What to know about respiratory acidosis
Many medical conditions or situations might lead to this. Chronic obstructive pulmonary disease (COPD) is a common group of diseases that are particularly likely to cause respiratory acidosis.
In this article, we look at the symptoms, causes, and treatment options for respiratory acidosis.
What is respiratory acidosis?
Respiratory problems can lead to inefficient gas exhange and the development of a pH imbalance in the blood.
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 would normally breathe out.
If it remains in the body, CO2 can shift the normal balance of acids and bases in the body, making its state more acidic. It mixes with water in the body to form carbonic acid.
With chronic respiratory acidosis, the body partially makes up for the retained CO2 and tries to maintain a near normal acid-base balance. The body's main response is to get rid of more carbonic acid and hold on to as much bicarbonate base in the kidneys as it can.
Respiratory acidosis can also be acute rather than chronic, developing suddenly from acute respiratory failure. A person will require emergency medical treatment for severe acute respiratory acidosis to:
- regain normal breathing
- restore 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 in the body, the pH measure 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 normal function is between 7.35 and 7.45.
Acidemia, which is highly acidic blood, occurs when pH of the blood is lower than 7.35. Alkalemia, which is blood with a high level of base, refers to a blood 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 occur as a result of increased CO2 from abnormal air exchange in the lungs. Instead, increased acid production in the body or a loss of bicarbonate might lead to metabolic acidosis, in addition to other causes.
It can occur because of diabetic ketoacidosis and kidney disease, as well as many other conditions.
Respiratory acidosis occurs when breathing out does not get rid of enough CO2. The increased CO2 that remains results in an acidic state. This can occur as a result of respiratory problems, such as COPD.
Doctors refer to the increased CO2 level in the bloodstream occurring as a result of respiratory acidosis as hypercapnia.
Hypercapnia in chronic respiratory acidosis can persist without dangerously acidic blood because of the body's responses to compensate. The kidneys get rid of more acid and reabsorb more base to try and create a balance.
Immediate medical attention is necessary if this kidney function is no longer enough to maintain the balance of acids and bases. A person should also seek medical attention in the event of acute respiratory acidosis from respiratory failure.
The symptoms of respiratory acidosis are generally the effects of raised CO2.
In chronic respiratory acidosis, these symptoms are less noticeable than in acute respiratory acidosis, because compensating responses in the body tend to keep blood pH near normal.
The acidifying effect of raised CO2 in chronic respiratory acidosis might reduce in the blood. 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 acute respiratory acidosis, or if chronic respiratory acidosis gets progressively worse over time, the effects of raised CO2 in the brain become more severe.
Symptoms can include:
- muscle jerking
In acute respiratory acidosis and deteriorating cases of chronic respiratory acidosis, blood rapidly becomes more acidic and dangerous.
Effects of a drastically lower pH in the blood include:
- reduced heart muscle function
- disturbances in heart rhythm, producing arrhythmias
- a drop in blood pressure
In acute respiratory acidosis, hospital staff might provide Bi-PAP, through a facemask.
The management of 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.
In acute respiratory acidosis, doctors can provide noninvasive positive-pressure ventilation, called Bi-PAP, through a facemask. This directly assists breathing.
In more severe conditions, a doctor improves respiration by inserting a tube into the airway for mechanical ventilation.
A person can prevent the onset of respiratory acidosis by maintaining healthy lung function.
The close management and monitoring of long-term respiratory illnesses, such as asthma and COPD, are essential to maintaining a good quality of life and avoiding further health problems.
Some medications, such as benzodiazepines and extremely strong painkillers, including opioids, reduce respiratory activity.
In the presence of chronic respiratory problems, or if chronic respiratory acidosis develops from a different condition, avoiding these types of medications where possible can reduce the risk of acid-base levels getting worse.
People who need these medications should take the smallest dose possible.
Since tobacco smoking has a strong association with developing COPD, quitting smoking is always the best option for reducing the risk of other respiratory problems.
Obesity can also reduce a person's ability to breathe efficiently, as well as increasing the risk of heart disease and diabetes mellitus. As a result, a balanced, nutritious diet and regular physical activity benefit both heart and lungs.
Respiratory acidosis is a condition that occurs when the body cannot get rid of enough CO2, which increases acid levels in the body beyond safe levels.
A person with chronic respiratory acidosis rarely experiences symptoms, as many systems in the body can compensate for these changes in acid/base balance.
However, acute respiratory acidosis might occur, which causes symptoms involving the brain, including confusion, stupor, drowsiness, and muscle jerks.
COPD, diabetic ketoacidosis, and kidney disease can lead to the condition, alongside many other diseases.
Doctors treat the underlying disease to address chronic respiratory acidosis, but can, in acute cases, provide breathing support by applying a facemask or inserting tubes in the airway. Medications that assist breathing can also promote a healthy exchange of gases.
The best way to prevent respiratory acidosis is to protect lung health.
How do I know when I have chronic respiratory acidosis if the symptoms are subtle?
If you do not have a significant chronic respiratory acidosis and have healthy kidney function, you likely will not notice symptoms until an acute episode occurs on top of the underlying acidosis.
If you have a chronic medical condition that can lead to having chronic respiratory acidosis, you will need to be aware of the potential symptoms that might lead up to an acute presentation. Your physician can work with you to try to prevent significant chronic respiratory acidosis from setting in or worsening.
A doctor can perform an arterial blood gas study to check levels of acid/base balance, in order to help determine a diagnosis of acute or chronic respiratory acidosis.Stacy Sampson, DO Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.