U.S. patent application number 16/868634 was filed with the patent office on 2020-10-22 for methods and apparatus for providing ventilation to a patient.
This patent application is currently assigned to ResMed Pty Ltd. The applicant listed for this patent is ResMed Pty Ltd. Invention is credited to David John Bassin, Michael Berthon-Jones, Clancy John Dennis, Steven Paul Farrugia, Gordon Joseph Malouf, Klaus Henry SCHINDHELM, Helmut Teschler.
Application Number | 20200330708 16/868634 |
Document ID | / |
Family ID | 1000004939366 |
Filed Date | 2020-10-22 |
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United States Patent
Application |
20200330708 |
Kind Code |
A1 |
SCHINDHELM; Klaus Henry ; et
al. |
October 22, 2020 |
METHODS AND APPARATUS FOR PROVIDING VENTILATION TO A PATIENT
Abstract
An apparatus to generate pressure support ventilation and a
method to control pressure support ventilation. The apparatus
comprises: at least one sensor adapted to measure at least one
respiratory parameter; a flow generator adapted for coupling with a
patient respiratory interface; and a controller, coupled to the at
least one sensor and the flow generator. The flow generator is
configured to provide a flow of breathable gas for pressure support
ventilation to the patient respiratory interface. The controller is
configured to control the pressure support ventilation with the
flow generator. The controller is further configured with a rest
mode and an exercise mode. The rest mode comprises a first value
set of control parameters for the pressure support ventilation and
the exercise mode comprises a second value set of control
parameters for the pressure support ventilation.
Inventors: |
SCHINDHELM; Klaus Henry;
(Sydney, AU) ; Malouf; Gordon Joseph; (Sydney,
AU) ; Farrugia; Steven Paul; (Sydney, AU) ;
Dennis; Clancy John; (Potts Point, NSW, AU) ;
Berthon-Jones; Michael; (Sydney, AU) ; Bassin; David
John; (Coogee, AU) ; Teschler; Helmut;
(Velbert, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ResMed Pty Ltd |
Bella Vista, NSW |
|
AU |
|
|
Assignee: |
ResMed Pty Ltd
Bella Vista NSW
AU
|
Family ID: |
1000004939366 |
Appl. No.: |
16/868634 |
Filed: |
May 7, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15430742 |
Feb 13, 2017 |
10668237 |
|
|
16868634 |
|
|
|
|
14356471 |
May 6, 2014 |
9597468 |
|
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PCT/AU2012/001367 |
Nov 7, 2012 |
|
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15430742 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 16/0051 20130101;
A61B 5/087 20130101; A61M 2016/0036 20130101; A61B 5/14551
20130101; A61M 16/1075 20130101; A61M 2016/0018 20130101; A61M
2205/502 20130101; A61M 2016/0027 20130101; A61M 2016/0033
20130101; A61B 5/0488 20130101; A61M 16/107 20140204; A61B 5/4866
20130101; A61M 16/0069 20140204; A61B 5/0816 20130101; A61B 5/024
20130101; A61M 16/16 20130101; A61M 16/0006 20140204; A61B 5/4836
20130101; A61M 2016/0039 20130101; A61M 16/024 20170801; A61M
2230/205 20130101; A61B 5/0205 20130101; A61B 5/085 20130101 |
International
Class: |
A61M 16/00 20060101
A61M016/00; A61M 16/10 20060101 A61M016/10; A61B 5/0205 20060101
A61B005/0205; A61B 5/0488 20060101 A61B005/0488; A61B 5/1455
20060101 A61B005/1455; A61B 5/00 20060101 A61B005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 7, 2011 |
AU |
2011904599 |
Jun 15, 2012 |
AU |
2012902501 |
Jun 26, 2012 |
AU |
2012902693 |
Claims
1. An apparatus to generate pressure support ventilation,
comprising: at least one sensor adapted to measure at least one
respiratory parameter; a flow generator adapted for coupling with a
patient respiratory interface, the flow generator configured to
provide a flow of breathable gas for pressure support ventilation
to the patient respiratory interface; and a controller, coupled to
the at least one sensor and the flow generator, the controller
configured to control the pressure support ventilation with the
flow generator, the controller being further configured with a rest
mode and an exercise mode, the rest mode comprising a first value
set of control parameters for the pressure support ventilation and
the exercise mode comprising a second value set of control
parameters for the pressure support ventilation, wherein the
controller is configured to receive a user activated trigger
stimulus, and to select, in response to the trigger stimulus, the
second value set of control parameters for the exercise mode,
wherein the apparatus further comprises one or more sensors
configured to activate the controller, wherein the one or more
sensors are configured to actuate the trigger stimulus, wherein the
one or more sensors comprise a diaphragm electromyogram sensor
and/or a vagal nerve sensor.
2. The apparatus of claim 1 wherein, in response to the trigger
stimulus, the controller sets a target respiratory control
parameter as a function of a presently detected respiratory
parameter sensed with the sensor.
3. The apparatus of claim 2 wherein the target respiratory control
parameter is a target respiratory rate and the detected respiratory
parameter is a measured respiratory rate.
4. The apparatus of claim 3 wherein the target respiratory control
parameter is a target ventilation and the detected respiratory
parameter is a measure of ventilation.
5. The apparatus of claim 4 wherein the target ventilation is a
target tidal volume and the measure of ventilation is a measure of
tidal volume.
6. The apparatus of claim 5 wherein the target ventilation is a
target minute ventilation and the measure of ventilation is a
measure of minute ventilation.
7. The apparatus of claim 5 wherein the second value set of control
parameters comprises an increase in target values with respect to
the first value set of control parameters.
8. The apparatus of claim 2 further comprising at least one user
accessible button to activate the controller, the button being
configured for actuating the trigger stimulus.
9. The apparatus of claim 2 wherein the one or more sensors
comprise the diaphragm electromyogram.
10. The apparatus of claim 2 wherein the one or more sensors
comprises the vagal nerve sensor.
11. The apparatus of claim 1, wherein the controller is further
configured with a cool down mode, and to receive another user
activated trigger stimulus to initiate the cool down mode, the cool
down mode comprising a third value set of control parameters for
the pressure support ventilation.
12. The apparatus of claim 11 wherein a value of the control
parameters of the cool down mode is varied from a respective value
of the control parameters of the exercise mode toward a respective
value of the control parameters of the rest mode.
13. The apparatus of claim 12 wherein a value of the control
parameters of the cool down mode is ramped from a respective value
of the control parameters of the exercise mode toward a respective
value of the control parameters of the rest mode.
14. A method for control of pressure support ventilation,
comprising: measuring at least one respiratory parameter with a
sensor; generating pressure support ventilation with a flow
generator adapted for coupling with a patient respiratory
interface; controlling, with a processor, the pressure support
ventilation in a rest mode and an exercise mode, the rest mode
comprising a first value set of control parameters for controlling
the pressure support ventilation and the exercise mode comprising a
second value set of control parameters for controlling the pressure
support ventilation; and receiving, in the processor, a user
activated trigger stimulus, and, in response to the trigger
stimulus, selecting the second value set of control parameters for
the exercise mode wherein one or more sensors activate the
controller, wherein the one or more sensors actuate the trigger
stimulus, wherein the one or more sensors comprise a diaphragm
electromyogram sensor and/or a vagal nerve sensor.
15. The method of claim 14 further comprising, in response to the
trigger stimulus, setting a target respiratory control parameter as
a function of a presently detected respiratory parameter sensed
with the sensor.
16. The method of claim 15 wherein the target respiratory control
parameter is a target respiratory rate and the detected respiratory
parameter is a measured respiratory rate.
17. The method of claim 15 wherein the target respiratory control
parameter is a target ventilation and the detected respiratory
parameter is a measure of ventilation.
18. The method of claim 17 wherein the target ventilation is a
target tidal volume and the measure of ventilation is a measure of
tidal volume.
19. The method of claim 17 wherein the target ventilation is a
target minute ventilation and the measure of ventilation is a
measure of minute ventilation.
20. The method of claim 17 wherein the second value set of control
parameters comprises an increase in target values with respect to
the first value set of control parameters.
21. The method of claim 14, wherein a user accessible button
actuates the trigger stimulus.
22. The method of claim 14, wherein the diaphragm electromyogram
sensor actuates the trigger stimulus.
23. The method of claim 14, wherein the vagal nerve sensor actuates
the trigger stimulus.
24. The method of claim 14, further comprising controlling pressure
support ventilation in a cool down mode in response to receiving
another user activated trigger stimulus, the cool down mode
comprising a third value set of control parameters for the pressure
support ventilation.
25. The method of claim 24 wherein a value of the control
parameters of the cool down mode is varied from a respective value
of the control parameters of the exercise mode toward a respective
value of the control parameters of the rest mode.
26. The method of claim 25 wherein a value of the control
parameters of the cool down mode is ramped from a respective value
of the control parameters of the exercise mode toward a respective
value of the control parameters of the rest mode.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application No.
15/430,742 filed Feb. 13, 2017, which is a continuation of U.S.
application No. 14/356,471 filed on May 6, 2014, now U.S. Pat. No.
9,597,468 which is a national phase entry under 35 U.S.C. .sctn.
371 of International Application No. PCT/AU2012/001367 filed Nov.
7, 2012, published in English, which claims priority from
Australian Provisional Patent Application Nos. AU2012902693 filed
Jun. 26, 2012, AU 2012902501 filed Jun. 15, 2012 and AU 2011904599
filed Nov. 7, 2011, all of the disclosures of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
2.1 Field of the Invention
[0002] The present technology relates to methods and apparatus for
the treatment and/or amelioration of respiratory disorders. In
particular, the present technology relates to methods and apparatus
for providing ventilation to a patient.
2.2 Related Art
[0003] The respiratory system of the body facilitates gas exchange.
The nose and mouth form the entrance to the airways of a
patient.
[0004] The airways consist, of a series of branching tubes, which
become narrower, shorter and more numerous as they penetrate deeper
into the lung. The prime function of the lung is gas exchange,
allowing oxygen to move from the air into the venous blood and
carbon dioxide to move out. The trachea divides into right and left
main bronchi, which further divide eventually into terminal
bronchioles. The bronchi make up the conducting airways, and do not
take part in gas exchange. Further divisions of the airways lead to
the respiratory bronchioles, and eventually to the alveoli. The
alveolated region of the lung is where the gas exchange takes
place, and is referred to as the respiratory zone. See West,
Respiratory Physiology--the essentials.
