The level of carbon dioxide in the blood is indicative of the health of the acid/base balance of the blood. Both acidic and alkaline conditions can cause an abnormally high carbon dioxide level in a blood test. Carbon Dioxide--also known as Bicarbonate, CO2, TCO2, Bicarb and HCO3--is considered high if the level reported is over the top reference range listed for the test.
Respiratory Causes
If the lungs do not operate properly, not enough carbon dioxide is exhaled, and it builds up in the blood.
Chronic lung diseases, such as asthma, are related to high carbon dioxide levels. Any kind of obstructive lung disease, including those related to smoking, will raise the carbon dioxide level in the blood. Lung infections and pneumonia will also cause high carbon dioxide levels as they obstruct the alveoli where CO2 and oxygen are exchanged.
Lung cancer, which is the uncontrolled growth of malignant cells, will obstruct the lungs and cause high CO2 levels.
Pulmonary hypertension, narrowing of the blood vessels in the lungs will cause a decrease in the exchange of carbon dioxide and oxygen.
Acute respiratory distress syndrome caused by lung inflammation and fluid in the lungs will cause high carbon dioxide levels. Fluid in the lungs can rapidly become fatal.
Hormonal Causes
Diseases that affect hormone levels can also affect the level of CO2 in the blood. Cushing's Syndrome, for example, produces abnormally high levels of cortisol, a steroid hormone that helps the body react to physical and emotional stress. High cortisol levels cause a high carbon dioxide level in the blood.
Conn's Syndrome, which causes high aldosterone levels from the adrenal glands, plays an important role in the regulation of electrolytes and carbon dioxide levels. Conn's Syndrome patients show high carbon dioxide levels.
Other Causes
Drugs that cause increases in bicarbonate levels include fludrocortisone, barbiturates, bicarbonates, hydrocortisone, loop diuretics and steroids can influence the level of C02 in the blood.
Severe vomiting, which disrupts breathing patterns can affect the acid/base balance and cause the bicarbonate level to rise.
Cystic Fibrosis and other diseases, Alpha-1 Antitrypsin genetic deficiency and trauma to the lungs will also cause elevated blood levels of carbon dioxide.
