1. Chapter 13:
Shock

2. Defining Shock Shock is best defined as inadequate tissue perfusion
Can result from a variety of disease states and injuries
Can affect the entire organism or it can occur at a tissue or cellular level
Shock is not adequately defined by:
Pulse rate
Blood pressure
Cardiac function
Hypovolemia
Loss of systemic vascular resistance

3. Components of the Circulatory System
The pump (heart)
The fluid (blood)
The container (blood vessels)
Any problem with the components can lead to inadequate perfusion.

4. Cardiac Output
Amount of blood separately pumped by each ventricle per minute, usually expressed in liters per minute
Determined by multiplying the heart rate by the volume of blood ejected by each ventricle during each beat (stroke volume)
Crucial determinant of organ perfusion
Depends on:
Strength of contraction
Rate of contraction
Amount of venous return available to the ventricle (preload)

5. Baroreceptor Reflexes
Help maintain BP by two negative feedback mechanisms:
By lowering BP in response to increased arterial pressure
By increasing BP in response to decreased arterial pressure
Figure 7-18 A

6. Chemoreceptor Reflexes
Low arterial pressure may stimulate peripheral chemoreceptor cells that lie within the carotid and aortic bodies
When oxygen or pH decreases, these cells stimulate vasomotor center of medulla
Figure 7-18 B

7. Compensatory Mechanisms
CNS Ischemic Response
Hormonal Mechanisms
Adrenal-medullary mechanism
Renin-angiotensin-aldosterone mechanism
Vasopressin mechanism
Atrial natriuretic factor
Reabsorption of tissue fluids
Splenic discharge of blood

8. Role of Adrenal Medulla in Regulating BP
Figure 7-8 A
Figure 7-8 A

9. Renin-angiotensin-aldosterone Mechanism in BP
Figure 7-8 B
Figure 7-8 B

10. Vasopressin (ADH) Mechanism in Regulating BP
Figure 7-8 C
Figure 7-8 C

11. The Body as a Container
The healthy body may be viewed as a smooth‑flowing delivery system inside a container
Container must be filled to achieve adequate preload and tissue oxygenation

12. The Body As a Container
The external size of the container of any particular human body is relatively constant
Volume of the container is directly related to the diameter of the resistance vessels
Any change in vessel diameter changes the volume of the fluid the container holds, thereby affecting preload
Figure 19-1
Figure 19-1

13. Blood Volume
Average adult male has a blood volume of 7% of total body weight
Average adult female has a blood volume of 6.5% of body weight
Volume increases significantly during pregnancy
Normal adult blood volume is 4.5‑5 L
Remains fairly constant in the healthy body

14. Plasma Approximately 92% water
The liquid portion of blood
Circulates salts, minerals, sugars, fats, and proteins throughout the body
Contains 3 major proteins:
Albumin
Globulins (alpha, beta, and gamma)
Fibrinogen

15. Capillary-Cellular Relationship in Shock
Stage 1: Vasoconstriction
Stage 2: Capillary and Venule Opening
Stage 3: Disseminated Intravascular Coagulation
Stage 4: Multiple Organ Failure

16. Capillary-Cellular Relationship in Shock
Figure 19-2

17. Classifications of Shock
Hypovolemic shock
Distributive shock
Neurogenic shock
Anaphylactic shock
Septic shock
Cardiogenic shock

18. Compensated Shock Characterized by signs and symptoms of early shock
Arterial blood pressure is normal or high
Treatment at this stage will typically result in recovery

19. Compensated Shock
Figure 19-3

20. Uncompensated Shock Characterized by signs and symptoms of late shock
Arterial blood pressure is abnormally low
Treatment at this stage will sometimes result in recovery

21. Uncompensated Shock
Figure 19-4

22. Irreversible Shock Characterized by signs and symptoms of late shock
Arterial blood pressure is abnormally low
Even aggressive treatment at this stage does not result in recovery

23. Irreversible Shock
Figure 19-5