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Flashcards in Shock and Hemodynamics Deck (22)
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1
Q

Pt factors that impair recognition of shock

A
Elderly
Athletes
Pregnant - extra volume
Medications (beta blocker, Ca channel blocker)
Pacemaker
Sepsis
2
Q

What do you look for in clinical exam to recognize shock

A
  • 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
Q

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

A

MAP in most cases

4
Q

What is MAP

A

average pressure at arterial level

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

5
Q

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

A

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
Q

Drawbacks to using MAP to assess tissue perfusion

A

less accurate as more time in dystole (tachycardia)

- variations in SVR may have acceptable MAP but CO2 too low

7
Q

What does lower pulse pressure indicate

A

suggests significant blood loss

  • result of increasing diastolic pressure from compensatory
8
Q

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

A

at least 80

9
Q

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

A

70

10
Q

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

A

80

11
Q

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

A

60

12
Q

ATLS Classifications of hemorrhagic shock

A

Class I, II, III IV

13
Q

how much blood do you lose before hypotension occurs

A

Class III–lose about 40% of blood

  • One of last sxs of shock
  • BP responds to volume loss
14
Q

Consequences of hypoperfusion

A

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

15
Q

What causes cardiogenic shock

A

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
Q

What is distributive/Septic shock

A

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
Q

What is shock

A

inadequate tissue perfusion/cellular oxygenation

18
Q

What are the 3 main types of shock

A

Hypovolemic
Cardiogenic
Distributive/septic

19
Q

What is hypovolemic shock

A

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
Q

Compensatory physiology ni shock

A

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
Q

Tests/labs to assess for shock

A

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
Q

Most common type of shock in surgery

A

hypovolemic