Physiology of Perfusion
Blood flow that brings oxygen to tissues?
What is perfusion?
Amount of blood the heart pumps with one beat
What is stroke volume?
Shock from big excessive blood loss or dehydration
What is hypovolemic shock?
Cells switch to making energy without oxygen and produce this acid
What is lactic acid (lactic acidosis)?
Two quick signs to check if someone may be in shock (any two)
What is low blood pressure, fast heart rate, low urine output, cool skin, altered mental status, low or irregular breathing?
Nervous system part that raises heart rate and tightens blood vessels
What is the sympathetic nervous system?
Extra Nuggets of Knowledge: Known as fight or flight response system.
Releases norepinephrine and epinephrine into the blood stream. Increases cardiac contractility. Speeds conduction velocity (how fast messages travel through the nerves to tell the body something). Dilates pupils. Shows the gut and dilates the bronchi.
The heart’s ability to squeeze and push out blood
What is heart contractility?
Shock from the heart not pumping well (like after a heart attack)?
What is cardiogenic shock?
The body speeds up heart rate and tightens vessels to try and keep blood pressure up. Name one of these responses.
What is increased heart rate or vasoconstriction?
First simple treatment for many shock patients to increase blood volume
What is give IV fluids?
The number used to estimate how well organs are getting blood (pressure)
What is mean arterial pressure (MAP)?
Extra Nuggets of Knowledge: “MAP is ultimately the blood pressure required to sustain organ perfusion and is roughly 60 mm Hg in the typical resting adult.” - AEMT Textbook
MAP ~ Diastolic blood pressure + 1/3 pulse pressure (systolic pressure - diastolic pressure)
This equation is meant to only approximate MAP
Blood coming into the heart before it pumps out. Affected by volume
What is preload?
Preload increase means the volume of blood within the ventricles increases which means the cardiac muscles are stretched, increasing the strength of contraction thus increasing cardiac outputShock from something blocking blood flow (like a big clot)?
What is obstructive shock?
When many organs start failing after prolonged poor blood flow.
What is multiple organ dysfunction (MODS)?
Symptoms: Fever, chills, rapid/irregular heartbeat, confusion, difficulty breathing, & severe abdominal pain
If first simple treatment does not fix low blood pressure, start this medication to tighten vessels
Formula: stroke volume x heart rate = ?
What is cardiac output?
The pressure the heart must push against to eject blood
What is afterload?
Shock from a huge blood vessel widening (like severe infection or allergic reaction).
What is distributive shock?
There main stages of shock?
What is compensated, decompensated, and refractory?
Compensated: Initial stage. Body successfully maintains blood pressure and vital organ perfusion despite reduced blood volume or cardiac output
Decompensated: Late stage. Critical. The body’s compensatory mechanisms fail (fast heart rate and vasoconstriction) resulting in inadequate blood pressure and organ perfusion
Refractory: Advanced stage. Cardiovascular failure where blood pressure and tissue perfusion remain critically low causing cellular hypoxia and anaerobic metabolism leading to MODS.
Two patient problems that make you give fluids with more caution
What are heart failure and kidney failure?
Special considerations: Aggressive fluid therapy increases the workload on the heart, worsening cardiogenic shock and increasing internal bleeding by breaking up clots that are forming or increasing the pressure in the vessels
The resistance blood meets in the body’s vessels
What is systemic vascular resistance (SVR)?
One thing that lowers cardiac output
What is low blood volume (or poor heart pumping)?
Name one common cause of low heart output
What is heart attack, severe bleeding, or bad heart rythym?
High afterload, low preload, poor contractility; or any combination of the three
A sign the body is not getting enough blood to organs
What is high lactate?
The immediate steps in order for a patient who may be in shock
What are check ABCs, get IV access, give fluids, start pressors, find cause?