🩸 Arterial Oxygen Content (CaO₂)
Calculate arterial oxygen content (CaO₂) carried per 100 mL of blood.
Clinical takeaway
Most oxygen is bound to haemoglobin; dissolved O₂ is small.
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When to use
Quantify oxygen content for delivery and shunt calculations.
How it works
CaO₂ = 1.34 × Hb × SaO₂ + 0.0031 × PaO₂. Normal ≈ 18–20 mL O₂/dL.
Key points
- Most oxygen is bound to haemoglobin; dissolved O₂ is small.
- Anaemia lowers content despite a normal SaO₂.
- Feeds into DO₂ and oxygen extraction calculations.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Haemoglobin | 15 g/dL |
|---|---|
| SaO₂ | 98 % |
| PaO₂ | 100 mmHg |
→CaO₂20.0mL O₂/dL
- Bound to Hb：19.7 mL/dL
- Dissolved：0.31 mL/dL
- Formula：1.34 × Hb × SaO₂ + 0.0031 × PaO₂
Frequently asked questions
- What is Arterial Oxygen Content (CaO₂)?
- Calculate arterial oxygen content (CaO₂) carried per 100 mL of blood.
- How is Arterial Oxygen Content (CaO₂) calculated? What is the core formula?
- CaO₂ = 1.34 × Hb × SaO₂ + 0.0031 × PaO₂. Normal ≈ 18–20 mL O₂/dL.
- When is Arterial Oxygen Content (CaO₂) used?
- Quantify oxygen content for delivery and shunt calculations.
- What are the key clinical points for Arterial Oxygen Content (CaO₂)?
- Most oxygen is bound to haemoglobin; dissolved O₂ is small. Anaemia lowers content despite a normal SaO₂. Feeds into DO₂ and oxygen extraction calculations.
- What are the limits and cautions when using Arterial Oxygen Content (CaO₂)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Arterial Oxygen Content (CaO₂) calculated in practice? Can you show a worked example?
- Inputs: Haemoglobin 15 g/dL, SaO₂ 98 %, PaO₂ 100 mmHg → Result: CaO₂ 20.0 mL O₂/dL（Bound to Hb: 19.7 mL/dL, Dissolved: 0.31 mL/dL, Formula: 1.34 × Hb × SaO₂ + 0.0031 × PaO₂）