Shock Flashcards
What is shock defined as?
A syndrome in which tissue perfusion is inadequate for the tissue’s metabolic requirement
What 3 things does normal circulation rely on?
Cardiac function
Intact and appropriately functioning vascular system
Circulating blood volume
How is MAP calculated?
Cardiac Output (CO) x Systemic Vascular Resistance (SVR)
How is oxygen delivery calculated?
DO2 = CO x [(1.34 x Hb x SaO2) + (PaO2 x 0.003)]
What are the 5 types of shock?
Hypovolaemic
Cardiogenic
Distributive
Obstructive
(Endocrine )
What is hypovolaemic shock?
A large loss of fluids through haemorrhage or ‘fluid deplete’ states
What are common causes of hypovolaemic shock?
Acute haemorrhage
Burns, severe dehydration
What is cardiogenic shock?
A reduced CO due to pump failure
What typically causes cardiogenic shock?
What are other less common causes?
Ischaemia induced myocardial dysfunction
Cardiomyopathies, valvular problems, dysrhythmias
What is distributive shock?
Disruption of normal vascular autoregulation, and profound vasodilation - poor perfusion
Give some examples of distributive shock?
Sepsis, anaphylaxis, acute liver failure, spinal cord injuries
What is obstructive shock?
Mechanical obstruction to normal cardiac output in an otherwise normal heart
What are the two types of obstructive shock?
Direct obstruction (PE / embolism)
Restriction of cardiac filling (tamponade, tension pneumothorax)
What is the most common cause of distributive shock?
Sepsis
List some haemodynamic changes in patients with shock?
Vascular abnormalities (vasodilation / constriction)
Maldistribution of blood flow
Microcirculatory abnormalities
Inappropriate activation of coagulation system
What 4 things should be monitored clinically in patients with shock?
Physical examination
Urine output
Biochemical levels
Neurological status
What pressures should be measured in patients with shock?
Blood pressure
Central venous pressure
Pulmonary artery pressures
Pulmonary capillary wedge pressures
What is gold standard in the clinical monitoring of shock?
Cardiac output
