For optimal use of an MDI, what is the correct initial action?

The correct initial action for optimal use of a metered-dose inhaler (MDI) is to exhale to functional residual capacity or residual volume. This step is crucial because it helps to prepare the lungs for the subsequent inhalation of the medication. By exhaling completely, the airway can be more open and ready to receive the medication most effectively. This action decreases the amount of air already in the lungs, allowing the inhaler to deliver a greater concentration of medication to the lungs where it is needed.

Inhalation should be performed softly and steadily after this initial exhalation, which helps ensure the medication reaches the deeper parts of the lungs. This preparatory step is essential for maximizing drug delivery and minimizing side effects.

The other options present steps that do not address this initial preparatory phase as effectively. Inhaling deeply before actuating, for instance, may not ensure that the drug is delivered optimally, especially if the inhaler's actuation is not timed well with the inhalation. Waiting for a couple of seconds after actuating is important for proper drug deposition but is not the initial action to take. Holding the breath before inhalation is also beneficial, but it is more relevant to the act of inhalation itself rather than preparing the lungs