[0005] A range of respiratory disorders exist.
[0006] Chronic Obstructive Pulmonary Disease (COPD) encompasses any
of a group of lower airway diseases that have certain
characteristics in common. These include increased resistance to
air movement, extended expiratory phase of respiration, and loss of
the normal elasticity of the lung. Examples of COPD are emphysema
and chronic bronchitis. COPD is caused by chronic tobacco smoking
(primary risk factor), occupational exposures, air pollution and
genetic factors. Symptoms include: dyspnoea on exertion, chronic
cough and sputum production.
[0007] Neuromuscular Disease (NMD) is a broad term that encompasses
many diseases and ailments that impair the functioning of the
muscles either directly via intrinsic muscle pathology, or
indirectly via nerve pathology. Some NMD patients are characterised
by progressive muscular impairment leading to loss of ambulation,
being wheelchair-bound, swallowing difficulties, respiratory muscle
weakness and, eventually, death from respiratory failure.
Neuromuscular disorders can be divided into rapidly progressive and
slowly progressive: (i) Rapidly progressive disorders:
Characterised by muscle impairment that worsens over months and
results in death within a few years (e.g. Amyotrophic lateral
sclerosis (ALS) and Duchenne muscular dystrophy (DMD) in
teenagers); (ii) Variable or slowly progressive disorders:
Characterised by muscle impairment that worsens over years and only
mildly reduces life expectancy (e.g. Limb girdle,
Facioscapulohumeral and Myotonic muscular dystrophy). Symptoms of
respiratory failure in NMD include: increasing generalised
weakness, dysphagia, dyspnoea on exertion and at rest, fatigue,
sleepiness, morning headache, and difficulties with concentration
and mood changes.
[0008] Chest wall disorders are a group of thoracic deformities
that result in inefficient coupling between the respiratory muscles
and the thoracic cage. The disorders are usually characterised by a
restrictive defect and share the potential of long term hypercapnic
respiratory failure. Scoliosis and/or kyphoscoliosis may cause
severe respiratory failure. Symptoms of respiratory failure
include: dyspnoea on exertion, peripheral oedema, orthopnoea,
repeated chest infections, morning headaches, fatigue, poor sleep
quality and loss of appetite.
[0009] Mechanical ventilators have been used to ameliorate the
above respiratory disorders.
BRIEF SUMMARY OF THE INVENTION
[0010] The present technology relates to providing ventilation and,
in particular, to methods and apparatus for providing ventilation
to awake patients.
[0011] The present technology also relates to methods and apparatus
providing ventilation to sleeping patients.
[0012] One aspect of one form of the present technology is a method
of providing ventilatory support, or ventilatory assistance, to
assist a patient to exercise.
[0013] One aspect of one form of the present technology is a
ventilator constructed and arranged to assist a patient to
exercise.
[0014] Another aspect of one form of the present technology is a
ventilator constructed and arranged to reduce a ventilatory
limitation to exercise as the result of disease.
[0015] An aspect of one form of the present technology is a
ventilator that is responsive the rate of respiration of a
patient.
[0016] Another aspect of one form of the present technology relates
to methods and apparatus for improving the comfort of awake
patients being provided with non-invasive ventilation.
[0017] Another aspect of one form of the present technology relates
to methods and apparatus for changing ventilation parameters of a
ventilator to match patient metabolic demand, in particular when
the metabolic demand is changing. In one form the present
technology provides an increase to either or both of ventilation
and ventilatory support as metabolic load increases.
[0018] Another aspect of one form of the present technology is a
ventilator that is configurable to move between a plurality of
different settings to assist a patient in an exercise regime, as
metabolic demand increases, and/or as metabolic demand
decreases.
[0019] One aspect of one form of the present technology is a
processor programmed to implement one or more algorithms.
[0020] Another aspect of one form of the present technology relates
to a ventilator having a plurality of predefined discrete activity
modes or states and moves manually or automatically between modes
or states (e.g. (i) Quiet sitting; (ii) Walking around; (iii)
Running). In another form, the ventilator has a predefined
continuous support pathway, and moves (manually or automatically)
along the pathway in response to demand. In this way, an indication
of change in metabolic demand and/or lung mechanics is input
manually or automatically. Preferably the modes or pathway will
have an Expiratory Positive Air Pressure (EPAP) value that ranges
from about 4 cmH2O to a limit of about 10 cmH2O. In one form the
limit is a predetermined limit. In other forms, the limit is not
predetermined and is calculated from a measure of intrinsic PEEP.
At this limit, an additional increase, or further increases in
demand preferably do not give rise to a further increase in EPAP,
hence the level of expiratory positive air pressure will remain
substantially constant. Manual adjustments may be made using a
remote control, e.g. with buttons and/or joystick.
[0021] Another aspect of the present technology relates to
apparatus that allows a patient to manually trigger a ventilator to
deliver a breath. In particular, the present technology may allow a
patient to manually trigger delivery by the ventilator of an
inspiration phase of a breath to the patient.
[0022] Another aspect of the present technology relates to
apparatus that allows a patient to manually cycle a ventilator, and
thus to manually cause the device to transition from the
inspiratory phase to the exhalation phase. Breaths may be cycled by
a mechanical ventilator when a set time has been reached, or when a
pre-set flow or percentage of the maximum flow delivered during a
breath is reached, depending on the breath type and the settings.
Here, preferably breaths can be manually cycled upon a manual cycle
command given by a patient.
[0023] Another aspect of the present technology relates to
apparatus that allows a patient to manually adjust the level of
pressure support or the target ventilation of a ventilator.
[0024] Another aspect of the present technology relates to
apparatus that allows a patient to manually adjust the level of End
Expiratory Pressure (EEP) or Expiratory Positive Air Pressure
(EPAP) of a ventilator.
[0025] Another aspect of one form of the present technology relates
to a controller for a ventilator constructed and arranged to
calculate a typical duration of a manually triggered breath or a
manually cycled breath.
[0026] Another aspect of one form of the present technology relates
to methods and apparatus that, in a first mode, allow a patient to
manually control one or more of the following features; triggering,
cycling, the level of pressure support, EEP, or EPAP and the level
of target ventilation. In a second mode, the apparatus may provide
one or more of automatic triggering, cycling or automatically
adjusting the level of pressure support, EEP, or EPAP and the level
of target ventilation. In some instances, the automatic adjustments
may be based, at least in part, on data obtained from the manual
triggering, cycling, target ventilation and/or pressure support
level established by the patient.
[0027] According to one form of the present technology, a portable
battery powered ventilator is provided. In one form the ventilator
comprises one or more manual controls constructed and arranged to
allow the patient to adjust a ventilator setting between different
modes or states, with at least some states being associated with
different activity or exercise levels. Alternatively or
additionally, the ventilator is constructed and arranged to
automatically adjust to different activity or exercise levels of
the patient.
[0028] In one form of the present technology, a controller for a
ventilator is provided, the ventilator being configured to deliver
a pressure support waveform to a patient, said pressure support
waveform having an inspiratory phase and a subsequent expiratory
phase, and the controller being configured to trigger adjustment of
at least one parameter of the ventilator in response to indication
of a change in metabolic demand and/or lung mechanics of the
patient.
[0029] In one form, a controller is programmed so that a magnitude
of change to the pressure during the expiratory phase is equal to
about one third of a magnitude of change during the inspiratory
phase.
[0030] Preferably the controller is further configured to accept a
signal from a metabolic demand responsive transducer, and to
determine a state of metabolic demand from said metabolic demand
responsive transducer. A metabolic demand responsive transducer may
be one or more of an oximeter, a flow sensor and an
electromyograph, e.g. a diaphragm electromyograph.
[0031] The following further aspects are preferred forms of the
present technology.
1. A controller for a ventilator configured to allow a patient to
manually, trigger a breath. 2. A controller for a ventilator
configured, preferably according to any one of the previous
aspects, to allow a patient to manually cycle a breath. 3. A
controller for a ventilator, preferably according to any one of the
previous aspects, constructed and arranged to calculate a typical
duration of a manually triggered breath. 4. A controller for a
ventilator, preferably according to any one of the previous
aspects, constructed and arranged to calculate a typical duration
of a manually cycled breath. 5. A controller for a ventilator,
preferably according to any one of the previous aspects,
constructed and arranged to automatically trigger to deliver a
first breath and to trigger to deliver a subsequent breath after
the elapse of a time duration calculated from a duration of at
least one manually triggered breath. 6. A controller for a
ventilator, preferably according to any one of the previous
aspects, constructed and arranged to automatically cycle to stop
delivery of a first breath and to cycle to stop delivery of a
subsequent breath after the elapse of a time duration calculated
from a duration of at least one manually cycled breath. 7. A
controller for a ventilator, preferably according to any one of the
previous aspects, the controller being configured to allow a
patient to manually adjust at least one of the following; a target
pressure support, a target ventilation level, IPAP, EPAP, a backup
rate, Ti min. and Ti max. 8. A controller, preferably according to
any one of the previous aspects, configured to change one of IPAP
or EPAP, in response of a change in the other one. 9. The
controller of aspect 8, wherein the change in the respective one of
the IPAP and EPAP, the change being a response to a change in the
other one, is based on a predetermined function. 10. A controller
for a ventilator, preferably according to any one of the previous
aspects, the controller being configured to; receive signals
indicative of level of movement of the patient; and in response to
the indicated level of movement, automatically adjust at least one
of the following; a target pressure support, a target ventilation
level, IPAP, EPAP, a backup rate, Ti min. and Ti max provided to
the patient. 11. A controller for a ventilator, preferably
according to any one of the previous aspects, the controller being
configured to; receive signals indicative of the speed of movement
of the patient; and in response to the indicated speed,
automatically adjust at least one of the following; a target
pressure support, a target ventilation level, IPAP, EPAP, a backup
rate, Ti min. and Ti max provided to the patient. 12. A controller
for a ventilator, preferably according to any one of the previous
aspects, the controller being configured to; receive signals
indicative of heart rate of respiration rate of the patient; and in
response to the indicated heart rate of respiration rate,
automatically adjust at least one of the following; a target
pressure support, a target ventilation level, IPAP, EPAP, a backup
rate, Ti min. and Ti max provided to the patient. 13. A ventilator
comprising the controller of any one of the preceding aspects. 14.
