LPN2009 l Volume 5, Number 610

By James Stockman, RN, BSNStudent • Texas Wesleyan University Graduate Program of NurseAnesthesia • Fort Worth, Tex.

DEEP VEIN THROMBOSIS (DVT) is a clot that formsmost commonly within the deep veins of the legs, butit can also occur in the pelvis or arms. DVT has beenincreasingly in the spotlight for the last 15 years due tothree factors: the rising cost of healthcare, an increasein preventive medicine, and our aging population.

In this article, I’ll fill you in on DVT, including whatyou need to know about taking care of a patient whoalready has it and how to prevent at-risk patients fromdeveloping it.

But first, let’s review the pathophysiology of DVT.

You’re so veinThe veins of the body consist of the superficial veinsthat run near the surface of the skin, and the deepveins, such as the great saphenous and popliteal veins,

Intoo deep:

Understandingdeepvein

thrombosis

Two million people will experience someform of deep vein thrombosis, or DVT, thisyear, so it’s easy to see why DVT is such an important topic. Here are the tools youneed to understand DVT from how it happens and who’s at risk to what you can do to help these patients.

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that are located underneath themuscles and run parallel to the ar-teries. Smaller veins connect the superficial and deep veins and helpmove blood from the skin to thedeep veins. Blood is then movedback to the heart with the aid ofvalves in the superficial and deepveins that allow unidirectional flow.Various factors influence blood flowthrough the legs: Valves in the veinsprevent backflow, while walking andmuscle movement in the legs aid

blood flow back to the heart. Sinceblood flow is already slowed as it’ssqueezed from the connecting veinsinto the deep veins, there’s a highrisk of clot (thrombus) formation ifany further slowing of the flow oc-curs. Any time blood slows or is

stationary, as in standing or sittingfor long periods, there’s the poten-tial for a thrombus to form.

Let’s now take a look at bloodflow to better understand thrombusformation.

Don’t slow the flow!Anything that alters the strength ofthe blood vessel wall can slow bloodflow and cause DVT. Think of thevascular system as an intertwiningwater hose. Normally, water flows

through the hose without any diffi-culty but if you kink the hose, youreduce the flow of water. Over time,dirt and other impurities build upwithin the hose and add to the re-duced flow. The same principle ap-plies to the vascular system. So

every time you sit down, curl yourlegs, or cross your arms, you reduceblood flow, which can cause smallclots to form. Normally, the bodyimmediately breaks down theseclots. However, when stasis of blood(venous stasis), vessel wall injury,and hypercoagulability—the threefactors known as Virchow’s triad—are present, an abnormal thrombuswill most likely form.

How does the thrombus form?Let’s take a look at that next.

A thrombus among usMechanical or physiologic damageto the vessel wall leads to plateletactivation. Examples of mechanicaldamage include high velocitytrauma in which bones are brokenand surgery, especially orthopedicor abdominal surgery. Examplesof physiologic damage include hy-pertension, in which the vessel wallweakens over time, and phlebitis,in which a vein is inflamed. Theplatelets adhere to one another andclump together, forming a throm-bus (see Picturing venous thrombosis).After a thrombus forms, it flowsin the body and is either dissolvedover time or grows and becomeslarge enough to occlude a vessel. Ifthe thrombus occludes a vessel, it’sknown as an embolus.

After an embolus forms, the bloodbehind the blockage slows and theveins expand to accommodate anincrease in volume. This leads to ageneral pooling of blood that slowsthe blood further and causes moreclots to form. Ultimately, thedrainage of the lymphatic systemslows, leading to edema of the affected extremity.

So who’s at risk for developingDVT? That’s up next.

Risks, risks everywhere...Patients who are most at risk forDVT are those undergoing major

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Picturing venous thrombosis

Tunica intima

Tunica media

Tunica adventitia

Thrombus

Valve

Endothelium

Internal elasticmembrane

Smooth muscle

External elasticmembrane

[ ]The most serious complication of DVT ispulmonary embolism (PE), in which the dislodged

thrombus obstructs the pulmonary artery bed.

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surgery, especially orthopedicsurgery. Other at-risk patients in-clude those who smoke or have lungdisease, diabetes, blood disorders,and peripheral vascular disease. Butremember, any hospitalized patientis at risk for DVT, especially thosewho’ll be immobile for an extendedperiod of time or are of advancingage. If your patient has any one ofthe three factors in Virchow’s triad,there’s the potential for DVT.

