Deep Vein Thrombosis in Hospitalized Patients a Review of Evidence-Based Guidelines for Prevention

Clinical DIMENSION

Deep Vein Thrombosis in Hospitalized Patients A Review of Evidence-based Guidelines for Prevention

Wendy Kehl-Pruett, ARNP, MSN, CCRN

Deep vein thrombosis affects many hospitalized patients because of decreased activity and therapeutic equipment. This article reviews known risk factors for developing deep vein thrombosis, current prevention methods, and current evidence-based guidelines in order to raise nurses’ awareness of early prevention methods in all hospitalized patients. Early prophylaxis can reduce patient risk of deep vein thrombosis and its complications. Keywords: Deep vein thrombosis, Thrombosis, Embolism, Risk factors, Prevention

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Venous thromboembolism results from a combination including high-dose anticoagulants and thrombolytics, of venous stasis, vein injury, and increased coagulation, may be contraindicated in certain inpatient popula- otherwise known as Virchow’s triad.1 Venous stasis tions; therefore, other methods of preventing DVT are occurs when patients are immobile and blood pools imperative. in the extremities, usually the leg veins. Vein injury can be the result of surgery, intravenous therapy, and phle- botomy. Increased coagulability is seen in inflamma- Deep vein thrombosis is a tory conditions and some infectious disease processes. complication of prolonged To prevent venous thromboembolism, the 3 compo- immobilization in hospital patients. nents of Virchow’s triad must be minimized during hospitalization. Deep vein thrombosis (DVT), a form of venous thromboembolism, is a complication of prolonged immobiliza- Patients in critical care units may be at risk of de- tion in hospital patients. Hospitalized patients are at veloping DVT and its complications. Critical care nurses increased risk of developing DVT due to immobility, must understand the risk factors for DVT and the vari- advanced age, acute medical illness, and central venous ous methodologies used to prevent this potentially life- catheters.2 Individuals who develop DVT are at fur- threatening condition. This article contains a review of ther risk for serious complications such as pulmo- risk factors and current methods for prevention of DVT nary embolism and death. Patients who develop DVT in hospitalized patients in order to raise clinician aware- can also have increased lengths of stay, which can ness of this preventable complication. The purpose of equate to increased avoidable costs. Treatment options, this article is to review risk factors for DVT, prophylaxis

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Y options, and current evidence-based guidelines for DVT These studies and meta-analysis,5 7 illustrate that prophylaxis, so that nurses may advocate for the initia- despite known risk factors and available prevention tion of early prevention measures in all hospitalized methods, medical patients are less likely to receive pro- patients. The guidelines presented are recommendations phylaxis than surgical patients. Researchers have also for early prevention that can reduce DVT occurrence noted that 75% of venous thromboembolism occurs in and prevent serious complications. medical patients.2,8 These statistics show an alarming trend toward underutilization of DVT prevention in PREVALENCE OF DEEP VEIN THROMBOSIS medical and surgical patients requiring hospitalization. The prevalence of DVT in the general population is 0.1%, which translates to 2 million people experiencing RISK FACTORS FOR DEEP VEIN DVT each year.1 Approximately one in every 1,000 per- THROMBOSIS IN HOSPITALIZED PATIENTS sons will experience DVT in the United States this year.3 Although all hospitalized patients have a possibility of Unfortunately, the incidence of DVT in hospitalized developing venous thromboembolism, certain factors Y medical patients has only been documented in clinical increase the risk of developing DVT (see Table 1).1,2,9 14 trials where prevention techniques were being studied. These risk factors include decreased mobility, age, obe- This rate has been reported at approximately 15%.4 sity, estrogen therapy, surgery, central venous catheters, General medical and surgical patients have a 10% to previous history of DVT, and many acute and chronic 40% risk of developing DVT while hospitalized, where- medical conditions that lead to hospital admission. as orthopedic surgery patients have a 40% to 60% risk.2 Medical conditions that can lead to increased risk in- The Deep Vein Thrombosis Free (DVT FREE) reg- clude cancer, inflammatory diseases, acute infections, istry is a national registry for patients who have ultra- heart failure, stroke, and chronic lung disease. sound-confirmed DVT.5 The registry’s purpose is to Decreased mobility is a major risk