The ventilator of aspect 13, the ventilator further comprising a
manual controller in communication with the ventilator controller,
the manual controller being configured to initiate a manual
adjustment of at least one of the following; a target pressure
support, a target ventilation level, IPAP, EPAP, a backup rate, Ti
min. and Ti max provided to the patient. 15. A ventilator,
preferably according to any one of the previous aspects,
constructed and arranged to be adaptable to changing patient
metabolic demand.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 shows apparatus including a push-button, a personal
computer and a ventilator in accordance with an aspect of the
present technology.
[0033] FIGS. 2a and 2b show graphs of pressure (y-axis) provided to
a patient, versus time (x-axis) in accordance with an aspect of the
present technology and a window in which manual triggering is
available. FIG. 2a shows an arbitrary triggering window during an
EPAP phase (e.g. an expiratory pressure phase in a pressure
waveform provided by a ventilator), in which the patient is free to
manually trigger a breath, but in this case, does not manually
trigger within the window. In the illustrated form, the window is
about 1 second long, although in other forms it may be of a
different size. By way of contrast, in FIG. 2b, the patient has
initiated early manual triggering.
[0034] FIGS. 3a and 3b shows a graph of pressure (y-axis) versus
time (x-axis) in accordance with an aspect of the present
technology in which manual cycling is available. FIG. 3a shows an
arbitrary cycling window during an Inspiratory Positive Airway
Pressure (IPAP) phase in which the patient is free to manually
cycle the ventilator, but in this case, the patient does not
manually cycle the ventilator. In the illustrated form, the window
is about 1.8 second long, although in other forms it may be a
different size. By way of contrast, in FIG. 3b, the patient has
initiated early manual cycling.
[0035] FIG. 4 shows a schematic of flow versus time for a
spontaneously breathing patient exhibited through inspiration and
expiration cycles of a breathing cycle. A detail of a portion of
the breath is shown in FIG. 5.
[0036] FIG. 5 shows a detail of FIG. 4. In particular, the Figure
shows a portion of a breath with two time points, namely the point
in time when a button trigger was manually activated ("button
trigger") and the time point when the ventilator would have
automatically triggered as flow would have exceeded a trigger flow
point, ("Standard trigger flow").
[0037] FIG. 6 illustrates over time pressure, and activation status
of a trigger button and a cruise-control button
[0038] FIGS. 7A and 7B show exemplary options of a pathway in
accordance with one aspect of the present technology. The X-axis is
metabolic demand, and the Y-axis is pressure. In FIGS. 7A and 7B,
two lines are shown, an EPAP line, and an IPAP line. The level of
pressure support at a given level of metabolic demand is the
difference between the two lines. As the level of metabolic demand
increases; both EPAP and IPAP may increase, e.g. at different
rates. Hence the level of support may increase from about 7 cmH2O
when demand is low, to about 15 cmH2O when demand is high. An
EPAPmax limit is defined. As metabolic demand increases, EPAP may
increase to a maximum level of EPAPmax, and a further increase in
metabolic demand may give rise to a further increase in IPAP, but
not to EPAP. The value of EPAPmax may vary from patient to patient.
In one form EPAPmax is about 10 cmH2O. In FIG. 7A, the EPAP and
IPAP lines are reflective of a continuous change in values in
response to changes in demand, however, in an alternative form
exemplarily seen in FIG. 7B, there may be discrete changes, hence
the lines resemble steps.
[0039] FIG. 8a shows a Positive Airway Pressure (PAP) device in
accordance with one form of the present technology.
[0040] FIG. 8b shows a schematic diagram of electric components for
a PAP device in accordance with one form of the present
technology.
[0041] FIG. 9 shows, in accordance with one form of the present
technology, a PAP device connected to a humidifier, providing a
supply of air via an air circuit to a patient interface that is
being worn by a patient. As depicted, the patient may be sitting
quietly reading a book prior to exercising.
[0042] FIG. 10 shows an alternative form of one aspect of the
present technology.
[0043] FIG. 11 shows an example flowchart for implementing control
of treatment in some aspects of the present technology.
[0044] The patient may move the ventilator between different stages
or states of demand manually, e.g. by pressing buttons on a remote
control. In another form, the ventilator will automatically detect
a change in demand e.g. by monitoring one or more of heart rate,
breathing (or respiratory) rate, and movement.
DETAILED DESCRIPTION
[0045] Some patients with certain forms of cardio-respiratory
disease, for example COPD or kyphoscoliosis, may benefit from
exercise, but find it difficult to exercise. The use of a
ventilator may assist the patient to perform exercise, when the
ventilator performs at least some of the work of breathing. Should
the patient's level of activity change (and corresponding metabolic
demand), then a set of ventilator parameters (e.g. level of
support, timing of breaths) that might have been appropriate for
the first level of activity may be inappropriate for a second level
of activity, for example when a patient is becoming more active, or
when becoming less active.
[0046] According to one aspect of the present technology, an
apparatus 10 is provided as shown in FIG. 1. The apparatus 10
comprises:
[0047] A ventilator device 12, for example a Positive Airway
Pressure (PAP) ventilator device, further for example a RESMED
STELLAR.RTM. ventilator;
[0048] A user input device or control member, preferably a
push-button 14, preferably connectable to other devices such as a
personal computer via a Universal Serial Bus (USB); and
[0049] A controller or a Personal Computer (PC) 16 running a
manuals triggering and/or cycling application.
[0050] In certain forms of the present technology, the Positive
Airway Pressure (PAP) device may be in the form of a device 4000
(see, e.g., FIGS. 8a and 9) that includes an embedded processor
4230 (see, e.g., in FIG. 8b) for executing one or more algorithms
that are stored in a memory 4260. This embedded processor 4230 may
be provided instead or in addition to the processor existing in the
Personal Computer 16 in apparatus 10. In the description
hereinbelow where reference is made only to one of the devices 16,
4230 or 12, 4000 it should be understood that same may be
applicable also to the other device 16, 4230 or 12, 4000 not
mentioned.
5.1 Systems, Algorithms and Processes
[0051] An aspect of the present technology is one or more
algorithms 4300 that may be executed by a controller 16 or a
processor 4230. In the accompanying figures algorithm 4300 is
indicated in FIG. 8b as being executed by processor 4230; however
it is to be understood that algorithm 4300 may also accordingly be
executed by controller 16.
5.1.1 Patient Intervention
5.1.1.1 Triggering and Cycling
[0052] In this embodiment, the apparatus 10 is programmed and
configured so that pressing the button 14 down will trigger the
ventilator 12 and releasing the button 14 will cause the ventilator
12 to cycle. The inventors have found that this configuration of
push to trigger and release to cycle is easy to use.
[0053] In an alternative configuration, there may be different
trigger and cycle buttons or different trigger and cycle
activators.
[0054] In one form, the normal spontaneous triggering and cycling
operation is unaffected.
[0055] In one form, the successful button-initiated triggering and
cycling are subject to certain timing window limits.
[0056] In this form, a digital communication interface 18 of the
ventilator, preferably a ResMed STELLAR.RTM. ventilator, that
allows for remote control of settings is used, similar to that used
in a sleep laboratory environment. A controller, such as a PC
application, monitors the push-button state and sends the
appropriate setting changes to the ventilator 12; temporarily
changing the parameter "Backup Rate" in the case of triggering and
the parameter "TiMax" for cycling.
[0057] "Backup Rate", with units of breaths per minute, is a
preferred parameter of the ventilator 12 that establishes the
minimum number of breaths per minute that the ventilator 12 will
deliver, if not otherwise triggered. This parameter may be used to
virtually instantaneously trigger a breath. This is so because, if
the ventilator 12 is currently in expiration, increasing
substantially the Backup Rate reduces the duration of the
expiration cycle and effectively triggers a subsequent breath.
[0058] "TiMax", with units of time, is a preferred parameter of the
ventilator 12 indicative of, the maximum time, from the
commencement of a first breath, before the ventilator 12 will
automatically change to expiration, if not otherwise cycled. If the
ventilator 12 is currently in inspiration, then setting the TiMax
to be very short can force a cycle (from inspiration to expiration)
in a manner similar to the way an increased backup rate forces a
trigger.
[0059] A particularity of the ventilator 12 preferably used with
this technology, preferably a ResMed STELLAR ventilator, is that
the allowable settings of TiMax may be determined by the current
setting of Backup Rate.
[0060] In the embodiments shown in FIGS. 2a, 2b and FIGS. 3a, 3b;
the, preferably STELLAR, ventilator 12 is configured as
follows:
[0061] For a patient breathing at a nominal 30 breaths per minute
(BPM):
Mode: S (i.e. "Spontaneous" mode for detecting a spontaneous breath
of a patient)
Backup Rate: 15 BPM
TiMax: 2.0 sec
5.1.1.2 Manual Triggering
[0062] The apparatus is further configured so that upon manual
activation of the trigger button the apparatus implements the
following steps:
(i) Set Backup Rate to 60 BPM (this has the side-effect of changing
the TiMax to 0.8 sec)
(ii) Wait 15 ms
[0063] (iii) Set Backup Rate back to 15 BPM (iv) Set TiMax back to
2.0 sec
[0064] In one form of the present technology, manual triggering of
a breath is only possible during an EPAP phase, and/or during a
defined portion of the EPAP phase.
[0065] However it is noted that in other forms of the present
technology, other settings may be used.
5.1.1.3 Manual Cycling
[0066] The apparatus is further configured so that upon manual
activation of the cycle button the apparatus implements the
following steps:
(i) Set Backup Rate to 60 BPM (this allows 0.2<TiMax<0.8)
(ii) Set TiMax to 0.3 sec
[0067] (iii) Wait 15 ms (iv) Set Backup Rate back to 15 BPM (v) Set
TiMax back to 2.0 sec
[0068] With reference to FIGS. 2a and 2b, the following exemplary
scenarios are illustrated. A patient progresses through one or more
breaths (one being shown). With the ventilator 12 set to a TiMax of
2 seconds, the next breath will not be delivered until the elapse
of 2 seconds. In the illustrated example (see FIG. 2b), the patient
manually triggers the ventilator 12 before the elapse of the 2
seconds, and thereupon the next breath will be delivered to the
patient. Manually triggering the ventilator may be possible in this
example within an "arbitrary triggering window" of 1 second that is
indicated in these figures. An exemplary beginning of a next breath
that is early manually triggered during this window is indicated in
FIG. 2b by a dashed line.
