19: Cardiovascular responses to shock Flashcards Preview

Cardiovascular Week 1 & 2 2016/17 > 19: Cardiovascular responses to shock > Flashcards

Flashcards in 19: Cardiovascular responses to shock Deck (21)
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1
Q

What is shock?

A

Some abnormality of the circulatory system resulting in inadequate tissue perfusion and oxygenation

2
Q

Outline the steps leading from shock to cellular failure.

A

Shock

Inadequate tissue perfusion

Inadequate tissue oxygenation

Anaerobic metabolism

Accumulation of metabolic waste products

Cellular failure

3
Q

What two factors does adequate tissue perfusion depend on?

A
  1. Adequate blood pressure
  2. Adequate cardiac output
4
Q

What is hypovolaemic shock?

A

Shock caused by loss of blood volume

5
Q

Outline the steps of hypovolaemic shock between loss of volume and inadequate tissue perfusion.

A
  1. Loss of blood volume
  2. Decreased venous return
  3. Decreased end diastolic volume
  4. Decreased stroke volume
  5. Decreased cardiac output and blood pressure
  6. Inadequate tissue perfusion
6
Q

Briefly summarise the Frank-Starling Law of the heart.

A

Increased/decreased EDV = increased/decreased stroke volume –> cardiac output

7
Q

What is cardiogenic shock?

A

Sustained hypotension caused by decreased cardiac contractility

8
Q

Outline the steps of cardiogenic shock.

A

Decreased cardiac contractility

Decreased stroke volume

Decreased cardiac output and blood pressure

Inadequate tissue perfusion

9
Q

Give an example of a condition which may cause obstructive shock.

A

Tension pneumothorax

10
Q

Imagine a patient has presented with a tension pneumothorax. Outline the steps of obstructive shock which lead to inadequate tissue perfusion.

A

Increased intrathoracic pressure

Decreased venous return

Decreased end diastolic volume

Decreased stroke volume

Decreased CO and BP

Inadequate tissue perfusion

11
Q

Give an example of an injury which may trigger neurogenic shock.

A

Spinal cord injury

12
Q

Outline the steps of neurogenic shock following an event like a spinal cord injury.

A

Loss of sympathetic tone

Massive venous and arterial vasodilatation

Decreased venous return and TPR

Decreased CO and BP

Inadequate tissue perfusion

13
Q

Outline the steps of vasoactive shock.

A

Release of vasoactive mediators

Massive venous & arterial vasodilation

Decreased venous return and TPR

Decreased CO and BP

Inadequate tissue perfusion

14
Q

Which mnemonic should be the first thing you think of when someone presents with shock?

A

ABCDE

15
Q

Apart from ABCDE, which other general treatments are given for shock?

A

High flow O2

Volume replacement

16
Q

What is a treatment which can be given for cardiogenic shock?

A

Positive inotropes (e.g Digoxin)

17
Q

Say someone had obstructive shock due to a tension pneumothorax - what is an immediate treatment?

A

Immediate chest drain

18
Q

What immediate treatment is given for anaphylactic shock?

A

Adrenaline

19
Q

What type of drug would you give to someone suffering septic shock?

A

Vasopressors (which cause vasoconstriction

20
Q

Name a cause of hypovolaemic shock.

A

Haemorrhage

Vomiting

Diarrhoea

Excessive sweating

21
Q

Compensatory mechanisms can maintain blood pressure until which percentage of total blood volume is lost?

A

> 30%