medisoft
Pulmonary Function Systems
EXPAIR Flow–Volume for Micro 5000, Blue Spiro, Hyp Air, Spiro Air, Body Pleth 5500, Ergocard 2013
Guide
23 Pages
Preview
Page 1
Flow Volume Introduction Flow Volume is a common module with the Medisoft Equipment controlled with the Exp’Air software suite. This section covers the systems including; Micro 5000 Blue Spiro (with Exp’Air software) Hyp’Air Spiro Air Body Plethysmograph 5500 Ergocard And the option packs available for the above modules. Many sections are common, however for specific instruction use the index to find the sections that relate to your actual product. As will many systems the manual is only an additional supplement to the on-screen instruction and help that is specific to the section of the software you are in at any time. We explain the principles and functions of the calibration in the following section.
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Table of functions and Button Controls Pharmacutical selector for Pre, Post or challenge testing
Start Test data collection Perform a Test without BTPS factors (Syringe check) Zero the Flow hrough the Pneumotachograph Predicted Value Column (Predicted Values for subject from selected group)
Cursor scroll bar (use to scroll through the parameter list)
Show the cursors for the minimum and maximum Vital Capacity and Tidal Volume, these can be relocated with the EDIT function
Dropdown menu activated from the placing the cursor on the TEST X Button and using the mouse righthand button
TEST X buttons mark the individual Test results The Cut button becomes active as soon as a test is started allowing the screen to be refreshed until ready to make a measurement. Penumotachograph selector for individual tests Zoom Function to enlarge or reduce the screen scales Selecting Pre, Post or challenge levels Spirometer selector for SPIRO AIR inplace of the Pneumotachograph Pre- Test value display column, by depressing the button the relating trace will be displayed overlaying the current trace on display These two buttons display the data aligned at TLC or RV This button aligns the loops relative to actual TLC
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FLOW VOLUME spirometry The derivation of the use of the word spirometry comes from the meaning of the measurement of breathing, In 1947, Robert Tiffeneau brought to spirometry a major concept, “lung capacity useable during exercise”, known for posterity by the name “Forced Expired Volume in 1 second” or “FEV1”. Spirometry is the most widely used of respiratory function testing its origin dates back to the measurement of vital capacity that was described by Hutchinson. It very quickly became clear that the measurement of VC was not enough to evaluate the characteristic changes of asthma or emphysema. In fact, for these ailments, VC was visibly less affected than the capacity to expire at a normal speed. The introduction of FEV made it possible to evaluate this expiratory problem specifically, and allowed the distinction between an obstructive ventilation problem and a restrictive ventilation problem. The third major stage was the introduction of the concept of flow. This made it possible to emphasize the fact that with the majority of pulmonary volumes there is a limit to the maximal flow that can be achieved. This concept explains why forced expiration has turned out to be so useful in clinical exploration. Forced spirometry testing expanded with the arrival of Differentiators and integrators coupled to XY recording devices to provide a visualisation of the Flow Volume curve arriving from the forced Spirometry effort. The test therefore has the sequence of four respiratory manoeuvres; • Calm respiration. • Maximum inspiration. • Forced maximum expiration. • Forced maximum inspiration if you want to study inspiratory capacity.
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The test is entered by selecting the tab screen.
on the top of the
The subject is prepared for the test and instructed in the method of the measurement, this is typically a period of tidal volume measurement followed by a full inspiration and without hesitation a forced expiratory effort to residual volume followed by a full inspiration. The test may be performed in the reverse breathing action or as a single expiration, all methods are discussed in the chapter. The screen for forced spirometry is shown in figure 1. The double presentation of both the volume time and the Flow Volume spirogram that allows monitoring of the patient’s effort.
Figure 1
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The scroll keys allow the selection from up to 8 efforts, the maximum number of efforts recommended by the ATS / ERS recommendations 2005. The progress of acceptability to the ATS / ERS recommendations is by activating the ATS button which in turn will then show the Acceptability
shown
The test that pass are also indicated at the base of each column of results in the table,
The Green tick
shows a pass
The red cross
a fail
It is possible to select the best expiratory value from one test and select the best inspiratory value from another test. This is by moving the selection dot from one column to the column of choice.
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Screen display during the test To perform this test the subject is normally seated in a chair with arms to avoid falling if dizzy during the effort. The feet should be flat on the floor and the subject is connected to the device through single subject barrier filter with a mouthpiece. Different schools of thought suggest the wearing or not of a noseclip during the forced effort. Our general recommendation is to use noseclips during all testing in most case obtains the best results. The subject is then connected to the Pneumotachograph or Spirometry ready to test and then
click the • •
button to commence the recording of the test.