factor that affects study the epidemiology of patients with DVT and eval- most hospitalized patients, because few patients are as uate current management of prophylaxis. In a prospec- active while hospitalized as they were at home. DVT tive study of data from this registry,5 the DVT FREE risk is higher in hospitalized patients because bedrest is Steering Committee reviewed data from 5,451 patients frequently ordered. Even those patients permitted to get enrolled within a 6-month period and found that 2,726 out of bed, remain in bed far more than they would at developed DVT while hospitalized. Of those patients, 1,362 were medical patients and 1,364 were surgical patients. Seventy-one percent of these combined medical TABLE 1 Risk Factors for DVT in and surgical patients had not received any type of DVT Hospital Patients prophylaxis 30 days prior to diagnosis. Researchers General Risk Factors confirmed that routine preventive measures were not provided to 58% of medical patients.5 Unfortunately, Decreased mobility because this is a retrospective review, reasons for Age absence of DVT prophylaxis were not given. Obesity Another large (n = 4,011) prospective registry of Smoking patients with confirmed venous thromboembolism was created to assess current DVT prevention methods and Previous history of DVT patient outcomes.6 A review of data obtained over a Acute medical illness 17-month period found that surgical patients received Central venous catheters DVT prophylaxis 66% of the time, whereas nonsurgical Surgery, orthopedic, or abdominal patients were given DVT prophylaxis only 23% of the time. It was further noted that even in the presence of Estrogen therapy known risk factors, most medical patients had not re- Cancer and cancer therapy ceived prophylaxis. Inflammatory conditions Researchers conducted a meta-analysis of 14 studies Acute infectious processes from 1994 to 2002 that assessed the use of DVT prevention in critical care patients.7 They concluded that Heart failure only 69% of 3,654 combined patients received some Chronic lung disease form of DVT prophylaxis. Even with improved tech- Stroke niques in prevention, 31% of patients still did not Varicose veins receive adequate screening or prevention.

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Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Deep Vein Thrombosis in Hospitalized Patients home because of monitoring equipment, intravenous lines, motherapy, inflammatory disease, acute infectious dis- drainage tubes, catheters, and other necessary medical ease, estrogen therapy, heart failure, and chronic lung equipment. Decreased venous circulation and vascular disease.2,9,10,12 Another important risk factor for DVT disease, including prior history of venous thromboem- in hospital patients is the use of central venous bolism and varicose vein, are also considered risk fac- catheters.2 These catheters lead to venous injury when tors in DVT.9,10,12 inserted and, if inserted in the femoral vein, can further Increasing age is another important risk factor for restrict activity levels. DVT. In a 21-year analysis of records from the National All of these risk factors should be considered when Hospital Discharge Survey, researchers found an in- determining patient risk for developing venous throm- creased incidence of DVT as subjects aged.13 Elderly boembolism. Although individual risk factors are im- patients have higher DVT rates as compared to younger portant in considering the need for DVT prophylaxis, persons, with DVT rates doubling with each increase in multiple risk factors lead to an even greater risk.2 There- decade of life.9,13 Especially at risk are patients over age fore, all patients should be screened for DVT risk upon 75,2,10,13 although some recommend evaluating all in- admission.2,9 Specific screening should include de- dividuals older than 60 years.12 Eighty-year-old patients creased mobility, age, obesity, and medical conditions are 100 times more likely than patients under 40 to that increase DVT risk. DVT prevention techniques develop DVT.1 This is important as the Centers for should then be initiated based on risk assessment. Disease Control and Prevention population projections predict that the population of 65- to 85-year-olds will increase by 44% over the next 15 years.15 This means AMERICAN COLLEGE OF CHEST that hospitals will have greater numbers of elderly PHYSICIAN GUIDELINES patients at increased risk of DVT. Also noted in the Since 1986, the American College of Chest Physicians analysis of discharge records was that although pulmo- (ACCP) has produced evidence-based guidelines on nary embolus rates in the elderly were higher than youn- antithrombotic and thrombolytic therapy.16 These ger hospital patients, the rates were constant and not guidelines provide healthcare providers with recommen- increasing as in DVT.13 