The patient can inhale through the unidirectional tube.
House returns and give the diagnosis is that the patient accidentally and unknowingly inhaled a tiny piece of food.
Leafy branches were often placed over a fire while the patient squatted on top and inhaled the steam.
This is an electric air compressor with a mouthpiece through which a patient inhales vaporized asthma medication.
In other tests, doctors sometimes have patients inhale an allergen or eat a particular food in an attempt to provoke a reaction.
In other tests, a patient either inhales or swallows a suspected allergen to provoke a reaction.
If the throat or larynx is affected, there may be a high-pitched musical sound (stridor) when the patient inhales.
There have been problems with the oxygen concentrators not being able to detect when the sleeping patient is inhaling.
But since patients are inhaling the steroids rather than swallowing them in a liquid it's much less likely.
Some spacers are equipped with a whistle, which sounds as a warning when the patient is inhaling too quickly.