venous return, deep venous thrombosis, blood clot, venous stasis, chronic venous insufficiency, leg edema, syncope, orthostatic stress, vasoconstriction of arterioles, post phlebitic syndrome, postthrombotic syndrome, Postural Tachycardia Syndrome, venous leg ulcer, venous congestion, lymphedema, venous reflux
Increase in blood contained in veins of lower limbs occurring on standing. Results in fall in pulse pressure and consequential baroreflex increase in heart rate and vasoconstriction of arterioles. Putting it in layman's terms it is simply a poor return of the blood from the legs and feet to the heart. One resulting complication is edema of the affected limb. The edema results from fluid and plasma collecting within the limb instead of processing through the cardiovascular system.
The main cause of this condition is the lack of, or damage to the bicuspid valves in the veins. In the normal pumping action of the heart blood flow is stopped from "backwashing" during the resting period of the heart from these valves. When damaged or when congenitally not there, the blood flows backwards. This can be either congenital or from trauma or disease.
Venous hypertension in diseased veins is thought to cause CVI by the following sequence of events. Increased venous pressure transcends the venules to the capillaries, impeding flow. Low-flow states within the capillaries cause leukocyte trapping. Trapped leukocytes release proteolytic enzymes and oxygen free radicals, which damage capillary basement membranes. Plasma proteins, such as fibrinogen, leak into the surrounding tissues, forming a fibrin cuff. Interstitial fibrin and resultant edema decrease oxygen delivery to the tissues, resulting in local hypoxia. Inflammation and tissue loss result. (1)
Another cause is Postural tachycardia syndrome (POTS). This is a disorder that is characterized by a pulse rate that is too high when the patient is standing. Instead of the blood returning it pools due to the inefficient pump action of the heart. Symptoms of this disorder include rapid heartbeat, lightheadedness with prolonged standing, headache, chronic fatigue, chest pain, and other nonspecific complaints.
Finally, prolonged sitting in cramped position will cause venous pooling. This is especially important to lymphedema patients. On any prolonged trip, patients with this condition should make every effort to move around, stand, stretch or walk.
The most obvious symptom is the swelling that will occur in the foot and lower leg of the affected limb. Other symptoms may include tight calves, legs and feet that feel "heavy," tired, achy or restless.
Treatment for venous pooling will ultimately focus on the underlying condition that causes it.
For the edema involved, that patient may need decongestive massage therapy to gently move the fluids from the leg or foot. Compression wrappings or compression hosery may be needed as well.
In the condition of the congenital lack of vein valves or in the situation of damaged vascular veins, surgical grafts may be required.(c) Pat O'Connor - Lymphedema People
Edema and Venous Pooling
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