Carolyn Henao
Day 1
As Marsha slowly regained consciousness, she became aware of the sights and sounds of the crowd
around her.
“What happened?” she asked.
Someone in the crowd iden ed himself as Jim, an EMT. He said that her car had veered o the side of
the road onto the shoulder and hit a tree. Martha quickly tried to raise herself o the ground but sank
back in pain. Jim gently lowered her shoulders and told her that she needed to lay s ll un l they could
put her on a stretcher.
“You may have neck or back injuries”, Jim said “and it looks like you may have broken your leg so I need
for you to lie very s ll.”
“What about my children?” Martha screamed. She suddenly remembered that they had been si ng in
the back seat.
“They are ne” Jim reported. “They were safely buckled in the back seat and their seat belts prevented
any injuries. The large engine in the Lumina absorbed most of the force of the impact.”
Martha relaxed as she heard a chorus from somewhere beside her “Mommy, we’re OK”.
“Thank heavens” Martha said. “I know that I felt a li le sleepy but I don’t remember what happened
next.”
Thinking back, Martha, a 49-year-old woman, realized that she had been feeling very red lately. She
found that she o en needed an a ernoon nap these days. She had a hard me keeping up with the
energy of her 7-year-old son Todd and 5-year-old daughter Sasha.
“I guess that I just don’t have the same old pep that I used to have” she admi ed to herself.
She also knew that, at 200 lbs on a 5’7” frame, she had put on a li le weight.
“I have just been too red to exercise” she told her doctor at her last visit when he had suggested that
she would do well to lose a couple of pounds.
“I only wish my husband wouldn’t awaken me every me I snore” she told him, “what I need is a good
night’s sleep.”
Marsha’s a en on was drawn back to the present as the EMT’s quickly loaded the stretcher into the
wai ng ambulance. They sped onto the highway which was busy with tra c at 3:00 p.m. in the
a ernoon. When they arrived at the emergency room, the physician immediately ordered X-Rays of
Marsha’s spine and leg.
Part 1 Ques ons
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1. What are some of the symptoms Marsha had? (5 points)
a. Marsha’s symptoms in general included being overweight, feeling red very o en, and
snoring while she sleeps. In this incident her symptoms involved pain from poten al neck
and back injuries as well as a poten al broken leg.
2. If you were the physician in the ER, what are some ques ons which you would ask Marsha to shed
more light on the cause of the accident? (5 points)
a. I would ask her if she remembers falling asleep behind the wheel as well as if she had any
other maladies that day. For example how was your overall state of being (any headaches,
pains, or stressors)? Were you red behind the wheel? Had you consumed any substances
this day or the day before? How is your memory? How many hours do you sleep on average
per night? How is your vision? Had you eaten anything this day? Etc.
3. List a few disease or condi ons that may explain what’s happening to Marsha. (5 points)
a. Narcolepsy, sleep apnea, insomnia, hypoglycemia, anemia, high blood pressure, obesity,
fa gue, hypothyroidism
Part II: The Test Results
Marsha’s physician, Dr. Chris Reeves, reported that her spinal X-Rays showed no damage due to the
accident.
He told Marsha “Your right bia and bula were fractured, and you su ered a mild concussion. We will
perform surgery to set the bones, t your leg with a cast, and a er a few days rest and a li le help with
crutches, you can be up and about again.”
A er her surgery, Marsha’s physician sat down to discuss the issue of her fa gue. Dr. Reeves told her that
her blood values indicated that her thyroid hormone levels as well as other hormone levels were normal.
He said that her blood chemistry was fairly normal but that her hematocrit was 51% and her blood
pressure was 135/95 mm Hg.
Dr. Reeves said, “these values in addi on to your weight and snoring indicate that you may have
obstruc ve sleep apnea.”
Marsha was surprised. “Can you explain what that is?” Marsha asked.
Dr. Reeves explained the condi on and then he said “I am recommending that you par cipate in a sleep
study at the hospital. They will monitor several parameters while you are sleeping and evaluate whether
you su er from periods of apnea while you sleep.”
“Oh no!” Marsha replied, “I can’t stand to wear a face mask to bed. I have seen pictures of people
wearing them and, not only would I scare my kids, I would not be able to sleep. Besides, how roman c,
can that look? I will look like an alien.”
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Dr. Reeves responded “you would do well to take your condi on seriously. If you have obstruc ve sleep
apnea, not only does it cost you sleep and lead to fa gue, this condi on is likely to cause long term
cardiovascular problems down the road. Some people even begin to experience arrythmias or irregular
heartbeats. You may also encounter distrac on issues when you try to concentrate and some loss of
memory. You have just seen how falling asleep while driving, has endangered both you and your
children. Marsha, this is nothing to kid around about.”
“All right, Dr. Reeves, but I don’t like it one bit. How do they expect me to sleep in a strange bed in a
clinic hooked up to wires everywhere on my body and with someone watching me and listening to me all
night?”
“Don’t worry, Marsha” responded Dr. Reeve, “just do the best that you can. It may make a big di erence
in your lifestyle if you can improve your energy.”
Part 2 Ques ons
4. De ne the term sleep apnea. (3 points)
a. A sleep disorder consis ng of symptoms where your breathing repeatedly starts and stops
throughout the night, which includes snoring and usually very restless and shallow sleep
cycles.
5. Can you consciously produce apnea right now? How? (5 points)
a. Technically, yes. You must fully relax all muscles of the throat and mouth and stop breathing
to produce what is “apnea.”
