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Cystic Fibrosis: Helping Your Child Cough Up Mucus

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Cystic fibrosis causes mucus to become thick and sticky, which can clog the lungs and cause serious problems. You can help your child maintain lung function and avoid complications from mucus buildup and blockage by performing an airway clearance technique (ACT). Postural drainage and chest percussion (PD & P) is one of several airway clearance techniques that help clear mucus from your child's lungs.

Key points:

  • To help keep the lungs clear, it is important to do an airway clearance technique (such as postural drainage and chest percussion) every day. PD & P works well when used regularly.
  • These techniques are one part of a larger treatment plan for cystic fibrosis.
  • You may not notice an improvement in your child's lung function right away. But studies show that stopping these treatments will cause decreased lung function after 3 weeks in older children who have mild to moderate lung problems.1

It is important for your child to visit his or her doctor regularly and make any needed changes in treatment.

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Cystic fibrosis causes abnormally thick and sticky mucus, which can collect in the lungs and other organs. Normally, mucus in the body is thin and fluid. The function of mucus is to lubricate organ passages and help remove bacteria. In people who have cystic fibrosis, the mucus is so thick that it gets stuck in the lungs and airways. This makes it hard to breathe and easy to get infections.

Infections in the respiratory system and lungs cause coughing, wheezing, and breathing problems. Chronic respiratory infections, including pneumonia and bronchitis, can develop. Serious lung problems can eventually lead to disability or death.

Test Your Knowledge

Too much mucus in the lungs can cause:

Difficulty breathing.
Lung infections.

Postural drainage helps drain mucus from the lungs. This can:

  • Help prevent infections. If you have fewer infections, you will likely have fewer lung problems.
  • Open airways, which can lead to better breathing.
  • Improve your child's quality of life.
  • Reduce your child's risk of having more serious problems.

Test Your Knowledge

Postural drainage helps prevent mucus from forming in the lungs.


There are several postural drainage positions. The different positions help drain mucus from different sections of the lungs. All people who have cystic fibrosis should do all the positions except babies, who should not be placed in the head-down position ("tipping"). Tipping a baby can cause reflux, which is when the contents of the stomach enter the esophagus.

Talk to your doctor or your respiratory therapist before starting PD & P. He or she can show you how the treatment is done and tell you how often and how long the treatment should be. Most doctors recommend that PD & P be done at least once a day.

PD & P is a time-consuming process. It usually takes 20 to 30 minutes. In general, a baby or small child who has no symptoms of congestion may require less treatment time than an older child who sounds congested and is coughing a lot.

At first, PD & P can seem complicated. But with help and practice, the treatment becomes easier, especially when you notice the benefits to your child. It is important to do these exercises exactly as instructed.

  • Before you start, gather the materials you need, such as tissues, pillows, a thin cloth, or towels. If you have a baby or small child, you may sit in a chair with the child in your lap. If your child is older, he or she may be in bed using pillows for the different positions. You may need to experiment to find the best place to do the treatment so that both you and your child are comfortable.
  • Position your child. Your doctor or therapist will recommend certain positions to use. For example:
  • Clap your child's back or chest with your cupped hand quickly and rhythmically. This loosens the mucus, allowing it to drain. Do not clap directly on the skin—cover the area with thin clothing or a cloth. Bend your hand at the wrist and form a cupClick here to see an illustration.. When you clap, you should hear a hollow "popping" sound. If you hear a slapping sound, your hand is not cupped enough. You may safely clap over the ribs, but do not clap below the lower ribs or over the spine or female breasts. Follow this procedure for each position.
  • How much force to use while clapping, and how long you clap, depends on the child. Consider the following:
    • Younger and smaller children require less force and time than older and larger children or teens.
    • Watch the child for signs of pain and discomfort. If you notice this, you may be using too much force.
    • Is your child congested but mucus isn't coming up? If so, you may need to use more force.
  • After clapping, apply vibrations. At the end of each position, you can vibrate the chest area to help loosen and move mucus. Have your child take a big breath and blow it out forcefully. As the child is blowing out, place your hand over the chest area and apply a little bit of pressure. Then quickly contract and relax your arm and shoulder muscles to produce vibrations throughout the chest area. To get the most out of this technique, ask your doctor or respiratory therapist to teach you how to do it properly. When your child is old enough, having his or her cooperation will make it easier to do this technique.
  • After vibrations, have your child huff and cough. A huff is a forced exhalation that moves mucus higher and makes it possible to cough up more mucus. Huffing is best learned through demonstration, so ask your doctor or respiratory therapist to show you and your child how to do it. Huffing involves taking a deep breath and then breathing out forcefully, saying "huff." Your child will do this 2 to 3 times before he or she coughs. If huffing is done well, you can actually hear the mucus moving upwards.

Test Your Knowledge

In postural drainage, you slap the chest with an open hand.


Each person has different needs, so talk with your doctor about the specific postures and procedures to use for your child.


  1. Boat TF, Acton JD (2007). Cystic fibrosis. In RM Kliegman et al., eds., Nelson Textbook of Pediatrics, 18th ed., pp. 1803–1817. Philadelphia: Saunders Elsevier.

ByHealthwise Staff
Primary Medical ReviewerJohn Pope, MD - Pediatrics
Specialist Medical ReviewerCatherine O'Malley, RRT - Respiratory Therapy
Last RevisedJune 9, 2011

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