Shock & Systemic Response to Injury Flashcards
What is a simple definition of shock?
Cardiovascular collapse
What are the main types of insult or injury?
Trauma, stress, sepsis, GA, Sx
A stress response caused by insult or injury results in
Initiating the sympathoadrenal axis
Leads to release of catecholamines
leads to release of cortisol
What is shock?
Failure of the cardiovascular system to deliver adequate oxygen & nutrients to tissues
Tissue perfusion is dependent on:
circulating blood/fluids
heart pump ability
vagal motor tone
vascular musculature
What are the main classifications of shock?
Cardiogenic
Hypovolaemic
Distributive/Vasogenic
(Obstructive)
What is cardiogenic shock?
Failure of the heart, so unable to push blood around the body
What is hypovolaemic shock?
Volume deficit preventing deliver of oxygen and nutrients to the body
In hypovolaemic shock, a reduction of circulating volume is caused by…
whole blood loss
fluid loss (dehydration)
intestinal hypersecretion
What is distributive/vasogenic shock?
Blood maldistribution where the volume is available within the body but cannot be distributed to the appropriate location (vascular tone issues)
Describe the path of Vasogenic/Distributive shock.
Entotoxemia/sepsis/anaphylaxis –> release of vasoactive substances –> extensive dilation –> pooling of blood –> massive maldistribution of blood volume
Septic causes of Vasogenic/distributive shock can lead to what syndrome?
Systemic inflammatory response syndrome (SIRS)
What are the 3 main causes of vasogenic/distributive shock?
Sepsis, anaphylaxis, neurogenic
What are the main characteristics of the early or acute phase of shock?
conservation of fluid volume
change in energy metabolism
accelerated metabolic rate
What changes within the body will be seen during the early or acute phase of shock?
Increased HR
Increased SV
Increased peripheral pulses
Increased CRT
How does the body respond to the early/acute phase of shock?
increases sympathetic tone to conserve and minimize any losses –> vasoconstriction peripherally; increase HR/SV so the heart works harder increasing cardiac output; chemoreceptors tell the body to reduce oxygen saturation so the kidney stops secretion to conserve
What main organs/tissues are affected by the early/acute phase of shock?
kidneys, heart, blood vessels
What occurs during the decompensatory phase of shock?
Insult to the body continues and the compensatory mechanisms are unable to keep up. This leads to breakdown of the gut wall, increasing toxins, and thus overwhelming the liver. The liver releases more inflammatory mediators causing autoregulatory escape. This leads to organ vasodilation, blood pooling, further maldistribution, release of more cytokines from hypoxic tissues, DIC initiated, multiple organ failure, then death.
What clinical signs can be seen in the compensatory phase of shock?
tachycardia, tachypnoea, hyperaemic MM, fast CRT, increased peripheral pulses
What clinical signs can be seen in early decompensatory phase?
progressive tachycardia, tachypnoea, prolonged CRT, cold extremities, weak peripheral pulses, anuria/oliguria, depression, lack of responsiveness
What clinical signs can be seen in the late decompensatory phase?
Hypotension, bradycardia, circulatory collapse, pale MM, anuria, collapse, severe depression
Also possible: recumbency, loss of consciousness
What are the main ways of treating shock?
Oxygen supplementation
Restoration of circulating volume through early aggressive fluid therapy
Glucocorticosteroids
Pain control
Cardiovascular support
Control of haemorrhage
What are some things to ask yourself when thinking of fluid therapy?
Crystalloid vs colloid?
Isotonic vs hypertonic?
Plasma/whole blood?
Synthetic blood products?
What is the shock dose rate of administration of crystalloid fluids?
90 ml/kg/hr
