Chest Physical Therapy (CPT) is the practice of clapping children on the back to clear mucus out of the lungs.

  • FairView (a Minnesotan non-profit health site) recommends it for chest infections.

    Chest physical therapy (CPT) is a method for clearing mucus out of the lungs. Keeping the lungs clear helps your child breathe easier. CPT involves 3 main steps:

    • Putting your child in certain positions
    • Clapping on the body
    • Having your child cough
  • University of Michigan Health department recommends "Postural Drainage and Percussion" to help children with Cystic Fibrosis.

    Postural drainage and chest percussion (PD & P) is one of several airway clearance techniques that help clear mucus from your child's lungs.

This practice seems to be more or less spread depending on the country. For example, I have rarely heard of it in Italy or the USA, but it seems to be quite popular in France.

Mechanically it does not seem to make any sense to me: the density and viscosity of the mucus seems to be too large to allow for its displacement through percussion.

Are there studies supporting its use?

  • 1
    I am worried these are two different claims.
    – Oddthinking
    Oct 17, 2019 at 5:58

1 Answer 1


The claims that clapping (percussion of the chest) as an effective method to remove mucus:

  • in children with acute respiratory diseases and in adults with chronic obstructive pulmonary disease (bronchitis, emphysema) are not supported by quality evidence.
  • in individuals with cystic fibrosis are supported by consistent evidence.

Children with acute respiratory diseases

Airway clearance therapy in acute paediatric respiratory illness: A state-of-the-art review (South African Journal of Physiotherapy, 2019):

The use of any external percussion or vibration method is currently not supported by high-level scientific evidence.

Individuals with Chronic Obstructive Pulmonary Disease (COPD)

Airway clearance in COPD: need for a breath of fresh air? A systematic review. (COPD, 2011):

The evidence for passive techniques such as postural drainage and percussion is low.

Individuals with cystic fibrosis

Chest physiotherapy compared to no chest physiotherapy for cystic fibrosis (Cochrane, 2015) (a review of evidence):

One study (12 participants) reported increased radioactive tracer clearance associated with all interventions compared to control, although this was only reported to have reached significance for postural drainage with percussion and vibrations.

Pulmonary Function and Sputum Production in Patients With Cystic Fibrosis: A Pilot Study Comparing the PercussiveTech HF Device and Standard Chest Physiotherapy (Chest, 2004):

The PTHF [PercussiveTech HF] device appears to be a safe and effective method of airway clearance in CF patients in this small pilot study.

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