RESP 120 Chapter 8

In what two forms is oxygen carried in the blood?

Dissolved in plasma and bound to hemoglobin.

What percentage of oxygen is dissolved in plasma?

~1.5%.

What percentage of oxygen is bound to hemoglobin?

~98.5%

How many oxygen molecules can one hemoglobin molecule bind?

Four.

What is the equation for arterial oxygen content (CaO₂)?

CaO₂ = (1.34 × Hb × SaO₂) + (0.003 × PaO₂)

What does the 1.34 constant represent in the CaO₂ equation?

The amount of oxygen (mL) that 1 gram of hemoglobin can carry.

What does the 0.003 constant represent in the CaO₂ equation?

The amount of oxygen dissolved in plasma per mmHg of PaO₂.

What is the normal CaO₂ value?

~19–20 mL O₂ / 100 mL blood.

What is the normal adult hemoglobin range?

~15 g/dL.

What is the equation for venous oxygen content (CvO₂)?

CvO₂ = (1.34 × Hb × SvO₂) + (0.003 × PvO₂)

What is the normal CvO₂ value?

~15 mL O₂ / 100 mL blood.

What is the equation for capillary oxygen content (CcO₂)?

CcO₂ = (1.34 × Hb × SaO₂) + (0.003 × PAO₂)

What is the normal CcO₂ value?

~20 mL O₂ / 100 mL blood.

What does the Hb–O₂ dissociation curve show?

The relationship between PaO₂ and SaO₂.

What is the normal shape of the Hb–O₂ dissociation curve?

Sigmoid (S-shaped).

What does cooperative binding mean?

Binding of one O₂ molecule increases hemoglobin’s affinity for the next.

What is the normal P50 value?

~27 mmHg.

What does P50 represent?

The PaO₂ at which hemoglobin is 50% saturated.

What causes a right shift of the Hb–O₂ dissociation curve?

↑ CO₂, ↑ temperature, ↑ 2,3-DPG, ↓ pH.

What causes a left shift of the Hb–O₂ dissociation curve?

↓ CO₂, ↓ temperature, ↓ 2,3-DPG, ↑ pH, carbon monoxide.

What is the normal oxygen delivery (DO₂)?

~1000 mL O₂/min.

What is the equation for oxygen delivery (DO₂)?

DO₂ = CaO₂ × Q × 10

What is the normal arteriovenous O₂ content difference (C(a-v)O₂)?

~4–5 mL O₂ / 100 mL blood.

What is the normal oxygen consumption (VO₂)?

~250 mL O₂/min.

What is the normal oxygen extraction ratio (O₂ER)?

~25%.

What is the normal physiologic shunt fraction (Qs/Qt)?

~2–5%.

What defines hypoxemia?

Decreased oxygen in arterial blood (↓ PaO₂).

What defines hypoxia?

Decreased oxygen delivery or utilization at the tissue level.

What are the four types of hypoxia?

Hypoxemic, anemic, circulatory, histotoxic.