6. List the anatomical structures which may cause an obstruc on in the airway while sleeping. (5
points)
a. the nose, roof of mouth, throat, esophagus, uvula, tonsils, tongue, diaphragm, lungs
[reproduced from the American Physiological Society, Levitsky, M. (2008), Figure 1, Advances in
Physiology Educa on]
The graph above shows es mated changes in the arterial PO2 and PCO2 during 30 seconds of apnea.
7. What changes have occurred to the PO2 in 30 seconds of apnea? (3 points)
a. PO2 decreased by 30 mmHg (100 to 70)
8. What changes have occurred to the PCO2 in 30 seconds of apnea? (3 points)
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a. PCO2 increased by 20mHg (40 to 60)
9. What would happen to the H+ content of the blood because of the apnea? (3 points)
a. INCREASE
10. The changes in the CO2 content of the blood due to apnea would lead to: (3 points)
a. ACIDOSIS
11. Apnea is associated with: (3 points)
a. HYPOVENTILATION
12. Where are the peripheral chemoreceptors located? (3 points)
i. the caro d sinus and aor c bodies
13. To which substance are the chemoreceptors most sensi ve? (3 points)
a. low PO2
14. Based on chemoreceptor ac vity, how do you think the respiratory center in the brain would alter
breathing? Provide speci c details about what ac ons are triggered to make this happen. (3 points)
a. As chemoreceptors monitor increased or decreased CO2 and O2 levels in the environment
and in the blood, they tell the respiratory centers in the brain to either increase or decrease
the rate of ven la on to balance out the necessary levels of CO2 and O2 to maintain a
normal pH / oxygena on in the blood and stable breathing. For example, during sleep apnea
as the O2 in the blood decreases and the chemoreceptors pick up on this, they will trigger
the respiratory center of the brain to gulp in air to the lungs to restore oxygen and release
CO2.
15. It appears from the results of Marsha’s hematocrit that she may have polycythemia. Explain how
this could be a compensatory e ect for her condi on. (5 points)
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i. Polycythemia indicates that Marsha has an increased red blood cell count in her
body. this can lead to fa gue, night sweats, dizziness, and trouble breathing while
lying down. All of these symptoms can play a role in sleep apnea occurring at night.
Part III: The Sleep Study
[reproduced from the American Physiological Society, Thompson, S., Ackermann, U. & Horner, R. (2001),
Figures 8 and 9, Advances in Physiology Educa on]
The above recordings are taken from a normal polysomnogram (le ) the polysomnogram of an individual
with sleep apnea (right). EEG, electroencephalogram; EMG, electromyogram; bands are placed around
the abdomen and rib cage to measure expansion and contrac on. Note that abdominal and rib cage
mo on are in phase during breathing on le recording. Following a period of apnea (right recording) the
pa ent is aroused enough to resume breathing.
16. What change occurred to the blood pressure during sleep apnea? Remember that apnea is the
speci c period occurring before arousal on the graph above. (3 points)
a. blood pressure is slowly creeping up and increasing during apnea
17. What change occurred to the heart rate during sleep apnea? (3 points)
a. heart rate slows down during apnea
18. What change occurred to the oxygen satura on of the blood during sleep apnea? (3 points)
a. oxygen satura on of the blood is decreasing during apnea
19. Which system of the body is ac vated to arouse the body? (3 points)
a. sympathe c
20. Normally, the system of the body ac vated during arousal would ____ heart rate. (3 points)
a. increase
21. With arousal, the pa ent would: (3 points)
a. hyperven late
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22. Apnea causes a rise in pulmonary resistance – vasoconstric on of the pulmonary capillaries in the
area low in oxygen. Which chamber of the heart would enlarge as a result pumping blood against
the high resistance of the vessels in the lungs? (3 points)
23. Marsha’s blood pressure as recorded by her doctor at 135/95 mm Hg is: (3 points)
a. hypertensive
24. Research studies have indicated that there is an associa on between sleep apnea and
cardiovascular disease. Based on the ndings above, what indica ons do you have that this is
occurring? (5 points)
i. The associa on between cardiovascular disease and sleep apnea can be supported
by evidence from Marsha’s health because her sleep apnea causes her blood
pressure to go up, over me causing hypertension and inevitably cardiovascular
disease over me.
Part IV: The Remedy
The CPAP
Marsha nally conceded that, to achieve a good night’s sleep, she was willing to try the CPAP equipment.
Anna, a respiratory therapist visited her at home and brought a mask with pieces called “pillows” which
t into her nasal openings and which covered her mouth as well.
Martha said to Anna “I don’t know how I will ever get used to wearing this and actually sleep, but I will
give it a try.”
Anna replied, “although it may take a couple of months, you will eventually nd that you sleep more
peacefully than before.”
Marsha did try and a er a period of about a month and a half she found that she actually missed
wearing it if she fell asleep without it. She would wake up and reach for the hose. “I nd the sound of
the air passing through the hose to be rather calming” she told her husband. “I think that this will work
out well for me.”
CPAP stands for con nuous posi ve airway pressure and this piece of medical equipment as a means to
alleviate the symptoms of obstruc ve sleep apnea.
25. How does con nuous posi ve airway pressure remove the obstruc on to air ow in the pharynx
region? (5 points)
i. Con nuous posi ve airway pressure involves the consistent ow of air pressure to
keep the pharynx open whether you are inhaling or exhaling. This prevents the
throat from ever closing, collapsing, or ge ng obstructed.
26. The force which normally in ates the lungs (Think of Boyle’s law) is: (3 points)
a. nega ve pressure
27. Does the CPAP change the force by which the lungs normally in ate? (3 points)
a. yes
28. Which part of the airway system is not held open by rings or plates of car lage? (3 points)
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a. terminal bronchioles
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i. le ventricle