Bleeding And Fluids

Question 1

What are the fluid compartments

Answer 1

Intracellular

Extracellular comprised of plasma (intravascular) and interstitial

Question 2

Which hormones retain and offload fluid

Answer 2

Fluid retention: ADH, aldosterone, oestrogen, glucocorticoids
Offload: ANP

Question 3

Compare the carotid sinus and carotid body

Answer 3

Carotid sinus is located at the base of the internal carotid just above the bifurcation and consists of baroreceptors
Carotid body is located at the bifurcation of the common carotid and is a small cluster of chemoreceptor cells

Question 4

Describe the Bezold-Jarisch reflex

Answer 4

Post MI or reduced preload leads to a sympathetic response causing hypercontractility. Hypercontractility is detected by LV pressure receptors and afferent vagal nerves stimulate the cortex to initiate a parasympathetic response. This leads to bradycardia, hypotension and slow shallow breathing

Question 5

What does saline do to your pH and strong ion difference

Answer 5

Causes a normal anion gap metabolic acidosis (Cl rises higher relative to Na)
Decreased strong ion difference

Question 6

Why do we give calcium in fluid resuscitation

Answer 6

Citrate in bags of blood binds to free calcium

Calcium is a cofactor for a lot of clotting factors

Question 7

Compare crystalloids and colloids

Answer 7

Crystalloids - small particles which can cross the cell membrane so over time get eliminated from the intravascular compartment
Colloids - large particles which cannot cross the cell membrane so stay in the intravascular compartment for longer exerting oncotic pressure

Question 8

What fluids would you give in neurosurgical rescue

Answer 8

Saline 3% or Mannitol which both have high osmotic/oncotic pressure so draw fluid from interstitial space to intravascular compartment

Question 9

What fluid would you give in burns and distributive shock

Answer 9

Hartmans

Question 10

Define shock

Answer 10

Reduced perfusion of end organs leading to inadequate oxygen delivery for their metabolic requirements

Question 11

What are the 4 types of shock and examples of each

Answer 11

Hypovolaemic - burns, bleeding
Distributive - sepsis, anaphylaxis, neurogenic
Obstructive - Tension pneumothorax, PE
Cardiogenic - arhythmias, myocardial contusions, metabolic disturbance

Question 12

What is anaphylaxis

Answer 12

IgE mediated hypersensitivity reaction

Question 13

How is anaphylaxis managed

Answer 13

Remove the trigger
Oxygen
Adrenaline 500micrograms IM (0.5ml)
Fluid challenge 500ml bolus
Chlorphenamine 10mg
Hydrocortisone 200mg

Question 14

What drug is given for a severe bradycardia

Answer 14

Atropine

Question 15

What initiates trauma induced coagulopathy

Answer 15

The trauma itself of traumatic shock leading to tissue hypoperfusion
This leads to acute traumatic coagulopathy which is then worsened by resuscitation associated coagulopathy

Question 16

What factors contribute to acute traumatic coagulopathy

Answer 16

Hyperfibrinolysis
Hypocoagulable state
(Thought to be due to protein C activation which inhibits thrombosis)

Question 17

What is DIC

Answer 17

Consumption coagulopathy - coagulation is impaired due to the lack of coagulation factors and platelets

Question 18

What factors contribute to resuscitation associated coagulopathy

Answer 18

Acidosis
Hypothermia
Dilution
Consumption of coagulation factors

Question 19

How is coagulopathy managed

Answer 19

Correct acidosis
Rewarm
Aggressive crystalloid resuscitation

Question 20

Compare bleeding from penetrating trauma to blunt trauma causing significant injury load in terms of vital signs

Answer 20

Penetrating - initial tachycardia then bradycardia an hypotension
Blunt - tachycardia with marked peripheral vasoconstriction

Question 21

Why are you tachypnoeic following shock

Answer 21

Reduced blood flow through peripheral chemoreceptors in carotid and aortic bodies leads to stagnant hypoxia so respiratory drive is increased

Question 22

What is the result of reduced stretch on the baroreceptors found in the aortic arch and carotid sinus

Answer 22

Reduced vagal activity an increased sympathetic activity on the heart + peripheral vasoconstriction + fluid movement from extra to intravascular

Question 23

Where are cardiac vagal c fibres located, when are they activated and what is their role

Answer 23

Located in LV myocardium
Activated when ventricle is underfilled and preload is reduced
Vagal response leads to profound bradycardia and reduced peripheral resistance so hypotension in order to protect the heart (reduced activity = reduced perfusion requirements)

Question 24

How is shock index calculated and what score is associated with higher mortality

Answer 24

HR/BP

>1 indicates higher mortality

Question 25

What are the NICE guidelines for fluid resuscitation following trauma

Answer 25

250ml crystalloid bolus only if no radial pulse (or central if penetrating torso injury)

Question 26

Who receives damage control resuscitation

Answer 26

``` Major haemorrhage (>4 units of blood needed in 2-4hrs) Shock (raised lactate, low mixed venous oxygen sats, eFAST) ```

Question 27

What is permissive hypotension

Answer 27

Penetrating trauma keep the systolic BP 70-80 | Blunt trauma or TBI patients keep the systolic BP 90

Question 28

What can increasing blood pressure with fluid therapy lead to

Answer 28

Dilution of clotting factors and Hb Disruption of any formed clots due to increased hydrostatic pressure Lower temperature

Question 29

What do we give for haemostatic transfusion (DCR)

Answer 29

1 unit of FFP to every 1-2 units packed red cells TXA (IV within 3 hours) Fibrinogen in the form of cryoprecipitate

Question 30

When is interventional radiology used

Answer 30

Active arterial pelvic haemorrhage

Question 31

Which cranial nerve innervates the baroreceptors in the aortic arch

Answer 31

Vagus