Simple Spirometry Guide Issue 1 Rev. 2.0 May 2012

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

Page 2 of 16

RELAXED spirometry The Vital Capacity is partitioned into four discrete areas these are as follows: Expiratory Reserve Volume (ERV) Inspiratory Capacity (IC) Tidal Volume (TV) Inspiratory Reserve Volume (IRV), the Inspiratory Capacity (IC) minus the Tidal Volume (TV) The manoeuvre is performed by two methods; each method may yield higher values in certain subject groups, which include those with obesity and respiratory muscle defects. The first method Expiratory Vital Capacity requires the subject to inhale to total lung capacity (TLC) first and then to gently exhale all the way out to residual volume (RV) The second method Inspiratory Vital Capacity requires the subject to be encouraged to breathe all the way out to residual volume (RV) then to fully inflate the lung to total lung capacity (TLC) Both methods are performed from a resting FRC level, the subject is encouraged to breathe normally at a resting level, tidal volume (TV) for a minimum of 3 stable, repeatable efforts before commencing the manoeuvre. As the tidal volume determines the separation of the other partitions it is essential that the subject is at a resting level before making the effort, an upward or downward shift in the tidal volume is an indication of either the subject is hyper-inflated at the commencement or is hyper-inflating during tidal breathing. Instrument drift can be removed using the zero button described later.

Page 3 of 16

The Vital Capacity Test is opened by selecting the Tab from the top of the screen test options. The default Test Transducer is displayed in the lower right hand side of the screen.

In order to start the measurements the choice of testing transducer can be made when using multiple instruments.

Prepare the subject connect your single patient barrier filter and mouthpiece to the Transducer, instruct the subject in the use of the noseclip and the test method. The subject will normally start with a period of quite breathing to establish the resting FRC level from which the subdivisions of Expiratory Reserve Volume (ERV) and Inspiratory Capacity (IC) will be related. The subject can follow the quite breathing with a full inspiration or Expiration in each case followed with the reverse procedure. When the subject is settled then connect the subject to the mouthpiece and commence the test, activate the button to view the recording on the screen. If the subject changes level or seems troubled then continue instruction at use the scissors to cut the trace back to the start of the screen so as to have the maximum tm of 60 seconds for the test procedure.

The scissors button refreshes the screen

.

Page 4 of 16

The Vital Capacity can be performed by starting with a deep inspiration (expiratory VC) or by starting with a deep expiration (inspiratory VC). Inspiratory VC Expiratory VC

Figure 1 Inspiration displays as an upward trace whilst expiration is a downward trace To terminate and record the test, click on



VC in volumetric cabin

When used with the volumetric cabin, the compression free VC maybe measured in addition this is the movement of air in and out of the cabin measured with a second pneumotachograph. This volume is free of the airways resistance and is produced by the thoracic cage movement. The test will be done with the door closed allowing the normal air flow measured at the lips to be superimposed with the vital capacity that is measured from the thoracic cage movement. The area under the two traces relates directly to the gas compression in the lung. The small icon situated under the test will indicate that the VC is a volumetric one (see figure 3).

Figure 2

Page 5 of 16

o Time Volume Curve This is the traditional Kymograph presentation of the volume curve against time. This screen of the computer presentation of the effort allows scaling and magnification of the effort.

Adjusts the scales

Figure 3 Volume-time display

Histogram display (On some versions)

* Where the histogram button does not exist, the feature can be viewed by constructing a report that can have one of more histogram displays to cover the parameters of interest.

Page 6 of 16



Adjusting the points of measurement shown with the cursor points in graphic below.

This function is activated with the right hand mouse button to activate EDIT when it is located on the Test # button above the table of results. This valuable tool allows the user to select the tidal volume minimum and maximum points to set the FRC level and then to adjust the Vital Capacity minimum and maximum values. This is demonstrated on the following screen Toggl e each of butto ns you wish to adjust and then place your curso r on the point you wish to meas ure the software will then recalculate the parameters based on your selection. The calculator button will restore the original setting. The Staircase button will level out a sloping trace when the slope is known to be the cause of an instrument drift and not a true physiological shift.

Page 7 of 16

o Display of the tests in the form of histograms The histogram display shown in Figure 4. Is obtained by designing this is to a report of your choice and using button to open the report module, it allows several variable from the test to be displayed in a bar graph format to see the reproducibility of the efforts.

