Sudden dyspnea and numbness in the hands and feet is the occurrence of hyperventilation syndrome, which is a common functional disorder that often occurs when patients are emotionally stimulated, overly stressed and anxious, and is more likely to strike in crowded situations. Patients show chest tightness and difficulty in breathing, and thus cannot help but gasp for air, which excessively expels carbon dioxide from the body, resulting in a significant decrease in the central and peripheral carbon dioxide concentration, causing numbness in the hands, feet and mouth and lips, and in severe cases, patients may even experience stiffness and twitching of the limbs. In this case, you should calm the patient to avoid excessive anxiety, and at the same time, you can find a paper cup or paper rolled into a tube and place it at the patient’s mouth and nose, so that the exhaled carbon dioxide will be sucked back into the body again. 10-15 minutes or so, the carbon dioxide concentration will rise significantly, and the symptoms will be relieved.