Respiratory acidosis

• Alternative Names

  Ventilatory failure; Respiratory failure; Acidosis - respiratory

• Causes, incidence, and risk factors

  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), which make the lungs less efficient at filling and emptying
  • 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 severe 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
  • Arterial blood gas (measures levels of oxygen and carbon dioxide in the blood; in respiratory acidosis, the level of carbon dioxide is too high)
  • Chest x-ray
  • Pulmonary function test
• Treatment

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

  • Bronchodilator drugs to reverse some types of airway obstruction
  • Noninvasive positive-pressure ventilation (sometimes called CPAP or BiPAP) or mechanical ventilation 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

  Seifter, JL. Acid base disorders. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier. 2007: chap 119.

Review Date: 8/8/2009

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., Inc.