Shock

Question 1

Examples of obstructive shock

Answer 1

Tamponade

Tension pneumothorax

Question 2

Neurogenic shock mechanism

Answer 2

Loss of sympathetic input

Peripheral vasodilation(low BP)

Low HR

Question 3

Most common cause of shock in trauma patients

Answer 3

Haemorrhage

Question 4

Cardiac output def

Answer 4

Volume of blood pumped/min

CO=HR*SV

Question 5

Stroke volume def

Answer 5

amount of blood leaving heart per beat

Question 6

Factors affecting stroke volume

Answer 6

Pre-load

contractility

After-load

Question 7

Role of vasopressors in haemorrhagic shock

Answer 7

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

Question 8

Earliest signs of shock

Answer 8

Increased HR

Cutaneous vasoconstriction

Question 9

Tachycardia threshold through ages

Answer 9

Infant: >160 bpm

Pre-school: >140bpm

School - puberty: >120

Adults: >100

Question 10

Change in pulse pressure with haemorrhagic shock

Answer 10

Results in narrowed pulse pressure

Question 11

Effect of haemorrhagic shock on Hb and HCT

Answer 11

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

Question 12

Causes of cardiogenic shock

Answer 12

Blunt injury

Tamponade

Air embolus

MI

Question 13

Beck’s triad of cardiac tamponade

Answer 13

Muffled heart sounds

Raised JVP

Low BP

Question 14

Cause of neurogenic shock

Answer 14

Isolated INTRACRANIAL injuries do NOT cause shock

So look for elsewhere including brainstem, thoracic and cervical spine

Question 15

Relationship between body weight and circulatory blood volume in an adult

Answer 15

7%

In a 70kg man, 5L of circulatory volume

Question 16

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

Answer 16

7% of their ideal body weight

Question 17

Relationship between body weight and circulatory blood volume in a child

Answer 17

8-9% of body weight

(70-80 ml/kg)

Question 18

Class I haemorragic shocks parameters

Blood loss

HR
BP

Pulse pressure

RR

UO

GCS

Base deficit

Answer 18

Blood loss <15%

HR <100
BP normal

Pulse pressure normal

RR <20

UO >30

GCS normal

Base deficit 0 to -2

Question 19

Class II haemorragic shocks parameters

Blood loss

HR
BP

Pulse pressure

RR

UO

GCS

Base deficit

Answer 19

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

Question 20

Class III haemorragic shocks parameters

Blood loss

HR
BP

Pulse pressure

RR

UO

GCS

Base deficit

Answer 20

Blood loss <40%

HR <140
BP reduced

Pulse pressure reduced

RR >30

UO <15 ml/hr

GCS reduced

Base deficit -6 to -10

Question 21

Class IV haemorragic shocks parameters

Blood loss

HR
BP

Pulse pressure

RR

UO

GCS

Base deficit

Answer 21

Blood loss>40%

HR >140
BP reduced

Pulse pressure narrow

RR >40

UO <5

GCS reduced

Base deficit -10 or less

Question 22

Blood transfusion for Class I to IV haemorrhagic shock

Answer 22

Class I- no

Class II- possible

Class III- yes

Class IV- major haemorrhage protocol

Question 23

Factors that influence the rate of flow through a cannula

Answer 23

Proportional to the radius to power of 4

Inversely related to the length

Question 24

The ratio of RBC:Platelets:FFP for resus

Answer 24

1:1:1

Question 25

The most accurate indicator of response to fluid resus

Answer 25

urine output

Question 26

Minimum urine output aim across different age groups

Answer 26

Less than 1yo: 2ml/kg/hr Children: 1ml/kg/hr Adults: 0.5ml/kg/hr

Question 27

Acid-base disturbances with hypovolaemic shock

Answer 27

Early: mild resp alkalosis due to high RR Later: mild acidosis due to anaerobic metabolism

Question 28

Patterns of response to the initial fluid resus

Answer 28

Rapid response Transient response Minimal or no response

Question 29

Estimated blood loss depending on response to resus

Answer 29

Rapid response: \<15% Transient 15\< \<40% Minimal or no response \>40%

Question 30

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

Answer 30

Rapid response yes Transient response yes Minimal response yes

Question 31

Blood preparations depending on response to fluid resus

Answer 31

Rapid response: cross-match and type specific Transient: Type-specific Minimal: O neg blood

Question 32

Difference between cross match and type-specific

Answer 32

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

Question 33

What blood product is given through autotransfusion

Answer 33

RBC platelets and plasma need to be transfused separately

Question 34

Definition of massive transfusion

Answer 34

\>10 units within 24hrs \>4 units in 1 hr

Question 35

Use of tranexamic acid in severely injured patients

Answer 35

First dose within 3 hours given over 10 mins Maintenance dose of 1g over 8 hours

Question 36

BP formula

Answer 36

MAP = CO\*SVR (afterload)