NEVER INHALE on a spirometer without a filter. Just think of all the crusted debri in the sensor that is dried and may flake off upon a deep inspiration. I have been in this business 30 years and some practices are TOO CHEAP to use a filter that costs about a dollar. The patient might start coughing because of what they inhaled and not realize why.
![Felix "Unfair" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/Oswujxm2Ag0/mqdefault.jpg)
NEVER INHALE on a spirometer without a filter. Just think of all the crusted debri in the sensor that is dried and may flake off upon a deep inspiration. I have been in this business 30 years and some practices are TOO CHEAP to use a filter that costs about a dollar. The patient might start coughing because of what they inhaled and not realize why.