Respiratory acidosis is a condition that occurs when the lungs cannot remove all of the carbon dioxide the body produces. This causes body fluids, especially the blood, to become too acidic.A.D.A.M.

Causes, incidence, and risk factors

Causes of respiratory acidosis include:

• Diseases of the airways (such as asthma and chronic obstructive lung disease)
• Diseases of the chest
• Diseases affecting the nerves and muscles that "signal" the lungs to inflate or deflate
• Drugs that suppress breathing (including powerful pain medicines, such as narcotics, and "downers," such as benzodiazepines), especially when combined with alcohol
• Severe obesity, which restricts how much the lungs can expand

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

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

Symptoms

Symptoms may include:

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

Signs and tests

The health care provider will perform a physical exam. Tests that may be done include:

• Arterial blood gas, which measures oxygen and carbon dioxide levels in the blood
• Basic metabolic panel
• Chest x-ray
• Pulmonary function test

Treatment

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

• Bronchodilator drugs to reverse some types of airway obstruction
• Noninvasive positive-pressure ventilation (sometimes called CPAP or BiPAP) or a breathing machine, if needed
• Oxygen if the blood oxygen level is low
• Treatment to stop smoking

Expectations (prognosis)

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

Complications

• Poor organ function
• Respiratory failure
• Shock

Calling your health care provider

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.

Prevention

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

Losing weight may help prevent respiratory acidosis due to obesity (obesity-hypoventilation syndrome).

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

References

1. Seifter JL. Acid-base disorders. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 120.
2. Effros RM, Swenson ER. Acid-base balance. In: Mason RJ, Broaddus CV, Martin TR, et al. Murray & Nadel's Textbook of Respiratory Medicine. 5th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 7.

Review Date: 8/16/2011.

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.