Carbon dioxide binding capacity of 21.2 is mildly low, and whether it is serious enough to require treatment depends on other values in the blood gas analysis and the primary disease. The normal range of carbon dioxide binding capacity is 22 to 31 mmol/L. Decrease in carbon dioxide binding capacity is common in diarrhea, vomiting causing excessive alkali loss, or fever, renal insufficiency causing metabolic acidosis. Hyperventilation due to overstress and excessive crying can lead to respiratory alkalosis, which can also cause a decrease in carbon dioxide binding capacity. If the pH value is in the normal range, it can be improved by giving appropriate sedation, comfort and correcting hyperventilation. If the carbon dioxide binding capacity is 21.2, other indexes are normal or close to normal, without fever, vomiting and renal insufficiency, the patient can have a normal diet and usually does not need to be treated; if there is a combination of pH value abnormality and acidosis, it is necessary to combine with the clinical analysis, and give sodium bicarbonate to correct the acidosis and improve the acid-base balance disorder. The above treatments must be carried out by health care professionals, and should not be handled blindly by oneself. If not accompanied by other abnormalities, the carbon dioxide binding capacity program can be reviewed at a later date.