This is part of a slide show I use to lead students through a case study on two patients with traumatic thoracic cavity injuries. We use the cases to explore the anatomy and physiology of this region. This is just the respiratory system portion of the larger lesson.

1. Kent Smith
Junction City High School
Junction City, KS
This presentation is intended to demonstrate how to
lead a case study as a means to helps students
explore content and use critical thinking skills.

2. OBJECTIVES
• Participate in an inquiry-driven case study
investigation
• Identify your patient’s diagnosis
• Identify your patient’s mechanism of injury
and the affects on physiology
• Identify key structures responsible for the
mechanics of breathing
• Identify the physiology of breathing
• Identify the value of case studies for
instruction

3. PATIENT 1
On August 31, 2010, a mounted patrol from A CO 173D BSB was attacked outside FOB Shank in Logar
Province, Afghanistan. One vehicle was struck by an Improvised Explosive Device, causing catastrophic
damage. The four crew members are evacuated to your Forward Surgical Team and your trauma team has
received the patients described below.
Patient #1 is a 20-year-old male with multi-system trauma. He is unresponsive and is being ventilated using a
bag-valve mask with high flow oxygen. The attending medic reports that assisted ventilation was started
because the patient displayed shallow, labored breathing at a rate of eight (8) breaths per minute. He has
evidence of facial trauma and multiple dressed and undressed wounds along his left thoracic, and abdominal
areas. Unit records show the Soldier is 5’ 5” tall and weighs 155 pounds. Upon entry, your patient’s blood
pressure is 88/60 and he is tachycardic with a pulse of 110 BPM.

4. PARAGRAPH 1
1. You begin your assessment at the head of
the patient. The A of the ABCs stands for
airway. You look, listen, and feel to determine
the quality of the patient’s airway. There is
trauma to the nasal and maxillary areas along
with the left orbit. This trauma explains why
the patient has an OPA in place instead of an
NPA. The patient shows some signs of cyanosis
and requires a secure airway. Determine what
has been done for the patient and what the
next step in airway management would be.
Figure 1. Divisions of the Pharynx. Adapted from "Figure 22.6 Divisions of the Pharynx," by OpenStax, 2022,
retrieved from https://openstax.org/details/books/anatomy-and-physiology-2e. CC-BY 4.0

5. • How do we know our patient needs an airway?
• Cyanosis – blue (cyan) coloration due to decreased oxygenation
• What is low oxygen called?
• Hypoxemia – low oxygen in blood
• Hypoxia – low oxygen in tissues
• What was done for our patient?
• OPA instead of NPA
• Oropharyngeal Airway (OPA) - (J-tube):
• Through the oral cavity to the oropharynx
• Keeps tongue from falling into oropharynx
• Only used if no gag reflex (unconscious)
• What is the oropharynx?
• Posterior to oral cavity (back of the throat)
• Passage for air and food
Figure 1. Divisions of the Pharynx. Adapted from "Figure 22.6 Divisions of the Pharynx," by OpenStax, 2022,
retrieved from https://openstax.org/details/books/anatomy-and-physiology-2e. CC-BY 4.0
AIRWAY MANAGEMENT

6. • Nasopharyngeal Airway (NPA) - (nasal trumpet):
• Through nasal cavity and nasopharynx into the oropharynx.
• Do not use in patient with facial trauma / fractures
• (could enter brain through fractured area)
• What is the nasopharynx?
• Posterior to nasal cavity
• Connects to oropharynx
• Passage for air only
Figure 1. Divisions of the Pharynx. Adapted from "Figure 22.6 Divisions of the Pharynx," by
OpenStax, 2022, retrieved from https://openstax.org/details/books/anatomy-and-physiology-
2e. CC-BY 4.0
AIRWAY MANAGEMENT

7. • How do we get a secure airway for this patient?
• Endotracheal Tube (ET Tube) –
AIRWAY MANAGEMENT

