respiratory acidosis

Respiratory acidosis is blood turning too acidic because the lungs are not clearing enough carbon dioxide. Think of carbon dioxide as exhaust: when ventilation cannot keep pace, the exhaust builds up, and since carbon dioxide forms acid in the blood, the pH falls.

The root problem is always inadequate ventilation relative to carbon dioxide production. This can come on suddenly, as in an opioid overdose, severe asthma attack, or chest injury, or develop slowly in chronic conditions such as advanced COPD or neuromuscular disease. In acute cases the pH drops sharply; in chronic cases the kidneys have time to retain bicarbonate and partly restore the pH.

Symptoms reflect the rising carbon dioxide and falling pH: drowsiness, confusion, headache and, when severe, a depressed level of consciousness sometimes called carbon dioxide narcosis. Treatment is to improve ventilation, by treating the cause and, when needed, supporting breathing with non-invasive or mechanical ventilation to clear the carbon dioxide.