Shock Flashcards

1
Q

What is shock?

A

A syndrome in which tissue perfusion is inadequate for the tissues metabolic requirement

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2
Q

What does perfusion depend on?

A

Cardiac function
Capacity of vasculature
Circulating blood volume

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3
Q

How do you calculate MAP?

A

CO x SVR

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4
Q

Name the five types of shock

A
Hypovolaemic 
Cardiogenic 
Obstructive 
Distributive 
Endocrine
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5
Q

Describe hypovolaemic shock

A

Acute haemorrhage

Fluid depeltion - severe dehydration/burns

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6
Q

Describe cardiogenic shock

A

Pump failure, reduced cardiac output

Primarily due to ischaemia induced myocardial dysfunction

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7
Q

Describe obstructive shock

A

Mechanical obstruction
Direct - PE, air/fat/amniotic fluid embolism
Restriction - tamponade, tension pneumothorax

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8
Q

Describe distributive shock

A

Septic, anaphylaxis, acute liver failure, spinal cord injuries
Disruption of normal vascular autoregulation and profound vasodilation

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9
Q

Describe endocrine shock

A

Severe hypothyroidism, addisonian crisis, thyrotoxicosis causes reduced cardiac output and vasodilation

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10
Q

What is the sympathy-adrenal response to shock?

A

Baroreceptors and chemoreceptors
Sympathetic release of noradrenaline/adrenaline
RAAS
Aims to maintain BP and Cardiac output

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11
Q

What is the neuroendocrine response to shock?

A

Release of pituitary hormones - ACTH, ADH, Opioids
Release of cortisol - fluid retention, insulin antagonist
Release of glucagon

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12
Q

What makes up the inflammatory response?

A

Activation of complement
Cytokines - IL/TNF alpha
Platelet activating factor
Lysosomal enzyme - myocardial depression
Adhesion molecules - damage to vessels
Endothelium derived mediators - NO
Imbalance between oxidants and anti-oxidants

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13
Q

What haemodynamic changes occur as a result of shock?

A

Vasodilation –> vasoconstriction
Maldistribution
Microcirculatory abnormalities
Abnormal coagulation (DIC)

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14
Q

What is the main clinical feature of shock?

A

Hypotension

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15
Q

What are the clinical features of cardiogenic shock?

A

Myocardial failure - chest pain, cold/clammy, oedema

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16
Q

What are the clinical features of obstructive shock?

A

Raised JVP, pulses paradoxes, signs of cause

17
Q

What are the clinical features of distributive shock?

A

Pyrexia, vasodilation, rapid capillary refill, anaphylaxis

18
Q

Describe class I hypovolaemia

A

<15% blood loss
Base deficit 0 to -2
Monitor for blood requirement

19
Q

Describe class II hypovolaemia

A

15-30% blood loss
Increased heart rate and reduced pulse pressure
Base deficit -2 to -6
Possible need for blood

20
Q

Describe class III hypovolaemia

A

31-40% blood loss
Increased heart rate, reduced BP, reduced pulse pressure, increased resp rate, reduced urine output and GCS
Base deficit -6 to -10
Need blood

21
Q

Describe class IV hypovolaemia

A

> 40% blood loss
Increased heart rate, reduced BP, reduced pulse pressure, increased resp rate, decreased urine output and GCS
Base deficit -10 or less
Massive transfusion protocol

22
Q

Name the way in which a patient with shock can be monitored

A
Examination 
Urine Output 
Neurological 
Biochemical 
BP 
Central venous pressure 
Pulmonary artery monitoring 
Pulse contour analysis 
Doppler ultrasound
23
Q

How is all shock managed initially?

A

ABCDE

Wide bore access

24
Q

How is oxygen delivery managed?

A

15 litre non-rebreather initially and then whatever level required for normal SpO2

25
What is the risk of fluids?
Fluid overload and pulmonary oedema
26
What is fluid challenge?
Assessment of response, not too fast that it causes stress response 300-500ml over 10-20 minutes
27
What are the three main types of fluid?
Crystalloid Colloid Blood
28
What are examples and issues with crystalloid?
Saline, hartmann's | Rapid loss from circulation to extracellular fluid, requires 3-4 times more than blood lost
29
What are examples and issues with colloids?
Gelatines, albumin | Can cause anaphylaxis, reduced volumes but no evidence of benefit
30
What pharmacological treatments can be used in shock?
``` Adrenaline Noradrenaline Vasopressin Dopamine Dobutamine ```
31
Name the mechanical support that can be used in shock
Balloon pump L/R VAD VA Echo