Deep venous thrombosis (DVT) is a common clinical problem, especially in patients with prolonged braking. DVT not only causes pain to patients, but also seriously affects their functional recovery and rehabilitation treatment, and even endangers their lives. This article briefly introduces the influence of braking on DVT formation, rehabilitation prevention and rehabilitation treatment of DVT. I. The effect of braking on the formation of DVT Braking (immobilization) refers to the body being forced to be at rest for a long period of time, and the common causes include bed rest, local immobilization and neurological paralysis. Braking is the most commonly used medical treatment for patients with serious diseases and injuries, and it helps to protect damaged tissues, reduce tissue burden, maintain stability and natural recovery process. DVT is one of the common complications of braking. The main mechanism of DVT formation due to braking is: 1. Decrease in blood volume From upright position to lying position, 500-700ml of blood volume in the lower extremities immediately enters the central circulation, and the pressure in the right atrium increases rapidly. The cardiovascular center regulates this by decreasing the secretion of antidiuretic techniques, so that renal tubular reabsorption decreases and urine increases. The fact that we have to urinate every morning and feel thirsty is the result of blood volume regulation. Some studies have shown that 20 days of mandatory bed rest reduces plasma volume by 15-20%, total blood volume by 5%-10%, heart volume by 11% and left heart end-diastolic volume by 6%-11%. Due to the decrease in blood volume, the beat-to-beat volume and cardiac output are correspondingly reduced by 6-13%, and the basal heart rate remains unchanged or increases. There is a significant reduction in exercise capacity due to decreased circulatory function. Inadequate fluid intake during prolonged bed rest is also one of the factors leading to reduced blood volume. 2. Blood flow velocity is slowed down After bed rest, blood flow velocity of abdominal aorta is reduced by 24.4%, femoral artery is reduced by 50%, middle cerebral artery is also reduced, but coronary artery flow velocity remains unchanged. The venous flow resistance of the lower extremities increased by 91%, the venous compliance increased, and the blood flow velocity slowed down significantly. 3.Increased blood viscosity Due to the decrease of blood volume, but not the decrease of blood organic fraction, resulting in a significant increase of blood viscosity. 4.Increased chance of thrombosis Due to increased blood viscosity and slow blood flow, the chance of thrombosis increases significantly, the most common ones are deep vein thrombosis, thrombotic vasculitis and pulmonary embolism. This is the basic principle of the possibility of DVT formation in long-term bed-ridden patients as high as 15%-50%. the occurrence of DVT is mostly in the lower limbs, leading to severe edema in the lower limbs, often combined with infection; deep vein embolism dislodged can cause lethal pulmonary embolism, and the morbidity and mortality rate is high. Second, the prevention of DVT The international neglect of venous thrombosis prevention is widespread. In a study of 5451 DVT patients in 183 hospitals in the United States, it was found that 3894 (71%) had no prophylaxis, of which 2295 (59%) were non-operative patients. DVT occurs more severely in non-surgical patients after admission than in surgical and trauma patients because the former often neglect DVT prophylaxis. key measures for DVT prophylaxis are to remove the underlying factors that trigger thrombosis, which include: 1. appropriate posture frequent upright posture is the most common and effective measure. For patients who can sit and stand on their own, patients should be encouraged to take sitting and standing positions several times a day. Patients who cannot sit and stand independently because of their condition, such as those with spinal fractures and spinal cord injuries, can also take the position of sitting against the bed with the head of the bed rocked high. Even in patients with spinal fractures, rocking the head of the bed and sitting against it will not cause the fracture to shift. Most patients with spinal instability have already undergone internal fixation surgery, so sitting in a leaning position will not cause instability of the spinal fracture, but rather accelerate the healing of the fracture due to local gravity. For patients with cardiopulmonary disease, adopting a sitting position not only prevents DVT, but also helps to reduce the burden on the heart and improve respiratory function. Because the upright posture can reduce venous return, thus reducing the preload of the heart, while the afterload of the heart does not increase, but may decrease. The upright posture facilitates the downward shift of the diaphragm, reduces inspiratory resistance, maintains a reasonable ventilation/perfusion ratio, and helps with coughing actions. Heart failure patients and patients with chronic emphysema spontaneously adopt a sitting or leaning posture, which indicates from another perspective that sitting is a reasonable functional compensatory measure for such patients. 2, appropriate water and fluid supplementation As the patient’s blood volume is reduced, giving the patient sufficient water intake is a necessary measure to prevent DVT. When replenishing body fluid, not only urine volume but also non-significant water loss should be considered, which is caused by water vapor excretion from exhalation and skin sweating. Non-significant water loss is approximately 800 ml/day. In the case of strenuous exercise, heat and sweating, water loss is more serious. 3.Appropriate physical activity Appropriate physical activity can promote venous blood flow and prevent DVT through the action of muscle pump. In the case that the patient’s injury site is unstable, activities can be performed in the non-injury site. For example, patients with spinal fractures can do lower and upper limb activities; patients with lower limb paralysis can be encouraged to do upper limb activities; and patients with femur fractures can do ankle activities. Even at the fracture site, performing muscle isometric contraction, i.e., exercises that have muscle contraction but do not cause joint movement, is an effective way to prevent DVT and also helps to promote fracture healing. Patients with cardiopulmonary disease should be careful when performing physical activities that the intensity of the exercise is not too high. In general, light non-resistance physical activity has minimal physical load and rarely induces cardiovascular and respiratory problems. ECG and oxygen saturation monitoring can be used during exercise or activity, respectively, if necessary. In cases where active activity is not possible, gentle passive exercise is also valuable. 4.Early activity on the ground Early entry into walking is beneficial to prevent the occurrence of DVT. Clinical experience shows that DVT rarely occurs in patients who have resumed walking. 5.Use of drugs that reduce blood viscosity Aspirin is the most common drug. Other anticoagulants are also drugs that can be considered, especially for patients with a history of thrombosis. 6.Pay attention to the early manifestation of DVT Pay attention to the early manifestation of DVT formation and take active measures, which can effectively prevent and stop the progress of the lesion. The main points of observation include: the skin temperature, color and elasticity of the limb; the circumference and pressure pain of the limb; and the abnormal sensation of the patient. early swelling of DVT often manifests as diffuse limb swelling with high tension, the skin temperature may increase, there is pressure pain, and the swelling gradually develops from the distal to the proximal end of the limb. In later stages, it manifests as sunken edema. If there is significant localized swelling of the limb without swelling of the distal limb, the most common possibility is heterotopic ossification rather than DVT.