From the Research
Low CO2 on a Basic Metabolic Panel (BMP) indicates metabolic acidosis, a condition where there's excess acid in the body, and the most recent and highest quality study 1 suggests that treatment of metabolic acidosis with sodium bicarbonate improves kidney and patient survival in patients with chronic kidney disease. This finding requires prompt evaluation to identify and treat the underlying cause. Common causes of metabolic acidosis include:
- Diabetic ketoacidosis
- Lactic acidosis from poor tissue perfusion
- Kidney disease
- Severe diarrhea
- Certain medications like metformin Initial management includes addressing the underlying cause while monitoring electrolytes and kidney function. For diabetic ketoacidosis, insulin therapy and fluid replacement are essential, as noted in studies 2, 3. For lactic acidosis, improving tissue perfusion and treating infection if present are priorities. Severe cases may require intravenous sodium bicarbonate, though this is controversial and used selectively, as discussed in 3. Patients with kidney disease may need dialysis. The body compensates for metabolic acidosis through increased respiratory rate to eliminate CO2, which is why patients may present with deep, rapid breathing (Kussmaul respirations), a concept also explained in 4. Follow-up testing should include arterial blood gases to determine the severity of acidosis, anion gap calculation to classify the type of acidosis, and tests specific to suspected causes such as ketones, lactate levels, or toxicology screens. It's also important to consider the differences in metabolic acidosis between patients with and without diabetes, as highlighted in 5. However, the most critical aspect of managing metabolic acidosis is to prioritize the treatment that improves morbidity, mortality, and quality of life, which, according to the latest evidence 1, includes the use of sodium bicarbonate in patients with chronic kidney disease.