively referred to as “information,” to be communicated between the user and system10. An example of information that may be conveyed to user108is a report detailing quantitative information pertaining to individual inexsufflations throughout a period during which the subject is receiving treatment and/or therapy. Examples of interface devices suitable for inclusion in user interface120include a keypad, buttons, switches, a keyboard, knobs, levers, a display screen, an electronic display150configured to display information, a touch screen, speakers, a microphone, an indicator light, an audible alarm, and a printer. Information may be provided to user108or subject106by user interface120in the form of auditory signals, visual signals, tactile signals, and/or other sensory signals. Although electronic display150is depicted inFIG. 1as a separate entity from user interface120, this is for illustrative purposes only. In some embodiments, electronic display150may be integrated, embedded, and/or combined with user interface120.

It is to be understood that other communication techniques, either hard-wired or wireless, are also contemplated herein as user interface120. For example, in one embodiment, user interface120may be integrated with a removable storage interface provided by electronic storage130. In this example, information is loaded into system10from removable storage (e.g., a smart card, a flash drive, a removable disk, etc.) that enables the user(s) to customize system10. Other exemplary input devices and techniques adapted for use with system10as user interface120include, but are not limited to, an RS-232 port, RF link, an IR link, modem (telephone, cable, Ethernet, internet or other). In short, any technique for communicating information with system10is contemplated as user interface120.

One or more sensors142of system10inFIG. 1are configured to generate output signals conveying measurements related to parameters of respiratory airflow and/or airway mechanics. These parameters may include one or more of flow, (airway) pressure, humidity, velocity, acceleration, and/or other gas or respiratory parameters. These parameters may pertain to one or more gas levels of the pressurized flow of breathable gas provided through pressure generator140and/or a flow of gas at or near the airway of subject106, for example within subject interface appliance184. As depicted inFIG. 1, one or more sensors142may be in fluid communication with conduit182and/or subject interface appliance184. In some embodiments, one or more sensors142may generate output signals related to physiological parameters pertaining to subject106.

The illustration of sensor142including two members inFIG. 1is not intended to be limiting. The illustration of a sensor142at or near subject interface appliance184is not intended to be limiting. The illustration of a sensor142at or near pressure generator140is not intended to be limiting. In one embodiment sensor142includes a plurality of sensors operating as described above by generating output signals conveying information related to parameters associated with the state and/or condition of an airway of subject106, the breathing of subject106, the gas breathed by subject106, the composition of the gas breathed by subject106, the delivery of the gas to the airway of subject106, and/or a respiratory effort by the subject. For example, a parameter may be related to a mechanical unit of measurement of a component of pressure generator140(or of a device that pressure generator140is integrated, combined, or coupled with) such as valve drive current, rotor speed, motor speed, blower speed, fan speed, or a related measurement that may serve as a proxy for any of the previously listed parameters through a previously known and/or calibrated mathematical relationship. Resulting signals or information from one or more sensors142may be transmitted to processor110, user interface120, electronic storage130, and/or other components of system10. This transmission may be wired and/or wireless.

Processor110of system10inFIG. 1is configured to provide information processing capabilities in system10. As such, processor110includes one or more of a digital processor, an analog processor, a digital circuit designed to process information, an analog circuit designed to process information, a state machine, and/or other mechanisms for electronically processing information. Although processor110is depicted inFIG. 1as a single entity, this is for illustrative purposes only. In some embodiments, processor110includes a plurality of processing units.

As is shown inFIG. 1, processor110is configured to execute one or more computer program modules. The one or more computer program modules include one or more of control module111, parameter determination module112, interface module113, metric storage module114, and/or other modules. Processor110may be configured to execute modules111-114by software; hardware; firmware; some combination of software, hardware, and/or firmware; and/or other mechanisms for configuring processing capabilities on processor110.

It should be appreciated that although modules111-114are illustrated inFIG. 1as being co-located within a single processing unit, in embodiments in which processor110includes multiple processing units, one or more of modules111-114may be located remotely from the other modules. The description of the functionality provided by the different modules111-114described herein is for illustrative purposes, and is not intended to be limiting, as any of modules111-114may provide more or less functionality than is described. For example, one or more of modules111-114may be eliminated, and some or all of its functionality may be incorporated, shared, integrated into, and/or otherwise provided by other ones of modules111-114. Note that processor110may be configured to execute one or more additional modules that may perform some or all of the functionality attributed below to one of modules111-114.

