anoxigén

Anoxigén (anoxia) is a medical condition characterized by an absence or severe deficiency of oxygen in the body's tissues. It can result from insufficient oxygen in inspired air, impaired oxygen transport in the blood, or the inability of cells to use oxygen. Without timely restoration of oxygen, cellular metabolism shifts to anaerobic pathways, leading to lactate accumulation and acidosis.

Mechanisms and types: The main categories are (a) hypoxic or ventilatory anoxia (low inspired oxygen, as at high altitude or in suffocation), (b) circulatory (ischemic) anoxia (poor blood flow, shock, heart failure), (c) anemic anoxia (low hemoglobin or red blood cell count), and (d) histotoxic anoxia (cells unable to use oxygen, e.g., due to cyanide poisoning).

Causes and clinical features: Common causes include drowning, airway obstruction, severe pneumonia or COPD, pulmonary edema, heart attack, shock, severe anemia, carbon monoxide poisoning, and cyanide poisoning. Symptoms include confusion, dizziness, shortness of breath, loss of consciousness, seizures; brain and heart are most sensitive to oxygen deprivation.

Diagnosis and treatment: Diagnosis relies on clinical signs and blood gas measurements showing low PaO2 or oxygen saturation, and elevated lactate. Treatment focuses on rapidly restoring oxygen delivery: secure airways, provide high-flow oxygen or ventilation, treat the underlying cause, and support circulation. Specific interventions include hyperbaric oxygen for carbon monoxide poisoning and antidotes for cyanide poisoning.

Prognosis and prevention: Prognosis depends on the duration of oxygen deprivation and promptness of treatment. Prevention emphasizes safe ventilation, rapid response to respiratory compromise, and avoidance of environments with depleted oxygen, such as smoke inhalation and enclosed spaces.