Note: Descriptions are shown in the official language in which they were submitted.
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ResPiratorY Test Apparatus
The present invention relates to an apparatus for
testing the respiratory ability of subjects.
There are a number of situations where it is necessary
or desirable to test the respiratory ability of a subject, and
indeed to improve that ability. For example, it is often
necessary to test and improve the respiratory ability of a
patient prior to a surgical operation and/or during the
rehabilitation of such a patient. As another example, it is
often desirable to improve the respiratory ability of athletes
lO or other sportsmen.
have now devised an apparatus for testing and
improving the respiratory ability of subiects.
In accordance with the present invention, there is
provided an apparatus which comprises a unit through which a
15 subject can inspire, this unit including a pressure sensing
device, and a data processing unit to which the pressure
sensing device is connected, and arranged to compare the time-
varying pressure, or a parameter thereof, with a prestored
target.
Preferably the apparatus is arranged to store a target
for each individual subiect. Preferably this target comprises
a time-varying pressure profile taken from the subject during
a pre-test trial inspiration, but then reduced by a
predetermined fraction in pressure amplitude. Additionally or
25 instead, the target may comprise an integral of the trial
inspiration pressure profile, reduced by a predetermined
fraction. Preferably the target is selected as the best result
from a number, say three, trial inspirations.
The apparatus is preferably arranged for the subject to
30 carry our successive test inspirations, the measured results
of each of these being compared against the target, with the
time intervals between successive tests progressively reducing.
Preferably, the apparatus prompts the subject to commence each
successive inspiration (e.g. by means of a display and/or
35 audible signal). Preferably a set of successive tests (e.g.
six tests) are carried out with the same interval (e.g. 60
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seconds) between them, then a second set of tests are carried
out with a smaller internal (e.g. 45 seconds) between them, and
50 on.
At each test, the apparatus is arranged to determine if
5 the subject has "passed" that test, in which case the apparatus
prompts the subject to carry out the next test, and so on. At
some stage, the subject will fail an individual test, and this
completes the exercise: the point in the overall program at
which the failure occurs is recorded.
10During each test, preferably the prestored target
profile is continuously displayed on a visual display, and the
measured profile is built up on the display as the subject
breathes in: the subject is thus able to compare his
performance with the target, and can adjust his effort in an
15 attempt to exceed the target. This "feedback" to the subject
is particularly valuable.
Preferably the apparatus requires the measured time-
varying profile to exceed the target profile by a predetermined
margin, in terms of the integral of that curve (e.g. the area
20 under the curve, which is therefore a measure of the work
done). Preferably also the apparatus requires the duration of
the measured time-varying profile to exceed a predetermined
fraction (e.g. 90%) of the duration of the target profile.
Preferably the apparatus is arranged to display one or
25 more of the following: the peak pressure of the target
profile, the average peak pressure from the successive test,
the integral of the target profile, the accumulating integral
of each test profile, and the accumulated integral of the
successive tests (corresponding to the total wor~ done by the
30 subject during the test program).
Preferably at each session of use, the subject creates
a fresh target, in the manner described above, against which
he compares his performance during the tests which he carried
out in that session.
35The peak pressure, measured typically over the first
second of each inspiration, gives an indication of measured
respiratory muscle strength. The integral of each test profile
is a measure of the work done. The accumulated integral, over
all tests completed successfully in the session, is a measure
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of respiratory endurance. These results therefore provide an
effective assessment of the subject's respiratory muscles.
Through use of the above-described apparatus in
successive sessions, I have found that the subject's
5 respiratory ability improves significantly (particularly muscle
strength and endurance).
An embodiment of the present invention will now be
described by way of example only and with reference to the
accompany drawings, in which:
FIGURE 1 is a schematic diagram of an apparatus in
accordance with the invention for testing the respiratory
ability of a patient;
FIGURE 2 is a typical time-varying measure of pressure
sensed in a trial use of the apparatus of Figure 1;
FIGURE 3 is a typical display of a target profile and
a measured profile; and
FIGURE 4 is a typical results grid following a test
session.
Referring to Figure 1 of the drawings, there is shown
20 an apparatus for carrying out respiratory tests, the apparatus
comprising a hand-held unit 10 having a mouthpiece 11, and
through which the patient or subject inspires, and a personal
computer 20 to which a manometer of the unit 10 is connected.
The computer 20 includes a visual display unit (VDU) 22 and
25 keyboard 24 is connected to a printer 26. The computer is
loaded with a respiratory test program in accordance with the
invention, arranged for the apparatus to function as follows.
The computer creates and stores a record for each
subject: thus for each subject, data is entered on the
30 computer keyboard 24 to identify the subject, and various other
items of data concerning the subject are also entered. In an
initial phase, a target pressure profile for the subject is
created and stored: thus, the VDU prompts the subject to break
in through the hand-held unit 10; the negative pressure created
35 within the air passage of the unit 10 is monitored by the
manometer, and a corresponding time-varying profile P as shown
in Figure 2 is displayed on the VDU and also stored. This
procedure is carried out three times, with an interval of time
(e.g. of two minutes) between each inspiration. The computer
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then selects the "best " pressure profile of the three (as a
combination of the largest peak and longest duration): the
computer then calculates a target profile T which is
predetermined fraction (e.g. 80~) in amplitude of the selected
"best" pressure profile; this target profile is then displayed
continuously on the VDU.
After a rest, the subject is prompted by the computer
to commence the testing phase. Thus, the subject breathes in
again through the hand-held unit 10, and a trace of the
10 measured pressure M is built up on the VDU, as shown in Figure
3: thus, as the subject breathes in, he can visually compare
his performance against the target profile being displayed.
Also the computer continuously calculates an integral of the
trace which is being created (i.e. the area under the curve,
15 therefore a measure of the work done), and displays this
accumulating figure on the VDU. The VDU also continuously
displays the corresponding final integral of the target
profile.
If at the end of this test the computer finds that the
integral of the subject's measured trace exceeds the integral
of the target profile by a predetermined margin (e.g. by 10%),
then the computer regards the subject as having "passedl' the
test. The computer then prompts the subject (via the VDU
and/or by an audible signal), to repeat the exercise, after an
interval of 60 seconds. The test proceeds in this manner,
until the subject has "passed " the test six times in
succession (with 60 seconds between each test). Then the test
proceeds six more times, with a reduced interval (45 seconds)
between successive tests, followed by six tests with 30 seconds
intervals, six test with 15 second intervals, six tests with
10 seconds intervals, and finally six tests with 5 seconds
intervals. However, at some stage during this test program,
the subject will fail to exceed his target.
Thus, Figure 4 shows the results for a subject who
35 passed all six tests for each of the 60, 45, 30 and 15 seconds
intervals tests (A to D), then passed four of the tests at 10
seconds intervals but then failed the next test. It will be
appreciated that the results for this subject can be
categorised as r'E4". The results table shown in ~igure 3 is
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displayed on the VDU, together with the accumulated total of
the intervals under the test curves (being a measure of the
total work done). This information can be printed out, and is
also stored by the computer in the data record for that
subject.
At the next session of use by the same subject, the
subject undergoes an initial phase as described above, and a
new target profile is created in the same manner. The test
then proceeds as described above.
It will be appreciated that as a result of successive
sessions of use of the apparatus, each subject improves his or
her performance, firstly by progressing further through the
full program of 36 tests, secondly by improving the accumulated
"work done" figure, and also by improving the average peak
15 pressure figure.