Parameter determination module112of system10inFIG. 1is configured to determine one or more gas parameters, respiratory parameters, and/or other parameters from output signals generated by sensor(s)142. The one or more gas parameter may include and/or be related to one or more of (peak) flow, flow rate, (tidal) volume, pressure, temperature, humidity, velocity, acceleration, gas composition (e.g. concentration(s) of one or more constituents such as, e.g., CO2), thermal energy dissipated, (intentional) gas leak, and/or other measurements related to the (pressurized) flow of breathable gas. One or more respiratory parameters may be derived from gas parameters and/or other output signals conveying measurements of the pressurized flow of breathable gas. The one or more respiratory parameters may include one or more of respiratory rate, breathing period, inhalation time or period, exhalation time or period, respiration flow curve shape, transition time from inhalation to exhalation and/or vice versa, transition time from peak inhalation flow rate to peak exhalation flow rate and/or vice versa, respiration pressure curve shape, maximum proximal pressure drop (per breathing cycle and/or phase), peak cough flow, average (or otherwise aggregated) cough flow, inspiratory tidal volume (for one or more respiratory cycles), expiratory tidal volume (for one or more respiratory cycles), and/or other respiratory parameters. Respiratory parameters may be determined on a breath-by-breath basis, on a cough-by-cough basis, and/or at other intervals.

For example, a peak cough flow parameter may be determined for individual respiratory cycles and/or individual inexsufflations. The peak cough flow parameter may be used as a basis for a determination how effectively subject106is able to clear secretions, how clear the airway of subject106is, and/or any other determination related to inexsufflation, respiratory therapy, and/or the condition of subject106. For example, inspiratory tidal volume may be determined for individual respiratory cycles and/or individual inexsufflations. The inspiratory tidal volume may be used as a basis for a determination how effectively subject106is able to clear secretions, how clear the airway of subject106is, and/or any other determination related to inexsufflation, respiratory therapy, and/or the condition of subject106. Using other parameters described herein in forming such a determination is contemplated within the scope of this disclosure. It is noted that by virtue of the systems and methods of inexsufflating subjects as described herein, such a determination may be formed by objective standards.

In some embodiments, determination of the peak cough flow parameter (and/or other parameters as described herein) by parameter determination module112may account and/or compensate for a length of conduit182(and/or volume of breathable gas within one or more components of delivery circuit180) used between a particular sensor142and the airway of subject106. For example, as depicted inFIG. 1, a sensor142used to generate output signals conveying information related to the peak cough flow parameter may be disposed at or near pressure generator140, which may be separated from the airway of subject106by, at least, a predetermined length of conduit182(and thus a predetermined volume of breathable gas therewithin). The length of conduit182may be about 3 feet, about 4 feet, about 6 feet, about 9 feet, about 12 feet, and/or other length. Common pertinent lengths of conduit182in mechanical ventilation systems may be between about 6 feet and about 9 feet. Parameter determination module112may be calibrated accordingly as compensation for the part of delivery circuit180disposed between a particular sensor142and the airway of subject106.

Control module111of system10inFIG. 1is configured to control operation of system10during inexsufflation of subject106. Control module111may be configured to control pressure generator140to adjust one or more levels of one or more gas parameters of the pressurized flow of breathable gas in accordance with one or more of a (respiratory) therapy regimen, one or more algorithms that control adjustments and/or changes in the pressurized flow of breathable gas, and/or other factors. Control module111may be configured to control pressure generator140such that one or more gas parameters of the pressurized flow of breathable gas are varied over time in accordance with a respiratory therapy regimen and/or treatment. Control module111may be configured to control pressure generator140to provide the pressurized flow of breathable gas at inhalation pressure levels during inhalation phases, and/or at exhalation pressure levels during exhalation phases. For example, pressure of the pressurized flow of breathable gas may be elevated (e.g., about ambient atmosphere) during inhalation to insufflate subject106. During this insufflation, one or more of a flow rate, an insufflation pressure, and/or an inhaled volume may be controlled by control module111. Responsive to the insufflation being completed (e.g., as determined in accordance with the therapy regimen), control module111may be configured to cause pressure generator140to reduce pressure of the pressurized flow of breathable gas (e.g., to below ambient atmosphere and/or to a negative pressure, or some other pressure lower than the insufflation pressure) to cause the gas in the lungs and/or airway of subject106to be expelled and/or drawn out quickly, thereby exsufflating subject106.

Parameters determined by parameter determination module112and/or received through one or more sensors142may be used by control module111, e.g. in a feedback manner, to adjust therapy modes/settings/operations of system10. Alternatively, and/or simultaneously, signals and/or information received through user interface120may be used by control module111, e.g. in a feedback manner, to adjust one or more therapy modes/settings/operations of system10. In some embodiments, user108may (e.g. manually) control one or more pressure levels used during operation of system10through user interface120. Control module111may be configured to time its operations relative to the transitional moments in the breathing cycle of a subject, over multiple breath cycles, and/or in any other relation to any detected events and/or occurrences.

