Deep Vein Thrombosis
Deep vein thrombosis (DVT) occurs when a blood clot (thrombus) forms in one or more of the deep veins in your body, usually in your legs.
WHAT IS DVT?
- Formation of a clot within a deep vein
- Deep veins are embedded intramuscularly in the deep fascia
- A clot begins as a small deposit of platelets, fibrin and red blood cells
- Often originate in the venous valve cusp pockets
- Thrombus extends and propagates
INCREASED RISK OF DVT
- Travel > 4 hrs within 2-3 wks.
- Strong family history.
- Postmenopausal HRT.
- Trauma to symptomatic limb < 60 days .
- Hospitalization in previous 6 months
- Vein injury and trauma from surgery
- Distension of veins
- Stress response to surgery – elevation of pro-coagulant factors, fibrinolytic shutdown
- Perioperative fluid loss – hyperviscosity
- Specific intraoperative orthopaedic risk factors for THR/TKR (Capper 1998) -heat activated cement, tourniquet effect
SITES FOR DVT
- Lower limbs
- Venous sinuses of soleus muscle in calf
- Femoral vein
- Iliac vein
- Upper limb its rare
- Axillary vein following trauma, neoplasm
Invasive – Ascending venography.
Non-invasive – Hand held Doppler,Directional Doppler, Doppler ultrasonography
- Physical Methods: Plethysmography.Thermography.Radionuclidescanning.Fibrinogen I 125 uptake studies
- Biological Methods: C – Reactive protein.,T-AT III complexes,Fibrinopeptide – A / TP antigen Circulating platelet aggregates, Plasminogen activator inhibitor, D – dimer.
PROPHYLATIC STRATEGIES FOR DVT
- Pharmacological: Heparin, LMWH, Clexane
- Intrinsic- walking
- Extrinsic- Deep Vein Thrombosis stockings, IPC[Intermittent Pnuematic Compression]
CLINICAL EFFECTS OF IPC
- Increases or replaces calf muscle pump
- Increase in blood flow (haemodynamics)
- Increases arterio-venous (AV) pressure gradient
- Decreases venous distension and venous pressure
- Increases skin blood flow – tissue perfusion
- Reduces oedema
- Increases fibrinolysis (assists in breakdown of fibrin deposits)
COMPLICATIONS OF DVT
Non healing leg ulcers
IPC: WHO AND WHEN???
Surgical patient:Pre-operatively,Intra-operatively,Post-operatively for at least 72 hours or until patient is fully mobile (at least five minutes in every hour)
Non-surgical patient:Immediately upon identification that the patient is at risk
- An alternative to other kinds of prophylaxis
- May be used in conjunction with pharmacological prophylaxis in high risk patients – no problems of interaction
- May be used with patients contraindicated for pharmacological prophylaxis e.g.: major bleeding disorders, increased risk of haemorrhage, gastrointestinal ulceration
- Safe, absence of bleeding complications
CONTRAINDICATIONS FOR IPC
- Severe arteriosclerosis or other ischaemic vascular diseases
- Known or suspected acute DVT or phlebitis
- Severe congestive cardiac failure
- Pulmonary embolism
- Any local condition in which the garments would interfere, including gangrene, recent skin graft, dermatitis or untreated, infected leg wounds