See Which surgical patients are atrisk for DVT? for more information.

It’s a signHow do you know if your patienthas DVT? And if he does, is he atrisk for more complications? Let’snow review signs and symptoms tobe alert for and then we’ll take alook at potential complications.

DVT may be difficult to recognizeimmediately because many patientsdon’t exhibit signs and symptoms ortheir symptoms are nonspecific. Signsand symptoms include:• edema or swelling of the affectedextremity• redness• pain or tenderness• an increase in the temperature ofthe affected extremity compared withthe rest of the body• cyanosis and mottling of the skindue to stagnant blood flow.

Although Homans’ sign (pain withdorsiflexion of the foot) has histori-cally been used to assess DVT, it’snot a reliable or valid sign; in fact,the literature suggests that up to50% of patients with DVT don’thave a positive Homans’ sign.

It can get complicatedThe most serious complication ofDVT is pulmonary embolism (PE),in which the dislodged thrombusobstructs the pulmonary artery bed.PE can be life-threatening and mayrequire mechanical ventilation. If

your patient complains of any ofthese signs and symptoms, notifythe healthcare provider immediately:• severe dyspnea• tachypnea• chest pain• cough• hemoptysis (coughing up blood).

Another complication occurringin 40% to 60% of patients withDVT is postthrombotic syndrome.Caused by a combination of fac-tors, such as back flow of bloodrelated to faulty valves and block-age that remains in the vessel, signsand symptoms of this syndromeinclude pain, increased swelling,skin ulcers, and hyperpigmenta-tion. How long postthromboticsyndrome persists depends on thepatient’s ability to form collateralcirculation around any remainingembolus. Treatment for this condi-tion is palliative, including antico-agulation therapy and elevating theaffected extremity to help decreaseswelling and pain.

Assessment = early detectionLet’s say you’re worried that youroverweight patient with diabeteswho doesn’t want to get out of hisbed to ambulate is developing

DVT. What do you do? Careful as-sessment will help detect early signsof a venous disorder of the legs. As-sess for:• limb pain• a feeling of heaviness• functional impairment• ankle engorgement• edema• differences in leg circumferencesbilaterally from thigh to ankle• an increase in the surface temper-ature of the leg, particularly the calfor ankle• areas of tenderness or superficialthrombosis.

One of the most reliable physicalindications of DVT is unilateraledema of the extremity. Measure theextremity and compare your findingswith baseline measurements todetect an increase in circumference.Changes should be reported anddocumented.

Diagnosis: DVTBecause DVT is often difficult todetect clinically, diagnostic studiesmay be indicated. If the healthcareprovider suspects DVT, he may or-der a venous ultrasound of the pa-tient’s legs, magnetic resonanceimaging (MRI), a venogram, or aD-dimer test.

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Which surgical patients are at risk for DVT?Risk level Patient population

Highest • Patients undergoing hip or knee surgery• Patients with multiple risk factors undergoing surgery• Patients with major trauma

High • Patients over age 60 undergoing surgery• Patients age 40 to 60 with additional risk factors undergoing surgery

Moderate • Patients with additional risk factors undergoing minor surgery• Patients age 40 to 60 with no additional risk factors undergoing surgery

Low • Patients younger than age 40 with no additional risk factors undergoing minor surgery

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Let’s take a closer look at thesetests.

Duplex venous ultrasonography,which may be performed at the bed-side, is one of the simplest diagnostictests for DVT. Ultrasound imagerycan reveal a thrombus in a deep vein;the Doppler ultrasound measures theblood flow velocity in veins and candetect flow abnormalities. Althougha duplex study is noninvasive and rel-atively simple to perform, its accura-cy depends on the technician’s skill.If the ultrasound is negative forDVT and the healthcare team stillsuspects that the patient has DVT, avenogram may be indicated to makea definitive diagnosis.

MRI is another noninvasive studythat can be used to detect DVT inthe proximal deep veins. Whether touse this test or a venogram dependson the patient’s clinical findings;MRI is more useful than venographyin patients with suspected DVT ofthe inferior vena cava or pelvic veins.