8. • How do we get a secure airway for this patient?
• Endotracheal Tube (ET Tube) –
• Through the oral cavity, oropharynx, laryngopharynx and larynx
• Past the epiglottis and vocal cords into the trachea.
• Balloon at the end prevents aspiration (breathing in vomit or other
debris)
Figure 1. Divisions of the Pharynx. Adapted from "Figure 22.6 Divisions of the Pharynx," by
OpenStax, 2022, retrieved from https://openstax.org/details/books/anatomy-and-physiology-
2e. CC-BY 4.0
AIRWAY MANAGEMENT

9. • What were the structures mentioned in the video?
• Larynx–
• Connects the pharynx to the trachea
• Three major cartilaginous structures
• Epiglottis
• Thyroid cartilage (Adam’s apple)
• Cricoid cartilage
• Epiglottis
• Flexible flap
• Covers tracheal open to prevent aspiration
• Vocal cords
• Muscle and mucosa
• Vibrate to produce sound
Figure 1. Divisions of the Pharynx. Adapted from "Figure 22.6 Divisions of the Pharynx," by
OpenStax, 2022, retrieved from https://openstax.org/details/books/anatomy-and-physiology-
2e. CC-BY 4.0
AIRWAY MANAGEMENT

12. Figure 2. Flail chest. Adapted from " File:7.1 – Flail chest case 4.png" by iEM student, 2018,
retrieved from
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.flickr.com%2Fphotos%2Fiem-
student%2F42995267201&psig=AOvVaw13-
SeODwtlwBixyGV_TCwz&ust=1697401862960000&source=images&cd=vfe&opi=89978449&ved=0
CBIQjhxqFwoTCKi2s-qw9oEDFQAAAAAdAAAAABAJ. CC BY-NC-SA 2.0 DEED
PARAGRAPH 2
2. Continuing to the B of your ABCs, you move to
assess the chest and breathing. As the patient is
ventilated, you notice paradoxical movement of a
section of the right anterior chest. This section is
approximately 4 cm x 5 cm. Breath sounds are
present at the apex and base of the right ride and
there is appropriate rise and fall of the chest aside
from the paradoxical movement. Determine the
anatomy and physiology responsible for normal
movement of the chest as well as the cause of the
paradoxical movement.

13. • What is paradoxical movement?
• Movements that are the opposite (paradox) of normal
• What is your diagnosis?
• Flail chest
• Three or more ribs fractured in at least two places
• What structures are involved?
• Ribs
• Intercostal (between ribs) muscles
• What is normal movement?
• Inspiration – thoracic cavity expands – chest rise
• Expiration – thoracic cavity collapses – chest fall
BREATHING
Figure 3. Paradoxical breathing. Adapted from " File:Paradoxical-breathing.png" by Baedr-9439, 2020, retrieved
from https://commons.wikimedia.org/w/index.php?curid=87461411. CC0 1.0

14. • What is actually happening? What tissue produces movement?
• Muscle tissue produces movement
• Inhalation (Inspiration):
• External intercostal muscles contract
• Pull the ribcage up and out
• Diaphragm contracts
• Moves down toward abdomen
• What happens to the volume of the chest?
• Chest volume increases
• What happens to pressure as volume increases?
• Intrapulmonary Pressure decreases (vacuum) – air flows into lungs
• Boyle’s Law: The pressure of a gas is inversely related to the
volume.
BREATHING
Figure 4. Normal inspiration and expiration. Adapted from "Figure 22.17 Normal Inspiration and Expiration," by
OpenStax, 2022, retrieved from https://openstax.org/details/books/anatomy-and-physiology-2e. CC-BY 4.0
Figure 5. Boyle’s Law. Adapted from "Figure 22.15 Boyle’s Law," by OpenStax, 2022, retrieved from
https://openstax.org/details/books/anatomy-and-physiology-2e. CC-BY 4.0

15. • Exhalation (Expiration):
• External intercostal muscles relax
• Ribcage falls down and in
• Diaphragm relaxes
• Moves back up
• What happens to the volume of the chest?
• Chest volume decreases
• What happens to pressure as volume increases?
• Intrapulmonary Pressure increases (vacuum) – air flows out of the
lungs
• Boyle’s Law: The pressure of a gas is inversely related to the
volume.
BREATHING
Figure 4. Normal inspiration and expiration. Adapted from "Figure 22.17 Normal Inspiration and Expiration," by
OpenStax, 2022, retrieved from https://openstax.org/details/books/anatomy-and-physiology-2e. CC-BY 4.0