This may be the result of earlier dations for preventing and managing arterial and ve- prevention, diagnosis, and treatment, which further re- nous thromboembolism in both medical and surgical inforces the need to initiate DVT prevention early dur- patients.17 Comprehensive literature searches are con- ing hospitalization. ducted to locate appropriate, current research material in order to answer well-defined questions for each guideline.16 Authors then review research material to Increasing age is another important evaluate the quality of studies, summarize information, risk factor for DVT. and balance risk-benefit concerns to produce evidence- based recommendations for preventing and treating thromboembolism.17 Grades are assigned to recommen- There are conflicting data on obesity as a risk factor dations to help providers determine the quality of in venous thromboembolism. Many researchers consider evidence reviewed in guideline formulation.18 Higher obesity to be a well-established risk factor.2,9,11,12,14 grades are assigned to strong, consistent evidence such However, a re-evaluation of the demographic data from as similar results in multiple randomized clinical trials. the Prophylaxis in Medical Patients with Enoxaparin Lower grades are assigned when evidence is inconsistent study group (MEDENOX) was conducted to evaluate or based on observational studies. Grading recommen- risk factors for DVT.10 MEDENOX was an international, dations assist healthcare providers in using the guide- double-blind, placebo-controlled, experimental trial that lines to provide individualized care to specific patients. evaluated the use of low-molecular-weight heparin in The latest revision, the Seventh ACCP Conference on medical patients.4 Using logistic regression analysis on Antithrombotic and Thrombolytic Therapy, was re- data from 1,102 patients enrolled in this earlier study, it cently published in September 2004.16 Despite these was found that obesity was not a statistically significant guidelines, hospitalized patients are still not receiving risk factor in the development of DVT.10 One explanation adequate protection against DVT. Conditions for which may be that obesity may contribute to other comorbidity recommendations are made include both arterial and factors that require hospitalization as well as enhance risk venous thromboses in cardiac, cerebrovascular, and pe- factors such as decreased mobility. ripheral vascular disease, as well as the prevention of Many disease processes increase the risk of DVT in venous thromboembolism. For the purpose of this hospitalized patients, including history of cancer, che- article, preventive measures discussed will be limited to

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Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Deep Vein Thrombosis in Hospitalized Patients venous thromboprophylaxis in medical, general surgi- They should be applied as soon as ordered and removed cal, and lower extremity orthopedic patients. Recom- once a shift for 30 minutes to assess underlying skin. mendations for other populations can be found by Intermittent pneumatic compression devices work by referring to the guidelines in their entirety.16 creating pressure on the leg muscles, using air-filled sleeves.21 This pressure assists in improving venous DEEP VEIN THROMBOSIS PREVENTION blood return while decreasing blood pooling and can TECHNIQUES be applied either in sequential compression devices or longitudinally in rapid inflation, asymmetrical compres- Mechanical Prophylactic Measures sion devices.21 Both devices look similar, provide about Mechanical measures for DVT prevention include exer- 45 mm Hg of pressure to the calf muscles, and have cises, range of motion, graduated stockings, and pneu- been shown to reduce DVT rates from 15% to 6.9% matic compression devices. Each improve venous return in a prospective, randomized study of 423 orthopedic andreducevenousstasisinthelegveins.19 These patients who had total knee replacements.21 Pneumatic measures are simple to use and do not increase the risk compression is safe with few contraindications and most of bleeding, making them ideal for most hospital patients tolerate these devices.19 Patients with com- patients. Mechanical measures are best suited for those plaints of feeling warm with the use of these devices individuals at low risk for developing DVT,11 or those can often be appeased by using the ventilation mecha- that have contraindications to the use of pharmacologic nism that allows cool air to circulate underneath the measures.9 plastic sleeves. Other complaints may involve patients Foot and ankle exercises encourage plantar and with restless leg syndrome who find it difficult to rest dorsiflexion to improve venous return, using a very with the continuous inflation/deflation mechanism of basic, natural technique.19 They