DEFINITION

1. DEFINITION • HYPOXIA: A condition in which the oxygen available is inadequate at the tissue level • Five types of hypoxia: • Anemic • Hypoxemic • Histotoxic • Circulatory • Hypermetabolic

2. Anemic Hypoxia • Having a decreased carrying capacity for oxygen, the pt with decreased or abnormal Hb • Anemia • Carbon monoxide poisoning • Methemoglobinemia • Sickle Cell Anemia • Treatment involves blood transfusions, hyperbaric chamber, bone marrow transplant

3. Hypoxemic Hypoxia • Low PAO2 due to the atmosphere • Hypoventilation – PCO2 is rising • Diffusion Defects • The PaO2 will be lower in all cases, but the PCO2 may or may not be increased. • Treatment: Compensatory actions to reduce inequalities, supplemental oxygen

4. Histotoxic Hypoxia • Inability for tissues to utilize oxygen available • Cyanide Poisoning will inhibit cellular metabolism from occuring; the cells can not process the O2 • Treatment: Reversal of poisoning, supplemental oxygen and/or ventilation

5. Circulatory Hypoxia • A decrease in cardiac output results in a low BP and a prolonged systemic transit time • The PaO2 can be high, but because of the time it takes to get to the tissues, the pt is hypoxic • Cardiovascular instability or failure • Shock • Arrhythmias • Treatment include increasing cardiac output with use of cardiovascular drugs and therapy, supplemental oxygen

6. Hypermetabolic Hypoxia • In some disease states the body requires a slight increase in metabolism (i.e. – wound healing requires 5% increase) • Extensive burns and some cancers will cause large increases metabolism to the point that supplemental O2 is required • Treatment: Supplemental O2 or FiO2