MDI Medical Abbreviation: Meaning in Respiratory Care

What MDI Means in Medicine

MDI stands for Metered-Dose Inhaler.

An MDI contains medication in a pressurized canister. When the inhaler is activated, it releases a measured dose as an aerosol that the patient breathes into the lungs.

MDIs are commonly used in respiratory care because they are portable, quick to use, and designed to deliver a consistent amount of medication with each puff.

What Conditions Are MDIs Used For?

MDIs are commonly used to deliver inhaled treatment for respiratory conditions.

They may be prescribed for conditions such as:

• Asthma
• Chronic obstructive pulmonary disease (COPD)
• Bronchospasm
• Other conditions involving narrowed or inflamed airways

The medication inside the inhaler may be intended for quick symptom relief or longer-term control, depending on the prescription.

How Is an MDI Used?

Correct technique is important because the medication must reach the lungs effectively.

General steps may include:

1. Shake the inhaler if instructed.
2. Breathe out fully before using it.
3. Place the mouthpiece in the mouth and seal the lips around it.
4. Begin breathing in slowly while pressing the canister.
5. Continue taking a slow, deep breath.
6. Hold the breath briefly after inhaling.
7. Wait before taking another puff if another dose is prescribed.

Specific instructions may vary by device, so patients should follow the directions provided with their inhaler.

Why MDI Technique Matters

Using an MDI incorrectly can reduce how much medication reaches the lungs.

A systematic review and meta-analysis found that inhaler technique errors were common among people using MDIs. Frequent problems included not fully exhaling before use, incorrect inhalation, and failing to hold the breath afterward.

This is why healthcare professionals may check inhaler technique during follow-up visits instead of assuming the device is being used correctly.

What Is an MDI Spacer?

A spacer is an attachment that can be used with some MDIs.

It holds the aerosol briefly after the inhaler is activated, giving the patient more time to breathe the medication in. This can make coordination between pressing the inhaler and inhaling easier.

Spacers are particularly useful when a patient has difficulty coordinating the inhaler correctly.

MDI vs Other Respiratory Terms

MDI is related to several respiratory care terms, but each one describes something different.

• MDI (Metered-Dose Inhaler): Delivers a measured aerosol dose from a pressurized inhaler.
• DPI (Dry Powder Inhaler): Delivers medication as a dry powder that is inhaled using the patient’s breath.
• Nebulizer: Turns liquid medication into a mist that is inhaled over several minutes.
• PEF (Peak Expiratory Flow): Measures how quickly air can be blown out of the lungs.
• FVC (Forced Vital Capacity): Measures how much air can be forcefully exhaled after a deep breath.
• NIF (Negative Inspiratory Force): Measures the strength of the muscles used to breathe in.

MDI, DPI, and nebulizers are medication-delivery devices. PEF, FVC, and NIF are measurements used to assess respiratory function.