It is possible to perform an expiratory only effort without the inspiratory values by un-checking the box However if the FIV values is selected then the test is looking to see a forced maximal inspiration after the expiration if the effort fails to match the volumes then the following dialogue box appears;
Figure 2
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The subject is requested to breathe is a relaxed manner for 2 to 3 tidal volumes before filling the lungs completely to Total Lung capacity and then to force all the volume out pushing all the way down to residual volume before another full inspiration to close the loop.
Normal Respiration Maximum Inspiration
Forced Maximum Re-inspiration
Visible tidal volume, if the option is activated
Forced Maximum Expiration
Figure 3
The expired volume and expired time graphic
When the expired volume exceeds the Predicted value then the bar graph turns Green
The timer says red until the expired time exceeds 6 seconds then the trace turns to green until the subject stops the exhalation, typically the subject is encouraged to continue to 10 seconds to meet the ATS criteria. To store the completed effort click on the button
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During the test the screen and test can be reset with the scissors button
.
When the test is complete the analysis can take place in several forms the post test screen shows the volume time on the left hand panel and the flow volume on the right hand panel. The graphics can be re-scaled with the Zoom control buttons
Below the volume time trace, the between the full volume against time to simple view of the FEV1 effort as a vitalogram. This trace can be expanded with the use of the to see the full expiration.
buttons allow to toggle a
Time Volume Trace
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Expiratory Curve
This button displays the expiratory volume as a function of time with the FEV1 points that are marked at the point of measurements. This is the spirogram of volume time efforts, each individual effort can be overlaid by depressing the TEST X button at the top of the Test data column.
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As many buttons as are depressed will be overlaid to see the reproducibility.
Figure 4 This graphic often referred to as a “Vitalogram” is a pictorial demonstration to the subject of the repeatability of the FEV1 efforts. It is a good incentive to attempt to get a better effort from the subject.
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Full Expiratory Curve
The ERS – ATS recommendations suggest that the subject should be encouraged to continue to breathe out for a long as possible and at least for 6 seconds of expiration. The graphic above indicates to the operator and subject the weakness of an effort and can be used as an incentive to obtain a better blow for longer.
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Display of the tabs corresponding to the measurement points This option is activated with the right hand mouse button when activated on the TEST X button this will open the dialogue box.
The EDIT button opens the edit screen this allows the adjustment of the points of the measurements.
The four markers when depressed allow the movement of the markers for the forced expired start and finish and the forced inspired start and finish.
The calculator button restores the markers to the computers findings.
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In this mode it is possible to see that the subject has fully reproducible efforts and has exceeded the 6 second good test criteria that is outlined by the ATS / ERS guidelines. The ATS acceptance criteria is a positive method of ensuring good quality in the testing performed and a excellent tool for the operator / Technician / Physiologist. The test is also helped with the expiratory time indicator that also shows the performance against the predicted marker. The timer and the volume indicator both start as soon as the expiration starts, the subject should be encourage to exhale for at least 6 seconds and to continue for as long as possible with 10 seconds the next target.
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Incentive Spirometry Sometimes with children or infirm subjects an incentive may assist a good or better measurement this is provided with a birthday cake where the candles must be extinguished. The force necessary to blow out the candles is set with reference to one of the following parameters, FVC FEV1 PEF The function is enabled by depressing the Birthday cake button allow the selection of the watch variable
this will then
The watch variable is selectable with the top drop down list. The test is activated by pressing the loop key during the initial inspiratory phase. FVC
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Flow/Volume Curve This shows the Flow/Volume curve with tidal volume displayed with the maximal curve Magnifies the scale of the Allows the scales to remain Flow display in proportion to each other
Checked the tidal loop is displayed, unchecked prevents the tidal loop
Indicate the range of the predicted value of the parameter. Figure 5
To maximise the Flow/Volume screen, double click on this screen With the left hand button the loops are drawn aligned at TLC whilst if the right hand button is active then the loops are aligned to RV. Alternatively the button Allows the loop data to be aligned at a true TLC volume.
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1.1 Table displaying the results in numerical format Displays the predicted values and the results of up to the 8 different tests carried out. 1.1.1
In « Pre-test » mode
Figure 6
Time at which the test was carried out.
Best pre-test
The best test is selected automatically however the operator can override the selection with a manual choice this is performed by simple task of moving the DOT under the column you wist to select allows choice of both inspiratory and expiratory efforts independent of each other. Best pre-test , or test selected manually In Post-test mode
Difference between Pre-Post
Figure 7 The Pre test button allows the overlay of the best pre and selected post test efforts, also by scrolling with the arrow heads it is also possible to present previous loop data and graphics overlaid with the current test.
