• Attach a fresh mouthpiece to the spirometer hose. Turn the spirometer on, choosing a chart speed of 5 mm/sec, and move the piston so the pen is at the center of the chart paper.
• The subject should put on the noseclip, place the mouthpiece attached to the hose in the mouth, and breathe in and out of the spirometer at a normal rate and depth.
• When the subject is used to the new situation, press the handswitch to start recording. The subject should breathe a few normal breaths, and then inspire maximally, exhale maximally, and then return to normal breathing for a few breaths. Press the handswitch to stop recording. This is the Vital Capacity Manoeuvre.

The figure below represents a sample tracing you might obtain in the lab. Determine values for VC and its subdivisions. Remember that you inspired first. Check your answer by clicking on the image.