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Respiratory Health

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Hill-Rom® Respiratory Care

Glossary of Terms

Active Cycle of Breathing Technique (ACBT)

Active Cycle Breathing Technique (ACBT) involves a group techniques which use breathing exercises. It can be changed to meet each person’s needs. The purpose of this technique is to improve the effectiveness of cough, lower airway spasms and to loosen and clear retained secretions.1

ACBT steps include:

  • Breathing control – normal, gentle breathing with the lower chest while relaxing the upper chest and shoulders.
  • Thoracic expansion exercises – deep breaths in.
  • Some use a three-second breath-hold to get more air behind the mucus. This may be done with chest clapping or vibrating, followed by breathing control.
  • Forced expiration technique - huffs of varied lengths with breathing control.

Amyotrophic Lateral Sclerosis (ALS)

ALS is a nervous system disease that weakens muscles with the body. The ability to clear respiratory secretions may be affected by respiratory muscle weakness. When the respiratory muscles are weakened, the lungs may not be able to clear secretions which can contribute to infection.15

Assisted Cough Technique

If the patient has a weak cough and you have mucus building in your lungs, they may benefit from coughing forcefully with an assisted cough. In an assisted cough, another person pushes on the chest to help the patient cough. This should be done while they are sitting up in a bed or chair.2

  1. The caregiver places the heel of one hand on the patients abdomen just above the navel and places the other hand on top of the first hand. He or she interlocks the fingers so that they are pulled away from the body.
  2. The caregiver keeps his or her elbows straight.
  3. The patient takes a deep breath and holds it.
  4. The patient coughs while the caregiver pushes upward and under the rib cage, one time. It may take practice to coordinate the cough with the motion.


Atelectasis is a complete or partial collapse of a lung or lobe of a lung. This is a serious condition that reduces the amount of oxygen available to your body.

There are two types of atelectasis; obstructive and nonobstructive. Obstructive atelectasis is caused by a blockage in the lungs. Non-obstructive atelectasis may be caused be injury, fluid, or a tumor.16

Autogenic Drainage (AD)

Autogenic drainage means “self-drainage.” It uses varied airflows with controlled breathing to move mucus. You can do this alone in a sitting position. There are three phases to autogenic drainage.8

  1. Dislodging mucus
    1. Completely exhale and then inhale varying small to normal breaths.
    2. Hold each breath for 1-3 seconds, then exhale completely again.
    3. Repeat this step 1-3 minutes or until crackles are heard when breathing out. 
  2. Collecting mucus
    1. Take in a slightly larger breath.
    2. Hold for 1-3 seconds and then exhale.
    3. Repeat this step for 1-3 minutes or until crackles are heard when breathing out.
  3. Clearing mucus
    1. Take in a slow deep breath.
    2. Hold breath for 1-3 seconds.
    3. Exhale forcefully with open throat or glottis to move the mucus into your mouth.
    4. Remove mucus from mouth into a container or tissue.

Breath Stacking

Breath stacking or stacked breathing is a technique meant to expand lung capacity and foster a productive cough. The goal is to expand the lower lobes of your lungs with air to strengthen both the tissue and the chest wall.4

  1. Sit on the edge of the bed or chair in an upright position.
  2. Take in a small breath, and hold this breath for one second. Concentrate on filling the bases of the lungs. Do NOT exhale!
  3. Take in a larger breath on top of the smaller breath, and then hold for one second. Do NOT exhale!
  4. Take in an even larger breath that will completely fill your lungs.
  5. Now hold your breath for three to ten seconds.
  6. Slowly exhale through pursed lips.
  7. Repeat this exercise two to four times per day.


Bronchiectasis is the result of an infection or other condition that injures the walls of your airways or prevents the airways from clearing mucus. When mucus can't be cleared, it builds up and creates an environment in which bacteria can grow. This may lead to repeated, serious lung infections which cause more damage to the airways of the lungs. With each infection, the airways may lose their ability to move air in and out. This can prevent enough oxygen from reaching your vital organs.18

Cerebral Palsy

Cerebral Palsy can affect the respiratory system by weakening the respiratory muscles and limiting the ability to take a deep breath, cough effectively, or to clear secretions. When the respiratory muscles are weakened, the lungs may not be able to clear secretions which can contribute to infection. With each infection, the lungs may lose their ability to move air in and out. This can prevent enough oxygen from reaching the vital organs.21

Chest Physical Therapy (CPT or Chest PT)

Chest Physical Therapy (CPT) often includes postural drainage and chest percussion. With postural drainage, the person is in varied positions (postures) that drain mucus from different lung parts. Gravity pulls mucus from small to large airways where it can be coughed up. With chest percussion the chest is clapped and vibrated to dislodge and move mucus. This is done in varied positions to drain all lung parts.5

Chronic Bronchitis

Chronic Bronchitis is a cough that occurs every day with sputum production that lasts for at least 3 months a year for at least two years in a row.