[0069] In an embodiment, this is achieved by increasing the backup
rate to a rate that is much faster than, a normal rate, for example
from 15 BPM to 60 BPM. At this relatively rapid rate, a new breath
(indicated accordingly by the dashed line) will be soon delivered.
However shortly thereafter, e.g. 15 ms later, the backup rate will
be returned to a lower level, e.g. a previous lower level of 15
BPM.
[0070] With reference to FIGS. 3a and 3b, in the midst of the
ventilator 12 delivering a breath to the patient, the patient
activates manual cycling--for example by releasing a
button--whereupon the ventilator 12 stops delivering the
breath.
[0071] In the illustrated embodiment, TiMax is set to e.g. 0.2 sec,
a duration that is soon passed, and therefore the ventilator 12 may
stop delivering the breath as indicated by the dashed lines in FIG.
3b. Here too there is an "arbitrary cycling window" during the IPAP
phase in which the patient is able to manually cycle the
ventilator. In these figures, the window is about 1.8 second
long.
[0072] Other forms of the present technology do not adjust TiMax or
Backup Rate, but directly activate triggering and cycling of a
ventilator. In one configuration, the ability of the patient for
manual intervention may be limited by time constraints.
[0073] FIG. 4 shows a schematic of a breath on a flow-time curve,
provided by a ventilator that is set to be in "Spontaneous" mode
(i.e. S mode). Inspiration is shown as positive flow and expiration
as shown as negative flow. This figure shows an example breath with
a long exhalation portion.
[0074] FIG. 5 shows a detail from FIG. 4. The Flow axis includes a
"trigger flow" threshold TF, and a prior art ventilator may be
configured to trigger or provide support to a breath of a patient
when measured patient respiratory flow exceeds the "trigger flow"
threshold TF. In accordance with the present technology, a
supporting breath can be delivered to the patient sooner than would
occur in the prior art or in the pre-settings of the ventilator by
the patient, e.g., manually, triggering the breath. In FIG. 5, for
example, a patient that feels that assistance is needed in order to
urge or assist him into inspiration may trigger a supporting breath
at an instance indicated by dashed line 20. This may be achieved,
as indicated above, by pushing a trigger button. Then, inspiration
assistance is provided and inspiration starts. As seen, this will
advance the support that a patient may be provided with by a factor
of time indicated in this figure as "trigger advance" TAD.
5.1.1.4 Pressure Support and EPAP
[0075] In another form of the present technology (not illustrated),
the patient manually increases the level of pressure support (e.g.
the difference between an IPAP level and an EPAP level) by
activation of a button.
[0076] In one form of the present technology, not shown, there is a
joystick that is used to adjust the level of pressure support. The
joystick has a natural neutral position. It may be pushed up, and
upon release, it will automatically return to the neutral position.
It may also be pushed down, and upon release, it will automatically
return to the neutral position.
[0077] In one form of the present technology, the apparatus is
configured so that once a patient has pushed up and released the
joystick, the pressure support will increase by, e.g., 3 cmH2O.
[0078] In one form of the present technology, the apparatus is
configured so that once a patient has pushed down and released the
joystick, the pressure support will decrease by, e.g., 3 cmH2O.
[0079] In alternative forms, the amount of change may be different
to 3 cmH2O, for example, 1 cmH2O, 2 cmH2O, 4 cmH2O, 5 cmH2O, or
some other amount.
[0080] Alternatively, moving the joystick may continuously change
the provided pressure support. The patient can then decide to lock
the instantaneous pressure support achieved at a particular point,
or let it automatically return to its initial level. The rate of
change of the pressure support, whether driven by the patient or
during the automatic return to a predefined rate, may also be
predetermined, manually adjustable or both.
[0081] For example, in a ventilator delivering a pressure waveform
having two levels, namely an inspiratory pressure (IPAP) and an
expiratory pressure (PEEP or EPAP), the patient may be able to
manually adjust one or both of IPAP and PEEP or EPAP.
[0082] In an, alternate, regardless of whichever of the IPAP and
EPAP are adjusted, the other may also change. The change may be
associated with a predetermined function. Thus, in response to the
patient's manual control inputs, the IPAP and EPAP will change
together, according to this predetermined function relating the
change in EPAP with the change in the IPAP.
[0083] In one form, the IPAP and EPAP may be approximately related
by the function:
.DELTA.(IPAP)=3.times..DELTA.(EPAP),
i.e., the patient increasing the IPAP by 3 cmH2O will automatically
increase the EPAP by 1 cmH2O.
[0084] It has to also be appreciated that in some instances,
instead of changing the pressure support, IPAP or EPAP, a patient
may manually (or the ventilator automatically) adjust a respective
target ventilation level.
[0085] Also, whilst any one of a number of ventilation parameters
may be individually adjustable by the patient, it is envisaged that
similar functionality may be better facilitated by offering various
modes of operation of the ventilator, each mode having specific set
of ventilation parameters. For example, instead of being offered a
large number of separate parameters for manual adjustment, a
patient may be offered three different modes: "resting", "gentle
exercise" and "moderate exercise". Each of these modes or states
may be associated with a specific set of ventilation parameters,
such as respiratory rate, pressure support, target ventilation
level, EEP, EPAP etc.
[0086] In one form, the patient may manually adjust the pressure
waveform provided by the ventilator, by selecting between running
values (i.e. non-discrete) or discrete values of metabolic demand
appropriate e.g. to the level of activity or work he is
experiencing. Selecting a certain metabolic demand accordingly sets
a corresponding location along the pathway 21, and together with
that a level of EPAP; IPAP and pressure support. Manual selection
of the metabolic demand may be performed by e.g. pressing buttons
on a remote control.
5.1.1.5 Tidal Volume
[0087] In one form, the ventilator comprises a control that allows
a patient to adjust a tidal volume setting of the ventilator.
5.1.1.6 Oxygen
[0088] In one form of the present technology, oxygen is delivered
to the patient. In accordance with one form of present technology,
a patient may manually increase or decrease the flow rate of
oxygen.
5.1.1.7 Humidification
[0089] In one form of the present technology, the patient can
adjust a level of humidification provided by the ventilator 12 or
4000 by a humidifier 5000 (see e.g. FIG. 9 where device 4000 is
shown with humidifier 5000). For example the patient may be able to
increase or decrease a level of relative and/or absolute
humidity.
5.1.1.8 Temperature
[0090] In one form, the patient can adjust a temperature of air
delivered.
5.1.1.9 Waveform
[0091] In one form of the present technology, the patient can
adjust the shape of the pressure waveform. For example, the patient
may be able to vary the pressure waveform from a more square wave
to a more rounded or smoother waveform. In alternative arrangement,
the patient may be able to select a waveform from a set of
predefined waveforms.
5.1.2 Cruise Control
[0092] In another form of the present technology, the apparatus 10
is programmed and configured to operate in a semi-automatic
fashion, e.g. to learn a pattern of manually activated triggers,
and/or cycles. The ventilator is able to learn from the patient a
setting appropriate to the current level of activity. In one form a
processor, e.g. 4230, is programmed to execute one or more
algorithms as follows. For example, the patient may manually
trigger the ventilator 12 or 4000 a number of times over several
breaths. The apparatus 10 calculates a patient preferred period
between breaths and then upon activation of a "CRUISE CONTROL"
mode, delivers breaths at the patient preferred rate.
[0093] In one form, the apparatus 10 is programmed and configured,
to determine a running average duration between manually triggered
breaths. In one form the apparatus 10 determines a running average
duration between manually cycled breaths.
[0094] In one form, the apparatus 10 is programmed and configured
to store a time, t0, when the manual trigger is first pressed, and
also to store the times, t1, t2, t3 when a new trigger and
subsequent triggers are pressed. For example, the times may be
stored in an array of time values t(i), having an array index i by
which time values, where i is an integer, e.g. so that some
consecutive time values of t(i) may be found. The differences
t1-t0, t2-t1 and t3-t2 are calculated and an average is taken and
stored.
[0095] In one form, the apparatus 10 is programmed and configured
to store a time, c0, when a manual cycle is first activated (e.g.
by release of a button), and also to store the times, c1, c2, c3
when subsequent cycles are activated. The differences c1-c0, c2-c1
and c3-c2 are calculated and an average is taken and stored.
[0096] FIG. 6 illustrates three lines: a pressure waveform
delivered by a ventilator (top), trigger button signal (middle) and
cruise button signal (bottom). When the trigger button is pressed,
the ventilator triggers to deliver a breath at a pressure of IPAP,
and when it is released, the ventilator cycles to deliver a breath
at a pressure of EPAP. The duration of the first inhalation portion
of the breathing cycle is TI1. The duration of the second and third
inhalation portions are TI2 and TI3, respectively. The durations of
the first, second and third exhalation portions are TE1, TE2 and
TE3 respectively.
[0097] In one form of the present technology, the apparatus 10
calculates TEcruise, as the average of the last three inhalations,
e.g. TI1, TI2 and TI3; and furthermore preferably the apparatus 10
calculates TEcruise, as the average of the last three exhalations,
e.g. TE1, TE2 and TE3. Preferably the average is calculated as a
running average, so that if the patient continues to manually
trigger and cycle, the average times will be updated. In one form,
the average may be calculated from last "k" recent stored time
values of t(i), with "k" being an integer not exceeding "m", where
"m" is a integer between "0" and "n", the number of samples.
[0098] Upon activation of the "CRUISE CONTROL" mode by pressing
e.g. the "cruise" button, the ventilator 12 will trigger and
subsequently cycle at the average cycle time calculated in the
averaging step. See FIG. 6, "Cruise Mode On".
[0099] For example, as shown in FIG. 6, when Cruise control is
activated, the last three inhalations are TI4, TI3 and TI2, and the
last three exhalations are TE3, TE2, and TEL
[0100] Hence
TIcruise=(TI4+TI3+TI2)/3
TEcruise=(TE3+TE2+TE1)/3
[0101] In one form of the present technology, output devices 4290
e.g. feedback lights and/or chimes are included (see FIG. 8b). When
the apparatus 10 has sufficient data a light and/or chime at e.g.
the ventilator 12 or 4000 will be activated to indicate that the
ventilator 12 or 4000 is ready to go into cruise control mode. See
FIG. 6 "Cruise Ready".
