The impairment of bodily functions leads to a decrease in bodily functions, and the body’s ability to resist infections decreases, and geriatric multi-organ insufficiency syndrome is a manifestation of a decrease in infection resistance. What are the main causes of decreased resistance to infection? Multi-organ insufficiency syndrome in the elderly is an important cause of death in elderly patients with critical illnesses. Since the occurrence of multi-organ insufficiency in the elderly is the simultaneous or sequential onset of two or more organs, and the process is similar to the domino phenomenon, it is important to identify which is the first organ, just like finding the first domino to fall in dominoes, in order to identify or block the occurrence of the chain phenomenon of organ insufficiency or failure, as well as the association between its various organs. The main rationale is that: 1. Aging lungs have a pathophysiological basis as initiators of organ insufficiency in the elderly. As we age, the lungs age and their function decreases. Therefore the same external stimuli lead to more serious lung disorders in the elderly than in young and middle-aged people, difficult to treat and poor prognosis. 2, the impact of the environment on the lungs. The lungs are the only important organ in direct contact with the outside world in a person’s life, and have the most contact with external stimuli, producing a strong inflammatory response and generating toxins and other damage to important organs. 3. The immune function of the elderly is low, and the special defense function of the lungs is weakened. Long-term, a large number of clinical treatment found that lung infections account for 75.4% to 82.8% of the causative factors in the development of multi-organ failure in the elderly. The above characteristics determine that the lung is the most fragile and vulnerable organ among the vital organs of the human body to damage by internal and external factors.