A broad term meaning diminished availability of oxygen to the body tissues.
Its causes are many and varied. There may be a deficiency of oxygen in the atmosphere, as in altitude sickness, or a pulmonary disorder that interferes with adequate ventilation of the lungs. Anemia or circulatory deficiencies can lead to inadequate transport and delivery of oxygen to the tissues. Finally, edema or other abnormal conditions of the tissues themselves may impair the exchange of oxygen and carbon dioxide between the capillaries and the tissues. The effect of hypoxia is to reduce the functional activity of tissues. The initial response may be one of temporarily increased activity. Terminally the tissue may be irreparably damaged.

• anemic h. — due to inadequate supply of hemoglobin in the blood.
• cerebral h. — may be acute or chronic causing either a tremor–convulsion syndrome or one of longer term weakness, ataxia, apparent blindness and lethargy.
• fetal h. — occurs as a result of deprivation of the fetus of oxygen during parturition, because it is delayed or the umbilical cord pinched off. Clinically there is weakness, imbecility, disinclination to suck, possibly hypothermia. Foals experience a much more violent, convulsive or dummy syndrome. See also neonatal maladjustment syndrome. Called also intrapartum hypoxia.
• intrapartum h. — see fetal hypoxia (above).
• ischemic h. — insufficient oxygen in tissues because of an inadequate blood supply.
• stagnant h. — inadequate supply of oxygen to tissues because of slow rate of passage of the blood through the tissues.

Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.