do not require anything these devices at night. other than patient comprehension and willingness to The ACCP guidelines currently recommend using perform exercises on a regular basis. For those patients mechanical prophylaxis measures in all hospitalized who are unable to perform foot and ankle exercises, patients with anticoagulant contraindications.2 Use in passive range of motion is an appropriate substitute to combination with anticoagulants is also recommended reduce venous pooling by passively exercising muscles. for those patients at high risk for developing DVT with- The use of these exercises is safe for all patients except out anticoagulant contraindications.2 Mechanical mea- those with bone injuries. Friction concerns may require sures should be used initially in surgical patients with a heel protection in those patients at risk for skin break- high risk for bleeding until anticoagulants can be re- down, and may be as simple as elevating heels off bed considered. Compression modalities were all found to linens to reduce friction. Early ambulation is another be safe and effective.19 However, to be effective, these useful technique for decreasing venous thromboembo- measures must be used for the duration of bedrest, not lism that is encouraged in patients with low risk of just a few hours a day.2 Nurses must encourage patient developing DVT.2 These low-risk patients include those use and compliance. under age 40 with no other risk factors, who have undergone minor surgery including laparoscopic sur- Pharmacologic Prophylactic Measures geries.2 Monitoring and therapeutic intervention equip- Pharmacologic measures involve various types of anti- ment should be evaluated for necessity as soon as coagulation in order to reduce blood coagulability. These patients are able to get out of bed. Those items that anticoagulants include aspirin, unfractionated heparin, are not necessary should be removed so that patients low-molecular-weight heparin, pentasaccharides, and may quickly return to their prior level of activity. warfarin. The medications are best used in patients with Graduated compression stockings are another option moderate to high risk factors in order to provide greater in the prevention of DVT that are easily tolerated by most protection than mechanical devices alone can provide.2 patients and can be continued on an outpatient basis.20 Aspirin decreases platelet aggregation and is consid- They are best used in hospital patients with low risk for ered effective prophylaxis treatment for arterial throm- DVT, especially when paired with foot and ankle ex- bosis, which consists mostly of platelet aggregates.22 ercises in those individuals who are able to perform Venous thrombi contain fibrin and red blood cells, them.20 Individuals with arterial insufficiency of the which is why aspirin is ineffective in preventing venous lower extremities should use stockings with caution as thromboembolism in patients.23,24 Current ACCP guide- arterial circulation is already compromised.2 Proper fit lines recommend not using aspirin as a sole means is required to obtain maximum benefit and avoid stock- for the prevention of venous thromboembolism in any ings that are too tight causing a tourniquet effect.19 patient.2 Those patients who are taking aspirin for other

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Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Deep Vein Thrombosis in Hospitalized Patients reasons should be considered for additional methods of heparin or low-molecular-weight heparin, whereas high- DVT prevention, such as mechanical measures, unfrac- risk critical care patients should receive low-molecular- tionated heparin, or low-molecular-weight heparins. weight heparin.2 Patients over the age of 40 having Unfractionated heparin is one option for DVT pro- moderate to high-risk general surgery with a limited phylaxis. It has been used for a number of years and side number of other risk factors should receive prophylaxis effects are well known.25 Heparin can be administered with either unfractionated heparin or low-molecular- intravenously or subcutaneously. Intravenous dosing weight heparin.2 provides immediate anticoagulant effect, whereas sub- Pentasaccharides are another class of medication cutaneous dosing leads to delayed response of approxi- used in the prevention of DVT. Fondaparinux, a syn- mately 1 hour.25 If given subcutaneously, low- to thetic pentasaccharide anticoagulant that can be given moderate-risk patients need twice-daily dosing, whereas subcutaneously once daily,22 is currently approved for high-risk patients may require dosing 3 times a day.2 thromboprophylaxis in patients undergoing orthopedic However it is administered, heparin requires activated surgery. In a randomized controlled trial of 849 elderly, partial thrompoplastin time monitoring and dose adjust- medical