Shock and Hypoxia Lesson

Resources: Hypoxia and Shock playlist from our YouTube channel

Hypoxia:

  1. Define Hypoxia.
  2. Define Oxygenation.
  3. Define Ventilation.
  4. How would oxygenation be potentially impacted if a patient is in a confined space?
  5. How would oxygenation be potentially impacted if a patient is at an elevated altitude, such as a city high in the mountains (Denver, for example)?
  6. What gas makes up the majority of the air that we inspire?
  7. The percentage of oxygen in atmospheric air is ____.
  8. Oxygenation is impacted by oxygen content in the inspired air. Assuming ventilation is normal and inspired oxygen content is also normal, what other major body function must be intact in order to have proper oxygenation?
  9. Inhalation is an active process. The _____ contracts and the chest wall muscles cause the chest to expand.
  10. What are the accessory muscles of breathing? (use simple terms)
  11. Define tidal volume.
  12. Exhalation is normally a ______process by design. Patients who are working to exhale have an increased work of breathing which can lead to fatigue and therefore hypoventilation.
  13. Define minute volume.
  14. Inspiratory capacity is the ______amount of air that can be inhaled and is typically 6-7 times the tidal volume. There are other terms that are trivial for us such as functional reserve capacity, residual volume, expiratory reserve volume and more.
  15. The pleura are key to effective ventilation as they are the mechanism by which the lung expands when the chest wall expands. Describe normal functioning of the pleura.
  16. What is the parietal pleura?
  17. What is the visceral pleura?
  18. What is normally in the pleural space?
  19. What is it called when there is blood in the pleural space?
  20. What is it called when there is air in the pleural space?
  21. What is it called when there is air and blood in the pleural space?
  22. CO2 is the primary breathing drive; chemical receptors sense the change in ___ when high levels of CO2 are present and send the signal to the brain so that the brain can increase the ventilation rate to get rid of the “exhaust” (CO2).
  23. The _____ (in the brain stem) controls rate and depth of breathing when not under voluntary control.
  24. Discuss the various sizes of oxygen tank and state which is most commonly carried in an EMS equipment pack.
  25. State the rule of thumb for determining the length of time remaining for 15 liters per minute in a D tank.

Shock:

Why Shock Kills - The Pathophysiology of Shock

Types of Shock

Cardiogenic Shock Notes:

•Typical signs (AMS, tachycardia, tachypnea, cool / pale / moist skin leading to hypotension)

•Treatment (rapid transport, maintain oxygenation and ventilation)

▾Loss of pump function / Congestive Heart Failure (CHF)

•large amount of left ventricular muscle mass infarcted (one large MI or multiple MI)

•chronic hypertension leads to left ventricular hypertrophy = decreased volume of chamber = reduced cardiac output

Hypovolemic Shock Notes:

•Typical signs (AMS, tachycardia, tachypnea, cool / pale / moist skin leading to hypotension)

•Loss of volume can be due to bleeding or vomiting or diarrhea or excessive sweating or poor intake

▾Treatment

•External bleeding control for wounds

Distributive Shock Notes:

▾Septic

•Typical signs (AMS, tachycardia, tachypnea, cool / pale / moist skin leading to hypotension)

•Inappropriate vasodilation due to systemic infection (also volume loss to third space due to vessel wall leaks, some cardiac dysfunction)

▾Neurogenic

•Inappropriate vasodilation due to loss of neurologic control (cord damage)

•Tissue oxygenation may remain relatively normal and the patient remain alert as long as supine

•Don’t overlook the possibility of hypovolemia as a result of the injuries that also caused the spinal cord injury

•Typical signs (AMS, no tachycardia, warm / flushed and dry below level of injury, no tachypnea, leading to hypotension)

▾Psychogenic

•Typical signs (AMS, tachycardia, tachypnea, cool / pale / moist skin leading to hypotension)

•Supine positioning, maintain oxygenation and ventilation

•Inappropriate bradycardia (vasovagal) and vasodilation; temporary

▾Anaphylactic

•Typical signs (AMS, tachycardia, tachypnea, cool / pale / moist skin leading to hypotension)

•Inappropriate vasodilation due to systemic allergic response

Obstructive Shock Notes:

•Typical signs (AMS, tachycardia, tachypnea, cool / pale / moist skin leading to hypotension)

•Something is compressing the container or pump or obstructing flow

▾Examples / Specific Causes

▾Supine Hypotensive Syndrome (know the definition)

•Large, gravid uterus compresses inferior vena cava reducing preload—tilt patient to left

▾Pulmonary Embolus (know the definition)

•Ax (sudden onset dyspnea, localized and pleuritic chest pain may be present)

•Tx—oxygen, rapid transportation

▾Tension Pneumothorax (know the definition)

•Tx (if open wound is present, release the seal)

•Ax (hypotension, absent unilateral lung sounds)

▾Cardiac Tamponade (know the definition)

•advanced—Tx (rapid transportation)

•Ax—JVD, muffled heart sounds, narrowing pulse pressure

  1. Define “shock”.
  1. List the three main components of the circulatory system.
  1. Explain how each of those components can cause shock if they malfunction.
  1. List at least five signs of shock.
  1. List five treatments for shock.
  1. In addition to the delivery of oxygen and glucose to the cells, what other important function is accomplished by perfusion?
  1. What do red blood cells (RBC’s) do in the body?
  1. What do white blood cells (WBC’s) do in the body?
  1. What do platelets do in the body?
  1. What is the plasma?
  1. Blood vessels have smooth muscle and sphincters that can dilate or contract and these are under the control of the _____ nervous system.
  1. Why does blood not flow backwards in the venous system?
  1. Define “compensated shock”.
  1. Define “decompensated shock”.
  1. Define “irreversible shock”.
  1. List four types of shock that fall into the category of “distributive” (“container”) shock.
  1. Although usually only found in old movies and EMS museums, you should be generally familiar with the PCPD / PASG / MAST trousers. Describe them briefly.
  1. Define “perfusion”.
  1. Define “stroke volume”.
  1. Define “preload”.
  1. Define “afterload”.
  1. Define “Starling’s Law”.
  1. Define “cardiac output” and explain how to calculate it.
  1. Define “pulse pressure”.
  1. What are “baroreceptors” and where are they located?