[0102] In this way, a patient can adjust a breath length from that
which would be delivered but for the patient intervention.
[0103] In one form of the present technology, a warning light
and/or chime will be activated if the patient attempts to enter
cruise control mode when the apparatus 10 is not ready to enter
cruise control mode.
[0104] In one form of the present technology, an indicator light
and/or chime will be activated if the patient successfully enables
cruise control mode, and remains activated while cruise control
mode is in effect.
5.1.3 Response to Changing Metabolic Demand or Lung Mechanics
[0105] Another aspect of one form of the present technology is a
device that is constructed and arranged to be able to provide
automatically a suitable pressure waveform in response to changing
metabolic demand.
[0106] Methods and apparatus are provided to determine a suitable
pressure waveform, including the steps of adjusting the level of
EPAP, and/or IPAP, and/or pressure support provided to the patient,
with pressure support being the difference between EPAP and
IPAP.
[0107] In another form, providing a sufficient pressure waveform
can be performed by following, e.g. at the controller 16, 4230 or
ventilator 12, 4000, a predefined continuous support pathway for
determining the required pressure waveform for the patient. An
example of such a continuous pathway can be seen indicated as 21 in
FIG. 7A. Here, the pathway 21 is illustrated by the hatched area
and is defined by an EPAP line and an IPAP line, that respectively
bound the pathway from below and above.
[0108] According to the pathway 21 of FIG. 7A, as the level of
metabolic demand increases, e.g. within a first, range of metabolic
demand values, the levels of IPAP and EPAP increase together, for
example increasing linearly, with it until an inflection point,
here indicated by `dotted line` 17, is reached. As the level of
metabolic demand increases beyond this line 17, the level of IPAP
also increases, preferably however here at a different rate,
optionally lower than before. The EPAP level as seen may be
maintained after this point at a constant level, here defined as
EPAPmax, which in one form is about 10 cmH2O. The level of pressure
support in the pathway is accordingly defined for each given value
of metabolic demand as the difference between IPAP and EPAP for
that given value. Here, the pressure support at a certain value of
metabolic demand is indicated by `double sided arrow` 19.
[0109] As seen in FIG. 7B, changes in the level of pressure support
may also vary discretely with change in metabolic demand. Here,
these discrete changes are obtained by the IPAP and EPAP lines
being stepped shaped. The optional lower rate of increase in IPAP
level after the inflection point indicated by line 17; is achieved
in this pathway by smaller steps of increase in the IPAP level.
[0110] In yet another form, pre-defined discrete levels of work or
metabolic demand of a patient may be defined, and the apparatus 10
or ventilator 12, 4000 may be configured to enable automatic
selection of (or movement between) these discrete levels. Such
pre-defined levels may be defined as: (i) Quiet sitting (e.g. when
the body is at rest); (ii) Walking around (e.g. when the body is at
normal average activity); (iii) Running (e.g. when the body is at a
high level of activity). And, the level of e.g. pressure support at
each mode can be: (i) Quiet sitting--about 7 cmH2O to about 9
cmH2O, more preferably about 7 cmH2O; at mode (ii) Walking
around--about 10 cmH20 to about 13 cmH2O, more preferably about 11
cmH2O; and at mode (iii) Running--about 14 cmH20 to about 17 cmH2O,
more preferably about 15 cmH2O.
[0111] Optionally, a form of apparatus 10 may be configured to
function with such discrete levels of metabolic demand and in
addition with the pathway 21. Thus, the dashed lines seen in FIG.
7A indicate the modes (i), (ii) and (iii) of such a form of
apparatus 10, and as seen selecting a mode may affect in this form
also the level of EPAP and IPAP that is provided to the patient.
For example, moving from mode (i) to (ii) may also increase the
levels of EPAP and IPAP in addition to pressure support.
5.1.4 Rate Responsive Ventilator
[0112] In one form, the pressure waveform provided by the
ventilator may be automatically set by detecting changes in
metabolic demand e.g. by monitoring one or more of heart rate,
breathing (or respiratory) rate, and movement, or state of
movement. In one form of the present technology a sensor configured
to provide a measure of metabolic demand, e.g. heart rate and
breathing (or respiratory) rates, provides an input to a processor.
In one form the metabolic demand responsive sensor is an oximeter
4273 used to detect heart rate and/or respiratory rates (see, e.g.,
oximeter 4273 indicated in FIG. 8b).
[0113] In one form an oximeter 4273 is used to provide a
photoplethysmogram (PPG). One or more respiratory parameters are
extracted from a PPG signal using a time-domain, and/or a
frequency-domain processing step. For example, wavelet-based
analysis may be used.
[0114] In one form a value for heart rate variability is determined
from a signal from an oximeter 4273. The value of heart rate
variability is used to estimate a level of activity of the vagal
nerve, and to infer a measure of metabolic demand.
[0115] In one form, in a further processing step, a respiratory
parameter extracted from a PPG signal is used, preferably in
conjunction with a parameter extracted from a flow sensor, to
estimate a respiratory rate, or as an input to a respiratory rate
state machine.
[0116] A control algorithm monitors the respiratory rate and in
response to a change of respiratory rate, or a change in state of a
respiratory rate state machine, adjusts one or more of IPAP and
EPAP.
[0117] In one example, when the estimated respiratory rate
increases, the ventilator or PAP device increases the IPAP level.
In a further example, when the estimated respiratory rate
increases, the ventilator or PAP device increases the EPAP
level.
[0118] In one example, when the estimated respiratory rate
decreases, the ventilator or PAP device decreases the IPAP level.
In a yet further example, when the estimated respiratory rate
decreases, the ventilator or PAP device decreases the EPAP
level.
[0119] In this way the ventilator is able to respond automatically
to the respiratory rate of the patient, and to assist the patient
to exercise.
[0120] In one form, actigraphy, e.g. accelerometers, are used to
detect movement of the patient. When a patient starts to walk or
exercise, the level of movement of the patient is detected and used
to respectively increase at least one of a respiratory rate (e.g.
breaths per minute), and/or level of pressure support and/or target
ventilation.
[0121] In one form, an exercise machine is connected to the
ventilator. When a patient begins to exercise, the movement of the
machine provides an input to the ventilator to alter a rate and or
a level of pressure support or target ventilation.
[0122] In one form, a wearable sensor is used to detect movement of
the patient and as an input to control the ventilator. For example,
a Global Positioning Sensor (GPS) may be used to detect a movement
of the patient. The change in location and the corresponding
differences in time may indicate the speed of the patient. The
measured speed can be used as an indication of whether and how
quickly the patient is moving. Such an indication may then be used
to trigger a corresponding change in the ventilation parameters,
such as provided respiratory rate, level of pressure support or
target ventilation level. In one configuration, the system may
include a lookup table which relates a specific speed with a
specific respiratory rate, pressure support or target ventilation
level. A maximum speed limit, i.e. higher than 1 m/s, may be
imposed and speeds higher than the speed limit may be ignored, as
they may be indicative of the patient movement being assisted by a
third party or by transportation means.
[0123] In one form, an analogue sensor or controller is used that
is configured to provide a greater level of support the harder it
is pressed. In another form, an analogue sensor or controller is
used to trigger and/or cycle the ventilator.
5.1.5 Determining EPAP
[0124] In one form of the present technology, expiratory pressure
level (EPAP) is set automatically to a level at or slightly below
the intrinsic positive end expiratory pressure (PEEP), e.g. as
determined by reducing or minimising Expiratory Flow Limitation
(EFL). The presence of EFL may be determined using a forced
oscillation technique.
[0125] In one form the presence of EFL is determined using a
technique such as that described in Peslin et al. (1993) EUR RESPIR
J, 6, 772-784, "Respiratory mechanics studied by forced
oscillations during artificial ventilation".
[0126] In one form the presence of EFL is determined by applying a
sinusoidal pressure waveform, e.g. at 5 Hz, 10 Hz and 20 Hz at the
entrance to the airways, e.g. using a loudspeaker placed in
parallel with the ventilator, or by applying an oscillatory
pressure waveform signal to a blower under the control of a
processor. The airway is modelled as a combination of resistance,
compliance and in one form, inertance. Complex impedances in
inspiration and expiration are determined. Intrinsic PEEP is
determined by adjusting EPAP and finding the lowest value of EPAP
which reduces the magnitude of the difference between the
inspiratory and expiratory values of the imaginary component of
complex impedance to a level close to that seen in normal patients,
or finding the lowest value of EPAP above which a further increase
no longer yields a significant decrease in this difference.
[0127] This step of determining an EPAP level using a forced
oscillation technique may, be combined with a step of determining a
respiratory rate from an oximeter 4273 and/or a flow sensor.
5.1.6 Patient Responsive Algorithm
[0128] In one form of the present technology, the processor e.g.
4230 is configured to execute an algorithm that includes the
following steps:
(i) Adjust tidal volume and respiratory rate to maintain minute
ventilation at a value between a predetermined minimum minute
ventilation and a predetermined maximum minute ventilation; (ii)
Receive a patient initiated synchrony stimulus; (iii) Determine a
minimum target respiratory rate on the basis of a patient initiated
synchrony stimulus; and (iv) Adjust respiratory rate in response to
the patient initiated synchrony stimulus.
5.2 Apparatus/Device
[0129] In one form of the present technology, a ventilator 12 takes
the form of PAP device 4000.
[0130] PAP device 4000 comprises mechanical and pneumatic
components 4100, electrical components 4200 and is programmed to
execute one or more algorithms 4300. The PAP device preferably has
an external housing 4010, preferably formed in two parts, an upper
portion 4012 of the external housing 4010, and a lower portion 4014
of the external housing 4010. In alternative forms, the external
housing 4010 may include one or more panel(s) 4015. Preferably the
PAP device 4000 comprises a chassis 4016 that supports one or more
internal components of the PAP device 4000. In one form a pneumatic
block 4020 is supported by, or formed as part of the chassis 4016.
The PAP device 4000 may include a handle 4018.
[0131] The pneumatic path of the PAP device 4000 preferably
comprises an inlet air filter 4112, and a pressure device 4140 such
as a controllable source of air at positive pressure (preferably a
blower 4142). One or more pressure sensors 4152 and flow sensors
4154 are included in the pneumatic path.
