Hameodynamic Shock

Question 1

What is haemodynamic shock?

Answer 1

-Acute condition of inadequate blood flow throughout the body
-Catastrophic fall in arterial blood pressure leads to
circulatory shock

Question 2

What can shock be due to?

Answer 2

-Shock can be due to fall in CO
-Or fall in TPR beyond capacity of the heart to cope

Question 3

What are the three shocks due to fall in cardiac output?

Answer 3

Cardiogenic shock
Mechanical shock
Hypovolaemic shock

Question 4

Cardiogenic shock
-What is it?
-Potential causes

Answer 4

What is it?:
-Acute failure of the heart to maintain cardiac output (pump failure)

Potential causes:
-Following MI- damage to left ventricle
-Due to serious arrhythmias
-Acute worsening of heart failure

Question 5

Features of cardiogenic shock
-Heart filling
-CVP
-Arterial BP
-Tissue perfusion

Answer 5

Heart filling:
-Heart fills, but fails to pump effectively

CVP:
-Central venous pressure ma be normal or raised

Arterial BP:
-Dramatic drop in the arterial blood pressure.

Tissues are poorly perfused:
-Coronary arteries may be poorly perfused -> exacerbates problem
-Kidneys may be poorly perfused -> reduced urine production (oliguria)

Question 6

Treatment of Cardiac Arrest
-Basic life support
-Advanced life support
-Adrenaline

Answer 6

Basic life support:
-Chest compression and external ventilation

Advanced life support:
-Defibrillation
-Electric current delivered to the heart
-Depolarises all the cells

Adrenaline:
-Enhances myocardial function
-Increases peripheral resistance

Question 7

Cardiac tamponade
-What is it?
-Pressure
-What does heart do?

Answer 7

What is it?
-Blood or fluid build up in pericardial space
-Restricts filling of the heart
-Affects right and left sides of heart

Pressure:
-High central venous pressure
-Low arterial blood pressure

What does heart do?
-Heart attempts to beat: continued electrical activity

Question 8

Pulmonary embolism
-What is it?
-Pressure
-Features
-Symptoms

Answer 8

What is it?
-Embolus occluded a large pulmonary artery

Pressure:
-Pulmonary artery pressure is high
-Central venous pressure is high
-Left atrial pressure is low
-Arterial blood pressure is low

Features:
-Reduced return of blood to left heart
-Limits filling of left heart

Question 9

How might an embolus reach the lungs?

Answer 9

Typically due to DVT
Portion of thrombus breaks off -> travels in venous system to RS of the heart -> pumped out via pulmonary artery to lungs

Question 10

Hypovolaemic shock
-What is it?
-Common cause
-What is severity of shock related to?

Answer 10

What is it?
-Reduced blood volume

Common cause:
-Most commonly due to haemorrhage

Severity of shock:
-Severity of shock is related to amount and speed of blood loss

Question 11

Hypovolaemic shock
-Haemorrhage: Pressure, CO, detection
-Features of compensatory response

Answer 11

Haemorrhage:
-Venous and arterial pressure falls
-Cardiac output falls
-Detected by baroreceptors

Compensatory response:
-Increased sympathetic stimulation
-Tachycardia
-Increased force of contraction
-Peripheral vasoconstriction
-Venoconstriction