Shock

Question 1

What is the definition of shock?

Answer 1

Inadequate organ perfusion and tissue oxygenation due to imbalance between oxygen delivery and tissue demand

Question 2

What determines tissue perfusion?

Answer 2

Mean arterial pressure

MAP= systemic VR x CO

CO= HR x SV

Question 3

What are the factors which can affect SV? Why is this important to consider in terms of shock?

Answer 3

Preload= degree of ventricular filling
Contractiltiy
After load- measure of lead against which heart working

SV influxes CO which then affects MAP which determines tissue perfusion

Question 4

What are the 4 main categories causing shock?

Answer 4

Cardiogenic
Obstructive
Distributive
Hypovolaemic

Question 5

What is cardiogenic shock and what can cause this kind of shock?

Answer 5

Ventricular pump failure= decreased SV= decreased CO= decreased MAP= decreased tissue perfusion

MI
Acute valve dysfunction
Arrhythmia

Question 6

What is mechanical/obstructive shock? What can cause this type of shock?

Answer 6

Impaired ventricular filling or obstruction of outflow i.e. factors decreasing SV= decreased CO

PE= blocking pulmonary vessels which leads to increased afterload of the heart
Cardiac tamponade= impairs ventricular filling

Question 7

What is distributive shock? What can cause this form of shock?

Answer 7

Reduced system VR with normal cardiac function

Sepsis
Anaphylaxis
Spinal trauma

I.e. all cause systemic vasodilation

Question 8

What is hypovolaemic shock and what causes it?

Answer 8

Loss of circulating volume with normal cardiac function

Trauma 
GI bleed 
Pancreatitis= 3rd space fluid loss i.e. fluid moves into interstitial space 
Burns 
Diarrhoea

Question 9

What is 3rd space loss and what kind of shock can this cause?

Answer 9

Too much fluid moves from intravascular space to interstitial space which leads to decreased circulating volume== decreased CO

Hypovolaemic shock

Question 10

How does reduced tissue perfusion result in cell death?

Answer 10

Decreased perfusion= cell hypoxia
Cell switches to anaerobic metabolism
Lactic acid accumulates which induces a metabolic acidosis
Acidosis causes cell membrane pumps to dysfunction causing influx of sodium and water into cells
Results in Intracellular oedema== cell death

Question 11

What are the 3 major compensatory mechanisms the body uses to combat shock?

Answer 11

Increase CO
-SNS stimulated= increased HR, SV and systemic VR (vasocontriction)

Redistributing blood

• vasoconstriction
• ADH and renin= decreased urine output

Increased O2 delivary to cells
-SNS stimulates bronchodilation, increased resp and tidal volume

Question 12

What are key things to examine in patient suspected of shock?

Answer 12

A= airway
B= RR + O2 sats + CX percussion/auscultation/expansion +trachea
-note: abnormal RR can be first sign of problem
C= BP + HR
D= blood sugars + GCS
E= urine output

Peripheral signs:

• cold
• clammy
• mottled skin= sign of hypoperfusion

Question 13

What are the specific signs for cardiogenic shock?

Answer 13

Raised JVP
Pulmonary oedema
Murmurs
Arrhythmias

Question 14

What are the specific signs of obstructive shock?

Answer 14

Raised JVP
Muffled heart sounds i.e. in cardiac tamponade when the fluid surrounds the heart
Pulsus paradoxus= fall in px BP of >10mmHg during inspiration

Question 15

What signs can help to distinguish between septic and anaphylactic causes of distributive shock?

Answer 15

Septic:

• warm peripheries
• pyrexia/hypothermia

Anaphylactic:

• bronchospasm
• angioedema
• rash

Question 16

What are specific signs of hypovolaemia shock?

Answer 16

Bleeding
Pulsation abdominal mass= AAA
Burns

Question 17

What are the key investigations for patient suspected of shock? What is the importance of each of these investigations?

Answer 17

FBC

• Hb for bleeding
• WCC= infection

Clotting profile

• if patient bleeding
• deseminated intravascular coagulation can occur in shock

Renal function

Liver functon

Amylase= if pancreatitis suspected

Toxicology= investigates possible overdose

ABG= shows signs of switch anaerobic resp which occurs in hypoperfusion

• metabolic acidosis
• increased lactate

Infection screen i.e. sepsis screen

• blood cultures
• urinalysis

Question 18

When and why would you use a ECG for a suspected shock patient?

Answer 18

If you suspected cardiogenic shock

MI
PE
Cardiac tamponade= small voltage complexes on ECG

Question 19

Why is it important to do a CXR in a patient suspected of shock?

Answer 19

Signs of lung infection

Pulmonary oedema

Globular heart in cardiac tamponade

Question 20

Why is an echo down for suspected shock patients?

Answer 20

Acute valvular regurgitation 
PE
Cardiac tamponade 
Hypovolaemia 
Wall defects in MI

Question 21

What are the different stages of the emergency treatment of shock following the ABCD regimen?

Answer 21

A

• maintain airway
• airway protection if GCS<8

B

• high flow oxygen via 15L non-rebreathe mask
• sit up if risk of pulmonary oedema

C

• large bore IV access x2
• control of haemorrhage
• fluid resuscitation i.e. “replace like for like” (blood/crystalloid/colloids)
• possible vasoconstrictors once intravascular volume optimised
• consider urinary catheterisation

D

• check glucose
• monitor GCS

Question 22

What are the possible further stages of management once the patient has received emergency treatment?

Answer 22

Regular obs and urine output

Treat the CAUSE

Analgesia

Organ support