asphyxia (ăsfĬk´sēə), deficiency of oxygen and excess of carbon dioxide in the blood and body tissues. Asphyxia, often referred to as suffocation, usually results from an interruption of breathing due to mechanical blockage of the breathing passages, paralysis of the respiratory muscles following electric shock, inundation of the lungs as may occur with pneumonia or drowning, or substitution of carbon monoxide for oxygen in the red blood cells. Symptoms of asphyxia vary but may include light-headedness, nausea, and gasping, followed by unconsciousness and death. An area quickly affected is the cerebral cortex, the brain center for speech and other conscious behavior; it can be irreparably damaged by as little as five minutes of oxygen deprivation. Damage to the medulla may result in interference with the heartbeat or other involuntary processes. Artificial respiration is the most practical first-aid procedure for asphyxia. Trained personnel can provide oxygen and employ techniques to maintain the heart rate and respiration (see resuscitator).