What causes low blood carbon dioxide

31/05/2022
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What causes low blood carbon dioxide


Low blood carbon dioxide can usually refer to a decrease in carbon dioxide partial pressure in arterial blood gas analysis, or a decrease in carbon dioxide binding capacity in blood biochemical tests. The partial pressure of carbon dioxide in arterial blood and the binding force of carbon dioxide in blood biochemistry are two completely different concepts of acid-base balance. The partial pressure of carbon dioxide in arterial blood is usually the partial pressure generated by carbon dioxide physically dissolved in the blood. A drop in blood pressure usually indicates that the patient is hyperventilated so that too much carbon dioxide is excreted, resulting in a drop in the partial
pressure of carbon dioxide in the arterial blood. Decreased carbon dioxide binding capacity in blood biochemistry usually indicates that there are fewer alkaline substances in the blood that can bind carbon dioxide. Therefore, the decrease in carbon dioxide binding capacity is an important indicator of the increase in the body's acidic products, the decrease in the alkaline products, and metabolic acidosis. When the body has metabolic acidosis, which leads to the reduction of alkaline substances and the decrease of carbon dioxide binding capacity, in order to compensate for the metabolic acidosis, the pH value can be maintained in a relatively normal range, and the respiratory function will expel carbon dioxide through excessive ventilation. so that the PH value can not be lowered excessively, at this time, the partial pressure of carbon dioxide in the arterial blood may drop.

Therefore, when the carbon dioxide binding capacity in the blood decreases, accompanied by a decrease in the partial pressure of carbon dioxide in the respiratory arterial blood gas analysis, it usually indicates that the patient's metabolic acidosis is compensated by breathing. At this point, if the pH is normal, we can diagnose the patient as having compensatory metabolic acidosis. Therefore, it can be understood that arterial blood carbon dioxide is an important indicator of respiratory acid-base balance, and carbon dioxide binding capacity in blood is an important indicator of metabolic acid-base imbalance.