Fundamentals
The physiologic process of delivering oxygen and nutrients to tissues via blood flow.
Answer: What is perfusion?
Cardiac output equals heart rate multiplied by this.
Answer: What is stroke volume?
True or False: Normal blood pressure always means adequate perfusion.
Answer: What is false?
The shock state caused by inadequate pump function.
Answer: What is cardiogenic shock?
Oxygen delivery depends on cardiac output and this blood component.
Answer: What is hemoglobin?
– The primary variables that determine tissue perfusion at the systemic level.
Answer: What are cardiac output, vascular resistance, and blood volume?
The Frank–Starling mechanism describes how this affects stroke volume.
Answer: What is preload?
A patient on high-dose vasopressors may have adequate MAP but poor perfusion because of this.
Answer: What is excessive vasoconstriction?
The shock state most associated with maldistribution of blood flow.
Answer: What is distributive shock?
The equation component that explains why anemic patients can be poorly perfused despite normal MAP.
What is decreased oxygen-carrying capacity?
The equation used to describe organ perfusion pressure.
Answer: What is MAP minus venous pressure (or ICP for cerebral perfusion)?
A failing ventricle may generate adequate pressure but still have poor perfusion due to this problem.
Answer: What is low forward flow?
The bedside sign that often indicates poor peripheral perfusion despite normal vitals.
Answer: What are cool extremities or delayed capillary refill?
The earliest organ system to show signs of hypoperfusion.
Answer: What is the kidneys (decreased urine output)?
This explains why septic patients may have normal SpO₂ but still be hypoxic at the tissue level.
Answer: What is impaired cellular oxygen utilization?
The minimum MAP generally required to maintain cerebral perfusion in adults.
Answer: What is approximately 65 mmHg?
Answer: What is approximately 65 mmHg?
A medication class that increases cardiac contractility to improve perfusion.
Answer: What are inotropes?
The lab value that reflects global tissue hypoxia.
Answer: What is lactate?
A classic sign of cerebral hypoperfusion.
Answer: What is altered mental status?
The phenomenon where capillary beds fail to reopen even after perfusion pressure is restored.
Answer: What is microvascular collapse or no-reflow phenomenon?
The term for inadequate perfusion leading to cellular hypoxia and organ dysfunction.
Answer: What is shock?
Why tachycardia can worsen perfusion despite increasing heart rate.
Answer: What is reduced diastolic filling time and decreased stroke volume?
The concept that explains why organs may be perfused differently during shock.
Answer: What is preferential blood flow or shunting?
Why blood pressure can improve before perfusion does during resuscitation.
Answer: What is restoration of pressure without restoration of flow or microcirculation?
Why lactate can remain elevated even after MAP normalizes.
Answer: What is persistent microcirculatory dysfunction?