There are several ways that you can correct for baseline drift in volume when using our spirometers. The best method depends on what software and sensor you are using.

If you have a Go Direct^® Spirometer (GDX-SPR) the easiest way to correct for baseline drift is to use the Adjusted Volume channel.

• In Graphical Analysis or Graphical Analysis Pro, click or tap Sensor Setup in the bottom right hand corner of the screen. Choose Sensor Channels and select the Adjusted Volume channel. Repeat data collection. Any baseline drift will return to zero after each ventilation cycle. Use the Adjusted Volume channel to perform your analysis.
• If you are using LabQuest App, tap on the Meter screen, choose Sensor Channels, and then select Adjusted Volume. Repeat data collection. Any baseline drift will return to zero after each ventilation cycle. 

If you are using the Spirometer (SPR-BTA) see the instructions below:

• If you are using Logger Pro you should use the baseline adjustment parameter that is available in the default Logger Pro file that launches when you use this sensor. This is located on page 2 of the Logger Pro File. It is also located on page 2 of the experiment files in Logger Pro associated with this sensor. Adjust the parameter to bring the baseline closer to zero.
• If you are using LabQuest App. From Graph screen, select Advanced from the Analyze menu, and choose Baseline Adjustment. Adjust the parameter to bring the baseline closer to zero. Please see the video below for detailed instructions on how to do this in LabQuest App. 
• If you are using Graphical Analysis or Graphical Analysis Pro, there is no good way to adjust for baseline drift with the Spirometer (SPR-BTA).

Please be aware that you can still get excellent data even if the baseline for volume has drifted. Tidal volumes can be calculated by just looking at the peak amplitude of each breath. Simply measure from trough to peak, or select each region from trough to peak for a single breath, and then select the statistics option in the software. This will give you the delta Y, which is the tidal volume.

You can also measure vital capacity directly by measuring the difference between the peak inhalation and peak exhalation. Select the entire region that corresponds to the maximal inhalation and maximal exhalation. Then select statistics to get the delta Y. This is vital capacity.

Please see experiment 7 in Human Physiology Experiments: Volume 2 for instructions on how to calculate lung volume parameters using this method.Spirometer (SPR-BTA)

Tips on using the Spirometer (SPR-BTA) with LabQuest