In some embodiments, operation of control module111may be governed through programmatic control, e.g. by an algorithm implemented through instructions that are executed by control module111. Such an algorithm may be designed to titrate operating conditions of system10such that a target operating condition is reached and/or accomplished over time. For example, the algorithm may use a target peak cough flow for individual inexsufflations. The algorithm may adjust one or more gas parameters of the pressurized flow of breathable gas, such as for example the inspiratory pressure level, based on the determine peak cough flow parameter of one or more recent inexsufflations. In some embodiments, alternatively and/or simultaneously, the algorithm may be designed to reach a target inspiratory tidal volume for individual inexsufflations.

Interface module113of system10inFIG. 1is configured to control user interface120and/or electronic display150to display information. The displayed information may pertain to (or be based on) one or more of the generated output signals, one or more parameters as determined by parameter determination module112, including but not limited to the peak cough flow parameter and the inspiratory tidal volume, and/or other information. In some embodiments, the displayed information may be an aggregation of one or more determined parameters. In some embodiments, the displayed information may be displayed in real-time, thus providing immediate feedback on the operation of system10and/or the efficacy of the treatment while the treatment is being administered to subject106.

Metric storage module114of system10inFIG. 1is configured to derive, determine, and/or store information on electronic storage130. The derived, determined, and/or stored information may be based on one or more generated output signals from one or more sensors142, one or more determined parameters from parameter determination module112, one or more operating conditions of system10as controlled through control module111, and/or other information related to the operation of system10. For example, metric storage module114may be configured to derive and/or determine metrics based on individual inexsufflations, sets of such inexsufflations, individual treatments including one or more of such inexsufflations, sets of such treatments, days including one or more such treatments, and/or other periods of treatment time including one or more such individual inexsufflations. Metric storage module114may be configured to subsequently store such metrics and/or other information as described herein on electronic storage.

In some embodiments, the derived and/or stored metrics include one or more of number of coughs per treatment, number of treatments per day, number of days or treatment, average (or otherwise aggregated) peak cough flow per treatment, average (or otherwise aggregated) peak cough flow per day that includes one or more treatments, average (or otherwise aggregated) inspiratory tidal volume, average (or otherwise aggregated) delivered pressure level for insufflation and/or exsufflation per individual inexsufflation, treatment, and/or day that includes one or more treatments, and/or other information pertaining to the treatment described herein.

In some embodiments, the information stored by metric storage module114may be an aggregation of one or more determined parameters. In some embodiments, the stored information is stored on removable electronic storage such that review and/or analysis may be performed after one or more treatments. For example, the stored information may be reviewed at a doctor's office, by virtue of using a software application, and/or remotely through a network-connected computing platform. Such review and/or analysis may reveal trends in one or more parameters over time. Such review and/or analysis may be used to adjust a therapy regimen for subject106. Such review and/or analysis may be used to verify and/or quantify a level of compliance with a prescribed therapy regimen.

In some embodiments, system10may transfer the stored information, e.g. through removable electronic storage and/or a network connection, to a client computing platform configured to perform the review and/or analysis described herein. Such a client computing platform may be further configured to present the stored information, and/or any results from the described review and/or analysis, to a user of the client computing platform, e.g. user108. By way of non-limiting example, a client computing platform may include one or more of a desktop computer, a laptop computer, a tablet computing device, a handheld computer, a NetBook, a smartphone, a gaming console, an interactive television, and/or other computing platform or computing device.

It will be appreciated that the description of the operation of pressure generator140by the electronic processor110and/or its modules is not intended to be limiting. Other controllers for opening pressure generator140responsive to pressurization along delivery circuit180fall within the scope of this disclosure. Other mechanical controllers are also contemplated.

FIG. 2illustrates a method200of inexsufflating a subject. The operations of method200presented below are intended to be illustrative. In some embodiments, method200may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of method200are illustrated inFIG. 2and described below is not intended to be limiting.

At an operation202, a pressurized flow of breathable gas is generated for delivery to the airway of a subject. In some embodiments, operation202is performed by a pressure generator the same as or similar to pressure generator140(shown inFIG. 1and described herein).

At an operation204, the pressurized flow of breathable gas is guided to the airway of the subject. In some embodiments, operation204is performed by a delivery circuit the same as or similar to delivery circuit180(shown inFIG. 1and described herein).

At an operation206, one or more output signals are generated that convey information related to one or more parameters, wherein the one or more parameters include one or both of a gas parameter and/or a respiratory parameter. In some embodiments, operation206is performed by a sensor the same as or similar to sensor142(shown inFIG. 1and described herein).

At an operation208, the pressurized flow of breathable gas is controlled to inexsufflate the subject. In some embodiments, operation208is performed by a control module the same as or similar to control module111(shown inFIG. 1and described herein).

At an operation210, a peak cough flow parameter is determined based on the one or more generated output signals. In some embodiments, operation210is performed by a parameter determination module the same as or similar to parameter determination module112(shown inFIG. 1and described herein).

Although the description provided above provides detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the disclosure is not limited to the expressly disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present disclosure contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.