Acutely Unwell Adult Flashcards
What is shock?
State of hypo-perfusion
Tissues do not receive adequate blood supply
Cellular and tissue hypoxia
‘Life threatening, generalised form of acute circulatory failure with inadequate oxygen delivery’
What force is relevant in blood vessels?
Capillary hydrostatic pressure
Changes throughout the capillary from venous to arterial end
What movement happens at the arterial end?
Fluid exits capillary since hydrostatic pressure > blood coloidal osmotic pressure
What movement happens at the venous end?
Fluid re-enters capillary since hydrostatic pressue < blood coloidal osmotic pressure
What is the capillary hydrostatic pressure at the venous end?
18mmHg
What is the capillary hydrostatic pressure at the arterial end?
35mmHg
What is the net filtration pressure at the arterial end?
+10mmHg
35mmHg-25mmHg
What is the net filtration pressure at the venous end?
-7mmHg
25mmHg-18mmHg
In shock where is the fluid lost to?
Interstitium
Explain distributive shock
Inflammation Increased vascular permeability 'leakier' Colloid osmotic pressure decreases Decreased venous reabsorption Fluid loss to the interstitum
Explain hypovolaemic shock
Loss of circulating blood volume
Explain cardiogenic shock
Failure of the pump
Problem with output - ‘delivery of blood’
Explain obstructive shock
Problem with output - ‘delivery of blood’
Obstruction within the circulatory system
Describe the pathophysiology of burns
Burn
Tissue damange
Clot formation and firbin
Necrotic cells release permeability factors
White cells can invade space
White cells in turn release permeability factors
White cells release cytokines
Eventual recruitment of fibroblasts promoting angiogenesis
Why do burns cause distributive shock?
Large number of permeability factors that are released at the site of damage
But these factors end up in the blood stream
Becomes a systemic problem as these factors invade healthy tissue
Overall blood vessels become leakier and more fluid is lost to the interstitum
Why is it called distributive shock?
Redistribution of fluid from in vessels to interstitum
‘Fluid moved to other spaces’