16. • What is paradoxical movement?
• Movements that are the opposite (paradox) of normal
• How does the flail section move on inhalation? Why?
• Section moves inward
• Low pressure pulls section in
• How does the section move on exhalation? Why?
• Section moves outward
• High pressure pushes section out
• What is key to the mechanics of breathing?
• Pressure moves air
• Inspiration – low intrapulmonary pressure – air moves in
• Expiration – high intrapulmonary pressure – air moves out
FLAIL CHEST
Figure 3. Paradoxical breathing. Adapted from " File:Paradoxical-breathing.png" by Baedr-9439, 2020, retrieved
from https://commons.wikimedia.org/w/index.php?curid=87461411. CC0 1.0

17. PATIENT 2
On August 31, 2010, a mounted patrol from A CO 173D BSB was attacked outside FOB Shank in Logar
Province, Afghanistan. One vehicle was struck by an Improvised Explosive Device, causing catastrophic
damage. The four crew members are evacuated to your Forward Surgical Team and your trauma team has
received the patients described below.
Patient #2 is a 24-year-old female with multi-system trauma. She is unresponsive and is being ventilated at a
rate of 12 breaths per minute using an endotracheal tube and bag-valve mask with high flow oxygen. The
attending medic reports that assisted ventilation was started because the patient was unresponsive and was
treated for a penetrating chest wound at the scene. She has multiple dressed and undressed wounds along
her right brachial, thoracic, and abdominal areas. The Soldier is 5’ 2” tall and weighs 120 pounds. Upon entry,
your patient’s blood pressure is 102/88 with a bounding pulse of 105 BPM.

18. Figure 6. Tension Pneumothorax. Adapted from " Chest Radiograph Tension Pneumothorax" by Scott Dulebohn
MD, 2023, retrieved from https://www.ncbi.nlm.nih.gov/books/NBK559090/figure/article-
27373.image.f1/?report=objectonly. CC BY-ND 4.0 DEED
PARAGRAPH 4
• 4. As you assess the chest, you identify two
penetrating wounds on the anterior right lateral thoracic
area. One dressed wound is located in the third
intercostal space, 3 cm lateral of the midclavicular line.
The second wound is a dime sized wound located along
the midaxillary line, 5 cm inferior to the left axilla. This
wound is undressed. It has significant oozing blood with
some pink foam. The wound produces a slight hissing
sound as the patient inhales.
• Breath sounds are significantly diminished compared
to the left side. You also note that the trachea is
displaced to the left and there is JVD. This is no doubt
causing your patient’s dyspnea. Determine what is
happening and how it is producing the signs of tracheal
deviation and JVD.

19. • What are the key signs in this paragraph?
• Dyspnea
• Shortness of breath / labored breathing
• Diminished breath sounds
• Where do we assess lung sounds?
• Apex to apex / middle to middle / base to base
• Tracheal deviation
• Trachea is shifted to one side
• JVD
• Jugular vein distention
• Veins in the anterior lateral neck
DYSPNEA
Figure 7. Parietal and visceral pleurae. Adapted from "Figure 22.14 Parietal and Visceral Pleurae of the
Lungs," by OpenStax, 2022, retrieved from https://openstax.org/details/books/anatomy-and-physiology-2e.
CC-BY 4.0
Figure 8. Systemic veins. Adapted from "Figure 20.35 Major Systemic Veins of the Body," by OpenStax, 2022,
retrieved from https://openstax.org/details/books/anatomy-and-physiology-2e. CC-BY 4.0

