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Flashcards in Shock Deck (10):

What is the equation for maBP

maBP = SV x HR x TPR or
maBP = CO x TPR


What is cardiac arrest and what are the three different electrical states that cause it?

Cardiac arrest is defined as when someone is unresponsive without a pulse. This can be due to asystole (no electrical activity), pulseless electrical activity or ventricular fibrillation.


How is PEA (pulse-less electrical activity) and VF (ventricular fibrillation) treated?

CPR and defibrillation to put the heart into the refractory period and try start again. Adrenaline is also administered to enhance heart function and to increase TPR to maintain BP.


What is haemodynamic shock?

Haemodynamic shock is due to inadequate blood flow due to either fall in TPR or CO or both. There are 4 types of shock.


What is cardiogenic shock?

Cardiogenic shock this is due to the heart failing in some way, it carries on filling but doesn’t pump resulting in BP and CVP falling or normal. The now poor perfusion to coronary arteries makes the situation worse.


What is mechanical shock?

Mechanical shock or obstruction of some sort such as cardiac tamponade or MPE and results in a low CO and an increase in CVP as blood backs up.


What is hypovolaemic shock?

Hypovolaemic shock occurs due to loss of blood (severe diarrhoea, vomiting or burns) resulting in a large loss of venous pressure and so CO drops. People with this shock are tachycardic, pale, sweating and cold.


How does your body compensate in hypovolaemic shock?

Your body tries to compensate by increase contractility, HR, veno and vaso constriction. Note when you lose blood the vasoconstriction results in lower hydrostatic pressure in capillaries so liquid comes back into the blood vessels giving you a physiological transfusion effect.


Why does vasoconstriction eventually make hypovolaemic shock worse?

Vasoconstriction eventually makes things worse by causing hypoxia and so the release of vasodilator metabolites.


What is Distributive shock?

Distributive shock is caused by low resistance this can occur due to septicaemia (septic shock) due to the endotoxins released by bacteria which cause massive vasodilation and the capillaries to become leaky.

Anaphylactic shock occurs very similarly but due to the release of histamine from mast cells, they also cause bronchoconstriction, this is treated with adrenaline. Patients will look red, warm and be tachycardic.