Deep vein thrombosis often occurs in patients having major surgery, particularly orthopedic surgical patients especially if they are immobilized for any length of time post-operatively. Deep vein thrombosis could eventuate in fatal pulmonary embolism; this is preventable with appropriate prophylaxis. Joanna Briggs Institute (2008) reviewed that the risk of deep vein thrombosis formation rises with the duration of the operative procedure and period of immobility. This paper will look at 5 different prophylactic methods for prevention of deep vein thrombosis post operative, which will include: The effectiveness of anti embolic stockings, the use of intermittent pneumatic compression device, effectiveness of combined anti-embolic stockings and intermittent pneumatic compression (mechanical methods), the use of pharmacological prophylaxis – low molecular weight heparin, and the effectiveness of combined mechanical and pharmacological methods. Many doctors prefer their patients to wear anti embolic stockings pre-operative, intra-operative and post operative as a preventative measure for deep vein thrombosis. Anti embolic stockings are designed to support the lower extremities and maintain compression of small veins and capillaries.
The constant compression forces blood into larger vessels which promote venous return and prevent circulatory stasis (Crisp & Taylor 2008, p.1566). There have been many research papers conducted on the effectiveness of anti embolic stockings in the prophylaxis of post-operative deep vein thrombosis. Most of them state that the use of anti embolic stockings is assessed according to individual risk factors, the type of surgery i.e. orthopedic, cardiac or abdominal and how long the patient will be immobilized. An earlier research done by Byrne (2001) stated that when wearing anti embolic stockings properly it reduces the incidence of deep vein thrombosis by more than 60%, but they have to be correctly sized and fitted to work efficiently (p. 278). But Morris and Woodcock (2004) argued that anti embolic stockings are popular choices because they are cheaper and easier to use, but they are not effective as other prophylactic methods especially in orthopedic surgery and therefore should be used as a background with another prophylactic method (p. 167).
Amaragiri and Lees (2009) also agree with this point by stating anti embolic stockings are effective in diminishing the risk of deep vein thrombosis in hospitalised patients, but they are more effective when combined with another prophylactic method, such as the use of intermittent pneumatic compression device (p.2). Intermittent pneumatic compression devices work similar to anti embolic stockings by promoting circulation by sequentially compressing the legs from the ankle upwards preventing stasis and encourage venous return (Crisp & Taylor 2008, p.1566). There are different types of intermittent pneumatic compression devices which all rely on pump intermittently inflating and deflating air bladders within the cuff that wraps around the legs and the cuffs can either cover the calf, whole leg or just feet, and they can inflate uniformly or sequentially with graded pressures (Morris and Woodcock, 2004, p.162).
Meguid (2011) claims the choice for using intermittent pneumatic compression device alone is influenced by patient risk factors for developing deep vein thrombosis and type of surgery they are undergoing. Intermittent pneumatic compression devices can be used as an alternative strategy for patients who at high risk for bleeding complications that are contraindicated for the use of pharmacological prophylaxis (p. 583). Earlier research done by Morris and Woodcock (2004) state intermittent pneumatic compression device prevents deep vein thrombosis by leaving the device on the legs longer for better protection against deep vein thrombosis (p. 162). But this research was contradicted by Urbankova, Quiroz, Kucher, and Goldhaber (2005) and they state that there is not an optimal period for how long an intermittent pneumatic compression device should be left on for (p. 1184). But according to Meguid (2011), they suggest the intermittent pneumatic compression device should remain on a patient until the patient is discharged or ambulating for more than 30mins daily. However the patient must be properly educated in the proper use of intermittent pneumatic compression device and being compliant does aid in the prevention of deep vein thrombosis (p. 583).
There are considerable ranges of potential prophylactic measures aimed at reducing the risk of deep vein thrombosis. According to Maclellan and Fletcher (2007) mechanical techniques such as anti embolic stockings and Intermittent Pneumatic Compression devices are aimed to counteract venous stasis (p. 418). The effectiveness of these mechanical prophylactic methods combined, most of the research was conducted on moderate to high risk patients and it included: age, health co-morbidities, type of surgery, and anticoagulant therapy and have history of deep vein thrombosis (Joanna Briggs Institute, 2008, p. 3). Maclelland and Fletcher (2007) state studies suggest the efficiency of mechanical prophylaxis appears to be equivalent to the use of pharmacological methods, but it depends on client risk factor and compliance issues of using both anti embolic stockings and intermittent pneumatic compression (p. 420). But according to Autar (2010), his study found there has been low compliance in minority of patients due to the discomfort which markedly increased when anti embolic stockings and intermittent pneumatic compression were combined for the increased efficiency, and therefore they should only be used during the period of immobility to the return of full ambulation (p. 91).
