Dalteparin (Fragmin) Anticoagulant+ Low-Molecular-Weight Heparin: Action an

 Deep Vein Thrombosis

What is Deep Vein Thrombosis?

Deep vein thrombosis also called phlebothrombosis. It is an acute thrombosis of deep veins. Deep vein thrombosis is very common in western countries, the exact cause of which is not known. Postoperative immobilisation, pressure on the calf muscles, sluggish blood flow and prolonged bed rest are the various factors that precipitate deep vein thrombosis. Commonly, it affects venous sinuses in the soleal muscles. It is a common starting place. It can also involve pelvic veins. Various factors responsible for deep vein thrombosis can be remembered as Thrombosis.

Thrombosis Virchow's Triad

• Endothelial injury
• Stasis
• Increased coagulability

Causes of Deep Vein Thrombosis 

• Trauma: Injury to the vessel wall.
• Hormones: increased coagulability.
• Road Traffic Accidents.
• Operations: cholecystectomy.
• Malignancy: sluggish blood flow.
• Blood disorders: polycythaemia.
• Orthopaedic surgery: obesity, old age
• Serious illness: stroke, MI.
• Immobilisation.
• Splenectomy.

Most common site of Deep Vein Thrombosis

• The common site of DVT is Lower Limb (Muscular calf vein).
• Upper DVT is rare. Can occur due to trauma or surgery.

Deep Vein Thrombosis Clinical Features and Early warning of DVT

• The maximum incidence occurs on the 2nd day and 5th-6th days in the postoperative period.
• The first complaint is usually oedema, erythema, dilated veins of the leg.
• Dull-aching or nagging pain in the calf muscles is present.
• Superficial blebs in the skin.
• Low-grade fever with increased pulse rate is characteristic.
• Phlegmasia alba dolens refersto white leg. It occurs when the thrombus extends from the calf region to the iliofemoral vein.
• Phlegmasia coerulea dolens refers to blue leg with loss of superficial tissues of the toes.

Dalteparin (Fragmin) Anticoagulant+ Low-Molecular-Weight Heparin: Action an

Uses

Signs of Deep Vein Thrombosis

• Homan's test: Forcible dorsiflexion of the foot results in severe pain in the calf region.
• Moses's test: (Ideally should not be done for fear of embolism): Tenderness over calf muscle on squeezing the muscle from side to side.

Investigation and Diagnostic study for Deep Vein Thrombosis

• Doppler study: It is ideal for femoral vein thrombosis or when thrombus extends into popliteal vein. Normal femoral vein gives a wind storm sound which completely disappears at the end of inspiration. No sound is heard if there is femoral thrombosis.
• Contrast venography: It is done by injecting radiopaque dye into dorsal venous arch with an inflatable cuff both above the ankle and above the knee. Clot appears as a filling defect. However, venography is not routinely done because it is expensive and invasive.

Duplex Scanning/ Doppler Study in Deep Vein Thrombosis

• The vein is larger than normal because of occlusion.
• Not completely compressible.
• Lacks respiratory variation.
• Does not show flow augmentation with calf compression.
• May have collateral flow.

Treatment for Deep Vein Thrombosis (DVT)

• Bedrest and elevation of limbs.
• Injection heparin 10,000 units IV bolus with continuous infusion of 30,000 to 45,000 units per day. During heparin therapy activated partial thromboplastin time (APTT) should be maintained at twice the normal value. Heparin is given for a period of 7-10 days.
• Warfarin, an oral anticoagulant is started 2-3 days before heparin is withdrawn because of the slow onset time of warfarin. Treatment with warfarin should continue for 6 to 12 months. Repeat duplex scan should be done to look for recanalisation of the veins. The dose of warfarin should be 10 mg twice a day. Treatment is monitored with prothrombin time and INR. International Normalized Ratio (INR) should be between 2.0 and 3.0
• Low molecular weight heparin (LMWH): It is given once or twice a day, in the form of injection. No blood monitoring required. Incidence of bleeding is less with LMWH.
• Inferior vena caval filters: They can be inserted percutaneously via femoral vein patients wherein lytic therapy is contraindicated.
• Surgery is not done regularly. However, in chronic cases, venous bypass has been attempted with moderate success.
• Plasma operation is done in iliofemoral thrombosis wherein the common femoral vein below the block is anastomosed to the opposite femoral vein using long saphenous, from the opposite side.
• May-Husni operation wherein popliteal vein is connected to long saphenous vein above.

Complications of Deep Vein Thrombosis

• Permanent oedema of the limb. The limb has an inverted beer bottle appearance.
• Pulmonary embolism because the thrombus is not attached to vessel wall.
• Secondary varicosity and nonhealing ulcer.

Thrombolytic Therapy (Thrombolysis): Acute Myocardial Infarction: Nursing Considerations

Prophylaxis of  Deep Vein Thrombosis

• Decrease obesity and advise exercises before surgery.
• Low dose heparin 5,000 units subcutaneous, 2 hours before surgery and 24 hours after surgery, and then every 12 hours for 5 days is given, during major surgeries such as cholecystectomy, abdominoperineal resection. 
• Intermittent pneumatic compression of the calf throughout the operation maintains the blood flow in the lower limbs. Inflation pressure is around 30-50 mmHg.
• Dextran 40 inhibits sludging of red blood cells and platelet aggregation.
• Aspirin along with dipyridamole has been used (antiplatelet agents).
• Early mobilisation, walking, adequate hydration.
• Low molecular weight heparin decreases the chances of bleeding.

Reference Manipal Manual of Surgery