呼吸功能衰竭是各种原因引起的肺通气和（或）换气功能障碍，导致严重缺氧，伴或不伴有二氧化碳储留，即在海平面大气压下呼吸自然空气时，动脉血氧分压（PaO。）低于60毫米汞柱和（或）二氧化碳分压高于50毫米汞柱时而引发的生理功能紊乱的临床综合征。呼吸功能衰竭的病因有； Respiratory failure is caused by various causes of pulmonary ventilation and / or ventilation dysfunction, leading to severe hypoxia, with or without carbon dioxide storage, that is, when breathing natural air at sea level atmospheric pressure, arterial partial pressure of oxygen (PaO.) Is lower than 60 mmHg and (or) partial pressure of carbon dioxide is higher than 50 mmHg when the clinical syndrome caused by physiological disorders. Causes of respiratory failure are;