HAEMODYNAMIC DISORDERS Flashcards
what is haemodynamics?
the movement of blood
how is fluid balance maintained?
hydrostatic pressure pushing fluid into tissues and colloid osmotic pressure (protein concentration) returning blood to the vessels
what is oedema?
observable swelling caused by an increased fluid in interstitial tissue apce
what can cause oedema?
increases in vascular volume, descreases in plasma protein concentrations, changes in endothelial cell walls, lymphatic obstructions, sodium retenstion and inflammation
how does sodium retention cause oedema?
excess sodium causes increased hydrostatic pressure so more fluid escspes into tissues
how does inflammation cause oedema?
blood vessel permeability increases leading to the migration of fluids, proteins and leukoctes from the blood into the tissues
what is hyperaemia?
increased blood flow into a particular tissue
what is congestion?
descreased blood flow/venous return out of a tissue
what is reactive hyperaemia?
local vasodilation in response to oxygen debt and accumulation of metabolic waste
what is active hyperaemia?
increased blood flow in response to an period of activeness e.g. during exercise
whats an example of reactive hyperaemia?
raynaud syndrome
what can cause congestion?
physical obstruction of veins or failure of the heart to pump the blood away from the affected area
what is local congestion?
compression of blood vessels, impairing venous return
what is systemic congestion?
heart failure leading to impaired venous return
what is the haemostatic strategy?
how the body prevents bleeding and stops bleeding whilst keeping blood within the damaged vessels
what is a haemorrhage?
extravasation of blood due to vessel rupture
how much blood can cause hypovolemic shock?
> 15% of blood lost
what is hypovolemic shock?
an emergency condition in which severe blood or other fluid loss makes the heart unable to pump enough blood to the body
what are petechia?
minute haemorrhages being 1-2mm diameter
what are purpura?
small haemorrhages of 3-10mm diameter
what are ecchymosis?
subcutaneous haematoma greater than 1cm diameter
tends to have colour changes due to metabolism of haemoglobin to bilirubin and hemosiderin
aka a bruise
what is thrombosis?
the process of clotting and the formation of a blood clot within the vessel which remains attached to the vessel wall
what are the 2 arterial thrombi?
mural thrombi and occlusive thrombi
what are mural thrombi?
a thrombus which doesnt occlude the vessel so has minor clinical events
whats occlusive thrombi?
a thrombus that blocks the vessel so metabolic waste accumulates and downstream tissues dont receive blood flow = major clinical events
where do venous thrombi tend to happen?
around valves