A low carbon dioxide (CO2) level in your blood, often identified in a metabolic panel, refers specifically to a low bicarbonate (HCO3-) concentration. This finding indicates your body has too much acid, a condition known as metabolic acidosis. Understanding this result involves recognizing bicarbonate’s role in maintaining your body’s delicate acid-base balance, along with potential underlying causes and their associated symptoms. This article explains what low CO2 levels signify in a medical context and outlines appropriate steps if such a result is found.
Understanding Carbon Dioxide in Your Blood
When a blood test reports “CO2 levels,” it primarily measures bicarbonate (HCO3-). Bicarbonate is a base that acts as a crucial buffer. It neutralizes excess acids produced by metabolic processes, maintaining blood pH within a narrow range of 7.35 to 7.45.
This buffering is vital; slight pH deviations disrupt essential bodily functions. Low bicarbonate levels indicate the body’s buffering capacity is overwhelmed, leading to an acidic state known as metabolic acidosis. The kidneys play a significant role in managing bicarbonate levels, either by reabsorbing it or by excreting acid to maintain pH balance.
Common Causes of Low CO2 Levels
Low bicarbonate levels, signaling metabolic acidosis, stem from various medical conditions where the body either produces too much acid or loses too much bicarbonate.
Diabetic ketoacidosis (DKA) is a common cause in uncontrolled diabetes, where insufficient insulin leads to acidic ketone body production, overwhelming the blood’s buffering system. Kidney disease also results in low bicarbonate levels, as impaired function reduces the body’s ability to excrete excess acids and produce sufficient bicarbonate. Severe diarrhea can lead to direct bicarbonate loss from the digestive tract.
Lactic acidosis develops from excessive lactic acid buildup, occurring during intense exercise, severe infections like sepsis, or prolonged lack of oxygen.
Certain medications, including some diuretics, aspirin overdose, metformin (especially with kidney impairment), and certain anticonvulsants, can induce metabolic acidosis. Toxic ingestions, such as methanol or ethylene glycol, also lead to acid buildup and lower CO2 levels.
Recognizing Symptoms of Low CO2
Symptoms associated with low CO2 levels primarily reflect the underlying metabolic acidosis and can vary depending on its severity. General symptoms include fatigue, weakness, nausea, vomiting, loss of appetite, headache, confusion, or dizziness.
A distinctive respiratory symptom is rapid and deep Kussmaul breathing. This pattern is the body’s compensatory mechanism to expel acidic carbon dioxide, attempting to raise blood pH and correct acidosis. In severe cases, metabolic acidosis can lead to neurological symptoms like altered mental status or lethargy. Cardiac symptoms, such as an accelerated or irregular heartbeat, can also manifest.
Next Steps When Your CO2 Levels Are Low
Discovering low CO2 levels on a lab report warrants consultation with a healthcare professional for thorough evaluation to identify the specific underlying cause. The doctor will likely order additional diagnostic tests, such as a comprehensive metabolic panel, blood glucose tests, and kidney function tests, to pinpoint the source of the metabolic acidosis.
Treatment focuses on addressing the root cause of the metabolic acidosis, rather than just the bicarbonate level itself. This may involve managing uncontrolled diabetes, treating kidney disease, or stopping certain medications. In some cases, sodium bicarbonate or sodium citrate pills might be prescribed to help balance blood acid levels.
Avoid self-diagnosing or self-treating based solely on a lab result, as underlying conditions can be complex. Seek immediate medical attention if you experience severe symptoms like profound confusion, significant difficulty breathing, or unresponsiveness.