e) Cough: is an explosive expulsion of air from the lungs acting as a protective mechanism to clear the air passages. The following series of actions occur when a patient coughs; 1) deep inspiration occurs; 2) the glottis (laryngeal opening) and the vocal cords close tight; 3) abdominal muscles contract and the diaphragm elevates causing an increase in intrathoracic and intra-abdominal pressures; 4) the glottis and vocal cords open; 5) an explosive expiration of air occurs traveling at the speed of sound which clears out mucous and any debris in the airways.

Take a deep breath and blow it out as fast as you can. Is this an effective cough? No, because the glottis and vocal cords were not closed and then suddenly opened, and the expulsion of air was therefore not explosive enough to effectively clear secretions. Consider the problem in patients who have had a laryngectomy and tra-cheostomy as described above. Do you think patients who cough through a tracheostomy opening in their neck would have an effective cough and why? What would happen if they also have chronic bronchitis and have a large amount of airway mucus to clear? Answer: Since their cough is ineffective, they may require mechanical suctioning through the tracheostomy opening in their neck to prevent drowning in their own secretions.

Jerome Brown, Gregorio Flores and Calvin Dorsett (Video Script, pg 43) (slides 5, 11 and 12) had a laryngectomy (surgical removal of the larynx) because of a smoking related cancer (slide l). Gregorio Flores also had chronic bronchitis from smoking. Can you imagine how they felt having to breathe permanently through a hole in their neck (tracheostomy), unable to cough effectively and unable to speak except in a buzzing voice through an electronic device.

3. Demonstrations: Simulating the breathing pattern and shortness of breath in patients with emphysema. Understanding the sensation of shortness of breath.

Breathing consists of inhaling and exhaling for the purpose of taking up oxygen and giving off carbon dioxide. In patients with advanced emphysema, the act of inhaling and exhaling are both very labored.

Demonstration A: Have students attempt to forcefully breathe out through a very narrow straw (e.g., coffee stirrer) and then maximally inhale (not through the straw) repeating this cycle rapidly five or six times. Note how hard it is to breathe. During the inhalations feel your neck muscles contract just above the heads (central portions) of your clavicles. In this demonstration, airflow obstruction is greatest during exhalation because it's hard to exhale through a narrow straw. As a result, air becomes increasingly trapped in your lungs at the end of a normal breath. This makes inhalation increasingly hard as well and requires contraction of your neck muscles as you try to forcefully inhale (stack) air into already hyperinflated lungs. This exercise closely simulates the labored breathing pattern and shortness of breath experienced by patients with emphysema. (see slides 18, 19, p).