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Review of collected data.
The review to a style of report you design is obtained by the use of the button
to open the report module, it allows several variable from the test to be displayed with full predicted mean, range or even previous visits. (Note: Currently this is not available in network mode of operation)
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Listed parameters and abreviation definition PARAMETER
ALTERNATIVE
UNITS
DESCRIPTION
FEV1
Litres
Forced Expired Volume at 1 second
FVC
Litres
Forced Vital Capacity
FEV1/FVC
%
Ratio FEV1/FVC
VEV1/VC
%
Ratio FEV1/VC
PEF
Litres per second
Peak Expiratory Flow
MEF
FEF25-75
Litres per second
Mean expiratory flow 25 -75% of the volume
MEF75
FEF25%
Litres per second
Flow at 75% volume from RV or 25% volume expired
MEF50
FEF50%
Litres per second
Flow at 50% volume from RV or 50% volume expired
MEF25
FEF25%
Litres per second
Flow at 25% volume from RV or 50% volume expired
Litres
Forced inspired volume at 1 second
Litres per second
Peak Inspiratory Flow
FIV1 PIF MEF50/MIF50
FEF50/FIF50
%
Ratio of flow at 50% of the volume expiratory / inspiratory
MEF/FVC
FEF/FVC
%
Ratio of mid-expiratory flow to forced vital capacity
MIF
FIF
FIF25
Litres per second
Mean inspiratory flow 25-75% of the volume
Litres per second
Inspiratory flow at 25% of the volume
FIF50
Litres per second
Inspiratory flow at 50% of the volume
FEF/VC
%
Ratio of Mid inspiratory flow to vital capacity
VC (f)
Litres
Flow Volume (FVC)
IRV (f)
Litres
Inspiratory Reserve Volume (from FVC)
ERV (f)
Litres
Expiratory Reserve volume (from FVC)
IC (f)
Litres
Inspiratory Capacity (from FVC)
EC (f)
Litres
Expiratory Capacity (from FVC)
V comp.
Litres
Compressed Thoracic Volume
Ti
Seconds
Inspiratory Time
FEV1/Ti
%
Ratio FEV1 / Inspiratory Time
P Avl.
cmH2O
Alveolar Pressure
Texp
Seconds
Expiratory Time
FVC insp
Litres
Inspiratory Forced Vital Capacity
VC - FVC
Litres
Vital Capacity (slow - relaxed) - Forced Vital Capacity
FEV0.5
Litres per second
Forced Expired Volume at 0.5 second
FEV3
Litres per second
Forced Expired Volume at 3 seconds
FEV6
Litres per second
Forced Expired Volume at 6 seconds
FEV1/FEV6
%
Ratio of FEV1 to FEV6
FVC @ 6 sec
Litres
Forced Vital Capacity at 6 seconds
FEF25 6sec
Litres per second
Expiratory flow at 25% expired volume relative to the FVC at 6 seconds
FEF50 6sec
Litres per second
Expiratory flow at 50% expired volume relative to the FVC at 6 seconds
FEF75 6sec
Litres per second
Expiratory flow at 75% expired volume relative to the FVC at 6 seconds
FEF 6sec
Litres per second
Mid expiratory flow 25-75% relative to the volume at 6 seconds
FEV1/FVC 6sec
%
Ratio of FEV1 to FVC @6 seconds
Extr. Vol.
Litres
Extrapolated volume
EV/ FVC
%
Ratio Extrapolated volume / Forced Vital Capacity
Note : two methods for calculating the MEF [Mean Expiratory Flow] are available : MEF = (FEF25 + FEF75) / 2 or (FVC / 2) / time FEF75 -> FEF25
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The instrument is quality checked with a simple daily calibration check using a 2 or 3 litre syringe. The accuracy should fall within 3% of the volume or 3.5% allowing for errors in the syringe itself. The BTPS conditions are set with the exhaled temperature at the lips set in the patient details screen and the environmental conditions set with the temperature and barometric pressure transducers. The humidity is set by the user. The standard BTPS equations are as follows; Water vapour as a function of temperature = 2 9.993 – (0.3952 + Ambient Temperature) + (0.3775 x Ambient Temperature )
ATPS -> BTPS = 310 x ( barometric pressure – Water vapour ) ((273 + Ambient Temperature) x ( Barometric pressure – 47.1))
Whilst ATPD -> BTPS = 310 x ( barometric pressure ) ((273 + Ambient Temperature) x ( Barometric pressure – 47.1))
Of course the ambient condition is neither dry nor wet so an ATP equation is used specific to the device and the mode of use.
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