Physiology of Shock Flashcards
What is Shock?
Condition of inadequate perfusion to sustain normal organ function
What are the 5 main classes of Shock
Hypovolaemic Cardiogenic Obstructive Distributive Cytotoxic
What is hypovolaemic shock
Loss of circulating volume
- reduced preload and cardiac output
What is cariogenic shock
Myocardial dysfunction
- reduction in systolic function and cardiac output
What is obstructive shock
Physical obstruction to filling of the heart
- reduced preload and cardiac output
What is distributive shock
Significant reduction in SVR beyond the compensatory limits of increased CO
What is cytotoxic shock
uncoupling of tissue oxygen delivery and mitochondrial oxygen uptake
What are the 4 compensatory mechanisms of hypovolaemic shock
Baroreceptor reflexes
Sympathetic mediated neurohormonal response
Capillary absorption of interstitial fluid
Hypothalamus-pituitary-adrenal response
In what 3 physiological ways can CO be increased
Increase HR
Increase SV
Increase both
What is the most common cause of cariogenic shock
MI
Acute valve dysfunction
What are some clinical signs of cardiogenic shock
hypotension Fatigue Syncope Pulmonary oedema Elevated JVP
What is positive intropy
an increase in force of cardiac contraction for any given preload
In terms of the nervous system how is positive intropy achieved
Sympathetic
What drugs can replicate positive intropy
Dopamine
Adrenaline
What is the treatment of cardiogenic shock
Intra-aortic balloon pump
