DO2 calculation: SaO2 92% (0.92), Hb 15 g/dL, CO 5 L/min, PaO2 70 mmHg. What is DO2?

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Multiple Choice

DO2 calculation: SaO2 92% (0.92), Hb 15 g/dL, CO 5 L/min, PaO2 70 mmHg. What is DO2?

DO2 is found from DO2 = CO × CaO2, where CaO2 = (Hb × 1.34 × SaO2) + (0.003 × PaO2). Compute CaO2: - Hb × 1.34 × SaO2 = 15 g/dL × 1.34 × 0.92 ≈ 18.49 mL O2/dL - Dissolved O2 = 0.003 × PaO2 = 0.003 × 70 ≈ 0.21 mL O2/dL - CaO2 ≈ 18.49 + 0.21 ≈ 18.70 mL O2/dL Convert CaO2 to per liter: 18.70 mL/dL × 10 dL/L ≈ 187.0 mL O2/L Now multiply by CO: - CO = 5 L/min - DO2 ≈ 5 L/min × 187 mL/L ≈ 935 mL/min So DO2 is about 930–940 mL/min (closest to 927 mL/min).

DO2 is found from DO2 = CO × CaO2, where CaO2 = (Hb × 1.34 × SaO2) + (0.003 × PaO2).

Compute CaO2:

  • Hb × 1.34 × SaO2 = 15 g/dL × 1.34 × 0.92 ≈ 18.49 mL O2/dL

  • Dissolved O2 = 0.003 × PaO2 = 0.003 × 70 ≈ 0.21 mL O2/dL

  • CaO2 ≈ 18.49 + 0.21 ≈ 18.70 mL O2/dL

Convert CaO2 to per liter: 18.70 mL/dL × 10 dL/L ≈ 187.0 mL O2/L

Now multiply by CO:

  • CO = 5 L/min

  • DO2 ≈ 5 L/min × 187 mL/L ≈ 935 mL/min

So DO2 is about 930–940 mL/min (closest to 927 mL/min).

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