Patent Application
20080060647
The following includes definitions of exemplary terms used throughout the disclosure and specification. Both singular and plural forms of all terms fall within each meaning:
“Signal”, as used herein includes, but is not limited to, one or more electrical signals, analog or digital signals, optical or light (electro-magnetic) signals, one or more computer instructions, a bit or bit stream, or the like.
“Night's Sleep”, as used herein includes, but is not limited to, a period of time in which the natural periodic suspension of consciousness occurs during which the powers of the body are restored and is not limited to day or night or a single occurrence. For example, a typical “night's sleep” may include the period during which an individual retires for the evening to his or her bed. This time span may be characterized by periods of wakefulness, partial sleep, sleep, disruptive sleep and other various stages of sleep. Hence, a night's sleep may be characterized by states of consciousness and partial or complete suspension of consciousness. A “night's sleep” can also be characterized by calendar days, hours, or minutes. For example, one night's sleep can be characterized by one calendar day. Similarly, two night's sleep can be characterized by two calendar days.
“Logic”, synonymous with “circuit” as used herein, includes but is not limited to hardware, firmware, software and/or combinations of each to perform a function(s) or an action(s). For example, based on a desired application or needs, logic may include a software controlled microprocessor, discrete logic such as an application specific integrated circuit (ASIC), or other programmed logic device. Logic may also be fully embodied as software. “Software”, as used herein, includes but is not limited to one or more computer readable and/or executable instructions that cause a computer or other electronic device to perform functions, actions, and/or behave in a desired manner. The instructions may be embodied in various forms such as routines, algorithms, modules or programs including separate applications or code from dynamically linked libraries. Software may also be implemented in various forms such as a stand-alone program, a function call, a servlet, an applet, instructions stored in a memory, part of an operating system or other type of executable instructions. It will be appreciated by one of ordinary skill in the art that the form of software may be dependent on, for example, requirements of a desired application, the environment it runs on, and/or the desires of a designer/programmer or the like.
“Time period” includes, but is not limited to, an interval of time characterized by the occurrence of a certain condition, event, or phenomenon or the lack thereof. “Time period” may also include the measure of an interval, which can be any number represented by year(s), month(s), week(s), day(s), or minute(s), or combinations of the foregoing. Examples of a time period include 1 month, 1 to 3 months, 2 weeks, 14 days, 14 to 16 days, 6 hours, 6 to 8 hours, 122 minutes, 120 to 180 minutes, 1 month and 3 weeks, 5 nights, 5-7 nights, etc.
“Incrementally” includes, but is not limited to, changing by a series of events that include quantity, value or extent; by at least one of a series of regular consecutive additions, subtractions or modifications; or by an amount or degree.
“Ramp function” includes, but is not limited to, increasing or decreasing by a constant or non-constant bend, slope, or curve; or a change in level or direction by a constant or non-constant slope.
“Usage data” includes, but is not to limited to, any form of data including combinations of data indicating the usage of a machine, therapy, modality, or feature. For example, “usage data” can include compliance data indicating the time during which a particular therapy was used by a patient. The data can be in any form such as, for example, months, weeks, days, hours, minutes, seconds, or combinations of the foregoing.
“Threshold value” includes, but is not limited to, the point or range that must be exceeded to begin producing an effect or result or to elicit a response; or any value, level, or point that is used for setting a limit or condition.
“Sensor data” includes, but is not limited to, any form of data including digital and or analog that is produced by a device that measures, determines or tracks parameters or variables. “Sensor data” can include raw data or data that has been conditioned or modified subsequent to its generation. “Sensor data” can include, for example, flow rate data, temperature data, pressure data, physiological data (e.g., heart rate, blood pressure, EKG, breathing rate, arterial oxygen content, etc.), valve position data, motor speed or r.p.m. (rotations per minute) data, motor current signals or data, and/or motor voltage signals or data.
The systems and methods described herein are suited for assisting the respiration of spontaneously breathing patients, though they may also be applied to other respiratory regimens including, for example, acute and homecare ventilation. Referring now to
Flow/pressure generator 106 can be a variable speed blower alone or in combination with one or more valves such as, for example, a linear valve, solenoid valve, and/or a stepper motor controlled variable position valve. The flow/pressure generator 106 can also be a constant speed blower with a linear, solenoid and/or motor-driven stepper valve. The sensor element(s) 110 can include a flow sensor, flow rate sensor, temperature sensor, exhaled gas concentration sensor, infra-red light emitter/sensor, motor current sensor, or motor speed sensor alone or in combination with the pressure sensor. Sensor(s) 110 may also measure physiological parameters of a patient such as, for example, heart rate, blood pressure, EKG, breathing rate, arterial oxygen content, body temperature, brain wave activity, etc. The data generated from sensor(s) 110 is fed back to the controller 102 for processing.
