Decrease in partial pressure of carbon dioxide refers to the decrease in carbon dioxide level in blood, which is common in hyperventilation and metabolic acidosis, and should be treated according to the cause. 1. Hyperventilation: Hyperventilation will cause respiratory alkalosis, which will cause a drop in partial pressure of carbon dioxide. For this situation, patients are advised to regulate their emotions, and if necessary, sedatives can be used. Emotional stabilization will help normal breathing; cardboard shells can also be used around the patient’s nostrils to prevent carbon dioxide from diffusing too quickly. 2. Metabolic acidosis: Correcting metabolic acidosis requires active treatment of the primary disease, such as replenishing fluids, correcting circulatory disorders, and improving tissue perfusion. If a decrease in partial pressure of carbon dioxide is detected, it is recommended to go to a specialized hospital for treatment rather than blindly treating the patient on your own.