[0132] The preferred pneumatic block 4020 comprises a portion of
the pneumatic path that is located within the external housing
4010.
[0133] The PAP device 4000 preferably has an electrical power
supply 4210, one or more input devices 4220, a processor 4230, a
pressure device controller 4240, one or more protection safety
circuits 4250, memory 4260, transducers 4270 and one or more output
devices 4290. Electrical components 4200 may be mounted on a single
Printed Circuit Board Assembly (PCBA) 4202. In an alternative form,
the PAP device 4000 may include more than one PCBA 4202. See, e.g.,
a component 4200 and a PCBA 4202 indicated in FIG. 8a.
[0134] The PAP device 4000 is connected to a patient 1000 via an
air circuit 4170 in use, e.g., as indicated in FIG. 9.
5.2.1 Electrical Components
5.2.1.1 Power Supply 4210
[0135] In one form of the present technology power supply 4210 is
internal of the external housing 4010 of the PAP device 4000. In
another form of the present technology, power supply 4210 is
external of the external housing 4010 of the PAP device 4000.
[0136] In one form of the present technology power supply 4210
provides electrical power to the PAP device 4000 only. In another
form of the present technology, power supply 4210 provides
electrical power to both PAP device 4000 and a humidifier 5000.
[0137] In one form of the present technology power supply 4210 is a
battery. Preferably the battery has at least enough energy to power
the PAP device 4000 to allow a patient to exercise for a period,
e.g. about 1 to about 2 hours, alternatively the period is about 2
hours to about 4 hours.
5.2.1.2 Input Devices 4220
[0138] In one form of the present technology, a PAP device 4000
includes one or more input devices 4220 in the form of buttons,
switches or dials to allow a person to interact with the device.
The buttons, switches or dials may be physical devices, or software
devices accessible via a touch screen. The buttons, switches or
dials may, in one form, be physically connected to the external
housing 4010, or may, in another form, be in wireless communication
with a receiver that is in electrical connection to a processor
4230.
[0139] In one form the input device 4220 may be constructed and
arranged to allow a person to select a value and/or a menu
option.
5.2.1.3 Processor 4230
[0140] In one form of the present technology, a processor 4230
suitable to control a PAP device 4000 is an x86 INTEL
processor.
[0141] A processor 4230 suitable to control a PAP device 4000 in
accordance with another form of the present technology includes a
processor based on ARM Cortex-M processor from ARM Holdings. For
example, an STM32 series microcontroller from ST MICROELECTRONICS
may be used.
[0142] Another processor 4230 suitable to control a PAP device 4000
in accordance with a further alternative form of the present
technology includes a member selected from the family ARMS-based
32-bit RISC CPUs. For example, an STR9 series microcontroller from
ST MICROELECTRONICS may be used.
[0143] In certain alternative forms of the present technology, a
16-bit RISC CPU may be used as the processor 4230 for the PAP
device 4000. For example a processor from the MSP430 family of
microcontrollers, manufactured by TEXAS INSTRUMENTS, may be
used.
[0144] The processor 4230 is configured to receive input signal(s)
from one or more transducers 4270, and one or more input devices
4220.
[0145] The processor 4230 is configured to provide output signal(s)
to one or more of an output device 4290, and a pressure device
controller 4240.
[0146] The processor 4230 is configured to implement the one or
more algorithms expressed as computer programs stored in memory
4260.
5.2.1.3.1 Clock 4232
[0147] Preferably PAP device 4000 includes a clock 4232 that is
connected to processor 4230.
5.2.1.4 Pressure Device Controller 4240
[0148] In one form of the present technology, pressure device
controller 4240 is located within processor 4230.
[0149] In one form of the present technology, pressure device
controller 4240 is a dedicated motor control integrated circuit.
For example, in one form a MC33035 brushless DC motor controller,
manufactured by ONSEMI is used.
5.2.1.5 Protection Circuits 4250
[0150] Preferably a PAP device 4000 in accordance with the present
technology comprises one or more protection circuits 4250.
[0151] One form of protection circuit 4250 in accordance with the
present technology is an electrical protection circuit.
[0152] One form of protection circuit 4250 in accordance with the
present technology is a temperature or pressure safety circuit.
5.2.1.6 Memory 4260
[0153] In accordance with one form of the present technology the
PAP device 4000 includes memory 4260, preferably non-volatile
memory. One or more of the algorithms described above are stored in
memory 4260 and executed by processor 4230 in use.
[0154] In some forms, memory 4260 may include battery powered
static RAM. In some forms, memory 4260 may include volatile
RAM.
[0155] Preferably memory 4260 is located on PCBA 4202. Memory 4260
may be in the form of EEPROM, or NAND flash.
[0156] Additionally or alternatively, PAP device 4000 includes
removable form of memory 4260, for example a memory card made in
accordance with the Secure Digital (SD) standard.
5.2.1.7 Transducers 4270
[0157] Transducers may be internal of the device, or external of
the PAP device. External transducers may be located for example on
or form part of the air delivery circuit, e.g. the patient
interface. External transducers may be in the form of non contact
sensors that transmit or transfer data to the PAP device.
5.2.1.7.1 Flow 4271
[0158] A flow transducer 4271 in accordance with the present
technology may be based on a differential pressure transducer, for
example, an SDP600 Series differential pressure transducer from
SENSIRION. The differential pressure transducer is in fluid
communication with the pneumatic circuit, with one of each of the
pressure transducers connected to respective first and second
points in a flow restricting element.
[0159] In use, a signal from the flow transducer 4271, is received
by the processor 4230.
5.2.1.7.2 Pressure 4272
[0160] A pressure transducer 4272 in accordance with the present
technology is located in fluid communication with the pneumatic
circuit. An example of a suitable pressure transducer is a sensor
from the HONEYWELL ASDX series. An alternative suitable pressure
transducer is a sensor from the NPA Series from GENERAL
ELECTRIC.
[0161] In use, a signal from the pressure transducer 4272, is
received by the processor 4230. In one form, the signal from the
pressure transducer 4272 is filtered prior to being received by the
processor 4230.
[0162] Processor 4230 uses a signal from the pressure transducer
4272 to assist in control of the pressure delivered to the patient
1000 via patient interface 3000.
5.2.1.7.3 Oximeter 4273
[0163] An oximeter 4273 in accordance with the present technology
may be an oximeter from one of the following manufacturers:
PHILIPS, MASIMO, NELLCOR. For example, a NELLCOR OxiMax sensor may
be used.
5.2.1.7.4 Electromyograph 4274
[0164] In one form of the present technology an electromyograph
(EMG) 4274 is provided. The EMG 4274 is configured to monitor
activity of the diaphragm of the patient.
5.2.1.8 Output Devices 4290
[0165] An output device 4290 in accordance with the present
technology may take the form of one or more of a visual, audio and
haptic unit. A visual display 4294 may be a Liquid Crystal Display
(LCD) or Light Emitting Diode (LED) display, and a display driver
4292 may be used for displaying information on the display
4294.
5.3 Additional or Alternative Aspects
[0166] An example form of a device for implementing one or more of
the methods of the present technology is illustrated in FIG. 10. In
some forms, the apparatus 100 may include a patient respiratory
interface 102, a delivery tube 110, a controller 104 and a flow
generator such as a servo-controlled blower 105.
[0167] The patient respiratory interface such as a mask 108 as
shown together with the delivery tube 110, provides a respiratory
treatment to the patient's respiratory system via the patient's
mouth and/or the patient's nares. Optionally, the patient
respiratory interface may be implemented with a nasal mask, nose
& mouth mask, full-face mask or nasal pillows or tracheostomy
tube.
[0168] With the flow generator, the apparatus 100 can be configured
to generate a respiratory pressure treatment at the patient
respiratory interface. To assist this end, the device may further
include a pressure sensor 106, such as a pressure transducer to
measure the pressure generated by the blower 105 and generate a
pressure signal p(t) indicative of the measurements of pressure. In
such a device, the delivery tube 110 may serve as the sense tube to
permit detection of pressure levels supplied to the mask or patient
respiratory interface.
[0169] The apparatus 100 may also optionally be equipped with a
flow sensor 107, which may be coupled with the patient respiratory
interface. The flow sensor generates a signal representative of the
patient's respiratory flow. The signals from the sensors may be
used to detect obstructive or central apneas, hypopneas,
cardiogenic airflow, respiratory rates and other respiratory
related parameters from the signals measured by the sensors as
discussed in more detail herein. In some forms, flow proximate to
the mask 108 or delivery tube 110 may be measured using a
pneumotachograph and differential pressure transducer or similar
device such as one employing a bundle of tubes or ducts to derive a
flow signal f(t). Alternatively, a pressure sensor may be
implemented as a flow sensor and a flow signal may be generated
based on the changes in pressure. Although the pressure or flow
sensors are illustrated in a housing of the controller 104, they
may optionally be located closer to the patient, such as in the
mask 108 or delivery tube 110. Other devices for generating a
respiratory flow signal or pressure signal may also be implemented.
For example, a motor RPM sensor may be utilized to estimate
pressure or flow information supplied by the flow generator device
based upon the characteristics of the system.
[0170] Based on flow f(t) and/or pressure p(t) signals, the
controller 104 with one or more processors 114 generates blower
control signals. For example, the controller may generate a desired
pressure set point and servo-control the blower to meet the set
point by comparing the set point with the measured condition of the
pressure sensor. Thus, the controller 104 may make controlled
changes to the pressure delivered to the patient interface by the
blower. Optionally, such changes to pressure may be implemented by
controlling an exhaust with a mechanical release valve (not shown)
to increase or decrease the exhaust while maintaining a relatively
constant blower speed.
[0171] With such a controller or processor, the apparatus can be
used for many different pressure treatment therapies, such as the
pressure treatments for sleep disordered breathing, Cheyne-Stokes
Respiration, obstructive sleep apnea (e.g., CPAP, APAP, Bi-Level
CPAP, AutoVPAP), etc., or combinations thereof by adjusting a
suitable pressure delivery equation. For example, the pressure
treatment therapies of the devices described in U.S. Pat. Nos.