Although it’s being replaced byultrasound, the venogram is stillconsidered by many healthcare

providers to be the gold standardfor diagnosing DVT. During thisinvasive test, the patient is placed ona fluoroscopic table that’s usually tilt-ed 45 degrees, and a contrast medi-um is injected into a superficial footvein. A clinician observes the flow ofcontrast medium by fluoroscopy andtakes X-rays; if the contrast mediumdoesn’t fill the veins normally, acuteDVT is confirmed. Complications ofvenography include hypersensitivityreactions to the contrast medium,acute renal failure because of the vol-ume of contrast medium used, andextravasation of the contrast medium(especially in patients with a historyof arterial insufficiency because oftissue necrosis and ulceration). Therisk of acute renal failure is higher inolder patients and in patients withdiabetes, hyperuricemia, or multiplemyeloma.

D-dimer test is a blood test tomeasure fibrin degradation frag-ments generated by fibrinolysis. Anelevated D-dimer level indicates athrombotic process but isn’t specificto DVT. This test is useful as anadjunct to noninvasive testing. If thepatient has a low clinical probabilityof DVT and a negative D-dimertest, DVT can be ruled out withoutan ultrasound.

It turns out your suspicions werecorrect—your patient has DVT.What’s the next step? Let’s look attreatment options next.

Anticoagulation is A-OKThe treatment goals for DVT are toprevent the thrombus from growingand fragmenting, which increasesthe risk of PE; to prevent recurringthrombi; and to let the body’s ownfibrinolytic system work. Anticoagu-lant therapy, with unfractionated he-parin, low-molecular-weight heparin(LMWH), or oral anticoagulantssuch as warfarin (Coumadin), is thefirst-line treatment. Thrombolytic

therapy or the factor XA inhibitorfondaparinux (Arixtra) may also beused. Depending on the patient’srisk factors, anticoagulant therapymay last from 6 months to 1 yearif he has idiopathic DVT or indef-initely if he continues to have re-curring thrombi. Let’s take acloser look.

Unfractionated heparin isadministered by I.V. infusion for5 to 7 days to prevent the growthof a thrombus and the developmentof new thrombi. An electronic infu-sion device is used to prevent theinadvertent infusion of large vol-umes, which can cause hemorrhage.Unfractionated heparin can also begiven subcutaneously to prevent thedevelopment of DVT. The dosageof unfractionated heparin dependson the patient’s activated partialthromboplastin time, internationalnormalized ratio (INR), and plateletcount. Heparin is at an effective(therapeutic) level when the patient’spartial thromboplastin time is 1.5times normal. Patients receivingunfractionated heparin for a longperiod of time (several days toweeks) are at risk for a suddendecrease in platelet count (30%)known as heparin-induced throm-bocytopenia (HIT). If HIT devel-ops, heparin must be discontinued.

Associated with fewer bleedingcomplications and a lower risk ofHIT than unfractionated heparin,LMWH, such as enoxaparin(Lovenox), may be used instead toprevent thrombus growth and newthrombi formation. Given in oneor two subcutaneous injections perday, doses are adjusted accordingto the patient’s weight and arebased on the specific product andfacility protocol. LMWH is moreexpensive than unfractionatedheparin, but it can be used safely inpregnant women and patients whotake it may be more mobile.

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When anticoagulant therapy is a no-no

Anticoagulant therapy is contraindicatedif your patient has:• bleeding from the gastrointestinal,genitourinary, respiratory, or reproduc-tive systems• hemorrhagic blood dyscrasias• an aneurysm• severe trauma• alcoholism• recent or impending surgery of theeye, spinal cord, or brain• severe liver or kidney disease• recent cerebrovascular hemorrhage• an infection• an open ulcerative wound• an occupation that involves a signifi-cant risk for injury• recently delivered a baby.

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An oral anticoagulant, such aswarfarin (a vitamin K antagonist), istypically administered with heparintherapy. Once the therapeutic level isreached, heparin can be discontinued.If the patient requires long-termtherapy, warfarin is frequently used.The dosage of warfarin depends onthe patient’s prothrombin time andINR; the therapeutic level is reachedwhen the patient’s prothrombin timeis 1.5 to 2 times normal or the INRis 2 to 3.

Thrombolytic therapy dissolvesthrombi in 50% of patients. Athrombolytic, such as activase(Alteplase) or reteplase (Retavase),is given within the first 3 days afteracute thrombosis. Thrombolyticscause less long-term damage to thevenous valves and reduce the inci-dence of postthrombotic syndrome;however, they have a higher risk ofbleeding than heparin. If bleedingcan’t be stopped, thrombolytictherapy must be discontinued.

