Which patients are at risk for developing deep vein thrombosis (DVT) or pulmonary embolism (PE)?
• Sue Bell, age 31, a triathlete who delivered her first child this morning and who used oral contraceptives for 7 years, most recently 1 year ago
• Ray Washington, age 86, a retired construction worker admitted through the emergency department (ED) for a fractured hip after falling in his bathtub
• Dawn Ashland, age 52, a nurse who was admitted for severe abdominal pain over the last 2 days and who had DVT in her left leg 2 months ago and is not taking an anticoagulant
You know the answer: All of them. But which patients would receive prophylaxis in your institution? Maybe, none of them.
Reasons for concern
Why are we concerned about prophylaxis for venous thromboembolism (VTE), a term that includes DVT and PE? Consider these VTE facts:
• 70% of VTEs found on postmortem examinations weren’t diagnosed while the patients were alive.
• PE is the most common preventable cause of death in hospitalized patients.
• Between 450,000 and 2,000,000 patients are affected by DVT each year.
• Just one episode of DVT increases the risk of post-thrombotic syndrome.
• Only 15% to 35% of hospitalized patients receive VTE prophylaxis that’s appropriate for their risk level.
Virchow’s triad describes three risk factors for DVT formation: venous stasis or obstruction, blood vessel injury, and blood coagulability. These processes are independent and cumulative. Risk increases when the patient has two or all three.
Most commonly, DVT occurs in a deep vein in the calf or thigh, but it can also occur in the arm, especially in patients with peripherally inserted central catheters.
Diagnosis is difficult because DVT is often clinically silent. Only about 50% of patients diagnosed with DVT have these classic signs and symptoms:
• pain or tenderness (Homans’ sign isn’t an indicator)
• unilateral edema
• dilated superficial vein with palpable cord.
PE results when a deep vein thrombus breaks loose from the vein wall and moves through the right side of the heart and into the pulmonary arterial circulation. If the thrombus blocks arterial blood flow to a large area of lung tissue, the result can be sudden death.Evidence-based guidelines
Given the serious risk of VTE in hospitalized patients, why don’t all institutions take a systematic approach to risk assessment and prophylaxis? It’s not because of a lack of information.
The American College of Chest Physicians (ACCP) has published evidence-based guidelines for VTE prophylaxis for more than 20 years. And as more evidence on VTE becomes available, experts update the guidelines. The current guidelines, which use graded evidence to support the recommendations, detail which conditions increase the risk of VTE and which prophylactic approaches should be used.
In 2004, a Six-Sigma discovery team at our institution asked if we were using this evidence to ensure that our patients receive appropriate prophylaxis 100% of the time. Here’s what the team found 3 years ago:
• No consistent standard process was used for assessing risk.
• Knowledge of VTE risk factors varied among clinicians.
• Elements of prophylaxis were incorporated into a variety of order sets.
• Prophylaxis was typically based on a patient’s diagnosis, not on a patient’s specific risk factors, such as a history of comorbidities.
Standard process needed
Clearly, our inadequate processes presented a safety issue for our adult patients. We needed a standardized process to determine each patient’s risk level and to institute risk-appropriate prophylaxis, so we formed a rapid-action team to reduce the incidence of VTE in our hospital.
Our performance measures for the project included:
• accurate patient-risk assessments
• risk-appropriate use of prophylaxis consistent with evidence-based recommendations
• a decrease in the number of patients developing DVT or PE during and 30 days after hospitalization.
Developing appropriate tools
After reviewing the literature, we developed a nursing risk assessment tool and a provider order set. Then, we developed and delivered educational materials on using the tools to the nurses and providers.
For nurses, we created an electronic documentation tool, using the four levels of risk from the ACCP guidelines with the Autar scale’s condition- and intervention-related assessment. Patient diagnosis, history, and other factors contribute to the score. The higher the score, the more aggressive the prophylaxis needed.
For providers, we created a one-page DVT prophylaxis order set. This form contains a brief summary of conditions at each ACCP risk level and the appropriate prophylaxis for the levels. As each patient is admitted, the order set is printed and added to the other provider orders.
Seeing risk differently
Our documentation audits showed a difference between the risk assessments of nurses and providers. Providers tended to underestimate the patient’s risk and the recommended level of prophylaxis. The provider order set had lots of information and decision-support on a busy, crowded page. The result: Many providers simply ignored it. Few worked through the information to arrive at the appropriate prophylaxis for the patient’s risk level. We did succeed in increasing awareness of the importance of VTE prevention, however, and some providers added some type of DVT prophylaxis to their diagnosis-specific order sets.
Our data indicated that our patients were consistently assessed for risk by nurses. So our next effort was an RN-initiated protocol to ensure risk-appropriate prophylaxis. Now, we evaluate all patients older than age 16 for VTE risk and initiate the protocol. When anticoagulation is indicated by the risk ranking, the nurse contacts the admitting physician to discuss further orders.
We exclude patients who have open leg ulcers or evidence of possible DVT from protocol prophylaxis. When patients have these findings, we contact the provider, who gives prophylaxis orders based on clinical judgment.
Our latest data indicate that 95% of eligible patients receive appropriate prophylaxis. And the number of VTE cases dropped from 30 in 2003 to 18 in 2006.
We’ve made excellent improvement, but questions remain. Are graded compression stockings (GCSs) appropriate for preventing VTE in patients at moderate risk? Current evidence indicates that patients using only GCSs show no significant reduction in VTE. Other studies show that using GCSs with anticoagulation or intermittent compression devices is more effective than either intervention alone. Also, GCSs have been shown to be effective in preventing post-thrombotic syndrome after VTE. To achieve a benefit, a patient must have properly fitted GCSs and wear them continually. Thigh-high GCSs tend to roll, creating a tourniquet-type effect that may decrease lower leg circulation. We need further research on the efficacy of GCSs.
Prophylaxis for hospitalized patients younger than age 16 is not included in our protocol. Is prophylaxis appropriate for that group?
Many of the items listed on the risk assessment tool are recorded in another part of the patient’s electronic record. An automated flow of collected data would reduce the potential for human recall error.
We also need to investigate which prophylaxis is appropriate after patients leave the hospital. Plus, we want to look at DVT education for outpatients who may be at risk.
Patient safety at your institution
As our program shows, a standardized process of risk assessment and appropriate prophylaxis can decrease the incidence of hospital-related VTE and its complications. I encourage you to initiate such a program at your institution. You know the dangers of VTE. And you know that extensive VTE evidence is avail-able. Use this knowledge to ensure
patient safety at your institution.
Autar R. Calculating patients’ risk of deep vein thrombosis. Br J Nurs. 1998;7(1):7-12.
Autar R. The management of deep vein thrombosis: the Autar DVT risk assessment scale revisited. J Orthop Nurs. 2003;7(3):114-124.
Beck DM. Venous thromboembolism (VTE) prophylaxis: implications for medical-surgical nurses. MEDSURG Nurs. 2006;15(5):282-287.
Geerts WH, Pineo GF, Heit JA, Bergquist D, Lassen MR, Colwell CW, et al. Prevention of venous thromboembolism. Chest. 2004;126(3):338S-378S.
Kehl-Pruett W. Deep vein thrombosis in hospitalized patients: a review of evidence-based guidelines for prevention. Dimens Crit Care Nurs. 2006;25(2):53-59.
For a complete list of selected references, visit www.AmericanNurseToday.com.
Mary Date, MSN, RN, CNN, is a Clinical Nurse Specialist at Immanuel St. Joseph’s, Mayo Health System in Mankato, Minnesota.