Shock Flashcards
What is shock
An abnormality in circulatory system resulting in inadequate tissue perfusion and oxygenation
What can cause inadequate tissue perfusion?
- Loss of blood volume
- sudden impairment of heart function
- physical obstruction
- excessive vasodilation and abnormal distribution of blood flow
What are the 4 types of shock?
- hypovolaemic shock
- cariogenic shock
- obstructive shock
- distributive shock
What is hypovolaemic shock
inadequate perfusion of the tissues due to loss of blood volume.
what is cardiogenic shock?
sudden severe impairment of heart function that causes insufficient blood to be provided to the tissues
what is obstructive shock
physical obstruction of circulation either into or out of the heart
what is distributive shock?
caused by excessive vasodilation and abnormal distribution of blood flow
what effect does hyopvolaemic shock have on the frank starling law
Decreases venous return, so decreases end diastolic volume.
this results in decreased SV and decreased CO/BP leading to inadequate tissue perfusion
what is the reason for the decreased SV in cardiogenic shock
decreased cardiac contractility
how does obstructive shock cause inadequate tissue perfusion?
increased intrathoracic pressure leads to decreased venous return.
how do neurogenic problems lead to shock?
- loss of sympathetic tone to blood vessels and heart leads to massive vasodilation
- decreased venous return and decreased SVR as well as decreased heart rate
what is vasoactive shock?
caused by release of vasoactive mediators which cause vasodilation leading to decreased venous return and blood pressure.
What is the first step of treatment for shock?
ABCDE
what are some of the potential methods of treating a patient with shock
- oxygen
- volume replacement - except cardiogenic shock
- treat cause
what drug can be given for cardiogenic shock\?
inotropes which increase cardiac contractility
for example - noradrenaline, adrenaline, dopamine, dobutamine
what drugs can be given for septic shock?
- vasopressor to increase the vascular tone and try to reduce the vasodilation
for example - vasopressin, adrenaline, noradrenaline , dopamine, terlipressin
what procedure needs to be done for a tension pneumothorax?
insert a chest drain immediately.
what can cause hypovolaemic shock?
- haemorrhage
- decreased ECFV due to vomiting, diarrhoea, sweating
at what percentage of blood loss can blood pressure no longer be maintained?
30%
why does haemorrhagic shock lead to tachycardia?
baroreceptor reflex recognises decreased BP and causes increase in sympathetic activity to increase the BP back to normal
why do patients have cool peripheries when in haemorrhagic shock?
they have increased SVR due to the baroreceptor reflex