(Note: Currently this is not available in network mode of operation)

Summary histogram Displayed on the right hand side of the screen represents the predicted values, alongside the best pre-test and the post selected test in the form of histogram. The histogram is the ERV at the bottom and then the components of IC with the TV as part of the IC. Against the Predicted Vital Capacity total. Shown in Figure 5

Figure 4

Figure 5 Page 8 of 16

o

Table displaying the results in numerical format

The table can be scrolled to see all the measured parameters of the tests, these are displayed in column format with the Predicted Values to the left of the screen and the measured efforts moving to the right. The best or selected test is denoted with a dot at the bottom of the column. The user can change the selection with the cursor to place the dot in the column of choice. The column formats for colour are selectable with a right hand mouse click on the top of the column. The parameter format is set by right clicking with the mouse in the predicted column in the parameter value. 

This is a « Pre-test » mode table

Best pre-test, or manually selected test

Figure 6 

This is a « Post-test » mode table Best pre-test, or manually selected test

Difference between Pre-Post

Figure 7

Page 9 of 16

 TV : VC : IRV : ERV : IC : EC : Ti : Ttot : Ti/Ttot : RF :

List of parameters and definition of abbreviations

Tidal Volume. Vital Capacity. Inspiratory Reserve Volume. Expiratory Reserve Volume. Inspiratory Capacity. Expiratory Capacity. Inspiratory cycle Time. Complete cycle Time. Ratio of the inspiratory Time over the total Time. Respiratory Frequency Or Breathing Frequency (BF)

The Vital capacity is a measure of the total breathing volume in a relaxed effort, it was historically referred to as the Slow Vital Capacity the word slow being dropped as it is a suggestion of the method of the test. This is not the case. The subject should fill and empty their lungs at their own pace but as a relaxed effort as opposed to the forced effort we discuss in a later chapter. Subjects with COPD do require significant time to perform the full effort and should be encouraged to ensure a full effort. The time of the full effort may come close to the current 60 seconds of data collection so it can be desirable with this type of subject to actually use the Cut button just before commencing the measurement in order to collect the full effort. Some schools of thought suggest collecting the measurement in two compartments to perform the inspiratory capacity in one effort and the expiratory reserve volume in a separate effort the Vital capacity being the total of the two. This approach may be necessary with some subject groups however it is dependant on the resting FRC level being the same for both measures for this to be correct or accurate. There is much controversy over the standard measurement of simple volumes, this comes from the original water bath volume displacement device where right or wrong it was assumed that the condition is 100% humidity with the temperature at room temperature for the BTPS condition adjustment. This changes with the complication of pneumotachograph devices where the correction adjustment must be set for the condition of both inspiratory and expiratory conditions. Slow moving air actually is more difficult to adjust for than fast moving air as the condition of the evolving gas can change within the breath.

Page 10 of 16

The addition of the computer and the ability to make changes to measurements as they occur has in many ways enhanced the measurement and the accuracy of the results obtained. Whilst the addition of the simple barrier filter adds new characteristics these include the fact that a capacitance can be developed between the filter membrane and the pneumotachograph mesh such that it causes a slow “bleed” of volume with a flow that is not zero causing over reading of the actual measured volumes, if this is thought to be a source of error, in the first instance use a fresh filer for each measurement. As with all measurements the patient’s co-operation is paramount to the success of the repeatability. 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 11 of 16

This develops the equations to; Using the concept of Expired Temperature (Expired T), Expired Humidity (Expired H), Ambient Temperature (Ambient T), Ambient Humidity (Ambient H) and Ambient Pressure (Ambient P) The Water Vapour Inspired (Wv insp) can be described as = (9.993 – (0.3952 x Ambient T) + ( 0.03775 x Ambient T) x Ambient T) x Ambient H / 100)

The Water Vapour Expired (Wv exp) can be described as = (9.993 – (0.3952 x Ambient T) + ( 0.03775 x Ambient T) x Ambient T) x Expired H / 100)

Thus developing the BTPS equations for a Pneumotachograph measuring at the lips to the following; Inspiratory BTPS = (310 /(273 + Ambient T)) x ((Ambient P – Wv insp) / (Ambient P - 47.1))

Expiratory BTPS = (310 /(273 + Ambient T)) x ((Ambient P – Wv exp) / (Ambient P - 47.1))

