Sometimes, breathing out does not remove enough carbon dioxide from the body. The leftover carbon dioxide results in a high level of acid in the blood. This is respiratory acidosis.

Many medical conditions and situations can lead to this. Chronic obstructive pulmonary disease (COPD) is the name for a group of diseases that are particularly likely to cause respiratory acidosis..

In this article, we look at the symptoms, causes, and treatment options.

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Respiratory acidosis refers to high levels of acid in the blood due to increased levels of carbon dioxide (CO2) in the body.

CO2 is a waste gas that a person with a healthy respiratory system exhales.

If this gas remains in the body, it can shift the natural balance of acids and bases. CO2 mixes with water in the body to form carbonic acid.

When respiratory acidosis is chronic, or lasting, the body partially makes up for the retained CO2 by trying to maintain a near-natural balance of acids and bases. Carbonic acid dissolves into hydrogen and bicarbonate. The kidneys excrete more hydrogen and retain bicarbonate to compensate for respiratory acidosis.

Respiratory acidosis can also be acute, developing suddenly from acute respiratory failure. When the acidosis is acute and severe, a person needs emergency medical treatment to:

  • restore healthy breathing
  • restore the acid-base balance
  • treat the cause of the respiratory failure

Acid-base balance and acidosis

When acid levels in the body are in balance with the base levels, the pH of blood is around 7.4.

A lower pH number reflects higher levels of acid, and a higher pH number represents higher base levels.

The narrow pH range for expected function is between 7.35 and 7.45.

Acidemia, which is highly acidic blood, occurs when the pH of the blood is lower than 7.35. Alkalemia, which is blood with a high level of base, refers to a pH higher than 7.45.

Doctors classify acidosis as either metabolic or respiratory, depending on the main cause of the acid-base imbalance.

Metabolic acidosis does not result from increased CO2 due to unhealthy air exchange in the lungs. Instead, it may stem from an overproduction of acid in the body or a loss of bicarbonate, among other factors.

Diabetic ketoacidosis and kidney disease, as well as many other conditions, can cause metabolic acidosis.

Respiratory acidosis occurs when breathing out does not get rid of enough CO2. The increased CO2 that remains results in overly acidic blood. This can result from respiratory problems, such as COPD.

When increased CO2 in the bloodstream stems from respiratory acidosis, doctors call this hypercapnia.

In people with chronic respiratory acidosis, hypercapnia can persist without the level of acid in the blood becoming dangerous because of the body’s responses to compensate. The kidneys get rid of more acid and reabsorb more base to try and restore a balance.

Immediate medical attention is necessary if this kidney response is no longer enough to maintain the balance of acids and bases. A person should also receive urgent medical attention if acute respiratory acidosis results from respiratory failure.

Here, learn the symptoms of acute respiratory failure.

The symptoms of respiratory acidosis stem from the effects of raised CO2 levels.

The symptoms of chronic respiratory acidosis are less noticeable than those of acute respiratory acidosis, because in chronic cases, the body compensates to help keep the blood pH balanced.

In the blood of people with in chronic respiratory acidosis, the acidifying effect of raised CO2 might reduce. However, the compensatory actions of the kidneys are not as effective for acid levels in the brain, leading to symptoms that affect thought, sleep, and memory.

These symptoms can include:

In people with acute respiratory acidosis or chronic respiratory acidosis that worsens over time, the effects of raised CO2 in the brain become more severe.

Symptoms can include:

  • confusion
  • drowsiness
  • stupor
  • muscle jerking

In these cases, the blood rapidly becomes more acidic and dangerous. Effects of a drastically low pH in the blood include:

Managing chronic respiratory acidosis focuses on treating the underlying illness that disrupts the breathing process and exchange of gases.

A doctor may also give treatments to improve respiration, including drugs that help open the passages to the lungs.

For people with acute respiratory acidosis, doctors can provide noninvasive positive pressure ventilation, called BiPAP, through a facemask. This directly assists breathing.

In more severe cases, a doctor improves respiration by inserting a tube into the airway for mechanical ventilation.

A person can take steps to support healthy lung function and prevent respiratory acidosis.

For anyone with a long-term respiratory illness, such as asthma or COPD, close management and monitoring are essential for maintaining a good quality of life and avoiding further health problems.

Also, for people with chronic respiratory problems, it can be important to avoid medications that reduce respiratory activity, such as benzodiazepines and extremely strong pain relief medications, including opioids. This can help reduce the risk of an acid-base imbalance developing or worsening.

People who need these medications should take the smallest effective dosages.

And because smoking tobacco has a strong association with developing COPD, reducing tobacco exposure is a crucial way to limit the risk of other respiratory problems.

Meanwhile, obesity can reduce the ability to breathe efficiently and increase the risk of heart disease and diabetes. Having a balanced, nutritious diet and getting regular exercise benefit both the heart and lungs.

Respiratory acidosis develops when the body cannot get rid of enough CO2, and this leftover gas raises the level of acid in the blood until it is unsafe.

When the condition is chronic, a person may have no noticeable symptoms because the body takes steps to compensate. Treatment involves addressing the underlying cause.

When the condition is acute, the symptoms involve the brain and can include confusion and drowsiness, for example. Initial treatment includes breathing support in an emergency care setting.

COPD is one of the main causes of respiratory acidosis. The best way to prevent the condition is to protect lung health.