Name_______________________ #_______
CT : A&P2
Respiratory System Case Study:
Pneumothorax
Go to:
http://www.mhhe.com/biosci/ap/saladin/student/olc/chap19casestudies.
html
Directions: Read the background. Using the internet and available
resources, answer the following questions. Check your answers!
Case Presentation
John, a healthy twenty-eight year old electrical engineer, was driving home
from work one evening when he experienced sudden stabbing pain in his right
pectoral and right lateral axillary regions. He began to feel out of breath and
both his respiratory rate and heart rate increased dramatically. As luck would
have it, John passed a hospital each day on his way home and was able to
get himself to the hospital’s emergency room. The emergency room physician
listened to John’s breathing with a stethoscope and requested blood gas
analysis and a chest x-ray. John answered a few of the doctor’s questions.
The doctor noted that John had no history of respiratory problems but was a
heavy smoker.
After viewing the chest radiograph, the doctor informed John that he had
experienced a spontaneous pneumothorax, or what is commonly called a
collapsed lung. The doctor explained that a hole had opened in John’s right
lung and that this hole had allowed air to leak into the cavity surrounding the
lung. Then, as a result of the lung’s own elastic nature, the lung had
collapsed. The doctor said he could not be certain of the cause of the
pneumothorax, but smoking cigarettes had certainly increased the likelihood
of it happening. He told John he was fortunate the pneumothorax was small,
which meant that relatively little air had escaped from the lung into the
surrounding cavity, and it should heal on its own. He instructed John to quit
smoking, avoid high altitudes, flying in nonpressurized aircraft, and scuba
diving. He also had John make an appointment for a re-check and another
chest x-ray.
Case Background
Spontaneous pneumothorax occurs when a blister on the surface of the lung
opens, allowing air from the lung to move into the pleural cavity. This occurs
because alveolar pressure is normally greater than the pressure in the pleural
cavity. As air escapes from the lung, the lung tissues will recoil, and the lung
will begin to collapse. The lung will continue to collapse until the difference
between the alveolar pressure and pleural pressure disappears or until the
collapsing of the lung causes the opening to seal.
The pneumothorax decreases the efficiency of the respiratory system, which
in turn results in decreased blood oxygen concentration, increased respiratory
rate, and increased heart rate. If the pneumothorax is small, the air that
escapes into the pleural cavity can be reabsorbed into the lung once the
opening has sealed shut. If the pneumothorax is large, a needle or chest tube
may have to be inserted into the pleural cavity to draw the air out and allow for
the reexpansion of the lung.
Questions
1. Define the following terms and explain how they may have been
affected by John’s spontaneous pneumothorax.
a. Visceral pleura
The serous membrane that covers the surface of a lung is called the visceral
pleura. Pneumothorax involves the rupture of this membrane.
b. Parietal pleura
a. Pleural cavity
c. As a result of a pneumothorax, the lung tissues recoil, and the lung
collapses. Explain how recoil and collapse are prevented in a healthy
lung?
d. How does elastic recoil function in breathing?
e. Why was John instructed to avoid high altitudes and flying in
nonpressurized aircraft?