An effective cough is necessary to eliminate respiratory obstructions and keep the lungs clear. It is an important part of treatment of patients with acute or chronic respiratory conditions.

The Cough Mechanism
The following series of actions occur when a patient coughs:

• Deep inspiration occurs.
• Glottis closes and vocal cords tighten.
• Abdominal muscles contract and diaphragm elevates, causing an increase in intrathoracic and intro abdominal pressures.
• Glottis opens.
• Explosive expiration of air occurs.

The Normal Cough Pump

1. A cough may be reflective or voluntary.
2. In the normal individual, the cough pump is effective to the seventh generation of bronchi. (There are a total of 23 generations of bronchi in the tracheal bronchial tree.)
3. Ciliated epithelial cells are present up to the terminal bronchiole and raise secretions from the smaller to the larger airways in normal individuals.

Factors that decrease the effectiveness of the cough mechanism and cough pump
1. Decreased inspiratory capacity because of:
A. Pain:

1. Acute lung disease.
2. Rib fracture.
3. Trauma to the chest.
4. Recent thoracic or abdominal surgery.

B. Specific muscle weakness that affects the diaphragm or accessory muscles of inspiration:

• High spinal cord injury.
• Anterior horn cell disease (Guillain–Barre syndrome).

C. Depression of the respiratory center associated with genera anesthesia or pain medication.
Inability of the patient to forcibly expel air as the result of:

• Spinal cord injury above.
• Myopathic disease and weakness such as muscular dystrophy.
• Tracheostomy.
• Critical illness that causes excessive fatigue.
• Chest wall or abdominal incision.

2. Decreased action of the cilia in the bronchial tree secondary to:

• General anesthesia and intubations.
• COPD (chronic obstructive pulmonary disease) such as chronic bronchitis, which is associated with a decreased number of ciliated epithelial cells in the bronchi.
• Smoking.

3. Increase in the amount or thickness of mucus caused by:

• Cystic fibrosis.
• Chronic bronchitis.
• Pulmonary infections such as pneumonia.
• Dehydration.
• Intubations.

Teaching an Effective Cough
Because an effective cough is an integral aspect of airway clearance, a patient must be taught the significance of an effective cough, how to produce an efficient and controlled voluntary cough, and when to cough.

1. Evaluate the patient’s voluntary or reflexive cough.
2. Place the patient in a relaxed and comfortable position for deep breathing and coughing.
1. Sitting or leaning forward is usually the best position for coughing.
2. The patient’s neck should be slightly flexed to make coughing more comfortable.
3. Teach the patient controlled diaphragmatic breathing, emphasizing deep inspiration.
4. Demonstrate a sharp, deep, double cough.
5. Demonstrate the proper muscle action of coughing (contraction of the abdominal).
6. Have the patient place the hands on the abdomen and make three buffs with expiration to feel the contraction of the abdominal.
7. Have the patient practice making a K sound to experience tightening the coval cords, closing the glottis, and contracting the abdominal.
8. When the patient has put these actions together, instruct the patient to take a deep but relaxed inspiration, followed by a sharp double cough. The second cough during a single expiration is more productive.
9. Use an abdominal binder or Glossopharynegal breathing in selected patients with inspiratory or abdominal muscle weakness to enhance the cough, if necessary.
10. Precautions, Never allow the patient to suck air in by gasping, because it.
• Increases the work (energy expenditure) of breathing and the patient fatigues more easily.
• Tends to increase turbulence and resistance in the airways and may lead to increased bronchospasm (further construction of airways).
• May push mucus or a foreign object deep into air passages.