Which instruction is most important to teach a patient using an aerosol inhaler with a spacer?

Question

Quizplus · Accepted Answer

As outlined in Box 21-1,it is important for the patient using an aerosol inhaler with a spacer to seal his or her lips tightly around the spacer's mouthpiece.Dose should be placed into the spacer and then inhaled one at a time.The drug works best when it is inhaled slowly and deeply.Breathing back into the spacer does no harm.

Which Instruction Is Most Important to Teach a Patient Using