Multi-organ insufficiency syndrome in the elderly is an important cause of death in elderly patients with critical illnesses. The impairment of body functions leads to a decline in body functions, and the body’s ability to resist infection decreases, and geriatric multi-organ insufficiency syndrome is a manifestation of decreased infection capacity. What is the differential diagnosis of decreased ability to resist infection? 1, the systemic inflammatory response is out of control MODSE early The body appears systemic inflammatory reflection (SIR) manifested as high metabolism (high oxygen consumption, oxygen consumption and oxygen supply appear pathologically dependent, hyperglycemia, protein catabolism enhanced negative nitrogen balance and hyperlactatemia) high power circulation (high cardiac output, low peripheral resistance) and excessive inflammatory response that temperature > 38 ℃ or < 36 ℃, heart rate > 90min, respiration >20/min or PaCO2 <4.3Kpa, leukocytes >12×109/ or <4×109/L, and uncontrolled release of multiple cytokines and inflammatory mediators. Once this inflammatory response is out of control, it triggers cell-cell interactions and causes cell damage through cytokines or other mediators that are toxic to the parenchymal cells of the raking organ. 2, tissue oxygen supply and demand metabolic disorders Patients in a state of severe stress and systemic inflammatory response out of control, sympathetic excitability increased, the body is in a high metabolic state, oxygen consumption increased, but these patients at this time there are different become tissue hypoxia, thus occurring oxygen supply and demand metabolic disorders. 3, tissue cell energy, nutrient metabolism disorders The body in the conditions of ischemia, hypoxia persists, with the development of disease, deterioration, mitochondrial body structure and function is damaged, will further affect the ability, nutrient metabolism. aTP production is insufficient, fat, protein metabolism can not enter the tricarboxylic acid cycle oxidation, the body nutrient metabolism disorder, protein decomposition to strengthen, total protein synthesis decline, a large number of branched chain amino acids The oxidation function, resulting in an increase in aromatic amino acids, branched-chain amino acids decline, the body is in negative nitrogen balance.