The most common factor is oxygen deprivation, which is caused by lack of oxygen in the brain or lung insufficiency. In patients with pulmonary hypertension, hypertension, pulmonary insufficiency, chronic obstructive pulmonary emphysema, pulmonary heart disease and chronic bronchial dilatation, there is a serious lack of oxygen saturation in the arterial blood, high partial pressure of carbon dioxide and low partial pressure of oxygen, which can lead to oxygen deprivation. In patients with obstructive pulmonary emphysema, pulmonary heart disease, and chronic bronchiectasis, there is a serious lack of oxygen saturation in the arterial blood, high partial pressure of carbon dioxide, and low partial pressure of oxygen, which may lead to incessant yawning due to lack of oxygen. 2.