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Flashcards in Shock and Hemodynamics Deck (22):
1

Pt factors that impair recognition of shock

Elderly
Athletes
Pregnant - extra volume
Medications (beta blocker, Ca channel blocker)
Pacemaker
Sepsis

2

What do you look for in clinical exam to recognize shock

- signs/sxs of hypoperfusion
- signs/sxs of catecholamine response
- baroreceptor reflex activation
consider underlying
- Consider underlying scenario
- Be very suspicious

Ex: decreased consciousness/anxiety tachypnea, shallow respirations, cool/clammy skin***, prolonged capillary refill ***, decreased urine output, JVD, in cardiogenic shock,
*** Or warm erythematous skin with nl cap refill in septic shock due to inflammatory mediators causing vasodilation

3

Is it better to use MAP or systolic/diastolic to assess BP

MAP in most cases

4

What is MAP

average pressure at arterial level

MAP= Systolic + (2/3)(Diastolic)

5

Why is MAP better than systolic/diastolic for tissue perfusion...

2/3 cardiac cycle are diastole
- remains constant as pressure wave propagates distally in veseles
- less prone to waveform dignal distortions from monitoring systems (over/underdamping)

6

Drawbacks to using MAP to assess tissue perfusion

less accurate as more time in dystole (tachycardia)
- variations in SVR may have acceptable MAP but CO2 too low

7

What does lower pulse pressure indicate

suggests significant blood loss

- result of increasing diastolic pressure from compensatory

8

If you can feel dorsalis pedis pulse, what is the rough BP

at least 80

9

If you can feel femoral pulse, what is the rough BP

70

10

If you can feel radial pulse, what is the rough BP

80

11

If you can feel carotid pulse, what is the rough BP

60

12

ATLS Classifications of hemorrhagic shock

Class I, II, III IV

13

how much blood do you lose before hypotension occurs

Class III--lose about 40% of blood

- One of last sxs of shock
- BP responds to volume loss

14

Consequences of hypoperfusion

tissue hypoxia -> anaerobic metabolism -> cell injury/death -> inflammatory cascade -> organ dysfunction

15

What causes cardiogenic shock

you get a lower cardiac output due to a lower heart rate or contractility (heart can't squeeze as well)

- Due to changes in HR and SV
(bradycardia, tachyarrhythmias prevent filling-->decreased stroke volume, heart failure)

16

What is distributive/Septic shock

decreased cardiac output due to combo of impaired preload and contractility (thus making stroke volume decrease)

Preload problems: lose vasomotor tone, capillary leak

Contractility issues: inflammatory mediators cause your heart not to work as well (myocardial depression)

Sepsis: get massive swelling/edema

17

What is shock

inadequate tissue perfusion/cellular oxygenation

18

What are the 3 main types of shock

Hypovolemic
Cardiogenic
Distributive/septic

19

What is hypovolemic shock

Not enough preload, so the heart can't pump as much out --> lower stroke volume

Subtypes:
-Hemorrhagic (trauma, GI bleed, maternal/fetal hemorrhage)
- Nonhemorrhagic (dehydration, gastroenteritis, infection)

20

Compensatory physiology ni shock

lower preload --> message to shut down vagus nerve --> Tachycardia

catecholamines released for heart to pump harder/faster. We get vasoconstriction/narrowed pulse pressure (- Pale, purple-- trying to redirect bloodflow to heart and brain)

** NOTE pulse pressure is increased in septic shock since you get vasodilation and decreased diastolic pressure)

RAAS-- body tells kidneys to conserve water

21

Tests/labs to assess for shock

Test: Serum lactic acid
Labs: ABG (pH/bicarb), lactate , CBC
- also procalcitonin--tells you if you should be concerned about microbial infection; virtual absence in health

22

Most common type of shock in surgery

hypovolemic