Cardiovascular responses to shock Flashcards
(14 cards)
Define shock
Abnormal state resulting in inadequate tissue perfusion and oxygenation.
What is the end result in the process of shock?
Cellular failure, as a result of inadequate perfusion
Two factors that Tissue perfusion depends on?
- MAP
2. CO
What happens in hypovolemic shock?
Lower blood volume–> lower venous return–> lower EDV + SV–> Lower CO + BP–> Inadequate tissue perfusion
Frank Starling law?
Higher EDV= Higher SV
What is the main cause of cardiogenic shock?
Sustained hypotension
What happens in cardiogenic shock?
Reduced contractility–> lower SV–> Lower CO + BP–> Inadequate tissue perfusion
What happens in tension pnuemothorax induced shock?
Increased intrathoracic pressure–> lower venous return–> lower EDV + SV–> Lower CO + BP–> Inadequate tissue perfusion
What happens in neurogenic shock?
Loss of sympathetic tone-> Venous and arteriolar dilatation–> lower venous return–> lower EDV + SV–> Lower CO + TPR–> Inadequate tissue perfusion
What happens in vasoactive shock?
Release of vasoactive mediators-> Venous and arteriolar dilatation–> lower venous return–> lower EDV + SV–> Lower CO + TPR–> Inadequate tissue perfusion
Steps for treatment for shock?
- ABCDE
- High flow Oxygen
- Volume replacement
- Immediate chest drain if tension pnemothorax
- Cardiogenic shock- Inotropes
- anaphylactic shock- adrenaline
- Septic shock - vasopressers
What are the common causes of hypovolemic shock?
- Haemorrhage
- diarrhoea, vomiting
What % of haemorrhagic blood loss can the body cope with?
upto 30%, not more.
Two clinical signs in haemorrhage?
- Cool peripheries- increased systemic vascular resistance
- small vol pulse- lower CO
- tachycardia- increased HR, baroreceptor reflex.
