Perfusion Basics
Delivery of oxygenated blood to tissues and removal of waste.
What is tissue perfusion?
What does delayed capillary refill indicate?
Poor perfusion.
What is the formula for cardiac output?
CO = HR × SV
What is shock?
Inadequate tissue perfusion
A blood clot in a deep vein, usually the legs.
What is a DVT?
What organ is most sensitive to decreased perfusion?
The brain
A patient is pale and cool—what does this suggest?
Decreased peripheral perfusion / vasoconstriction.
What does stroke volume depend on?
Preload, afterload, and contractility.
Name one type of distributive shock.
Septic, neurogenic, anaphylactic.
What is the most dangerous complication of a DVT?
Pulmonary embolism.
Name one factor that decreases perfusion.
Hypotension, low cardiac output, hypovolemia, clots, vasoconstriction, etc
What early neurological sign appears with poor cerebral perfusion?
Confusion or altered mental status.
A MAP below what number indicates risk of inadequate perfusion?
MAP < 65 mmHg
What shock type causes warm, flushed skin?
Early septic shock.
Name one risk factor for DVT.
Immobility, surgery, pregnancy, smoking, estrogen therapy, obesity.
What lab value reflects oxygen-carrying capacity?
Hemoglobin
Which vital sign often changes first when perfusion drops?
Heart rate (tachycardia).
What does an elevated lactate level indicate?
Tissue hypoxia and anaerobic metabolism
What is the primary issue in hypovolemic shock?
Low circulating blood volume.
What key sign suggests a PE?
Sudden shortness of breath, chest pain, tachycardia.
What is the main determinant of perfusion pressure?
MAP (mean arterial pressure).
What does mottled skin indicate?
Severe hypoperfusion / advanced shock.
If afterload increases, what happens to cardiac output?
It decreases.
What type of shock results from a weak or failing heart?
Cardiogenic shock.
How do clots impair perfusion?
They block blood flow → tissue becomes ischemic.