CHRONIC VENOUS INSUFFICIENCY
Venous insufficiency results from obstruction of the venous valves in the legs or a reflux of blood back through the valves. Superficial and deep leg veins can be involved. Resultant venous hypertension can occur whenever there has been a prolonged in-crease in venous pressure, such as occurs with deep venous throm-bosis.
Because the walls of veins are thinner and more elastic than the walls of arteries, they distend readily when venous pressure is consistently elevated. In this state, leaflets of the venous valves are stretched and prevented from closing completely, allowing a backflow or reflux of blood in the veins. Duplex ultrasonography confirms the obstruction and identifies the level of valvular incompetence.
When the valves in the deep veins become incompetent after a thrombus has formed, postthrombotic syndrome may develop (Fig. 31-16). This disorder is characterized by chronic venous sta-sis, resulting in edema, altered pigmentation, pain, and stasis der-matitis. The patient may notice the symptoms less in the morning and more in the evening. Obstruction or poor calf muscle pump-ing in addition to valvular reflux must be present for the develop-ment of severe postthrombotic syndrome, which includes stasis ulceration (Caps et al., 1999). Superficial veins may be dilated. The disorder is long-standing, difficult to treat, and often disabling.
Stasis ulcers develop as a result of the rupture of small skin veins and subsequent ulcerations. When these vessels rupture, red blood cells escape into surrounding tissues and then degenerate, leaving a brownish discoloration of the tissues. The pigmentation and ulcerations usually occur in the lower part of the extremity, in the area of the medial malleolus of the ankle. The skin becomes dry, cracks, and itches; subcutaneous tissues fibrose and atrophy. The risk of injury and infection of the extremities is increased.
Venous ulceration is the most serious complication of chronic ve-nous insufficiency and can be associated with other conditions affecting the circulation of the lower extremities. Cellulitis or der-matitis may complicate the care of chronic venous insufficiency and venous ulcerations.
Management of the patient with venous insufficiency is directed at reducing venous stasis and preventing ulcerations. Measures that increase venous blood flow are antigravity activities, such as elevating the leg, and compression of superficial veins with elastic compression stockings.
Elevating the legs decreases edema, promotes venous return, and provides symptomatic relief. The legs should be elevated frequently throughout the day (at least 15 to 30 minutes every 2 hours). At night, the patient should sleep with the foot of the bed elevated about 15 cm (6 inches). Prolonged sitting or standing still is detrimental; walking should be encouraged. When sitting, the patient should avoid placing pressure on the popliteal spaces, as occurs when crossing the legs or sitting with the legs dangling over the side of the bed. Constricting garments such as panty girdles or tight socks should be avoided.
Compression of the legs with elastic compression stockings re-duces the pooling of venous blood and enhances venous return to the heart. Elastic compression stockings are recommended for people with venous insufficiency. The stocking should fit so that pressure is greater at the foot and ankle and then gradually de-clines to a lesser pressure at the knee or groin. If the top of the stocking is too tight or becomes twisted, a tourniquet effect is cre-ated, which worsens venous pooling. Stockings should be applied after the legs have been elevated for a period, when the amount of blood in the leg veins is at its lowest.
Extremities with venous insufficiency must be carefully pro-tected from trauma; the skin is kept clean, dry, and soft. Signs of ulceration are immediately reported to the health care provider for treatment and follow-up.