Oxygen Delivery (DO₂) — Bedside Thinking

The Truck Analogy

When a patient isn’t improving, it’s easy to chase the PaO₂.

But oxygen delivery depends on three things.

Think of hemoglobin like a truck carrying oxygen to tissues.

---

The Three Levers

1. Load the trucks → increase saturation (SaO₂)

Load up the trucks = Increase FiO2

• FiO₂ / FdO₂

• Oxygenation

---

2. Add more trucks → increase hemoglobin (Hgb)

More trucks on the road = Transfuse, increase Hb

• Transfusion

• Oxygen-carrying capacity

---

3. Move them faster → increase flow (Q)

Trucks driving faster = Increase ECMO Flow

• ECMO flow (see note below)

• Cardiac output

---

Quick Bedside Check

If oxygen delivery is low, ask:

• Is saturation adequate?

• Is hemoglobin adequate?

• Is the flow adequate?

Fix the weak link

Look at the problem with an open mind and fix it.

---

Common Mistake

Low PaO₂ → increase FiO₂

Helps—but only to a point.

Beyond that:

• Minimal gain in delivery

• Rising PaO₂ may be harmful

Think: Hb + Flow + Saturation—not PaO₂ alone.

---

Important Note: VV vs VA ECMO Response

---

Takeaway

Saturation + Hemoglobin + Flow = Oxygen Delivery

Don’t chase PaO₂ in isolation.

---

Learn More

Subscribe to LifeSupport.Training to receive updates and read the ECMO 143: AI-Assisted Journey newsletter, along with the new ECMO Tools section.

You can also use AI ECMO Educator, a free Custom GPT designed to support ECMO and ECPR learning for ICU clinicians and trainees.

Educational content only. Follow your institutional protocols and clinical judgment.