ABSTRACT

Factors that restrict normal breathing and gas exchange are medically important and have a variety of causes, ranging from heart failure to allergy, infection, cancer, emphysema, and hereditary disease. When patients complain to their physicians that they are “out of breath,” the first step in finding out why and how to cure or mitigate this condition is to quantitatively measure the mechanical parameters of the respiratory system by

spirometry

and to compare them with those of “normal” persons of similar sex, age, body mass and height, etc. Deviations from the norm in these tests are only the first step in complete diagnosis, which can also involve CAT scans, MRI, blood-gas tests, etc.