Hemoconcentration is usually caused by low water intake or excessive water consumption in the body, which is usually not a big problem and can be reviewed after drinking more water, and if there is a significant decrease, it means the problem is hemoconcentration. The following are several common causes. Insufficient water intake Coma patients or patients with mental disorders do not feel thirsty and do not know that they need water and water intake is insufficient, or oral or upper gastrointestinal lesions can not enter water or water sources are cut off, such as in the desert and accidents can not get water. Increased water demand patients with high fever or in hot environments require increased water but not enough supplementation. Excessive water loss 1, vomiting diarrhea, intestinal thinning, gastrointestinal drainage so that a large amount of digestive fluid is lost and not replenished; 2, uremia or renal tubular insensitivity to antidiuretic hormone (ADH) and excretion of large amounts of dilute urine accepting solute diuretics (mannitol, glycine, etc.) or high protein salt-containing diet intake and osmotic diuresis, uncontrolled diabetes mellitus patients excreting large amounts of glycosuria and renal concentration dysfunction The result is that the kidney drains more sodium than it drains. 3, high temperature and heavy physical work with a lot of sweating; 4, tracheotomy and hyperventilation can cause a large loss of water from the airway this lost water is pure water, in the case of accompanied by insufficient water intake can easily cause hypertonic dehydration.