HUMAN RESPIRATION UNDER THE CONDITION OF SEVERE ANEMIA INVESTIGATED WITH THE AID OF FRACTIONATION EFFECTS OF OXYGEN ISOTOPES

The dependence of overall fractionation effect of respiration between O-16(2) and (OO)-O-16-O-18 (delta(IU)) on varying levels of hemoglobin concentration within blood is investigated. Experiments are carried o ut on 6 healthy humans and 6 patients suffering from various degrees o f chronic anemia. Delta(IU)-values of anemic patients are decreased to wards 0 parts per thousand, meaning that within anemia rates of O-16(2 -) and (OO)-O-16-O-18-transport are aligned together more than they ar e under healthy conditions. On the basis of a resistance model of resp iration, it is concluded that within anemia the entire oxygen transpor t system is more limited by blood flow than it is in healthy humans. T his limitation starts to influence respiration far above a hemoglobin concentration of 8 g/100 ml.