Chronic Obstructive Pulmonary Disease (COPD)

As chronic obstructive pulmonary disease (COPD) progresses the symptoms usually worsen and the lungs produce large amounts of mucus due to chronic bronchitis. There is a risk of infection if the mucus is allowed to collect in the airways.17


Coughing is the body’s way of removing foreign material or mucus from the lungs. It clears the upper airway passages with high-speed airflow.8

Cystic Fibrosis

People with Cystic Fibrosis have thick, sticky mucus that builds up in their airways. This buildup of mucus makes it easier for bacteria to grow and cause infections which may create more damage to the airways of the lungs. With each infection, the airways may lose their ability to move air in and out. This can prevent enough oxygen from reaching the vital organs.19

High Frequency Chest Wall Oscillation (HFCWO)

A HFCWO system consists of an inflatable garment attached to an Air Pulse Generator that rapidly inflates and deflates the inflatable garment. This causes the chest wall to be gently compressed and released which creates airflow within the lungs. This process moves mucus from the small airways toward the large airways where it can be cleared by coughing or suctioning.6


Huffing is a type of cough often referred to as huff cough. It is used when standard cough isn’t enough to clear mucus from the lungs. A huff cough is a gentle cough, like making a “huffing” sound onto a mirror or window to steam it up. It also involves taking a breath in and actively exhaling. Since it is not a harsh or forceful cough it can be less tiring.9

  • Begin in a sitting position with your chin slightly upward.
  • Use your diaphragm (stomach muscle) to breathe in slowly.
  • Hold the breath for 2-3 seconds.
  • Force the breath out of your mouth in one quick burst of air.
  • Make sure the back of your throat is kept open.

Intrapulmonary Percussive Ventilation (IPV)

Intrapulmonary percussive ventilation is a form of chest physical therapy administered to the airways by a pneumatic device. The device utilizes high-frequency oscillatory ventilation to create short bursts of air and inject them into the airway. By delivering these bursts of air, the mucus in the small airways of the lungs is broken down and the lungs can move it to the large airways. Once the mucus is in the large airways, it can be coughed out or suctioned to keep the airway passages clear.

This therapy is generally intended to treat people suffering from pulmonary disease as well as other conditions that make it difficult to breathe.7

Lung Volume Recruitment (LVR)

Lung Volume Recruitment (LVR) therapy is designed to stretch the lungs and chest wall to increase chest compliance and reduce airway resistance to airflow. The desired outcome is to improve lung volumes, higher peak cough flows, and improved airway clearance.11

Mechanical Insufflation-Exsufflation (MI-E)

MI-E therapy is the most common airway clearance treatment for people with neuromuscular conditions and diseases. This is due to the weak cough they develop over time because as their muscles weaken they are not able to effectively move air out of their lungs. An effective cough is necessary to remove retained secretions. Retained pulmonary secretions may lead to airway obstruction, increased work of breathing, and infection.

MI-E therapy creates an effective cough for the patient to remove retained secretions. The therapy provides a big breath of positive airflow into the lungs, then quickly switches to negative airflow to pull the air out of the large airways of the lungs. When the air is pulled from the large airways it also brings the secretions with it.3

Muscular Dystrophy

People with muscular dystrophy have progressive muscle weakness and this can affect the muscles associated with breathing. Eventually the use of a breathing assistance device (ventilator) is needed, initially at night but possibly also in the day. There may also be issues with clearing secretions or mucus. The buildup of mucus makes it easier for bacteria to grow and cause infections which creates damage to the lungs. With each infection, the lungs may lose their ability to move air in and out. This can prevent enough oxygen from reaching the vital organs.20

Oscillating Positive Expiratory Pressure (Oscillating PEP)

An Oscillating PEP device delivers the same therapy of a PEP device with the added bonus of vibrations. The vibrations are meant to shake the mucus loose so the patient’s lungs can clear it with coughing.10

Physical Exercise

Exercise can be another good way to help clear mucus from your lungs. Also, when you exercise regularly, your muscles are able to do more work with less oxygen.8