patients,27 fondaparinux was found to reduce ments based on results.25 the incidence of DVT from 10.5% in the placebo control group to 5.6% in the treatment group. Dose adjust- ments may be required in those individuals with renal Unfractionated heparin is one impairment,2,22 and fondaparinux should not be used in 22 option for DVT prophylaxis. patients with renal failure. Despite a low occurrence of major bleeding,27 one concern is the lack of response to protamine sulfate as an antidote.22 Warfarin offers the convenience of a pill that can be Low-molecular-weight heparins, including enoxa- taken orally in the hospital and continued at home for parin, dalteparin, and tinzaparin, can be administered those patients at risk after discharge. However, it does subcutaneously without coagulation monitoring.25 They have a narrow therapeutic window and requires fre- offer easy and convenient administration in hospital quent monitoring of prothrombin time or international patients with fixed dosing available in prefilled syringes normalized ratio.28 A large number of foods, drugs, and with common doses for thromboprophylaxis. The disease processes alter warfarin’s effectiveness, making it MEDENOX trial was a randomized clinical trial that difficult to regulate. Many hospitalized patients are re- evaluated the safety and efficacy of 2 different doses ceiving antibiotic therapy, which commonly interferes of enoxaparin in 1,102 medical patients.4 This study with warfarin dosing.28 Elderly patients should be showed a decrease in DVT incidence from 14.9% in the started on lower doses and monitored more frequently. placebo group to 5.5% in participants who were given Major side effects include bleeding that can be life enoxaparin 40 mg/d. Dalteparin and tinzaparin are ap- threatening and may preclude use in a large number of proved for use in orthopedic surgery patients and are hospital patients.28 currently being studied for use in medical patients. Current ACCP guidelines recommend low-molecular- Low-molecular-weight heparins have been shown to weight heparin, fondaparinux, or warfarin for initial and be safe for use in the elderly,14 although dose adjust- continued thromboprophylaxis in orthopedic patients ments may be necessary in obese patients25 and indi- having hip or knee surgery.2 Continued prophylaxis is viduals with renal impairment.2,25 Patients at higher risk strongly recommended in orthopedic patients for ap- of bleeding should be started on low-molecular-weight proximately 1 month after surgery. In patients that have heparin rather than unfractionated heparin. The Prime undergone elective hip replacement, continued prophy- study,26 a randomized, double-blind, placebo-controlled laxis with low-molecular-weight-heparin or warfarin is trial involving 959 high-risk medical patients at multiple preferred over fondaparinux. However, fondaparinux facilities, concluded that enoxaparin was only slightly is preferred over low-molecular-weight heparin for con- more effective than unfractionated heparin, but had tinued prophylaxis use after fractured hip repair.2 significantly lower bleeding risk. Current ACCP guidelines recommend unfractionated Combination Therapy heparin or low-molecular-weight heparin prophylaxis in Combination therapy using mechanical and pharmaco- all acutely ill medical patients without anticoagulant logic methods needs to be considered in patients with contraindications who have more than 1 risk factor for high-risk for DVT and those who need lower doses of DVT.2 Critical care patients with moderate risk of DVT anticoagulants.11 Patients undergoing high-risk general should receive prophylaxis with either unfractionated surgery with multiple risk factors are candidates for

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Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Deep Vein Thrombosis in Hospitalized Patients combination therapy.2 Elderly medical patients should sult of underutilization of these mechanisms or failure also be considered for combination therapy because of to use prophylaxis at all, patients are faced with risk of multiple risk factors and increased risk of bleeding. Me- DVT and other life-threatening complications. Hospi- chanical measures have few contraindications and are talized patients often present with a variety of risk fac- good adjuncts for those individuals that require reduced tors. Nurses’ knowledge of these risk factors can increase dosing of pharmacologic measures.11 awareness and allow for prompt identification and intervention in those individuals that require prophylaxis. Prevention mechanisms may include mechanical devices, IMPLICATIONS FOR NURSING PRACTICE anticoagulants, or both. When started early, these mea- Nurses are key players in the prevention of DVT and its sures may not prevent all DVT, but can certainly reduce complications. Nurses