EXPAIR Flow –Volume Testing Issue 1 Flow Volume rev 2.0 May 2012

Table of functions and Button Controls

Page 2 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.

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.

Page 4 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.

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

Page 5 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.

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 Best FVC numeric

Best Expiratory Shape Best Inspiratory Shape Best FEV1 Numeric

Meets ATS – ERS BTS It is possible to select the best expiratory value from one test and select the best inspiratory value from another test. By using the selection criteria under the column. Page 6 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.

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

Page 7 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.

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

Page 8 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.

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.

Page 11 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.

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 Medisoft has three incentive graphical formats;

FEV6 Achievement to land the plane, clearing the tree is indication that the FEV 1 and PEF is complete, landing the plane is the 6 seconds of expiration

The birthday cake is a direct measure of FEV1 to predicted blow our all the candles in one second.

For the adults, a timer for exhaled time and a bar graph of volume effort

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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. Page 16 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.

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. Page 17 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.

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

Forced Expired Volume at 1 second

FEV1

Litres

FVC

Litres

Forced Vital Capacity

FEV1/FVC

%

Ratio FEV1/FVC

VEV1/VC

%

Ratio FEV1/VC

Litres per second

Peak Expiratory Flow

PEF 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

FIV1 PIF

Litres per second

Peak Inspiratory Flow

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

Litres per second

Mean inspiratory flow 25-75% of the volume

Litres per second

Inspiratory flow at 25% of the volume

MEF50/MIF50

FIF25 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 Forced Expired Volume at 6 seconds

FEV6

Litres per second

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 Page 19 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.

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.

Page 20 of 24 Issue 1 Flow Volume rev 2.0 May 2012. 99-Man Flow Volume.