How can a patient avoid the problem of terminating inhalation when a plume from a pressurized metered-dose inhaler (pMDI) impacts the oropharynx?

Question

Quizplus · Accepted Answer

A "cold Freon effect" can occur when the aerosol plume from a pMDI reaches the back of the mouth and the patient stops inhaling. This problem can be corrected by using a valved holding chamber connected to the pMDI. A valved holding chamber, which has a volume usually between 140 and 750 mL, enables the plume from a pMDI to expand. It incorporates a one-way valve that permits the aerosol to be drawn from the chamber during inhalation only, diverting the exhaled gas to the atmosphere and not disturbing the aerosol remaining in suspension in the chamber.

How Can a Patient Avoid the Problem of Terminating Inhalation