are with patients at time of ad- patient risk. Nurses who are taking bedrest orders need mission and take care of patients throughout their to be aware of patient risk factors and inquire if DVT hospital stay. They are in the ideal position to assess prophylaxis is appropriate for hospitalized patients. The patient risk factors early and ask for DVT prophylaxis. ACCP guidelines offer a synthesis of the most current and Admission assessments are an opportune time to eval- scientific recommendations for DVT prevention and uate patient risk factors such as mobility, age, previous treatment.16 history of DVT, and medical conditions that increase the risk of developing DVT in hospital patients. Patient risk assessment should be ongoing throughout hospitali- References zation but especially with condition changes. A worsen- 1. Colwell CW, Hardwick ME. Natural history of venous thromboembolism. Tech Orthop. 2004;19:236-239. ing of patient condition warrants a re-evaluation of risk 2. Geerts WH, Pineo GF, Heit JA, et al. Prevention of venous factors, just as a significant improvement in condition thromboembolism. Chest. 2004;126:338S-400S. may signal the need to reconsider previous risk factor 3. White RH. The epidemiology of venous thromboembolism. Circulation. 2003;107:I4-I8. assessment. 4. Samama MM, Cohen AT, Darmon JY, et al. A comparison of Once a patient is considered at risk for developing enoxaparin with placebo for the prevention of venous throm- DVT, nurses must advocate for timely prevention mech- boembolism in acutely ill medical patients: prophylaxis in medical patients with enoxaparin study group. N Engl J Med. anisms. This may mean notifying physicians of risk 1999;341:793-800. factors and asking for orders to initiate prophylaxis early 5. Goldhaber SZ, Tapson VF. A prospective registry of 5451 pa- or following an established hospital protocol. Bleeding tients with ultrasound-confirmed deep vein thrombosis. Am J Cardiol. 2004;93:259-262. potential needs to be considered when contemplating the 6. Arcelus JI, Caprini JA, Monreal M, Suarez C, Gonzalez-Fajardo J. use of anticoagulants. Nurses are patient advocates and The management and outcome of acute venous thromboem- it is important for nurses to assess patient risk early and bolism: a prospective registry including 4011 patients. J Vasc Surg. 2003;38:916-922. ask medical providers for DVT prevention. 7. Geerts WH, Selby R. Prevention of venous thromboembolism Once prophylaxis orders are obtained, they need to in the ICU. Chest. 2003;124:357S-363S. be initiated as soon as possible. These orders may include 8. Ageno W, Turpie AG. Deep venous thrombosis in the medi- cally ill. Curr Hematol Rep. 2002;88(1):73-78. mechanical, pharmacologic, or both. Regardless of the 9. Anderson FA, Spencer FA. Risk factors for venous thrombo- type of prophylaxis ordered, patient education is neces- embolism. Circulation. 2003;107:I9-I16. sary to improve compliance and acceptance of these mea- 10. Alikhan R, Cohen AT, Combe S, et al. Risk factors for venous thromboembolism in hospitalized patients with acute medical sures. Explanations of why prevention is important in illness: analysis of the MEDENOX study. Arch Intern Med. reducing risk of DVT and pulmonary embolism will help 2004;164:963-968. patients understand the rationale for their use. Treating 11. Goldhaber SZ, Fanikos J. Prevention of deep vein thrombosis and pulmonary embolism. Circulation. 2004;110:e445-e447. DVT after it has developed may be too late, as DVT can 12. Leizorovicz A, Mismetti P. Preventing venous thromboembo- lead to life-threatening complications such as pulmonary lism in medical patients. Circulation. 2004;110:IV13-IV19. embolus. Treatment usually involves higher doses of anti- 13. Stein PD, Hull RD, Kayali F, Ghali WA, Alshab AK, Olson RE. Venous thromboembolism according to age. Arch Intern coagulants than used in prophylaxis, which can magnify Med. 2004;164:2260-2265. bleeding complications. Early prevention in all patients is 14. Kucher N, Leizorovicz A, Vaitkus PT, et al. Efficacy and safety the best option as risk of DVT and complications are of fixed low dose dalteparin in preventing venous thromboembolism among obese or elderly hospitalized patients: a sub- reduced while treatment options may be avoided. group analysis of the PREVENT trial. Arch Intern Med. 2005; 165:341-345. 15. Centers for Disease Control and Prevention. Census popula- SUMMARY tion projections summary. Available at: http://wonder.cdc.gov/ Deep vein thrombosis affects approximately 15% of hos- popu00.html. Accessed February 15, 2005. 16. Hirsh J, Guyatt G, Albers GW, Schunemann HJ. The seventh pitalized patients each year despite well-documented, ACCP conference on antithrombotic and thrombolytic ther- effective preventative mechanisms. Whether this is a re- apy: evidence-based guidelines. Chest. 2004;126:172S-173S.