6,532,957, 6845,773 and 6,951,217, which are incorporated herein by
reference in their entireties, may be implemented with a apparatus
100 of the present technology. For example, as described in these
patents, the controller and flow generator may be configured to
provide pressure support ventilation. Such a treatment may ensure
delivery of a specified or substantially specified target
ventilation, for example, a minute ventilation, a gross alveolar
ventilation or a alveolar ventilation, to the patient interface
during the course of a treatment session by comparing an measure of
ventilation with the target ventilation; or delivery of a tidal
volume by comparing a measure of tidal volume with a target tidal
volume. Thus, if a patient's respiration causes the measured
ventilation to fall below or rise above the target ventilation over
time, the flow generator will compensate with an increase or
decrease respectively in the supplied pressure support ventilation.
This may be accomplished with pressure variations that provide a
bi-level form of therapy or some other form of therapy that may
more smoothly replicate changes in a patient's respiration cycle.
While the form of FIG. 10 illustrates a flow generator for
generating such pressure support ventilation, as described herein,
in some cases a apparatus may be implemented for monitoring without
a flow generator for a pressure treatment.
[0172] Optionally, the apparatus 100 may also include additional
diagnosis sensors 112 that may be contact or non-contact sensors.
For example, the device may include an oximeter. The oximeter may
generate a signal representative of a blood oxygen level of a
patient. A suitable example oximeter or monitor device may
optionally be any of the devices disclosed in International Patent
Application No. International Application No. PCT/AU2005/001543
(Pub. No. WO/2006/037184) or International Patent Application No.
PCT/AU1996/000218 (Pub. No. WO/1996/032055), the disclosures of
which are incorporated herein by cross-reference. As disclosed in
these incorporated PCT applications, the monitor may serve as
diagnosis sensors that can also optionally provide a blood pressure
and/or heart or pulse rate monitor for measuring a heart rate
and/or blood pressure of the patient.
[0173] In some forms, the diagnosis sensors may also include an ECG
monitor. Such a device may be configured to detect cardiac-related
characteristics such as a heart rate and may also determine
respiratory parameters (such as central or obstructive apneas,
hypopneas, etc.) Optionally, these parameters may be determined by
the analysis algorithms of controller 104 based on transmission of
the ECG data to the controller or they may be determined by the
monitor and be transmitted to the controller 104.
[0174] In some forms, the diagnosis sensors may include a movement
sensor. For example, a suprasternal notch sensor or chest band may
be implemented to generate a movement signal that is indicative of
patient effort during respiration. Other suitable sensors may
include the movement sensing devices disclosed in International
Patent Application No. PCT/AU1998/000358 (Pub. No. WO1998/052467),
the disclosure of which is incorporated herein by cross-reference.
The movement sensors thus may provide a measure of patient effort
and/or respiration rate and may be used as an alternative to a flow
sensor or in conjunction with other flow sensors as discussed in
more detail herein.
[0175] Some forms may monitor respiratory parameters with
non-contact infrared or wireless biomotion sensors. One such
example is the BiancaMed Doppler device which uses low power pulses
of radio frequency energy transmitted and reflected back to a
sensor to detect respiration rate, heart rate and movement, etc.
Alternatively, or in addition thereto, contact respiratory
monitoring devices such as a respiratory band or movement sensitive
bed may be implemented to monitor patient respiratory
parameters.
[0176] The signals from the sensors may be sent to the controller
104. Optional analog-to-digital (A/D) converters/samplers (not
shown separately) may be utilized in the event that supplied
signals from the sensors are not in digital form and the controller
is a digital controller. Based on the signals from the sensor(s),
the controller assesses the condition of the patient.
[0177] The controller may optionally include a display device 116
such as one or more warning lights (e.g., one or more light
emitting diodes). The display device may also be implemented as a
display screen such as an LCD or a touch sensitive display.
Activation of the display device 116 will typically be set by the
controller based on an assessment of the condition by the apparatus
100. The display device may be implemented to visually show
information to a user of the apparatus 100 or a clinician or
physician. The display device 116 may also show a graphic user
interface for operation of the apparatus 100. User, clinician or
physician control of the operation of the apparatus 100 may be
based on operation of input switches 118 that may be sensed by the
controller or processor of the apparatus.
[0178] Optionally, the controller may also include a communications
device 120 for receiving and/or transmitting data or messages by
the apparatus 100. For example, the communications device may be a
wireless transceiver such as Bluetooth or WIFI transceiver. The
communications device may also be a network communications device
such as a phone modem and/or network card and may be implemented to
send messages via the internet directly or through a computer to
which the detection device may be docked. The communications device
120 may communicate with a remote device 122.
[0179] The controller 104 or processor 114 will typically be
configured to implement one or more particular control
methodologies such as the algorithms described in more detail
herein. Thus, the controller may include integrated chips, a memory
and/or other control instruction, data or information storage
medium. For example, programmed instructions encompassing such a
control methodology may be coded on integrated chips in the memory
of the device. Such instructions may also or alternatively be
loaded as software or firmware using an appropriate data storage
medium. In still further forms, control over parameters of
treatment may be set in accordance with a patient synchronization
demand so as to permit a suitable treatment for mobility or
exercise.
[0180] Some forms of the present technology involve an apparatus to
generate pressure support ventilation. The apparatus may include at
least one sensor adapted to measure at least one respiratory
parameter and a flow generator adapted for coupling with a patient
respiratory interface. The flow generator may be configured to
provide a flow of breathable gas for pressure support ventilation
to the patient respiratory interface. The apparatus may also
include a controller coupled to the at least one sensor and the
flow generator. The controller may be configured to control the
pressure support ventilation with the flow generator. The
controller may also be further configured with a rest mode and an
exercise mode, the rest mode having a first value set of control
parameters for the pressure support ventilation and the exercise
mode having a second value set of control parameters for the
pressure support ventilation.
[0181] In some cases, the controller may be configured to receive a
user activated trigger stimulus, and, in response to the trigger
stimulus to select the second value set of control parameters for
the exercise mode. In response to the trigger stimulus, the
controller may set a target respiratory control parameter as a
function of a presently detected respiratory parameter sensed with
the sensor. The target respiratory control parameter may be a
target respiratory rate and the detected respiratory parameter may
be a measured respiratory rate. The target respiratory control
parameter may be a target ventilation and the detected respiratory
parameter may be a measure of ventilation. Optionally, the target
ventilation may be a target tidal volume and the measure of
ventilation may be a measure of tidal volume. Still further, the
target ventilation may be a target minute ventilation and the
measure of ventilation may be a measure of minute ventilation. In
some cases, the second value set of control parameters may comprise
an increase in target values with respect to the first value set of
control parameters.
[0182] Optionally, the apparatus may further include at least one
user accessible button to activate the controller such that the
button may be configured for actuating the trigger stimulus. Still
further, the apparatus may also include a diaphragm electromyogram
sensor to activate the controller such that the sensor may be
configured for actuating the trigger stimulus. In some cases, the
apparatus may include a vagal nerve sensor to activate the
controller such that the sensor may be configured for actuating the
trigger stimulus.
[0183] In some cases, the controller of the apparatus may be
further configured with a cool down mode, and configured to receive
another user activated trigger stimulus to initiate the cool down
mode. The cool down mode may include a third value set of control
parameters for the pressure support ventilation. The controller may
be configured such that a value of the control parameters of the
cool down mode may be varied from a respective value of the control
parameters of the exercise mode toward a respective value of the
control parameters of the rest mode. The controller may be
configured such that a value of the control parameters of the cool
down mode may be ramped from a respective value of the control
parameters of the exercise mode toward a respective value of the
control parameters of the rest mode.
[0184] Some forms of the present technology may involve a method
for control of pressure support ventilation. The method may include
measuring at least one respiratory parameter with a sensor. It may
also include generating pressure support ventilation with a flow
generator adapted for coupling with a patient respiratory
interface. It may further include controlling, with a processor,
the pressure support ventilation in a rest mode and an exercise
mode. The rest mode may have a first value set of control
parameters for controlling the pressure support ventilation and the
exercise mode may have a second value set of control parameters for
controlling the pressure support ventilation.
[0185] The method may further include receiving a user activated
trigger stimulus, and, in response to the trigger stimulus,
selecting the second value set of control parameters for the
exercise mode. The method may also include, in response to the
trigger stimulus, setting a target respiratory control parameter as
a function of a presently detected respiratory parameter sensed
with the sensor. The target respiratory control parameter may be a
target respiratory rate and the detected respiratory parameter may
be a measured respiratory rate. The target respiratory control
parameter may be a target ventilation and the detected respiratory
parameter may be a measure of ventilation. The target ventilation
may be a target tidal volume and the measure of ventilation may be
a measure of tidal volume. The target ventilation may be a target
minute ventilation and the measure of ventilation may be a measure
of minute ventilation. The second set of control parameters may
include an increase in target values with respect to the first
value set of control parameters. In some such methods, a user
accessible button actuates the trigger stimulus. In some such
methods, a diaphragm electromyogram sensor actuates the trigger
stimulus. Still further, in some such methods, a vagal nerve sensor
actuates the trigger stimulus.
[0186] Optionally, the methods may also include controlling
pressure support ventilation in a cool down mode in response to
receiving another user activated trigger stimulus, the cool down
mode may have a third value set of control parameters for the
pressure support ventilation. In some cases, a value of the control
parameters of the cool down mode may be varied from a respective
value of the control parameters of the exercise mode toward a
respective value of the control parameters of the rest mode. In
some cases, a value of the control parameters of the cool down mode
may be ramped from a respective value of the control parameters of
the exercise mode toward a respective value of the control
parameters of the rest mode.
[0187] In some forms, the apparatus 100, such as when implemented
to provide a pressure treatment to patient suffering respiratory
insufficiency, COPD or other similar ailments, may serve to enhance
physical activity or mobility for a patient. For example, the
apparatus may be implemented to provide non-invasive ventilation to
provide respiratory support for patients during mobility. Such a
non-invasive ventilation may enhance exercise capacity in COPD
patients or emphysemic patients. Thus, in some forms, a pressure
treatment methodology, such as a control algorithm for non-invasive
pressure support ventilation, may be implemented to promote
exercise or patient mobility with suitable pressure support
modes.
[0188] As a COPD patient gradually, exercises, their tidal volume
and respiratory rate will increase. When the patient then rests,
the tidal volume and respiratory rate decreases. In some forms of
the present technology, a patient-responsive non-invasive
ventilation methodology of the apparatus may be configured to adapt
to patients' varying respiratory needs during exertion or
exercise.
