Which of the following type of hypoxia presents with normal aerial O2 concentration?
In anaemic hypoxia, a reduction in hemoglobin concentration of the blood is accompanied by a corresponding decline in the O2-carrying capacity of the blood. Although the PaO2 is normal in anemic hypoxia, the absolute quantity of O2 transpoed per unit volume of blood is diminished. As the anemic blood passes through the capillaries and the usual quantity of O2 is removed from it, the PO2 and saturation in the venous blood decline to a greater extent than normal. Must Know: Classification of hypoxia: Hypoxic hypoxia, in which the PO2 of the aerial blood is reduced. Anemic hypoxia, in which the aerial PO2 is normal but the amount of hemoglobin available to carry O2 is reduced. Ischemic or stagnant hypoxia, in which the blood flow to a tissue is so low that adequate O2 is not delivered to it despite a normal PO2 and hemoglobin concentration. Histotoxic hypoxia, in which the amount of O2 delivered to a tissue is adequate but, because of the action of a toxic agent, the tissue cells cannot make use of the O2 supplied to them. Ref: Loscalzo J. (2012). Chapter 35. Hypoxia and Cyanosis. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.
Anaemic hypoxia
Stagnant hypoxia
Histotoxic hypoxia
Hypoxic hypoxia