For pulmonary function testing here at Greene Memorial, we use what's called a Body Plethysmograph. It consists of a plexiglas chamber (right) connected to a computer (left). For most of the test, the patient sits in the open chamber. However, there are some parts of the test where the door is closed. The plexiglas front of the chamber allows the patient to feel less closed in, making the procedure much more tolerable.