Peripheral perfusion - capillary refill time Flashcards
What is CRT?
Capillary refill time, measures how well the vascular system is functioning.
What can a quick CRT test alert?
Dehydration or blockage of tissue perfusion by other means. Care needs to be taken to restore normal vascular flow.
What does CRT enable an indirect evaluation of?
The mechanical power of the heart, volume of circulating blood and partly evaluation of vasodilatation and vasoconstriction mechanisms in the periphery.
How is this measured in humans?
By capillary nailbed refill time, which is measured in the fatty pads of the hands or heels in children.
What is used to investigate CRT in animals?
Oral pigment-free mucosa.
How?
Push mucosa, observe colour reaction, measure time.
What is microcirculation?
Deals with the flow of blood from arterioles to capillaries.
Which structures control the flow of blood between the arterioles and the capillaries?
Precapillary spinchters
Why are the precappilary spinchters important?
Capillaries consist only of one layer of endothelial cells. They have no smooth muscle in the vessel wall. Only way of vasoconstriction !
How does the precapillary spinchters work?
Contain muscle fibres that allow them to contract –> restriction of bloodflow to the capillary beds. Blood flow directly from arterioles to venules through the throughfare channel.
Does all capillary beds contain blood at all times?
No, blood is supplied to all parts of the body, but not all CB contain blood at all times.
What is normal CRT time?
1-2 seconds
CRT is decreased by..?
Vasodilatation
CRT is increased by…?
Vasoconstriction
CRT is a physical examination parametre that contributes to?
Differential diagnosis of the cause of low tissue oxygenation.
