Coughing is effective in maintaining a patent airway. Coughing permits the client to remove secretions from both the upper and lower airways. The series of events in cough mechanism are
1. Deep Inhalation:
This increases lung volume and airway diameter. Thus air can pass to partially obstructing mucus plugs or other foreign matter.
2. Closure of the Glottis.
3. Active contraction of the expirations muster:
When the expiratory muscles contract against the closed glottis, high intrathoracic pressure is developed.
4. Opening of Glottis:
With high intrathoracic pressure, glottis is opened and a large flow of air is expelled at a high speed providing momentum for mucus to move to the upper airway. After the cough mucus can be expectorated or swallowed.
The various coughing techniques include cascade, huff, quad coughing, and controlled coughing.
1. Cascade Cough:
Ask the client to take a slow deep breath and hold it for 2 seconds, while contracting expiratory muscles. Tell the client to open the mouth and perform a series of coughs throughout exhalation, thereby coughing at lowered lung volumes. This helps for airway clearance and maintains a patent airway in clients with large volumes of sputum.
2. Huff Cough.
In this the client on exhalation opens the glottis by saying the word “huff”. The huff cough stimulates a natural cough reflex. This method is useful for clearing central airway. Clients, who practice this regularly, inhale more air and may progress to cascade cough.
3. Quad Cough.
This is used for client without abdominal muscle control e.g. clients with spinal cord injuries. The client or nurse pushes inward and upward on the abdominal muscles to the diaphragm while the client breathes with maximal expiratory efforts, causing the cough.
4. Controlled Coughing.
Ask the client to take two slow, deep breaths, inhaling through nose and exhaling through mouth. Inhale deeply third time and hold breath to count of 3. Cough fully for two or three consecutive coughs without inhaling between cough. Tell the client to push all air out of lungs. Client should be cautioned to cough properly and not just clearing the throat. Instruct the client to cough 2 or 3 times every 3 hour during walking hours.
The effectiveness of cough is determined by the amount of sputum expectorated and the client’s report of swallowed sputum.
Clients with upper and lower respiratory tract infections and chronic pulmonary disease should practice coughing exercise every 2 hours while they are awake and clients with copious amount of sputum must cough hourly while awake and expectorate out sputum till the acute phase of sputum production is over.
AUTHOR : ASHA ARAVIND
Coughing Techniques – A Simple Nursing Guide