Shock Flashcards

1
Q

Examples of obstructive shock

A

Tamponade

Tension pneumothorax

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2
Q

Neurogenic shock mechanism

A

Loss of sympathetic input

Peripheral vasodilation(low BP)

Low HR

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3
Q

Most common cause of shock in trauma patients

A

Haemorrhage

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4
Q

Cardiac output def

A

Volume of blood pumped/min

CO=HR*SV

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5
Q

Stroke volume def

A

amount of blood leaving heart per beat

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6
Q

Factors affecting stroke volume

A

Pre-load

contractility

After-load

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7
Q

Role of vasopressors in haemorrhagic shock

A

Contra-indicated as a first-line as worsen tissue perfusion

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8
Q

Earliest signs of shock

A

Increased HR

Cutaneous vasoconstriction

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9
Q

Tachycardia threshold through ages

A

Infant: >160 bpm

Pre-school: >140bpm

School - puberty: >120

Adults: >100

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10
Q

Change in pulse pressure with haemorrhagic shock

A

Results in narrowed pulse pressure

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11
Q

Effect of haemorrhagic shock on Hb and HCT

A

Massive blood loss may only produce a slight decrease in initial haematocrit or haemoglobin

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12
Q

Causes of cardiogenic shock

A

Blunt injury

Tamponade

Air embolus

MI

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13
Q

Beck’s triad of cardiac tamponade

A

Muffled heart sounds

Raised JVP

Low BP

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14
Q

Cause of neurogenic shock

A

Isolated INTRACRANIAL injuries do NOT cause shock

So look for elsewhere including brainstem, thoracic and cervical spine

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15
Q

Relationship between body weight and circulatory blood volume in an adult

A

7%

In a 70kg man, 5L of circulatory volume

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16
Q

Relationship between body weight and circulatory blood volume in an obese adult

A

7% of their ideal body weight

17
Q

Relationship between body weight and circulatory blood volume in a child

A

8-9% of body weight

(70-80 ml/kg)

18
Q

Class I haemorragic shocks parameters

Blood loss

HR
BP

Pulse pressure

RR

UO

GCS

Base deficit

A

Blood loss <15%

HR <100
BP normal

Pulse pressure normal

RR <20

UO >30

GCS normal

Base deficit 0 to -2

19
Q

Class II haemorragic shocks parameters

Blood loss

HR
BP

Pulse pressure

RR

UO

GCS

Base deficit

A

Class II haemorragic shocks parameters

Blood loss <30%

HR <120
BP normal

Pulse pressure reduced

RR <30

UO <30ml/hr

GCS normal

Base deficit -2 to -6

20
Q

Class III haemorragic shocks parameters

Blood loss

HR
BP

Pulse pressure

RR

UO

GCS

Base deficit

A

Blood loss <40%

HR <140
BP reduced

Pulse pressure reduced

RR >30

UO <15 ml/hr

GCS reduced

Base deficit -6 to -10

21
Q

Class IV haemorragic shocks parameters

Blood loss

HR
BP

Pulse pressure

RR

UO

GCS

Base deficit

A

Blood loss>40%

HR >140
BP reduced

Pulse pressure narrow

RR >40

UO <5

GCS reduced

Base deficit -10 or less

22
Q

Blood transfusion for Class I to IV haemorrhagic shock

A

Class I- no

Class II- possible

Class III- yes

Class IV- major haemorrhage protocol

23
Q

Factors that influence the rate of flow through a cannula

A

Proportional to the radius to power of 4

Inversely related to the length

24
Q

The ratio of RBC:Platelets:FFP for resus

A

1:1:1

25
Q

The most accurate indicator of response to fluid resus

A

urine output

26
Q

Minimum urine output aim across different age groups

A

Less than 1yo: 2ml/kg/hr

Children: 1ml/kg/hr

Adults: 0.5ml/kg/hr

27
Q

Acid-base disturbances with hypovolaemic shock

A

Early: mild resp alkalosis due to high RR

Later: mild acidosis due to anaerobic metabolism

28
Q

Patterns of response to the initial fluid resus

A

Rapid response

Transient response

Minimal or no response

29
Q

Estimated blood loss depending on response to resus

A

Rapid response: <15%

Transient 15< <40%

Minimal or no response >40%

30
Q

Need for surgical input depending on the response to the initial fluid assessment

A

Rapid response yes

Transient response yes

Minimal response yes

31
Q

Blood preparations depending on response to fluid resus

A

Rapid response: cross-match and type specific

Transient: Type-specific

Minimal: O neg blood

32
Q

Difference between cross match and type-specific

A

Type-specific (group and save) finds out the blood type (eg AB, or O) and looks for other known antigens on the receiver’s blood

Cross-match looks at mixing of the two bloods either:

  • Electronically: computer analyses to see if there is any reaction, without actually mixing the blood
  • Manually: mixing the two blood and looking for clot formation, more accurate but takes longer
33
Q

What blood product is given through autotransfusion

A

RBC

platelets and plasma need to be transfused separately

34
Q

Definition of massive transfusion

A

>10 units within 24hrs

>4 units in 1 hr

35
Q

Use of tranexamic acid in severely injured patients

A

First dose within 3 hours given over 10 mins

Maintenance dose of 1g over 8 hours

36
Q

BP formula

A

MAP = CO*SVR (afterload)