20. • What is your diagnosis?
• Tension pneumothorax – medical emergency
• Air collects in the pleural cavity
• What is actually going on?
• Diminished breath sounds – why?
• Air in the pleural cavity, what and where is that?
• Between parietal and visceral pleura
• Parietal – stuck to the chest wall
• Visceral – stuck to the lungs
• What is the normal physiology?
• Pleural fluid reduces friction / maintains negative pressure
Pneumothorax - Pulmonary Disorders - Merck Manuals
DYSPNEA
Figure 7. Parietal and visceral pleurae. Adapted from "Figure 22.14 Parietal and Visceral Pleurae
of the Lungs," by OpenStax, 2022, retrieved from https://openstax.org/details/books/anatomy-
and-physiology-2e. CC-BY 4.0
Figure 9. Pneumothorax. Adapted from " Blausen 0742 Pneumothorax" Blausen.com staff (2014).
'Medical gallery of Blausen Medical 2014'. WikiJournal of Medicine 1 (2).
DOI:10.15347/wjm/2014.010. ISSN 2002-4436.

21. • How does air build up in the pleural cavity?
• Let’s review the mechanics of breathing.
• Intercostals and diaphragm contract
• Chest wall lifts, diaphragm drops
• Increased volume = decreased pressure
• Path of least resistance
• Why do lungs collapse?
• Decreased negative pressure prevents inflation
• Increased positive pressure crushes the lung
Pneumothorax - Pulmonary Disorders - Merck Manuals
Professional Edition
DYSPNEA
Figure 7. Parietal and visceral pleurae. Adapted from "Figure 22.14 Parietal and Visceral Pleurae
of the Lungs," by OpenStax, 2022, retrieved from https://openstax.org/details/books/anatomy-
and-physiology-2e. CC-BY 4.0
Figure 9. Pneumothorax. Adapted from " Blausen 0742 Pneumothorax" Blausen.com staff (2014).
'Medical gallery of Blausen Medical 2014'. WikiJournal of Medicine 1 (2).
DOI:10.15347/wjm/2014.010. ISSN 2002-4436.

22. • Review symptoms
• Diminished breath sounds
• Air collects in the pleural cavity
• Tracheal deviation
• Trachea is shifted to one side
• Pressure shifts everything
• Away from injury
• Jugular vein distention
• Where do jugular veins lead?
• Superior vena cava
• Right atrium
• Why is there a backup?
• Pressure on the heart prevents filling (preload)
DYSPNEA
Figure 7. Parietal and visceral pleurae. Adapted from "Figure 22.14 Parietal and Visceral Pleurae of the
Lungs," by OpenStax, 2022, retrieved from https://openstax.org/details/books/anatomy-and-physiology-2e.
CC-BY 4.0
Figure 8. Systemic veins. Adapted from "Figure 20.35 Major Systemic Veins of the Body," by OpenStax, 2022,
retrieved from https://openstax.org/details/books/anatomy-and-physiology-2e. CC-BY 4.0

25. • Encoding strategies have been shown to increase memory as evidenced by increased
assessment scores.
• Strategies are:
• Organization: grouping content to illustrate relationships
• Schema activation: activating prior knowledge to form connections
• Elaboration: increasing and expanding connections
• Imagery: forming mental pictures
• How does this relate to case studies?
• Content is grouped according to disorder and relationships are developed between symptoms and
anatomy or physiology
• Students draw on prior knowledge to evaluate their patient and find a diagnosis, which forms a
connection with the patient and the disorder
• Inquiry and discussion or peer teaching requires elaboration
• Students form a mental picture of their patient as they write their case study.
THE RESEARCH

26. • A study by Bonney (2015) compared test scores students in an introductory college biology
course.
• Case study instruction showed 18% increase in performance over class discussion and text reading.
• “How does each method help improve your ability to…”
• Communicate knowledge of scientific concepts in writing: 81% vs. 63% (discussion) & 59% (textbook
reading)
• Communicate orally: 81% vs. 68% & 50%.
• Bonney, K. M. (2015). Case study teaching method improves student performance and
perceptions of learning gains. Journal of Microbiology & Biology Education, 16(1), 21–28.
https://doi.org/10.1128/jmbe.v16i1.846
THE RESEARCH

27. OTHER CASE STUDIES

28. OTHER CASE STUDIES