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17. Schunemann HJ, Munger H, Brower S, et al. Methodology for safety profile of a low-molecular weight (enoxaparin). The the guideline development for the seventh American College of Prime Study Group. Haemostasis. 1996;26:49-56. Chest Physicians conference on antithrombotic and thrombo- 27. Cohen AT, Gallus AS, Lassen MR, et al. Fondaparinux vs. lytic therapy. Chest. 2004;126:174S-178S. placebo for the prevention of venous thromboembolism in 18. Guyatt G, Schunemann HJ, Cook D, Jaeschke R, Pauker S. acutely ill medical patients (ARTEMIS). Thromb Haemost. Applying the grades of recommendation for antithrombotic 2003;1(suppl):P2046. and thrombolytic therapy. Chest. 2004;126:179S-187S. 28. Ansell J, Hirsh J, Poller L, Bussey H, Jacobson A, Hylek E. The 19. Morris RJ, Woodcock JP. Evidence-based compression: pre- pharmacology of the vitamin K antagonists. Chest. 2004;126: vention of stasis and deep vein thrombosis. Ann Surg. 2004; 204S-233S. 239:162-171. 20. Yang JC. Prevention and treatment of deep vein thrombosis and pulmonary embolism in critically ill patients. Crit Care Nurs Q. 2005;28:72-79. 21. Lachiewicz PF, Kelley SS, Haden LR. Two mechanical devices ABOUT THE AUTHOR for prophylaxis of thromboembolism after total knee arthro- plasty. J Bone Joint Surg. 2004;86B:1137-1141. Wendy Kehl-Pruett, ARNP, MSN, CCRN, is a critical care nurse with 22. Weitz JI, Hirsch J, Samama MM. New anticoagulant drugs. 17 years of experience in medical and cardiac intensive care. She Chest. 2004;126:265S-286S. recently completed a dual Master_s degree in nursing education and 23. Gerotziafas GT, Samama MM. Prophylaxis of venous throm- adult health primary care at the University of South Florida in Tampa boembolism in medical patients. Curr Opin Pulm Med. 2004; Fla., while working part-time in the intensive care unit at Edward 10:356-365. 24. Goldhaber SZ, Turpie AG. Prevention of venous thromboem- White Hospital in St. Petersburg, Fla. Currently she is employed as a bolism among hospitalized medical patients. Circulation. nurse practitioner for Infectious Disease Consultants of St. Petersburg. 2005;111:e1-e3. Address correspondence and reprint requests to: Wendy Kehl-Pruett, 25. Hirsh J, Raschke R. Heparin and low molecular weight heparin. Chest. 2004;126:188S-203S. ARNP, MSN, CCRN, Infectious Disease Consultants of St. Petersburg 26. Lechler E, Schramm W, Flosbach CW. The venous thrombotic 1955 First Avenue North, Suite 101, St. Petersburg, FL 33713 risk in non-surgical patients: epidemiological data and efficacy/ 727.898.3464 ([email protected]).

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