Chronic pulmonary heart disease often causes hypotension, but usually acute pulmonary heart disease attacks are associated with varying degrees of elevated blood pressure. The causes of hypotension due to chronic pulmonary heart disease are as follows. Chronic obstructive diseases of the bronchi and lungs, such as slow-onset lung, bronchial asthma, bronchiectasis, tuberculosis, and interstitial lung disease, usually lead to hypoxia and increased carbon dioxide, which can cause hypercapnia. Conditions such as low partial pressure of oxygen and increased partial pressure of carbon dioxide. This condition causes pulmonary vasoconstriction, pulmonary vascular reduction, and increased pulmonary resistance through various mechanisms of biological factors and ion changes, and therefore, pulmonary hypertension can occur, as well as leading to the production of hypotension. Widespread or recurrent nodular pulmonary arteritis and multiple small pulmonary artery embolisms can also cause pulmonary hypertension, pulmonary heart disease, and trigger hypotension.