Unlike LMWH, which acts onthrombin and factor Xa, fonda-parinux only inhibits factor Xa.Because it doesn’t affect platelets,fondaparinux doesn’t cause HIT.Fondaparinux is given subcuta-neously at a fixed dose once a dayand is excreted unchanged by thekidneys; therefore, it must be usedwith caution in patients with renalinsufficiency and it’s contraindicat-ed in patients with renal failure.

Surgery may be necessary if anti-coagulant or thrombolytic therapyis contraindicated, the patient isat high risk for PE, or his venousdrainage is so compromised thatpermanent damage is likely (seeWhen anticoagulant therapy is a no-no). Thrombectomy, or removal ofthe thrombus, is the procedure ofchoice under these circumstances.During this procedure, a catheteris used to deliver a thrombolyticdirectly into the clot to dissolve it.

A vena cava filter may also be placedthrough the catheter into the groin,just below the junction of the inferi-or vena cava and the lowest renalveins, to trap large emboli and pre-vent PE. About the size of a quarter,this filter made of wire mesh catchesany clots that break off the DVT

and head for the lungs via the inferi-or vena cava. A vena cava filter forshort-term use has recently beenintroduced, designed to be removedonce the increased risk of PE sub-sides.

So what can you do to help yourpatient who’s receiving anticoagulanttherapy? Let’s delve into the care ofa patient with DVT next.

Take careWhen caring for a patient withDVT, you must:

Monitor for potential complica-tions, such as bleeding or HIT.Spontaneous bleeding anywhere inyour patient’s body is the most com-mon complication of anticoagulanttherapy. Bleeding from the kidneys,bruises, nosebleeds, and bleedinggums are early signs of excessiveheparin dosage. To immediatelyreverse the effects of heparin, thehealthcare provider may order I.V.protamine sulfate. Protamine sulfateis most effective in reversing theeffects of unfractionated heparin, butit may also be used in patients receiv-ing LMWH. If your patient receiv-ing warfarin experiences bleeding,the healthcare provider may orderoral or low-dose I.V. vitamin K or aninfusion of fresh frozen plasma or

prothrombin concentrate. HIT isanother complication you mustwatch out for. Early signs and symp-toms of HIT include a decreasingplatelet count, the need for increas-ing doses of heparin to maintain thetherapeutic level, and hemorrhagiccomplications (skin necrosis at the

injection site or sites distal to thethrombus, skin discoloration,hematomas, purpura, and blistering).If your patient develops HIT, thehealthcare provider may order adirect thrombin inhibitor, such asI.V. lepirudin (Refludan) or arga-troban.

Monitor for drug interactions.If your patient is taking an oralanticoagulant, you must monitorhis medication schedule becausemany medications and supplementsaccelerate or inhibit the effects ofwarfarin.

Provide pain relief. Depending onthe extent and location of the throm-bus, your patient may be on bed restfor 5 to 7 days. To promote circula-tion and increase comfort, periodi-cally elevate his feet and lower legsabove his heart. Help him performactive and passive leg exercises, par-ticularly with the calf muscles, toincrease venous flow. Apply warm,moist packs to the affected leg, asordered, to reduce the discomfort ofthe thrombus. An analgesic may alsobe ordered to control pain.

Encourage early ambulation.Once he’s ambulatory, instruct yourpatient to avoid sitting for morethan 2 hours at a time. He shouldwalk at least 10 minutes every 1 to

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Teach your patient the signs and symptoms of PE, such as shortness of breath, chest pain,

blue nail beds, and tachypnea.[ ]

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2 hours if possible to help preventvenous stasis.

Perform discharge teaching.Educate your patient about the signsand symptoms of DVT to report,such as new swelling or increasedswelling of the affected limb, skinbreakdown, pain, and weak or absentpulses. Also teach him the signs andsymptoms of PE, such as shortnessof breath, chest pain, blue nail beds,and tachypnea. Instruct him to go tothe ED immediately if he experi-ences any of these symptoms. Informyour patient about the risk of bleed-ing associated with anticoagulanttherapy and the signs and symptomsto be alert for, such as changes inmental status, a racing pulse, andextremely pale skin (see Patient teach-ing for anticoagulants). If your patientis going home on warfarin, tell himto avoid foods high in vitamin K,such as avocados, broccoli, brusselssprouts, cabbage, green onions, liver,and green leafy vegetables. Andmake sure he understands that he’llneed regular blood draws to monitorhis prothrombin time and INR. Ifhe’s going home on unfractionatedheparin, he’ll need his partial pro-thrombin time monitored on a