Although discomfort issues can be a problem with patients being non-compliant with the prescribed treatment, but Morris and Woodcock (2004) found there had been a reduction in rates of deep vein thrombosis in general surgical patients when the intermittent pneumatic compression and anti embolic stockings were worn together. There has been a suggested reason as to why the combination works and it is believed that stockings prevent distension and the intermittent pneumatic compression empties the veins, preventing stasis. Morris and Woodcock (2004) concluded that little research has been done on whether stockings improve the velocity augmentation of intermittent pneumatic compression, but one study had found reductions rates when they are worn together compared to intermittent pneumatic compression alone (p. 168). Therefore insufficient evidence to support these combined treatments. Pharmacological method for prophylaxis of deep vein thrombosis involves the administration of low molecular weight heparin, which is an antithrombotic drug. The role of the medication is to stop the progression of the formed clot and also to prevent a blood clot from occurring post operatively in patients undergoing orthopedic and general surgery (Meguid, 2011).
Low molecular weight heparin is used mainly on high risk patients who are undergoing major orthopedic surgery such as Total Hip Replacement (THR) and Total Knee Replacement (TKR). According to a study done by Green (2003) High risk patients are classified as over 40 years of age, undergoing major procedures, immobilized for long periods and who have additional risk factors for thrombosis, should be prescribed low molecular weight heparin (p. 98). When prescribing low molecular weight heparin the surgeon must balance the risks: the risk of developing a clot and the risk of bleeding (Westrich and Bornstein, 2009). However low molecular weight heparin has a downside which is cost and therefore cannot be administered to everybody, as Meguid (2011) points out that patient population plays a large role in determining the need and therapy for deep vein thrombosis prophylaxis and therefore selecting the best therapy based on risk factors, history and current medical condition is elusive (p. 586). According to Westrich and Bornstein (2009) they state no single method of prophylaxis is ideal and therefore a multimodal approach is ideal (p. 235).
However mechanical (anti embolic stockings and intermittent pneumatic compression) and pharmacological (low molecular weight heparin) methods for prevention of deep vein thrombosis are reserved for high risk patients and the type of surgery they are undergoing, as both of these methods are proved to be effective. The pharmacological method targets coagulation factors, whereas mechanical methods mainly focus on the prevention of venous flow stasis (Maclellan and Fletcher, 2007). An earlier research done by Byrne (2001) suggests early ambulation is a noninvasive and effective way of increasing venous return and preventing clot formation. However if patients are immobilized for a period of time then they will receive anticoagulant therapy in conjunction with mechanical prophylaxis (p. 278). In addition to this point Joanna Briggs Institute (2008) also agrees that patients who are in the high risk category and undergoing major orthopedic and general surgery should be offered low molecular weight heparin to conjunction with mechanical prophylaxis, but patients should be encouraged to mobilize as soon as possible after surgery (p. 3).
Maclellan and Fletcher (2007) state when pharmacological methods cannot be used due to contraindicated patients who are at risk of bleeding, then mechanical methods may then become crucial for deep vein thrombosis prophylaxis (p. 419). All prophylactic methods mentioned are effective to an extent. However, it is clearly indicated that more research is required for the effectiveness of anti-embolic stockings, how long an intermittent pneumatic compression device should remain on a patient to maximize the effect and the effectiveness of combined mechanical prophylaxis alongside with Low Molecular Weight Heparin. The most common point that stood out was early ambulation after surgery.
Prevention of deep vein thrombosis post-operatively is an important issue. Suitable prophylaxis for the individual is determined by accurate assessment by the surgeon. Assessment includes patient age, risk, weight, personal history of deep vein thrombosis and pharmaceutical history, medical history, type of surgical intervention and length of immobility post-operative. Modern methods of deep vein thrombosis prophylaxis include use of simple cost effective measures which will reduce the incidence of deep vein thrombosis during the post operative period significantly. This in turn will prevent death from possible pulmonary embolism as a consequence.