High total carbon dioxide refers to the increased partial pressure of carbon dioxide in human blood, which can be caused by lung diseases, thoracic deformity, metabolic acidosis or respiratory acidosis. 1. Lung diseases: chronic bronchitis, chronic obstructive pulmonary disease, bronchial asthma and other diseases can cause a decline in pulmonary ventilation, alveolar ventilation is reduced, which leads to obstruction of carbon dioxide discharge in the lungs, carbon dioxide retention in the lungs caused by an increase in the partial pressure of carbon dioxide in the blood. 2. Thoracic deformity: when there is thoracic deformity or a large amount of hydrothorax, the expansion of the thorax is limited, which affects the normal lung ventilation function and leads to an increase in the partial pressure of carbon dioxide in the blood. 3. Metabolic or respiratory acidosis: both can lead to increased partial pressure of carbon dioxide in the blood. There are many other causes of high total carbon dioxide, such as myasthenia gravis, etc. It is recommended to consult a doctor in time to make a clear diagnosis and then carry out targeted treatment.