Shock

Question 1

Define Shock

Answer 1

Where bp/cirulating blood volume is reduced to a level where tissue oxygenation is inadequate leading to cellular hypoxia and irreversible tissue injury

Question 2

What are the 3 categories of shock?

Answer 2

Vasodilatory (anaphylaxis, neurogenic, septic)
Cardiogenic (myocardial damage, arrhythmias, outflow obstruction, pericardial disease)
Hypovolaemia

Question 3

Compare short term and long term control of bp

Answer 3

Short term regulates vessel diameter, HR and contractility

Long term regulates blood volume (RAAS)

Question 4

Mechanism of decompensation in shock?

Answer 4

Decompensation is where body unable to compensate for change in blood volume in shock, so it worsens and leads to MOF

Question 5

Mechanism of hemodynamic decompensation in hypovolaemic and pump failure (cardiogenic) shock?
Include the primary problems

Answer 5

Fall in CO increases arterial resistance leading to tachycardia and a further fall in CO and hypotension.
Primary problem in hypovolaemia: low blood vol
Primary problem in pump failure: fall in CO

Question 6

Outline pathology (compensation and consequence) of vasodilatory shock

Answer 6

Primary problem: vasodilation
Consequence: hypotension
Compensation: CO rises, tachycardia

Question 7

Clinical signs of shock?

Answer 7

Cold, clammy, tachycardic, prolonged refill time (reduced in vasodilation),

Question 8

What are 3 humoral and 3 neural ways of controlling bp?

Answer 8

Humoral: Renin-Angiotensin
Aldosterone
ADH

Neural: carotid and aortic baroreceptors
medullary cardiac and vasomotor centres
PNS

Question 9

What are definitions for hypotension? What are pitfalls?

Answer 9

Systolic <90mmHg
SBP <20mmHg fall below patients norm

May not know patients normal pressure, medication, elderly, fitness levels

Question 10

In hypovolaemia, what’s the prime problem, the compensation and the consequence?

Answer 10

Prime problem: inadequate volume / fall in cardiac output
Compensation: increased resistance, tachycardia
Consequence: hypotension

Question 11

What are clinical signs of hypovolaemia?

Answer 11

Cold, clammy peripheries
Tachycardia
Prolonged capillary refill time
Empty veins

Question 12

What are 3 mechanisms leading to shock?

Answer 12

Inadequate circulating volume
Failure of the pump
Damage to control of resistance

Question 13

In pump failure what’s the prime problem, compensation and consequence?

Answer 13

Fall in cardiac output
= increased resistance/tachycardia
= increased capacitance

Question 14

What are clinical signs of pump failure?

Answer 14

Cold clammy peripheries
Prolonged cap refill time
Peripheral oedema
Bi-basal crackles
Hepatomegaly

Question 15

What are the consequences/signs of poor tissue perfusion from shock?

Answer 15

Lactic acidosis
Oliguria
Altered consciousness

Question 16

What are signs of compensation?

Answer 16

SNS activation
Tachypnoea
Renal response

Question 17

How is shock managed and assessed?

Answer 17

Airways - high flow O2
Breathing - ventilatory assistance
Circulation - fluid resuscitation 
Disability - conscious level
Exposure/environment/examination

Question 18

3 circulatory features of shock are hypovolaemia, pump failure or vasodilation. How do the signs differ in vasodilation to hypovolaemia/pump failure?

Answer 18

Vasodilation: full veins, bounding pulse and warm/dry perfusion
Hypovolaemia & pump failure: empty veins, thready pulse and cold/clammy perfusion