What is Respiratory Acidosis?
Respiratory acidosis is a condition where your body struggles to exhale the proper amount of carbon dioxide, causing a build-up in your system. This accumulation of carbon dioxide results in a decrease in the ratio of bicarbonate, a buffer that helps maintain body pH balance, to carbon dioxide, which lowers the pH, making the body more acidic. If you aren’t breathing sufficiently, two common symptoms are respiratory acidosis (an excess of carbon dioxide) and hypercapnia (too much carbon dioxide in your bloodstream).
Your kidneys try to balance out this condition by getting rid of more acid in the form of hydrogen and ammonium and by absorbing more bicarbonate. These actions carried out by your kidneys help to bring your body’s pH levels back to normal, aiding in the compensation for the excess of carbon dioxide present.
What Causes Respiratory Acidosis?
The breathing centers in our brain help control the amount of air going in and out of our lungs. The sensors in our body, also known as chemoreceptors, help regulate our breathing based on the levels of carbon dioxide, oxygen, and pH, or acidity, in our blood.
Chemoreceptors located in the brain are sensitive to changes in our blood’s pH or acidity levels. When our blood acidity decreases, it affects the way we breathe in order to maintain the proper levels of carbon dioxide and oxygen. If our breathing is disturbed, the level of carbon dioxide in our blood can increase, leading to what’s known as an acid-base disorder. Sometimes, breathing difficulties could be due to a mismatch between air supply and blood flow in the lungs.
There are three types of respiratory acidosis: acute, chronic, or a combination of both. Acute respiratory acidosis refers to a sudden increase in blood carbon dioxide levels because of breathing failure. This could be due to a stroke, the use of drugs like opioids that can depress the central nervous system, or muscle diseases that prevent the use of respiratory muscles such as myasthenia gravis, muscular dystrophy, or Guillain-Barre Syndrome. However, our bodies can slightly adjust to this sudden rise in carbon dioxide, but this happens only minutes after the incidence.
On the other hand, chronic respiratory acidosis can occur because of chronic obstructive pulmonary disease (COPD), where the reflexes that respond to low oxygen or excess carbon dioxide become less responsive. Sometimes, fatigue of the diaphragm due to a muscle disorder can also cause chronic respiratory acidosis. It can also be seen in obesity-related breathing issues—known as obesity hypoventilation syndrome or Pickwickian syndrome, a nerve disease called amyotrophic lateral sclerosis, and in people with severe chest wall defects. For individuals with chronic lung disease, an additional event such as pneumonia can worsen acidosis by disrupting the balance of ventilation and blood flow in the lungs.
In a condition called respiratory acidosis, the body responds by slightly raising calcium levels in the blood and moving potassium out of cells, which can lead to mild high potassium levels in the blood, or hyperkalemia. But in chronic respiratory acidosis, the kidneys slowly adjust over several days to help regulate these changes.
Risk Factors and Frequency for Respiratory Acidosis
Respiratory acidosis occurs at different rates in the United States and around the world, depending on the cause. It’s more common in people in the final stages of COPD (a lung disease). Also, people who have had surgery are at a greater risk for developing respiratory acidosis.
Signs and Symptoms of Respiratory Acidosis
Respiratory acidosis is a condition typically caused by an underlying issue, and its symptoms depend on how long, severe, and advanced the condition is. People with this condition might experience shortness of breath, anxiety, wheezing, or trouble sleeping. In some situations, they might appear blue due to low oxygen levels in their blood. If the condition is severe and they’re not breathing adequately over a long period, they might have additional symptoms like confusion, involuntary muscle jerks, and even seizures.
Respiratory acidosis leads to an excess of carbon dioxide in the blood, which can cause the blood vessels in the brain to widen. If it’s severe enough, this can increase the pressure inside the skull and lead to optic nerve swelling, which increases the risk of potentially life-threatening conditions like brain herniation and even death.
When respiratory acidosis is prolonged, it can lead to memory loss, poor coordination, an overabundance of red blood cells, high blood pressure in the lungs, heart failure, and daytime sleepiness and headaches due to stopping breathing during sleep. If the source of the respiratory acidosis is clear, it’s important to remove or reverse it.
- Shortness of breath
- Anxiety
- Wheezing
- Trouble sleeping
- Bluish skin color due to low oxygen levels in the blood
- Confusion
- Involuntary muscle jerks
- Seizures (in severe cases)
- Increased pressure inside the skull
- Optic nerve swelling
- Memory loss (in prolonged cases)
- Poor coordination (in prolonged cases)
- Overabundance of red blood cells (in prolonged cases)
- High blood pressure in the lungs (in prolonged cases)
- Heart failure (in prolonged cases)
- Daytime sleepiness due to stopping breathing during sleep (in prolonged cases)
- Headaches due to stopping breathing during sleep (in prolonged cases)
Testing for Respiratory Acidosis
If your doctor suspects you have respiratory acidosis, which is a condition where there’s too much carbon dioxide (CO2) in your blood, they may order a couple of tests including an arterial blood gas (ABG) and a serum bicarbonate level test. These tests help assess the acidity or alkalinity of your blood.
In respiratory acidosis, the ABG results will reveal a high level of carbon dioxide (PCO2) in your blood (>45 mmHg), high bicarbonate levels (HCO3-) (>30 mmHg), and low blood pH (<7.35) – a measure that tells how acidic or alkaline your blood is. bicarbonate and ph levels provide an indication about body is compensating for the imbalance in blood.
Your doctor could then classify your respiratory acidosis as either acute or chronic. Acute respiratory acidosis occurs when the bicarbonate level in your blood increases about one milliequivalent per liter (mEq/L) for every ten millimeters of mercury (mmHg) increase in carbon dioxide over a short period. On the other hand, chronic respiratory acidosis happens when bicarbonate levels rise by four mEq/L for each ten mmHg increase in carbon dioxide, but this change happens over several days.
If your body doesn’t compensate in these ways, then you might have a mixed respiratory-metabolic disorder, which is a combination of respiratory acidosis and a metabolic problem.
If the doctor can’t figure out why you have respiratory acidosis, they might also ask for a drug screen. This is because certain drugs can also cause changes in your carbon dioxide levels.
Treatment Options for Respiratory Acidosis
If a doctor diagnoses you with respiratory acidosis, which is a condition where there’s too much carbon dioxide in your blood, they will then focus on treating whatever is causing it. It’s crucial to take it slowly when reducing the level of carbon dioxide in your blood, as doing it too quickly can upset the balance in your spinal fluid and potentially cause seizures.
Medications can often be used to improve your breathing, especially if you have a condition affecting your airways. Some medicines, known as bronchodilators, can help widen the airways to make it easier to breathe. These include beta-agonists, anticholinergic drugs, and methylxanthines. If your respiratory acidosis was caused by an overdose of opioids, the doctor might use a medication called naloxone to help reverse the effects.
What else can Respiratory Acidosis be?
These are the possible conditions that doctors would look into when they evaluate respiratory problems:
- Botulism
- Bronchitis
- Diaphragm disorders
- Diaphragmatic paralysis
- Asthma
- Opioid use
- Sedative, hypnotic, anxiolytic use disorder
- Chronic obstructive pulmonary disease (COPD)
- Obesity
