Shock

Question 1

What is the most important thing which must be done for a person who has suffered a cardiac arrest?

Answer 1

Maintenance of blood flow around the body with chest compressions.

Question 2

What is the use of defibrillation in cardiac arrest?

Answer 2

This depolarises all the cells and puts them into the refractory period so that in theory, the heart will begin beating in sinus rhythm.

Question 3

What is haemodynamic shock?

Answer 3

This is a sudden fall in blood pressure leading to inadequate blood flow throughout the body.

Question 4

What two features of the CVS system can be affected to cause shock?

Answer 4

Fall in cardiac output, fall in TPR.

Question 5

What is the difference between cardiogenic and mechanical shock?

Answer 5

Cardiogenic is when the heart cannot pump blood Out sufficiently, whilst in mechanical shock the ventricle cannot fill properly

Question 6

What can cause cardiogenic shock?

Answer 6

MI, arrhythmias, acute/worsening heart failure.

Question 7

Give two examples of mechanical shock

Answer 7

Cardiac tamponade and pulmonary embolism

Question 8

What is cardiac tamponade?

Answer 8

This is when there is a build up of fluid in the pericardium, and this leads to increased pressure and this restricts the filling of the heart.

Question 9

Why can pulmonary embolism lead to shock?

Answer 9

This causes increased pressure in the pulmonary artery, and so RV is unable to empty and this leads to raised CVP. There is also reduced LA filling. This leads to low arterial blood pressure.

Question 10

What percentage of blood volume must be lost to cause a shock response?

Question 11

Following haemorrhage, how does the body respond?

Answer 11

This leads to a lowered CVP and therefore lowered CO and BP which is detected by baroreceptors - increased sympathetic response which leads to tachycardia and vasoconstriction and venoconstriction to try and increase BP

Question 12

What can occur as a response to increase TPR?

Answer 12

There can be internal transfusion due to the lowered capillary hydrostatic pressure and so net movement of fluid into the capillaries.

Question 13

What symptoms are associated with internal transfusion?

Answer 13

Tachycardia, weak pulse, pallor and cold extremities.

Question 14

What is decompensation?

Answer 14

This occurs after some time in shock. The vasoconstriction leads to local tissue injury and so they release vasodilatory which leads to a catastrophic fall in TPR.

Question 15

What is a consequence of decompensation?

Answer 15

Low TPR leads to low BP. Organs are not sufficiently perfused and this leads to multi organ failure.

Question 16

What are long term responses to hypovolaemia?

Answer 16

The body tries to adjust for this by the action of RAAS and ADH.

Question 17

What is distributive shock?

Answer 17

This is where the fall in BP is caused by a large decrease in TPR and so increased circulation volume.

Question 18

What happens in septicaemia?

Answer 18

Endotoxins released by bacteria cause vasodilation and also vessel leaky mess so there is a drop in TPR and blood volume. The baroreceptors detect the drop In BP and there is a sympathetic response.

Question 19

How would a patient with septicaemia present?

Answer 19

Warm, red extremities and tachycardia.

Question 20

What is anaphylactic shock?

Answer 20

This is where there is release of histamine from mast cells leading to vasodilation and fall in TPR. SNS is stimulated by baroreceptors, but there is impaired perfusion of vital organs.

Question 21

What is the treatment for anaphylaxis?

Answer 21

Adrenaline as this causes vasoconstriction.

Question 22

How will a patient with anaphylaxis present?

Answer 22

They will have rapid pulse, collapsed, warm, red extremities,

Question 23

What is the major consequence of shock?

Answer 23

Decreased tissue perfusion leads to multi-organ failure.

Question 24

What two conditions are you at increased risk of if you have long term hypertension?

Answer 24

LV hypertrophy, and risk of heart failure.

Question 25

What is the treatment for hypertension?

Answer 25

Weightloss, exercise. Reduced salt intake,

Pharmacologically: diuretics, ACE inhibitors and vasodilators.