Oxygenation Physiology

Question 1

What is V/Q mismatch

Answer 1

Inadequate ventilation but normal perfusion

This is also referred to as shunt, commonly caused by some sort of obstruction in alveoli

Examples of this are pulm-edema, COPD, drowning, etc.

Question 2

What is dead space ventilation?

Answer 2

The opposite of V/Q mismatch; adequate ventilation but inadequate perfusion

Question 3

What is the 50:50 club?

Answer 3

PaCo₂ ≥ 50

AND

PaO2 ≤ 50

Refers to acute obstructive pathology that requires PPV to resolve

Question 4

What does high lactate levels indicate

Answer 4

Metabolic stress

NOT an indicator of hypoxia, sepsis, or any other pathology

Question 5

What are the steps of aerobic glycolysis

Answer 5

1. Glucose is broken down to two pyruvate acid
2. Krebs Cycle
3. Oxidative phosphorylation

Question 6

Define PaO₂

Answer 6

Partial pressure of oxygen in plasma

Question 7

Define PO₂

Answer 7

Partial pressure of oxygen in environment

Question 8

Define PAO₂

Answer 8

Partial pressure of oxygen in alveoli

Question 9

Define SaO₂

Answer 9

Amount of hemoglobin in blood that are saturated

Question 10

Define SpO₂

Answer 10

Total saturation of of O₂ bound to Hgb

Question 11

Define SvO₂

Answer 11

Mixed venous O₂ saturation measured by a pulmonary artery catheter

Question 12

Define ScvO₂

Answer 12

Central venous O₂ sat

Note that central line measurements are 5% to 8% higher

Question 13

Define CaO₂

Answer 13

Arterial O₂ content bound to Hgb

Question 14

Define DO₂

Answer 14

Total delivery of O₂ over the course of a minute

Question 15

When confronted with a pt in acute hypoxia, what is the first major question to ask?

Answer 15

Is this an oxygenation problem or a deadspace issue