Types of Airway Clearance Techniques

Reviewed by: HU Medical Review Board | Last reviewed: May 2022

The thick, sticky mucus of cystic fibrosis (CF) clogs the airways, so it must be cleared using airway clearance techniques (ACT). The techniques used vary by age and are usually combined with other treatments such as bronchodilators and antibiotics for maximum benefit. The goal is to get the mucus moving so that it can be coughed up or swallowed. Ultimately, airway clearance techniques help the person with CF breathe easier and reduce the probability of lung infections.1

Most people with CF must perform ACTs daily, usually two to three times a day. Sessions last 20 minutes or longer.

Coughing and huffing

Huff coughing is the foundation of airway clearance techniques. It involves inhaling and then exhaling slowly and strongly. It is not as forceful as full-blown coughing but may work better and be less tiring. A cycle of four to five huff coughs are usually combined with other ACTs.

Coughing should be encouraged and never suppressed. Coughing and huffing help rid the lungs of mucus. People with CF should always cough or huff into a tissue that is then thrown away. Hands should be thoroughly washed after coughing/huffing.2

Postural drainage and percussion

Postural drainage and percussion is also known as chest physical therapy (chest PT). For this airway clearance technique, the person with CF gets into several different positions to help drain mucus from different areas of the lungs. Gravity then pulls the mucus from the smaller airways to the larger ones, where it is coughed out. Percussion involves clapping or vibrating the chest to shake the mucus loose. Clapping is done for three to five minutes. The person then huff coughs to get the mucus out. Each session lasts 20 to 40 minutes.2 It should be performed before eating or 1.5 to 2 hours after meals to decrease the chance of vomiting.

The vest

High-frequency chest wall oscillation is the full name for what most people call the vest or oscillator. Brand names are The Vest System, inCourage, Smart Vest, and AffloVest. This inflatable vest wraps around the chest and connects to a machine that vibrates at a high frequency. The vibrations loosen and thin the mucus. After 5 minutes of vibration, the person turns off the machine and huff coughs. Sessions generally last 20 to 30 minutes.2

Positive expiratory pressure therapy (PEP)

PEP stands for positive expiratory pressure therapy. With this technique, a mask or mouthpiece attaches to what is called a resistor. The person breathes in normally and breathes out against the resistance. This helps get air deeper into the lungs.

Another version of PEP is called oscillating positive expiratory pressure (oscillating PEP) or intrapulmonary percussion ventilation. This ACT requires the person to blow all the way out many times through a device that vibrates the air in the lungs, dislodging mucus. This is followed by huff coughing. Brand name for these devices are FlutterTM, AcapellaTM, RC-CornetTM and Aerobika®. PEP generally takes about 20 minutes to perform.2


Exercise helps loosen mucus in the lungs and causes coughing, which helps clear the lungs. It also strengthens breathing muscles and the heart.

Active cycle of breathing technique (ACBT)

Active cycle of breathing technique or ACBT includes a group of breathing techniques to help get air behind the mucus so that it can be cleared. ACBT techniques include:

  • Breathing control: Relaxed upper chest and shoulders
  • Chest expansion: Deep breathing causes chest expansion. Sometimes it is done while holding the breath for 3 seconds, and sometimes done with chest clapping or vibrating.
  • Forced expiration: Huffs for different lengths of time combined with breathing control.3

Autogenic drainage

Autogenic drainage means self-drainage. With this ACT, a three-step process helps move the mucus from the smaller to large airways. This technique requires training by a respiratory therapist, hard work and practice. It can take from 20 to 45 minutes. It is generally only used for ages 8 and up.4

Supporting drugs

Bronchodilators and mucolytics (mucus thinners) help thin the mucus so it is easier to move out. These drugs are used before or with airway clearance techniques to help open the airways. Inhaled antibiotics are taken after ACTs to treat the newly opened airways.2

Babies and toddlers

Parents must perform airway clearance techniques for infants and very young children. The ACT most commonly used for babies and toddlers includes postural drainage and percussion.5

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