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Oxygen Delivery (DO₂) Calculator
Pulmonology / Critical Care
Oxygen delivery (DO₂) quantifies the total amount of oxygen delivered to peripheral tissues per minute. It depends on cardiac output and arterial oxygen content (CaO₂). Critical DO₂ (<330 mL/min) may indicate supply-dependency and hemodynamic compromise.
Enables VO₂ and O₂ extraction ratio
Formula
CaO₂ = (Hgb × 1.34 × SaO₂/100) + (0.0031 × PaO₂) [mL O₂/dL]
DO₂ = CaO₂ × CO × 10 [mL O₂/min]
VO₂ = CO × (CaO₂ − CvO₂) × 10 [mL O₂/min]
O₂ Extraction Ratio = VO₂ / DO₂ × 100 [%]
DO₂ = CaO₂ × CO × 10 [mL O₂/min]
VO₂ = CO × (CaO₂ − CvO₂) × 10 [mL O₂/min]
O₂ Extraction Ratio = VO₂ / DO₂ × 100 [%]
Reference Values
| Parameter | Normal Value | Clinical Significance |
|---|---|---|
| CaO₂ | 18–21 mL O₂/dL | Arterial oxygen content |
| DO₂ | 950–1150 mL O₂/min | Total O₂ delivery to tissues |
| VO₂ | 200–250 mL O₂/min | Tissue O₂ consumption |
| O₂ Extraction Ratio | 20–30% | >50% suggests O₂ debt |
| Critical DO₂ | ~330 mL O₂/min | Supply-dependency threshold |
Clinical Notes
Optimizing DO₂: Increase Hgb (transfusion if <7–8 g/dL), improve SaO₂ (supplemental O₂, mechanical ventilation), or increase cardiac output (fluids, inotropes).
O₂ Extraction Ratio >50% suggests tissues are compensating for low DO₂ — early sign of circulatory shock. SvO₂ <60% is a concerning threshold.
O₂ Extraction Ratio >50% suggests tissues are compensating for low DO₂ — early sign of circulatory shock. SvO₂ <60% is a concerning threshold.
For educational use only. Not a substitute for clinical judgment.