Control logic 104 includes instructions for generating one or more embodiments of the therapy modalities illustrated in
As will be described in the following embodiments, the change in initial pressure P1 to final pressure PT can occur over widely varying durations of time and according to constant and/or non-constant changes in pressure. While varying durations and profiles of pressure changes from initial pressure P1 to final therapy pressure PT will be described, the particular duration(s), initial pressure P1, a final therapy pressure PT, and profile of the pressure changes that are suitable for a particular patient are preferably set by a sleep therapist, respiratory therapist, sleep doctor, or other sleep professional. In one example, these settings may be set or adjusted through a interface such as a keypad. It is contemplated that the patient may set or adjust one or more of these parameters him or herself. It is also further contemplated that the system may set or adjust one or more of these parameters on its own in an automatic manner based on one or more feedback loops. It is also contemplated that settings or adjustments can occur through a remote or non-attached adjustment device that is in wireless communication with the system. It is also contemplated that settings or adjustments can occur through information that is downloaded to the memory of the system over a network, memory card, disk or similar device.
The embodiment of
Even though a ramp function has been added to each night's sleep pressure, the duration of the ramp function is a relatively short period of time compared to the duration of the night's sleep. Hence, even though a ramp function appears in the pressure output, the pressure is still considered to have been maintained for the night's sleep. Other variations in the magnitude of the pressure for purposes of comfort or compliance may be added to each night's sleep and fall within the meaning of maintaining a general pressure level or a mean pressure level during the night's sleep.
Pressure profile 704 is shown as a nonlinear profile. Pressure profile 704 has a non-constant rate of change from initial pressure P1 to final therapy pressure PT. The changes in pressure from night to night are initially large starting from the initial night (N1) and progressively diminish until the final therapy pressure PT is reached on the last night (Nn).
Pressure profile 706 is also shown as a nonlinear profile. Pressure profile 706 also has a non-constant rate of change from initial pressure P1 to final therapy pressure PT. The changes in pressure from night to night are initially small starting from the initial night (N1) and progressively grow larger until the final therapy pressure PT is reached on last night (Nn).
Though pressure profiles 704 and 706 have been described as having a non-constant rate of change, it is contemplated that these pressure profiles may have portions thereof that include a constant rate of change and portions thereof that include a non-constant rate of change. For example, pressure profile 704 may have a portion thereof that includes a constant rate of change beginning from initial starting pressure P1 on night N1 that changes to a portion thereof having in non-constant rate of change some nights later. Similarly, pressure profile 706 may have a portion thereof that includes a non-constant rate of change beginning from initial starting pressure P1 on night N1 that changes to a portion thereof having in constant rate of change some nights later. Still further, pressure profiles 704 and 706 may include additional portions thereof having either constant or non-constant rates of change.
Referring now to
As shown in
Flow diagram 800 illustrates one embodiment of control logic 104. In block 802, the system generates a first or initial pressure level of breathing gas (e.g., P1). In block 804, the pressure level of breathing gas is increased from the first or initial pressure level to a second pressure level over a duration equal to or greater than one night's sleep. In block 806, the second pressure level is maintained over a duration of least one night's sleep.
Referring now to
In block 902, the system generates a pressure/flow output. For example, during the initial night of operation, the pressure output generated would generally be the starting or initial pressure P1. Block 904 tests to determine whether an increment threshold has been exceeded. The increment threshold determines whether conditions have been satisfied to increase the pressure from the present level to the next level or increment. The increment threshold may have several embodiments. In one embodiment, the increment threshold may take the form of a time duration such as, for example, one night's sleep. In another embodiment, the increment threshold may take the form of a level of compliance such as, for example, six hours of continuous therapy usage. In another embodiment, the increment threshold may be based on one or more physiological sensors connected to a patient. For example, the increment threshold may take the form of an apnea level that detects whether an apnea has occurred over a certain time duration. If the increment threshold is not exceeded in block 904, then the logic loops back to block 902 where the present pressure level is maintained.
If the increment threshold is exceeded in block 904, the logic of advances to block 906. In block 906, the pressure level is adjusted to the next increment because the increment threshold has been exceeded in block 904. The next pressure increment or pressure change may be defined by, for example, the type of pressure profile specified or other parameters including a specified pressure increment. In block 908, the logic determines whether the next pressure increment is the final pressure increment or final pressure. If the next pressure increment is not the final pressure, the logic loops back to block 902 where a pressure output is generated according to the next pressure increment. If the next pressure increment is the final pressure, the logic of advances to block 910 where the final pressure is output and maintained.
Illustrated in
The logic flow shown and described herein may reside in or on a computer readable medium or product such as, for example, a Read-Only Memory (ROM), Random-Access Memory (RAM), programmable read-only memory (PROM), electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk or tape, and optically readable mediums including CD-ROM and DVD-ROM. Still further, the processes and logic described herein can be merged into one large process flow or divided into many sub-process flows. The process flows described herein may be rearranged, consolidated, and/or re-organized in their implementation as warranted or desired so long as the relative order is maintained. For example, other related or unrelated process flows can be interjected between the specified process blocks without affecting the functionality or results obtained.
While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, embodiments of the invention can be further modified to incorporate additional features such as proportional airway pressure, exhalation unloading, proportional assist ventilation, etc. Still further, the present invention may be applied to a bi-level pressure modality where each output pressure increment would have an inspiratory positive airway pressure (IPAP) and an expiratory positive airway pressure (EPAP). For example, in the Figures, initial pressure P1 may have an inspiratory pressure level (e.g., P1I) and an expiratory pressure level (e.g., P1E) where each inspiratory and expiratory pressure level is adjusted according the same approach as P1 would have been (e.g., by pressure increments). Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept.
