Carbon Dioxide Toxicity SymptomsHypercapnia, also known as hypercarbia or carbon dioxide toxicity, causes dangerous levels of CO2 in the blood. In most cases, it signals a respiratory problem such as poor lung function, but it can also happen among deep divers, particularly when they do not breathe adequately, or have contaminated oxygen supplies. 


Knowing the signs and symptoms of carbon dioxide toxicity can save lives and equip medical personnel and first responders to act quickly.


Common Causes of Carbon Dioxide Toxicity 

To identify a person with carbon dioxide toxicity, begin by assessing whether they have a heightened risk of hypercapnia. The most common causes of carbon dioxide toxicity include: 

  • Conditions that affect gas exchange. Pulmonary embolism and other emergencies may make it impossible for the body to use all the oxygen a person inhales. 
  • Diving. Divers have an increased risk of hypercapnia, especially when they hyperventilate, forget to breathe, or dive very quickly and deeply. Dysfunctional equipment may also play a role. These risk factors, in conjunction with the increased oxygen demands of diving, put divers in danger. 
  • Chronic obstructive pulmonary disease (COPD). Particularly in the later stages of the disease, gas exchange can become a problem. 
  • Sleep apnea. Severe sleep apnea may cause a buildup of CO2 that becomes especially dangerous for people with underlying health conditions. 
  • Being obese or overweight. People with very high body mass indexes (BMIs) may have trouble getting sufficient oxygen, especially during exertion. Their risk of anesthesia-related hypercapnia also increases. 
  • Some nervous and muscular system disorders. Any condition that affects the body’s ability to assess oxygen needs, the brain’s ability to control the lungs, or the muscles’ ability to control breathing can cause hypercapnia. People with muscular dystrophy and Guillain-Barré syndrome may be especially vulnerable. 
  • Rare genetic disorders. Disorders that affect the production of the protein alpha-1-antitrypsin may increase the risk of hypercapnia. 
  • Lifestyle issues such as smoking or leading a sedentary lifestyle. 


Symptoms of Carbon Dioxide Toxicity 

Mild hypercapnia often causes no symptoms. As toxicity increases, a person may experience symptoms such as: 

  • Drowsiness
  • Skin that looks flushed
  • Trouble concentrating or thinking clearly
  • Dizziness or disorientation 
  • Shortness of breath 
  • Hyperventilation 
  • Feeling tired 
  • Changes in the color of the skin 


Severe hypercapnia can cause organ or brain damage, and even death. Some symptoms include: 

  • Paranoia, depression, confusion, delusions, or unusual thoughts 
  • Inability to communicate effectively with others 
  • A rapid or slow heartbeat 
  • Loss of consciousness
  • Panic attacks 
  • Seizures 
  • The sensation that one is suffocating or cannot breathe


Carbon dioxide toxicity symptoms are rather nondescript, and can also occur with numerous other ailments, including hypoxia, heart disease, airway obstructions, and more. And so the symptoms alone are not diagnostic of hypercapnia, but merely suggestive. Measuring blood gas can help diagnose this dangerous condition. In some cases, scans of the heart or lungs can help determine the underlying cause. 


Treating Carbon Dioxide Toxicity

Treating carbon dioxide toxicity requires providers to identify the underlying cause. Ventilation and medication support are key to buying time and saving lives. Though suctioning may help maintain a patent airway in people with diseases that increase the risk of hypercapnia, suctioning also increases CO2 levels. A 2006 analysis found that hypercapnia increases in the 10 minutes following suctioning. This information demands that providers only suction when there are clear indications for doing so, and that they suction for the shortest possible period of time. Preoxygenation may also help reduce carbon dioxide toxicity. 


The right emergency suction machine helps you manage respiratory emergencies without delaying treatment. Effective devices offer consistent and reliable suctioning to you can reduce suction time and improve patient outcomes. To choose the right device for your agency or system, download our free guide, The Ultimate Guide to Purchasing a Portable Emergency Suction Device.