Health Information

Respiratory acidosis

Respiratory acidosis


Ventilatory failure; Respiratory failure; Acidosis - respiratory

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.

I Would Like to Learn About:

  • Causes

    Causes of respiratory acidosis include:

    • Diseases of the airways (such as asthma and chronic obstructive lung disease)
    • Diseases of the chest (such as scoliosis)
    • 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
  • Exams 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
  • Outlook (Prognosis)

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

  • Possible Complications

    • Poor organ function
    • Respiratory failure
    • Shock
  • When to Contact a Medical Professional

    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.

Related Information

  AsthmaBreathing difficul...Obesity hypoventil...     Asthma in adults...


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.

Seifter JL. Acid-base disorders. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 120.


Review Date: 9/1/2012  

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.

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