[0189] Accordingly, FIG. 11 illustrates an example of a methodology
of a controller for such an apparatus. During use, the controller
will generally permit a change to pressure support control
parameters, such as an increase in ventilation (e.g., tidal volume)
and respiratory rate at levels, that are suitable for exercise or
mobility up to a maximum ventilation, such as a minute ventilation,
and/or maxium respiratory rate so as to provide pressure support at
those levels. In order to achieve the desired levels, the apparatus
may be configured to respond to a user or patient stimulus for
setting the synchronization of the apparatus with the patient's
exercise requirements.
[0190] For example, the apparatus may provide NIV at initial levels
in a rest mode to provide a pressure support suitable for a patient
at rest at 400. Thus, the apparatus may begin treatment by
accessing stored values of target parameters for the rest mode
where those values of the target parameters are suitable for
controlling ventilation or pressure support for patient rest. The
user or patient may then begin to exercise. During exercise or
shortly before, the patient may then provide a stimulus, such as
executing a trigger, to initiate a modification procedure of the
apparatus so that the apparatus may begin an exercise mode at 401.
The modification procedure permits the values of the target
parameters of the pressure support to be modified or set such that
the pressure support will be provided at more suitable levels
(e.g., increases in target ventilation (e.g., minute ventilation or
tidal volume) or in target respiratory rate, or in the maximum or
minimum values suitable for controlling pressure support) for
exercise at 402. Thus, the modification procedure of the exercise
mode may allow enforcement of different minimum and/or maximum
values and/or target values of respiratory control parameters in
the exercise mode at 403 from the rest mode.
[0191] In some such forms, the triggered change or, increase to the
values of the control parameters of the pressure support
ventilation for the exercise mode may optionally be predetermined.
In such a case, the executed trigger may result in the apparatus
accessing one or more stored values for the control parameters for
the pressure support where the stored values of the control
parameters are associated with the exercise mode. Such target,
minimum and/or maximum values may be previously entered by a
physician or clinician. For example, a respiratory rate target or
ventilation target may be set as a physician selectable
proportional function of the values of the control parameters of
the rest mode so as to permit a proportional increase (or decrease)
of the parameters from the rest mode. Optionally, in some forms,
some of the values of the control parameters of the pressure
support ventilation of the exercise mode may be learned so as to
better synchronize with the level exercise of the user or patient.
For example, the apparatus may learn the exercise respiratory rate,
minute ventilation and/or tidal volume of the patient during an
initial exercise period of the exercise mode or in response to a
stimulus signal of the patient, such as by measuring these
parameters from a flow signal in the initial period. Thereafter,
such learned values may then be set for the control parameters of a
later time period of the exercise mode.
[0192] In some forms, the stimulus for entering the exercise mode
or making an adjustment to target values to accommodate the
patient's state of exercise may be made by the patient by pressing
a button of the treatment apparatus or a button on a remote control
(e.g., a wired, wireless or infrared transmitter to transmit to an
exercise mode signal or exercise synchronization signal to a
receiver of the apparatus). Alternatively, the stimulus signal may
be a detected physiological stimulus such as for example, a signal
from a diaphragm electromyogram sensor, a signal from a sensor that
is responsive to activation of the vagal nerve e.g. an oximeter, or
an evaluation of a signal from a flow sensor.
[0193] In some forms, as further illustrated in FIG. 11, the
apparatus may be configured to receive additional stimulus signals
or executed triggers from the patient as the exercise progresses or
cools down in or from the exercise mode. For example, with each
additional stimulus signal, a new set of control values may be
established. For example, at 404 a patient or user may trigger
learning or loading of a further set of values for the control
parameters. The new targets may then be set as the control
parameters for the delivery of the pressure support ventilation at
405. The apparatus 100 may then control the pressure support in
accordance with the new settings at 403. Each set of control values
may be higher or lower than the previous control values based on an
increase or decrease of activity.
[0194] For example, in some forms, the exercise mode may have a
predetermined time interval, such as a maximum time set by a
physician or clinician. In some such forms, a timer may begin when
the exercise mode starts and the mode may terminate when a preset
maximum time is reached. During the exercise mode, the apparatus
may deliver pressure support ventilation with the exercise mode
control values that are suitable for patient exercise. At the
conclusion of the exercise mode, the apparatus may switch to the
rest mode, so as to deliver pressure support ventilation with the
rest mode control values that are suitable for patient rest.
Optionally, the apparatus or remote control may include a button to
terminate the exercise mode before the maximum time is reached.
[0195] Still further, in some forms, the termination of the
exercise mode may initiate a cool down mode. During the cool down
mode, the values of the control parameters may be varied over a
selectable period of time. For example, the values may be ramped
from the values of the target parameters of the exercise mode to
the values of the target parameters of the rest mode. For example,
the respiratory rate and/or ventilation targets may be
automatically modified so as to ramp down or be gradually stepped
down over a period of time to the rest mode values.
5.4 Other Aspects
[0196] The present technology may be packaged as an exercise module
or accessory to be used with a range of different ventilators.
[0197] Preferably the parameters that are adjustable by the patient
are adjustable within limits. Such limits may be established by a
clinician prior to use by the patient.
5.5 Advantages
[0198] One advantage of the present technology is that it allows
ventilators to more closely match a patient's need, particularly in
the face of a changing need, e.g. increasing or decreasing, such as
when a patient attempts to exercise.
[0199] An advantage of the present technology is that it is easier
and more comfortable for patients to use when compared to a
ventilator that may have one fixed setting of e.g. minute
ventilation, or pressure support.
[0200] In addition, the present technology allows a patient to
pre-empt a need for a sooner breath, or an increased level of
support. By pressing on the relevant button momentarily before they
require a breath, the system can respond just as the patient
actually needs the breath.
5.6 REFERENCE SIGNS LIST
[0201] apparatus 10
[0202] ventilator 12
[0203] button 14
[0204] pc 16
[0205] digital communication interface 18
[0206] inflection point 17
[0207] pressure support 19
[0208] Pathway 21
[0209] Apparatus 100
[0210] Patient respiratory interface 102
[0211] Controller 104
[0212] Blower 105
[0213] Pressure sensor 106
[0214] Flow sensor 107
[0215] Mask 108
[0216] Delivery tube 110
[0217] Additional diagnosis sensors 112
[0218] Processor 114
[0219] Display device 116
[0220] Input switches 118
[0221] Communications device 120
[0222] Remote device 122
[0223] Patient interface 3000
[0224] pap device 4000
[0225] external housing 4010
[0226] panel 4015
[0227] chassis 4016
[0228] handle 4018
[0229] pneumatic block 4020
[0230] pneumatic component 4100
[0231] inlet air filter 4112
[0232] blower 4142
[0233] pressure sensor 4152
[0234] flow sensor 4154
[0235] Air circuit 4170
[0236] electrical component 4200
[0237] PCBA 4202
[0238] power supply 4210
[0239] input device 4220
[0240] processor 4230
[0241] clock 4232
[0242] pressure device controller 4240
[0243] protection circuit 4250
[0244] memory 4260
[0245] transducer 4270
[0246] flow transducer 4271
[0247] pressure transducer 4272
[0248] Oximeter 4273
[0249] Electromyograph 4274
[0250] output device 4290
[0251] algorithm 4300
[0252] humidifier 5000
5.7 Other Remarks
[0253] Unless the context clearly dictates otherwise and where a
range of values is provided, it is understood that each intervening
value, to the tenth of the unit of the lower limit, between the
upper and lower limit of that range, and any other stated or
intervening value in that stated range is encompassed within the
technology. The upper and lower limits of these intervening ranges,
which may be independently included in the intervening ranges, are
also encompassed within the technology, subject to any specifically
excluded limit in the stated range. Where the stated range includes
one or both of the limits, ranges excluding either or both of those
included limits are also included in the technology.
[0254] Furthermore, where a value or values are stated herein as
being implemented as part of the technology, it is understood that
such values may be approximated, unless otherwise stated, and such
values may be utilized to any suitable significant digit to the
extent that a practical technical implementation may permit or
require it.
[0255] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this technology belongs.
Although any methods and materials similar or equivalent to those
described herein can also be used in the practice or testing of the
present technology, a limited number of the exemplary methods and
materials are described herein.
[0256] When a particular material is identified as being preferably
used to construct a component, obvious alternative materials with
similar properties may be used as a substitute.
[0257] It must be noted that as used herein and in the appended
claims, the singular forms "a", "an", and "the" include their
plural equivalents, unless the context clearly dictates
otherwise.
[0258] All publications mentioned herein are incorporated by
reference to disclose and describe the methods and/or materials
which are the subject of those publications. The publications
discussed herein are provided solely for their disclosure prior to
the filing date of the present application. Nothing herein is to be
construed as an admission that the present technology is not
entitled to antedate such publication by virtue of prior invention.
Further, the dates of publication provided may be different from
the actual publication dates, which may need to be independently
confirmed.
[0259] Moreover, in interpreting the disclosure, all terms should
be interpreted in the broadest reasonable manner consistent with
the context. In particular, the terms "comprises" and "comprising"
should be interpreted as referring to elements, components, or
steps in a non-exclusive manner, indicating that the referenced
elements, components, or steps may be present, or utilized, or
combined with other elements, components, or steps that are not
expressly referenced.
[0260] The subject headings used in the detailed description are
included only for the ease of reference of the reader and should
not be used to limit the subject matter found throughout the
disclosure or the claims. The subject headings should not be used
in construing the scope of the claims or the claim limitations.
[0261] Although the technology herein has been described with
reference to particular embodiments, it is to be understood that
these embodiments are merely illustrative of the principles and
applications of the technology. In some instances, the terminology
and symbols may imply specific details that are not required to
practice the technology. For example, although the terms "first"
and "second" may be used, unless otherwise specified, they are not
intended to indicate any order but may be utilised to distinguish
between distinct elements. Furthermore, although process steps in
the methodologies may be described or illustrated in an order, such
an ordering is not required. Those skilled in the art will
recognize that such ordering may be modified and/or aspects thereof
may be conducted concurrently or even synchronously.
[0262] It is therefore to be understood that numerous modifications
may be made to the illustrative embodiments and that other
arrangements may be devised without departing from the spirit and
scope of the technology.
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