急性呼衰系指呼吸障碍发生在数日或一个月以内,吸空气时 PaO_2<60 Torr;慢性呼衰则指呼吸衰竭持继达一个月以上,PaO_2<50 Torr。正常人在海平面卧位 PaO_2=100-0.4×年龄,吸烟、肥胖、高龄者由于闭合气量增加,肺泡动脉氧压差增大,PaO_2稍有降低。任何原因所致的呼衰,均应立即进行监护,进一步了解其病生理情况,观察病情变化,以便及时采取有效措施, Acute respiratory failure refers to respiratory failure occurs within a few days or a month, PaO_2 <60 Torr when inhaling air; chronic respiratory failure refers to respiratory failure persist for more than a month, PaO_2 <50 Torr. Normal PaO2 = 100-0.4 × sea age, smoking, obesity, elderly people due to increased closed volume, alveolar artery oxygen pressure increased PaO_2 slightly lower. Respiratory failure caused by any reason, should be immediately guardianship, to further understand its disease and physiological conditions, observation of changes in condition in order to take timely and effective measures,