monthly basis as well. If your patientis going home on LMWH or fon-daparinux, teach him the propertechnique for subcutaneous injec-tions into the abdomen (2 inchesfrom the umbilicus) and make surehe knows to rotate the injectionsites. Have him demonstrate thetechnique back to you. Let himknow it’s common to experiencesome bruising around the injectionsites but to contact his healthcareprovider if the bruises begin tospread. Finally, assist your patientwith setting up follow-up appoint-ments, which may include a com-puted axial tomography scan of hischest to check for PE and magneticresonance venography or a venousDoppler scan to monitor the statusof the thrombus.

But how about steps you can taketo prevent your at-risk patients fromdeveloping DVT? Let’s take a minuteto review prevention strategies.

Your role in preventionElastic compression stockings,which exert sustained, evenly dis-tributed pressure over the calves tohelp increase blood flow in the deepveins, are usually ordered for pa-

tients with venous insufficiency toprevent DVT. They may be knee-high, thigh-high, or like pantyhose.The healthcare provider may ordershort-stretch elastic wraps instead,which are applied from the toes tothe knee in an overlapping spiralpattern using a one- or two-layersystem. Intermittent pneumaticcompression devices may also beused with elastic compressionstockings to prevent DVT. Thesedevices consist of plastic knee- orthigh-high leg sleeves attached toair hoses and an electric controller.The leg sleeves fill with air to applypressure to the ankle, calf, and thigh.

If your patient is receiving com-pression therapy, inspect his skin forsigns of irritation and his calves fortenderness whenever you remove thestockings or wraps. Report any skinchanges or tenderness to the health-care provider immediately.

The moral of the story:PreventionDVT is a serious, but preventable,condition. With diligent care, yourpatient with DVT will not only re-cover, but avoid recurrence as well.And with an eye on prevention,your at-risk patients will be lesslikely to develop DVT. LPN

Selected referencesDay MW. Recognizing and managing deep veinthrombosis. Nursing. 2003;33(5):36-42.

Pathophysiology Made Incredibly Visual! Philadelphia,PA: Lippincott Williams & Wilkins, 2008:66-67.

Smeltzer SC, Bare BG, Hinkle JL, Cheever KH.Brunner and Suddarth’s Textbook of Medical-SurgicalNursing.11th ed. Philadelphia, PA: LippincottWilliams & Wilkins;2007:1004-1010.

Surgical Care Made Incredibly Visual! Philadelphia,PA: Lippincott Williams & Wilkins; 2007:185.

Stockman J. In too deep: understanding deep veinthrombosis. Nursing Made Incredibly Easy! 2008;6(2):29-38.

Turka J. Is this on the level? Nursing Made Incred-ibly Easy! 2006;4(4):7-9.

Wound Care Made Incredibly Visual! Philadelphia,PA: Lippincott Williams & Wilkins;2008:107.

Zajac PM. Going with the flow: warfarin. NursingMade Incredibly Easy! 2004;2(4):52-57.

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Patient teaching for anticoagulants

Teach your patient who has been prescribed an anticoagulant the following:• Take the anticoagulant at the same time each day, usually between 8 a.m. and 9 a.m.• Because other medications affect the action of anticoagulants, don’t take vitamins,cold medicines, antibiotics, aspirin, mineral oil, or anti-inflammatory drugs withoutconsulting your healthcare provider.• Avoid alcohol because it may change your body’s response to the anticoagulant.• Avoid food fads, crash diets, or marked changes in eating habits.• Avoid injury that can cause bleeding.• If you experience faintness, dizziness, increased weakness, severe headaches orabdominal pain, reddish or brown urine, red or black stool, any unusual bleeding, nose-bleeds, bruises that enlarge, or rash, contact your healthcare provider immediately.• Contact your healthcare provider before having dental work or elective surgery andinform the dentist or surgeon that you’re taking an anticoagulant.• For women, contact your healthcare provider if you suspect you’re pregnant.• Wear or carry identification indicating the anticoagulant you’re taking.• Keep all appointments for blood tests.

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