L10- Physiology of shock

Question 1

Name 3 derteminants of blood flow or cardiac output

Answer 1

• Changes in Pressure gradient
• Changes in resistance
• Changes in stroke volume & heart rate

Question 2

What are the derteminants of stroke volume?

Answer 2

• venous return
• Preload (Frank-Starling)
• Afterload
• Contractility
• Blood volume

Question 3

What is the most common event during shock?

Answer 3

Reduced Mean Arterial Pressure (MAP)

*↓ MAP results in ↓ blood flow to tissues

Question 3

Formula of cardiac output

Answer 3

CO = MAP - RAP/ TPR

Question 3

Name the 3 types of shock

Answer 3

• hypovolaemic: Loss of fluid leading to decreased blood volume
• Cardiogenic: Heart failing to act as a pump. Ventricular muscles fail to function normally
• vasogenic or vascular: Due to vasodilation, decreasing TPR and thus MAP

Question 4

What is the goal of physician on shock?

Answer 4

To increase MAP

which is to happen at cost of reducing blood flow to tissues and organs, further ensuing organ damage

Question 4

Which 2 mechanisms compensate for changes in blood pressure?

Answer 4

• Baroreceptors (stimulate the SNS and downregulate the PNS)
• Cerebral ischaemic response (is stimulated by MAP of < 50 mmHg. Stimulates SNS

Question 5

what are the causes of vascular shock?

Answer 5

• ↓SNS activity (neurogenic),
• ↑Histamine (anaphylactic)
• ↑ Toxins (septic)