Effect of increasing arterial oxygen content and oxygen delivery in patients with severe anemia

Tissue oxygen delivery depends on arterial oxygen content (CaO₂) and cardiac output. CaO₂ in turn depends on the hemoglobin concentration, arterial oxyhemoglobin saturation (SaO₂), and arterial oxygen tension (PaO₂) according to the formula CaO₂ = (1.34 × hemoglobin concentration × SaO₂) + (0.0031 × PaO₂). With higher hemoglobin concentrations of 15 or 10 g/dL (rows 1 and 2), the contribution of PaO₂ is less significant. However, at lower hemoglobin concentrations of 5 g/dL, increasing the PaO₂ from 100 to 300 mmHg can increase the CaO₂ by approximately 10%, from 7 to 7.7 mL O₂/dL (rows 3 and 4). Refer to UpToDate for additional details.