Dehydration fever refers to a condition in which the body consumes a large amount of water due to a lesion that cannot be replenished immediately, resulting in a metabolic disorder, and is a phenomenon in which the body’s heat dissipation is affected, resulting in an increase in body temperature. In severe cases, it can cause deficiency and even life-threatening, and it needs to rely on fluid infusion to replenish body fluids. The diagnosis of dehydration fever: 1. Hypertonic dehydration: blood concentration, blood cell count, hemoglobin, hematocrit and blood Na+ can be increased, and plasma osmolality also significantly exceeds the normal high limit. The urine is concentrated and the specific gravity is high. 2. Hypotonic dehydration: Blood Na+ and Cl- often decrease, but due to renal blood circulation disorders, non-protein nitrogen, creatinine and urea can also increase, and blood is also concentrated. The urine often has less sodium (<10mmol/L) or no sodium. 3, according to the condition, clinical manifestations can be done: central venous pressure check the normal value of 6-12cmH2O (1cmH2O = 0.098kPa), central venous pressure drop indicates insufficient blood volume. Electrocardiogram, ultrasound, X-ray examination, etc. Second, the identification points of dehydration fever: Clinically, it is not difficult to make a diagnosis of dehydration based on history, symptoms and signs. After the diagnosis of dehydration is made, it can be determined which type of dehydration it is based on serum sodium concentration.