TABLE OF MEASURED PARAMETERS within the software NAME Tidal Vol. VC IRV ERV IC EC TI TTOT TI/TOT RF

UNIT L L L L L L Sec Sec % Cycles per min

DESCRIPTION Tidal Volume Vital Capacity Inspiratory Reserve Volume Expiratory Reserve Volume Inspiratory Capacity Expiratory Capacity Inspiratory Time Total Time Ratio of Inspiratory Time to total time Respiratory Frequency

Page 12 of 16

Short Form Instructions to Performing the Vital Capacity Testing. Select the VC option from the main tabs on the top of the screen. Instruct the subject in the method of the test; “We require you to sit upright in a comfortable condition with your feet flat on the floor, when I ask you I need you to place your mouth to the mouth piece and get comfortable. You will be able to breathe in and out with room air. When you are comfortable and relaxed I may place the nose clips onto your nose to make a seal, continue to breathe through your mouth. We will perform the test more than once, I would like you to breathe normally in a relaxed pattern until I instruct you to take a deep breath all the way in until you are completely full, then I want you to breathe all the way out until you are completely empty, before returning to normal breathing. I will instruct you through the whole manoeuvre” This will allow us to measure the EVC the expiratory Vital capacity measured from the TLC to the RV, not all subjects can perform this test well in both directions so it can be necessary to reverse the instructions and to measure from RV to TLC the instructions then reversing to; “We require you to sit upright in a comfortable condition with your feet flat on the floor, when I ask you I need you to place your mouth to the mouth piece and get comfortable. You will be able to breathe in and out with room air. When you are comfortable and relaxed I may place the nose clips onto your nose to make a seal, continue to breathe through your mouth. We will perform the test more than once, I would like you to breathe normally in a relaxed pattern until I instruct you to breathe all the way out as far as you can and then to take a deep breath all the way in until you are completely full, before returning to normal breathing. I will instruct you through the whole manoeuvre”

The test has the facility to be edited, on the basis that the subject was rested and relaxed breathing at a normal FRC level, then the EDIT function allows the user to change the points of measurement for the Tidal Volume and Vital Capacity minimum and maximum values. The changing of the Tidal Volume minimum value will influence the measure of the lung subdivisions in this effort is later imported to the FRC measurement.

Page 13 of 16

Therefore care and respiratory knowledge must be applied to any changes on these values.

Normal breathing at FRC Level

In un-rested or relaxed subject with an unstable FRC level, the mean of the tidal breaths is used

Relating the Vital Capacities and Lung Sub-Divisions The aim of the measurement is to obtain the recording in a rested position, however in some cases the subject can not produce a repeatable resting pattern, when this occurs it is normal to take the mean of the tidal breaths as the resting level for the definition of the ERV and IC components of the Vital capacity. This is shown in the figure above.

Page 14 of 16

This simple diagram shows the relationships of the different volumes and capacities of the lung. MEF 25 = FEF 75 MEF 50 = FEF 50 MEF 75 = FEF 25 MEF 25-75 The mean flow FEF 25-75 between 25% And 75% of the volume FEV1 Forced Expired Volume in 1 second TLC Total Lung Capacity FIVC Forced Inspiratory Vital Capacity PEF Peak Expiratory Flow PIF Peak Inspiratory Flow PIF50 Peak inspiratory flow at 50% of the volume TV Tidal Volume ERV Expiratory Reserve Volume IC Inspiratory Capacity RV Residual Volume VC Vital Capacity FRC Functional Residual Capacity

Page 15 of 16

Overlay of all data with a quality control test with a two-litre syringe included. Points to remember; 1. Select and deselect tests to overlay with the TEST X button, if depressed it displays if raised it is not displayed. 2. Right clicking on the TEST X button opens the EDIT function 3. The Kymo drum icon when depressed means the test device is the Spirometer, when raised it is the Pneumotachograph. 4. Use the Magnify glasses to expand or decrease the screen scales. 5. The syringe icon when depressed indicates that you wish to test without BTPS factors like in the case of testing with a syringe. 6. Remember the DOT at the bottom of the TEST X column is the selected test. If you want to override the TEST selected move the DOT to the column you wish to report. 7. When using the Pneumotachograph, if you experience a drift, first stop the test, remove the subject, press the ZERO button, wait a second or two and then re-start the TEST.

Page 16 of 16