Human Respiration Under the Condition of Severe Anemia Investigated with the Aid of Fractionation Effects of Oxygen Isotopes

Abstract

The dependence of overall fractionation effect of respiration between ¹⁶O₂ and ¹⁶O¹⁸O (δ_IU) on varying levels of hemoglobin concentration within blood is investigated. Experiments are carried out on 6 healthy humans and 6 patients suffering from various degrees of chronic anemia.

δ_IU-values of anemic patients are decreased towards 0‰ meaning that within anemia rates of ¹⁶O₂₋ and ¹⁶O¹⁸O-transport are aligned together more than they are under healthy conditions.

On the basis of a resistance model of respiration, it is concluded that within anemia the entire oxygen transport system is more limited by blood flow than it is in healthy humans. This limitation starts to influence respiration far above a hemoglobin concentration of 8 g/100 ml.

Key Words:

• anemia
• blood flow
• fractionation effects
• isotope analysis
• oxygen transport
• resistance model of respiration
• respiration
• stable oxygen isotopes