How should metered dose inhalers (MDI) be administered and at what rate?

• A. Preferably with a spacer, ensuring lips seal around tube; 1 puff to 5 inhales and 5 exhales or at least 1 min; 2-4 puffs, up to 8 for severe cases
• B. Administer without spacer; 1 puff every breath; repeat every 30 seconds
• C. Use only with a nebulizer; no spacer; 4 puffs total
• D. Inhale rapidly for 1 puff and wait 2 minutes between puffs

Answer: (A)

Metered-dose inhalers reach the lungs best when you don’t rely on perfect coordination between pressing the canister and inhaling. A spacer serves as a reservoir that slows and broadens the plume, making it much easier for a child or a distressed patient to inhale the medication deeply into the airways. With the lips sealed around the spacer (or around the mouthpiece) to prevent leaks, shake the inhaler, exhale fully, then actuate once as the patient begins a slow, deep inhalation through the spacer. After each actuation, the patient should take several slow breaths (about five) to draw the medication into the lungs, and hold the breath briefly if possible to give the drug time to deposit. Between puffs, wait about a minute to let the spacer re-pressurize and to maximize delivery. Dosing commonly starts with two puffs and can be repeated as needed, typically 2–4 puffs per dosing opportunity, up to a total of eight puffs in more severe cases. This approach improves lung delivery and reduces throat irritation and symptoms from mis-timed inhalations. The other options fall short because they omit the spacer, encourage improper pacing or dosing, or rely on nebulization or rapid inhalation that isn’t as effective for MDI delivery.