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.
Ventilatory failure; Respiratory failure; Acidosis - respiratory
Causes of respiratory acidosis include:
- Diseases of the airways, such as asthma and COPD
- Diseases of the lung tissue, such as pulmonary fibrosis, which causes scarring and thickening of the lungs
- Diseases that can affect the chest, such as scoliosis
- Diseases affecting the nerves and muscles that signal the lungs to inflate or deflate
- Medicines that suppress breathing, including powerful pain medicines, such as narcotics (opioids), and "downers," such as benzodiazepines, often when combined with alcohol
- Severe obesity, which restricts how much the lungs can expand
- Obstructive sleep apnea
Chronic respiratory acidosis occurs over a long 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, before the kidneys can return the body to a state of balance.
Some people with chronic respiratory acidosis get acute respiratory acidosis because an acute illness makes their condition worse and disrupts their body's acid-base balance.
Symptoms may include:
- Easy fatigue
- Shortness of breath
- Tremors (shaking)
- Warm and flushed skin
Exams and Tests
The health care provider will perform a physical exam and ask about symptoms.
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
- CT scan of the chest
- Pulmonary function test to measure breathing and how well the lungs are functioning
Treatment is aimed at the underlying disease, and may include:
- Bronchodilator medicines and corticosteroids 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
- For severe cases, a breathing machine (ventilator) might be needed
- Changing medicines when appropriate
How well you do depends on the disease causing the respiratory acidosis.
Complications that may result include:
- Poor organ function
- Respiratory failure
When to Contact a Medical Professional
Severe respiratory acidosis is a medical emergency. Seek medical help right away if you have symptoms of this condition.
Call your provider if you have symptoms of lung disease that suddenly get worse.
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.
Use your CPAP device regularly if it has been prescribed for you.
Effros RM, Swenson ER. Acid-base balance. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 7.
Seifter JL. Acid-base disorders. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 110.
Strayer RJ. Acid-base disorders. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 116.
- Last reviewed on 8/3/2020
- Denis Hadjiliadis, MD, MHS, Paul F. Harron, Jr. Associate Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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