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Airway Clearance Techniques

What are airway clearance techniques?

Airway clearance techniques (ACTs) are ways to loosen thick, sticky mucus so it can be coughed up and cleared out of the lungs. If you have a lung disease such as cystic fibrosis or chronic obstructive pulmonary disease (COPD), you may have a lot of mucus in your lungs. If the mucus builds up in your airways, it can be hard to breathe. It also makes it easier to get infections.

There are many airway clearance techniques. Most are easy to do. Your healthcare provider can help you decide which are best for you. Your provider will help you learn how to do the techniques.

Techniques for loosening and coughing up mucus include:

  • deep coughing
  • huff coughing
  • postural drainage and percussion
  • autogenic drainage
  • active cycle of breathing therapy
  • positive expiratory pressure therapy
  • oscillating positive expiratory pressure
  • high-frequency chest wall oscillation (the vest)
  • physical exercise

ACTs are often used with other treatments, such as inhaled medicine.

  • If a bronchodilator has been prescribed for you, use it to open your airways before or with an airway clearance technique.
  • If you are using an inhaled antibiotic, use it after you have done an airway clearance technique. The medicine will work better if your airways are more open.

When you are trying to loosen and cough up mucus, make sure that you drink enough fluids so you stay well hydrated. If you are not getting enough fluids, your mucus will be stickier and harder to cough up. Ask your healthcare provider how much you should drink each day. Your provider may also recommend medicine, such as guaifenesin, to help keep mucus thin and easier to cough up.

Deep coughing

ACT coughing is a deep, controlled cough. Start by taking a deep breath. Hold the breath for 2 to 3 seconds. Then use your stomach muscles to push out the air with force. A deep cough is less tiring and more effective in clearing mucus out of the lungs than a "regular" cough.

Huff coughing

Huff coughs are used in many of the airway clearance techniques. To "huff," take a breath that is slightly deeper than normal. Use your stomach muscles to blow the air out in 3 breaths, making a "ha, ha, ha" sound. It is like "huffing" onto a mirror or window to steam it up. It is not as forceful as a cough but can work better and be less tiring. Follow a huff cough with controlled breathing and a deep cough if you feel mucus moving.

Postural drainage and percussion

Postural drainage and chest percussion are 2 techniques usually used together.

  • For postural drainage, you lie down in certain positions (postures) so that gravity can help mucus drain from different parts of the lungs.
  • With chest percussion (clapping) someone claps your chest to loosen and move mucus. They may also vibrate their hands on your chest to help move the mucus. This is done in different positions to drain all parts of your lungs.

This is also called chest physical therapy, CPT, or chest PT. Your provider can help you learn the techniques. Usually you need another person to help with the clapping. Some adults can do it alone with a mechanical percussor.

Autogenic drainage (AD)

Autogenic drainage means self-drainage. AD involves learning to breathe at different levels to move mucus out of the lungs. Learning to do it right takes some training and practice. It works best for people over 8 years old.

Get comfortable in a position that allows your diaphragm to work easily. The diaphragm is the large flat muscle between the lungs and the abdomen. It moves when you breathe in (inhale) and breathe out (exhale). Always breathe in through your nose and out through your mouth.

  1. To loosen mucus, take 1 deep breath, breathe out fully, and take several slow normal breaths. Try not to cough in this phase. If you do need to cough, do a huff cough.
  2. To move the mucus into the middle airways, take breaths that are just slightly deeper than normal and breathe out normally. Do this for 10 to 20 breaths. Try not to cough.
  3. Move the mucus out by breathing and huff coughing. Take 10 to 20 really deep breaths.

Active cycle of breathing therapy (ACBT)

Active cycle of breathing therapy (ACBT) combines 3 breathing methods to loosen and move mucus out of the lungs:

  1. Relaxed breathing (also called breathing control)
  2. Deep breaths, often with holding each breath for 3 seconds, followed by breathing out slowly and completely
  3. Huff coughs (usually 1 or 2)

You repeat this cycle for the time recommended by your healthcare provider or until you do not think you can cough up any more mucus. You may need some practice before you find what combination of breathing control, deep breaths, and huff coughs works best for you.

Positive expiratory pressure (PEP) therapy

Positive expiratory pressure (PEP) therapy uses a hand-held device that changes pressure in the lungs to loosen mucus. The PEP device has a one-way valve, a mouthpiece, and a way to set the resistance pressure.

To do PEP, sit up straight. Make a tight seal around the mouthpiece of the device with your lips. Take a deep breath and then breathe out slowly with moderate force for as long as you can. You will feel resistance when you breathe out. Breathing out through the device creates a pressure in your airways that helps open up small airways deep in the lungs.

Take 15 to 20 deep breaths through the PEP device. Then do 2 or 3 huff coughs. Repeat the breathing and huff coughing several times.

Oscillating positive expiratory pressure (oscillating PEP)

For this method you blow all the way out many times through a handheld device that vibrates the airways to loosen mucus. Some devices also change the pressure inside the lungs, which loosens mucus. After taking and holding a deep breath, you breathe out through the device. You repeat 10 or 12 breaths like this and then huff and cough. You will need to repeat the cycle of blowing out through the device and then huffing and coughing many times to clear out enough mucus.

High-frequency chest wall oscillation (the vest)

For this technique you wear an inflatable vest. The vest is attached to a machine that quickly inflates and deflates the vest, making it vibrate. The vest vibrates your chest to loosen mucus. Every 5 minutes you stop the machine and cough or huff.

Physical exercise

Physical exercise can be another good way to help bring up mucus in the lungs. Also, when you exercise regularly, your muscles are able to do more work on less oxygen.

Ask your healthcare provider what techniques or exercises will work best for you.

For more information, contact:

The National Heart, Lung, and Blood Institute
Web Site:

The Cystic Fibrosis Foundation
Web Site:

Developed by RelayHealth.
Published by RelayHealth.
Last modified: 2009-08-26
Last reviewed: 2009-08-07
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
2010 RelayHealth and/or its affiliates. All Rights Reserved.
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