Positive Expiratory Pressure (PEP) Therapy

PEP therapy is delivered by a hand held device with either a facemask or mouthpiece. The device allows air to easily flow into the lungs but creates resistance when the patient exhales. The resistance helps air move behind the mucus and holds the airways open so the patient’s lungs can clear the mucus with coughing.10

Post Lung Transplant

Respiratory complications affect every lung transplant recipient to at least some degree. Respiratory infections and progressive lung damage are the most frequent cause of unfavorable outcomes. Such complications disrupt the pulmonary defense system, impairing clearance of airway secretions.12

Postural Drainage & Percussion (PD&P)

The Postural Draining & Percussion (PD&P) therapy requires the person to get into a variety of positions (postures) that drain mucus from different areas of the lungs. Gravity pulls mucus from small airways to the large airways where they can be coughed up.5

Primary Ciliary Dyskinesia

Primary Ciliary Dyskinesia causes the cilia to malfunction. When the cilia do not move mucus out of the respiratory tract, the lungs and airways may become very inflamed and become perfect breeding ground for bacteria as the mucus sits. The build-up of mucus can cause bronchiectasis, pneumonia, and permanent lung damage.22

Spinal Injury / Quadriplegia

People with cervical and thoracic spinal cord injuries may experience difficulty breathing or coughing. Coughing is the main mechanism for clearing the airways. When patients have difficulty taking a deep breath and coughing, secretions may build in the lower airways which may cause infections, obstructions, and respiratory failure.13

Spinal Muscular Atrophy (SMA)

SMA is a disease that affects the motor nerve cells in the spinal cord and leads to debilitating and often fatal muscle weakness. There are four classifications SMA, type I, II, III, and IV which are based on age of onset and highest attained milestone of motor development. As the disease progresses and the muscles weaken, the respiratory system is compromised. Respiratory infection and pneumonia are a constant risk so airway clearance of retained secretions is important. Non-invasive ventilation is frequently used to prolong survival.14

Disclaimer: Information on this site should not be used as a substitute for talking with your physician. 

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  2. Spinal Cord Injury: Assisted Cough Topic Overview (2014, February 1). Retrieved August 20, 2015, from
  3. J R Bach. Chest. Mechanical Insufflation-Exsufflation. Comparison of peak expiratory flows with manually assisted and unassisted coughing techniques. 1993;104(5):1553-1562
  4. Stacked Breathing Exercises. (2015, July 14). Retrieved August 20, 2015, from
  5. Chest Physiotherapy Therapy. (n.d.). Retrieved August 20, 2015, from
  6. The Vest® Airway Clearance System Mode 105 User manual (145330 REV 8)
  7. Critical Care Therapy and Respiratory Care Section. (n.d.). Retrieved August 20, 2015
  8. Fink, J. Forced Expiratory Technique, Directed Cough, and Autogenic Drainage. Respir Care 2007;52(9):1210 –1221
  9. Huff Cough Technique. (n.d.). Retrieved August 20, 2015, from
  10. Beyond Manual Chest Physiotherapy. (n.d.). Retrieved August 20, 2015, from
  11. Lung Volume Recruitment Policy. (n.d.). Retrieved August 20, 2015, from
  12. Santacruz, J; Meta, A; "Airway Complications and Management after Lung Transplantation", Proceedings of the American Thoracic Society, Vol. 6, No. 1 (2009), pp. 79-93.
  13. Spinal Cord Injury (n.d.). Retrieved August 20, 2015 from
  14. SMA Respiratory Muscle Weakness. (n.d.). Retrieved August 20, 2015, from
  15. ALS Breathing Difficulties. (n.d.). Retrieved August 20, 2015, from
  16. Atelectasis. (2015, June 15). Retrieved August 20, 2015, from
  17. What are the signs and symptoms of COPD. (2013, July 31). Retrieved August 20, 2015, from
  18. What are the signs and symptoms of Bronchiectasis. (2014, June 2). Retrieved August 20, 2015, from
  19. What are the signs and symptoms of Cystic Fibrosis. (2013, December 26). Retrieved August 20, 2015, from
  20. Muscular Dystrophy. (2014, November 27). Retrieved August 20, 2015, from
  21. Respiratory Health. (n.d.). Retrieved August 20, 2015, from
  22. Primary Ciliary Dyskinesia. (n.d.). Retrieved August 20, 2015, from
  23. Airway Clearance in Duchenne Muscular Dystrophy. (n.d.). Retrieved August 20, 2015, from