Incentive spirometers are handheld devices used to promote lung recovery after illness, infection, or surgery. This is a very basic device , which operates via a piston system. Essentially, when the user breathes in, pistons on the inside of the tube will rise, actively measuring the amount of air taken in by the lungs.
A spirometry exam will be given before you are diagnosed with asthma to determine if asthma is really the problem. Sometimes, breathing problems can be attributed to allergies or other ailments.