Download Perfusion

Oxygenation and Perfusion
Taylor ch. 38
Perfusion
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Exemplar is circulation assessment
Objectives for this lecture are to
follow…
Perfusion
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Describe factors affecting perfusion.
Relate the physiological process involved in
circulation and perfusion.
Explain assessment techniques used to
determine perfusion status.
Describe the basic diagnostic and laboratory
tests utilized to determine the client’s
perfusion status.
Perfusion
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This begins with the lungs’ ability to distribute
the erythrocytes or red blood cells to and
from the pulmonary capillaries
Remember that the cardiovascular system
and the respiratory system work together in
the body.
Good perfusion to body organs and the
peripheral system means that these target
areas are receiving adequate oxygenation.
Perfusion
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Typically, if a client has a disease
process involving the lungs, the
cardiovascular system will also be
affected, thereby affecting perfusion
and oxygenation.
Perfusion
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Since blood pressure is a good indicator of
perfusion, changes in it will affect perfusion
to the body. These changes are affected by:
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Cardiac output (CO)
Peripheral vascular resistance (PVR)
Blood volume
Blood viscosity
Arterial elasticity
Let’s look at each of these factors.
Perfusion: Cardiac Output
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Remember, CO is the amt of blood produced
in 1 minute.
As CO increases B/P rises, which increases
perfusion to the body.
Perfusion: Cardiac Output
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CO increases due to:
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Increased heart rate
Greater heart contractility
Increase in blood volume
However, a rapid or significant increase
in heart rate decreases the heart’s filling
time, causing a decrease in B/P
Perfusion: Peripheral
Resistance
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Arteries and arterioles are covered by
smooth muscle that adjusts the lumen
size as needed, depending on tissue
needs.
The smaller the vessel lumen, the
higher the PVR.
Perfusion: Blood Volume
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Circulating blood volume in adults is
about 5000 mL
Increase in blood volume, increases B/P
such as with IV infusion
Decrease in blood volume decreases
B/P such as with hemorrhage
Perfusion: Viscosity
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Thickness of the blood
Hematocrit: percentage of blood cells
in the blood determines viscosity
Anticoagulants and birth control pills
are examples of 2 meds that will affect
viscosity
Perfusion: Elasticity
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Normally arterial walls are elastic
Reduced elasticity: greater resistance
to blood flow
Pulse and Perfusion
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Palpable bounding of blood flow at various
points in the body
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Good indicator of circulatory status and thus
perfusion
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If pulse is present, there is some level of
vascular perfusion of tissue
Assessment of Tissue
Perfusion
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Palpation of pulse sites and grading
Assess condition of skin, mucosa, nail
beds
Color of skin, lips, mouth, and
conjunctivae
Assessment
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Inspect lower extremities for changes of
color, temperature, and condition of the
skin
Ask about history of leg pain
Skin and nail texture, hair distribution
on lower legs, feet, and toes
Assessment
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Palpate the legs and feet for color and
temperature
Assess capillary refill: blanching the
nail bed for several seconds
When pressure is released, full color
should return in less than 2 seconds