Causes of respiratory acidosis include:

• Diseases of the airways (such as asthma and chronic obstructive lung disease ), which send air into and out of the lungs
• Diseases of the chest (such as scoliosis ) that make the lungs less efficient at filling and emptying
• Disease of the nerves and muscles that "signal" the lungs to inflate or deflate
• Drugs (including powerful pain medicines, such as narcotics, and "downers," such as benzodiazepines), especially when combined with alcohol
• Severe obesity

Chronic respiratory acidosis occurs over a long period of time. This leads to a stable situation, because the kidneys increase chemicals that help restore the body's acid-base balance.

Acute respiratory acidosis is a severe condition in which carbon dioxide builds up very quickly and before the kidneys can return the body to a state of balance.

Symptoms may include:

• Confusion
• Easy fatigue
• Lethargy
• Shortness of breath
• Sleepiness

A chest x-ray or CT scan is a helpful way of checking the lung's appearance without having to biopsy it.

Pulmonary function tests are a series of breathing tests that evaluate lung capacity.

An arterial blood gas test involves having blood drawn and directly measuring the amounts of oxygen, carbon dioxide, and acids.

Treatment is aimed at the underlying lung disease, and may include:

• Bronchodilator drugs to reverse some airways obstruction
• Methods to stop smoking
• Noninvasive positive-pressure ventilation (sometimes called CPAP or BiPAP) or mechanical ventilation if needed
• Oxygen if the blood oxygen level is low

How well you do depends on the disease causing the respiratory acidosis.

• Poor organ function
• Respiratory failure
• Shock

Severe respiratory acidosis is a medical emergency. Seek immediate medical help if you have symptoms of this condition.

Call your health care provider if you have symptoms of lung disease.

Do not smoke. Smoking leads to the development of many severe lung diseases that can cause respiratory acidosis.

Losing weight may help prevent obesity hypoventilation syndrome.

Be careful about taking sedating medicines, and never combine these medicines with alcohol.

Murray J, Nadel J. Textbook of Respiratory Medicine. 3rd ed. Philadelphia, Pa: WB Saunders; 2000:191-192.

Marx J., Hockberger R, Walls R. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. St. Louis, Mo: Mosby; 2005.

Ford MD. Clinical Toxicology. 1st ed. Philadelphia, Pa: WB Saunders; 2001:92.