Why Hypercapnia Occurs with COPD

Hypercapnia Symptoms and Treatments

Alveoli in the lungs.
Alveoli in the lungs. Dorling Kindersley/Getty Images

Hypercapnia is a condition that occurs when there is too much carbon dioxide in the blood. While it is sometimes caused by things such as hypoventilation or a narcotic drug overdose, a much more common cause is COPD. If you have COPD, it's important to know the hypercapnia symptoms, as well as the treatments available.

The COPD and Hypercapnia Link

Generally speaking, when we breathe, we inhale oxygen and exhale carbon dioxide.

These two respiratory gases are exchanged deep within the lungs, in tiny, grape-like clusters, or air sacs, called alveoli.

In people with COPD, this process is impaired because the alveoli are destroyed, leaving less surface area for oxygen to get from the lungs into the bloodstream and for carbon dioxide to get from the blood into the lungs to be exhaled. This results in a low amount of oxygen in the blood, a condition called hypoxemia, and high levels of carbon dioxide.

Causes of Hypercapnia

Aside from COPD, there some other conditions that can lead to these high levels of carbon dioxide in the blood. Some examples include:

Symptoms of Hypercapnia

Many people don't even realize they have hypercapnia. In cases where it develops slowly over time and is extremely mild, you may not experience any symptoms at all.

If symptoms do occur, they may initially be in the form of headaches, inability to think straight or feeling drowsy or sleepy. Because it's so easy to miss the signs of mile hypercapnia, awareness is key.

On the other hand, symptoms of severe hypercapnia are more pronounced. Severe hypercapnia may eventually lead to respiratory failure and possibly death, and symptoms include:

  • Flushed skin
  • Dizziness
  • Rapid breathing
  • Increased blood pressure
  • Increased heart rate
  • Muscle twitches

Treatment for Hypercapnia

Treatment for hypercapnia depends upon its severity, and starts with addressing the underlying cause. If treating the underlying COPD is ineffective for reversing hypercapnia, additional treatment may be required.

  • Noninvasive Ventilation: Noninvasive ventilation provides ventilatory support to a patient through the upper airways. It enhances the breathing process by giving the patient a mixture of air and oxygen from a flow generator through a tightly fitted facial or nasal mask.
  • Intubation and Mechanical Ventilation: Intubation is the process of inserting a special tube through the mouth and then into the airway. The tube then gets hooked up to a mechanical ventilator that takes over active breathing for the patient.

When to Call the Doctor

Hypercapnia can lead to respiratory failure and death if left untreated. If you have COPD, being aware of hypercapnia symptoms is key to early detection.

Call your doctor as soon as possible if you experience any change in your COPD symptoms or general health.


Disorders of Gas Exchange: Hypercapnia and Hypoxia. Stanford University.

Toxicity of Carbon Dioxide Gas Exposure, CO2 Poisoning Symptoms, Carbon Dioxide Exposure Limits, and Links to Toxic Gas Testing Procedures. http://www.inspectapedia.com/hazmat/CO2gashaz.htm

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