How to clear airway secreations in lungs; airway clearing techniques

 


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

The Normal Cough Pump

A cough may be reflexive or voluntary. When a person coughs, a series of actions occurs (Box 25.7).47 Under normal conditions, the cough pump is effective to the seventh generation of bronchi. (There are a total of 23 generations of bronchi in the tracheobronchial tree.) Ciliated epithelial cells are present up to the terminal bronchiole and raise secretions from the smaller to the larger airways in the absence of pathology.

Factors that Decrease the Effectiveness of the Cough Mechanism and Cough Pump

The effectiveness of the cough mechanism can be compromised for a number of reasons including the following

Decreased inspiratory capacity

 Inspiratory capacity can be reduced because of pain due to acute lung disease, rib fracture, trauma to the chest, or recent thoracic or abdominal surgery. Weakness of the diaphragm or accessory muscles of inspiration as a result of a high spinal cord injury or neuropathic or myopathic disease decrease a patient’s ability to take in a deep breath. Postoperatively, the respiratory center may be depressed as the result of general anesthesia, pain, or medication.

Inability to forcibly expel air

 A spinal cord injury above T12 and myopathic disease, such as muscular dystrophy, cause weakness of the abdominal muscles, which are vital for a strong cough. Excessive fatigue as the result of critical illness and a chest wall or abdominal incision causing pain all contribute to a weak cough. A patient who has had a tracheostomy also has difficulty producing a strong cough, even when the tracheostomy site is covered.

Decreased action of the cilia in the bronchial tree.

Action of the ciliated cells may be compromised because of physical interventions such as general anesthesia and intubation or pathologies such as COPD including chronic bronchitis, which is associated with a decreased number of ciliated epithelial cells in the airway. Smoking also depresses the action of the cilia.

Increase in the amount or thickness of mucus

 Pathologies (e.g., cystic fibrosis, chronic bronchitis) and pulmonary infections (e.g., pneumonia) are associated with an increase in mucus production and the thickness of the mucus. Intubation irriates the lumen of the airways and causes increased mucus production, whereas dehydration thickens mucus

Teaching an Effective Cough

Because an effective cough is an integral component of airway clearance, a patient must be taught the importance of an effective cough, how to produce an efficient and controlled voluntary cough, and when to cough. The following sequence and procedures are used when teaching an effective

cough.

1. Assess the patient’s voluntary or reflexive cough.

2. Have the patient assume a relaxed, comfortable position for deep breathing and coughing. Sitting or leaning forward usually is the best position for coughing. The patient’s neck should be slightly flexed to make coughing more comfortable.

3. Teach the patient controlled diaphragmatic breathing, emphasizing deep inspirations.

4. Demonstrate a sharp, deep, double cough.

5. Demonstrate the proper muscle action of coughing (contraction of the abdominals). Have the patient place the hands on the abdomen and make three huffs with expiration to feel the contraction of the abdominals . Have the patient practice making a “K” sound to experience tightening the vocal cords, closing the glottis, and contracting the abdominals.

6. When the patient has put these actions together, instruct the patient to take a deep but relaxed inspiration, fol- lowed by a sharp double cough. The second cough during a single expiration is usually more productive.

7. Use an abdominal binder or glossopharyngeal breathing in selected patients with inspiratory or abdominal muscle weakness to enhance the cough, if necessary.

Additional Techniques to Facilitate a Cough and Improve Airway Clearance

To maximize airway clearance, several techniques can be used to stimulate a stronger cough, make coughing more comfortable or improve the clearance of secretions.

Manual-Assisted Cough

If a patient has abdominal weakness (e.g., as the result of a mid-thoracic or cervical spinal cord injury), manual pressure on the abdominal area assists in developing greater intra-abdominal pressure for a more forceful cough. Manual pressure for cough assistance can be applied by the therapist or the patient.

Therapist-Assisted Techniques

With the patient in a supine or semireclining position, the therapist places the heel of one hand on the patient’s abdomen at the epigastric area just distal to the xiphoid process. The other hand is placed on top of the first, keeping the fingers open or interlocking them . After the patient inhales as deeply as possible, the therapist manually assists the patient as he or she attempts to cough. The abdomen is compressed with an inward and upward force, which pushes the diaphragm upward to cause a more forceful and effective cough. This same maneuver can be performed with the patient in a chair . The therapist or family member can stand in back of the patient and apply manual pressure during expiration.

Self-Assisted Technique

While in a sitting position, the patient crosses the arms across the abdomen or places the interlocked hands below the xiphoid process . After a deep inspiration, the patient pushes inward and upward on the abdomen with the wrists or forearms and simultaneously leans forward while attempting to cough.

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