There are two ways to easy ways to
display the Tidal Volume in LabChart.
The first utilises the Spirometry extension which
is available for both the Windows and Macintosh versions of LabChart (the most
recent version can be obtained from software downloads on our website). You
first need to state in the spirometry settings which channel is displaying the Spirometry Flow and which will be the Spirometry Volume. Then there are extra
options available in the Channel drop down (small white triangle next to Channel Name):
Select the ‘Tidal Volume’... option and modify the
settings to suit your requirements. This
channel will then display the Tidal Volume for both recorded and incoming data.
If you do not wish to utilise the extension, then
the channels can be set up manually:
In the first channel you can record the raw data
from the spirometer. This will be your
Spirometry Flow. (Details of how to calibrate the flow head can be found in
the spirometer users guide.) To determine Spirometry Volume, in a second
channel you will need to integrate the flow signal using the ‘integrate...’
option in the channel drop down menu.
NB depending on your preference you may wish to add
a reset eg. Reset each cycle here. This
prevents any drift in the volume signal that could be caused by uneven
inspiration/expiration ratios, however will have no bearing on your Tidal
Volume calculation.
Finally in a further channel you can
determine the Tidal Volume by calculating the height of each Volume cycle using
cyclic measurements. Choose Cyclic Measurements from the channel drop down
menu, check the source channel is set to the spirometry flow data, the measurement
is set to ‘Height’ and if necessary change the preset detection to respiratory
flow. Click OK and the Tidal Volume will be displayed in the channel.