Published: 18 Jun 2025

ICD9: 276.2      ICD10: E87.2      ICD11: 5C73.0

Respiratory acidosis is a condition that occurs when the lungs can't remove enough carbon dioxide (CO2) from the body.
This leads to a buildup of CO2 in the blood, causing the blood to become more acidic.

Here's a breakdown:

Carbon Dioxide (CO2): CO2 is a waste product produced by the body's cells.
The Lungs' Role: The lungs are responsible for exhaling CO2. They take oxygen (O2) into the body and expel CO2.
Acid-Base Balance: The body needs to maintain a specific balance between acids and bases in the blood. This balance is measured by pH. Too much acid (low pH) or too much base (high pH) can disrupt bodily functions.
Acidosis: Acidosis means the blood has too much acid (a lower than normal pH).
Respiratory: This refers to the problem originating in the respiratory system (lungs and airways).

Therefore, Respiratory Acidosis is a condition where the lungs are not effectively removing carbon dioxide, causing a buildup of CO2 in the blood, which then lowers the blood's pH, making it more acidic.

Causes of Respiratory Acidosis:

Anything that impairs the lungs' ability to exhale CO2 can lead to respiratory acidosis. Common causes include:

Lung diseases:
Chronic Obstructive Pulmonary Disease (COPD): Emphysema and chronic bronchitis
Severe asthma: Bronchospasm restricts airflow.
Pneumonia: Inflammation and fluid in the lungs.
Pulmonary edema: Fluid buildup in the lungs.
Pulmonary embolism: A blood clot in the lungs.
Cystic fibrosis: Causes thick mucus buildup in the lungs.
Conditions affecting breathing muscles or nerves:
Amyotrophic lateral sclerosis (ALS) or Lou Gehrig's disease: Weakens respiratory muscles.
Guillain-Barré syndrome: Damages nerves controlling breathing.
Muscular dystrophy: Weakens respiratory muscles.
Myasthenia gravis: Affects nerve-muscle communication.
Spinal cord injuries: Can impair nerve signals to breathing muscles.
Central Nervous System (CNS) Depression:
Overdose of opioids or sedatives: Depresses the respiratory center in the brain.
Brain injuries or stroke: Can damage the respiratory center.
Obesity Hypoventilation Syndrome (OHS): Excess weight compresses the chest and abdomen, making it harder to breathe deeply.
Severe kyphoscoliosis: A severe curvature of the spine that restricts lung expansion.
Mechanical Ventilation Issues: Improper settings on a mechanical ventilator can lead to CO2 buildup.

Symptoms of Respiratory Acidosis:

Symptoms vary depending on the severity and how quickly the condition develops. They can include:

Shortness of breath (dyspnea)
Wheezing
Confusion
Headache
Drowsiness or fatigue
Tremors
Seizures (in severe cases)
Cyanosis (bluish discoloration of the skin due to low oxygen levels)

Diagnosis:

Respiratory acidosis is diagnosed through blood tests, specifically an Arterial Blood Gas (ABG). This test measures:

pH: Will be lower than normal (below 7.35)
PaCO2 (Partial Pressure of Carbon Dioxide): Will be higher than normal (above 45 mmHg)
HCO3- (Bicarbonate): May be normal in acute respiratory acidosis, but will be elevated in chronic respiratory acidosis as the kidneys try to compensate.
PaO2 (Partial Pressure of Oxygen): May be low if there is also an underlying lung problem.

Treatment:

Treatment focuses on improving ventilation and addressing the underlying cause. Possible treatments include:

Oxygen therapy: To increase oxygen levels in the blood.
Bronchodilators: To open up the airways in conditions like asthma or COPD.
Non-invasive ventilation (NIV): Such as BiPAP or CPAP to support breathing.
Mechanical ventilation: In severe cases, a ventilator may be needed to assist or control breathing.
Treating the underlying cause: Antibiotics for pneumonia, reversing opioid overdose, etc.
Chest physiotherapy: To help clear mucus from the airways.
Medications: To manage underlying conditions such as COPD or asthma.

Complications:

If left untreated, respiratory acidosis can lead to:

Cardiac arrest
Respiratory failure
Organ damage
Death

In summary, respiratory acidosis is a serious condition that requires prompt diagnosis and treatment. It is essential to identify and address the underlying cause to improve ventilation and restore acid-base balance. If you suspect you have respiratory acidosis, seek medical attention immediately.