Patients continue to have poor outcomes after suffering blood clots in the legs or arms, despite physician orders for therapy with sequential compression devices (SCDs). As a nurse, you can play a pivotal role in improving outcomes by evaluating patients at risk for deep vein thrombosis (DVT) and by using SCD properly and safely to prevent complications of thrombi and pulmonary embolism (PE). The Joint Commission now uses the term venous thromboembolism (VTE) to encompass both DVT and PE. (See Understanding venous thromboembolism.)
Understanding venous thromboembolism
More than 2.5 million people are diagnosed with deep vein thrombosis (DVT) each year. DVT results from clot formation in a deep vein, usually in the leg. It can lead to pulmonary embolism (PE), in which the clot breaks loose, travels through the bloodstream to the lungs, and lodges there. In the lung, the clot inhibits blood flow and can damage part of the lung or even lead to death. Venous thromboembolism (VTE) is the umbrella term for DVT and PE.
Incidence of upper-extremity DVT has risen from increasing use of indwelling venous access catheters, permanent pacemakers, and internal cardiac defibrillators. With today’s shorter hospital stays and more same-day surgeries, patients with DVT may lack symptoms while hospitalized or may not develop symptoms until after discharge. Mortality for lower-extremity DVT ranges from 13% to 21%; for upper-extremity DVT, it may be as high as 48%. With PE, mortality can be as high as 25%; the condition causes roughly 10% to 25% of hospital deaths.
The deep veins in the legs return venous blood to the right atrium and lungs. Contractions of leg muscles and one-way venous valves push blood forward from the feet to the heart’s right atrium. This occurs because the venous system is a low-pressure system; muscles act as pumps to increase the velocity of returning blood, forcing blood upward to the heart. One-way venous valves open in response to pressure of the blood to prevent backward flow and blood pooling in the venous system. DVT risk increases with damage or trauma to the venous system or the lungs and with patient immobility.
Three broad categories of factors in the image below, known as Virchow’s triad, contribute to VTE. The chart describes these factors and the conditions that can cause them.
Promoting better outcomes
To enhance patient outcomes, clinicians should focus on VTE prevention. This is best achieved through risk stratification, identification of at-risk patients, and use of VTE prophylaxis (pharmacologic, mechanical, or a combination). Hospital patients are at higher risk for VTE because of their limited mobility, active disease processes, and comorbidities. Those with cancer, trauma, surgery, and obstetric diagnoses have the highest risk for VTE complications.
Mechanical devices, such as SCDs, are the first choice for VTE prophylaxis. These methods are as efficacious and reduce risk as much as pharmacologic methods, without causing bleeding complications. (Be aware, though, that SCD therapy is contraindicated in DVT, compartment syndrome, extremity deformity, and an open infected wound of the extremity.)
Traditionally, physicians’ orders for SCD or other types of mechanical compression therapy have lacked all the components needed to provide adequate therapy. These orders should specify:
- whether to use bilateral or single sleeves
- whether to use sleeves on the lower or upper extremities
- whether to use knee-length or thigh-length sleeves
- duration of continuous SCD therapy
- criteria for discontinuing SCD
- instructions for sleeve removal every 8 hours to assess skin integrity and neurovascular status of the extremity. Neurovascular assessment should include checking for the “5 Ps” of ischemia—pain, pulse, pallor, paresthesia, and paralysis.
VTE risk assessment
On arrival at the hospital, adult medical and surgical patients should undergo VTE risk assessment by a physician or a licensed independent practitioner (LIP). Risk assessment includes three categories: age, primary admitting diagnosis, and past medical history (including a family history of thrombosis, coagulopathy, blood clots, or clotting disorders).
SCD therapy is effective for patients at moderately high risk for VTE. It should begin on admission and continue as long as the patient has limited mobility. (See Physician-ordered, nurse-driven SCD protocol.)
Physician-ordered, nurse-driven SCD protocol
The authors of this article, who are clinical nurse specialists, conducted a study at their hospital to evaluate acute-care nurses’ knowledge of safe, correct use of sequential compression device (SCD) therapy in preventing venous thromboembolism (VTE) in hospitalized adults. This descriptive correlational study used an investigator-developed, multiple-choice knowledge questionnaire based on evidence-based practices. It was administered to a target population of acute-care registered nurses and licensed practical nurses in the 394-bed, nonteaching, multi-campus community hospital to determine nurses’ knowledge level.
The study explored how knowledge scores related to the nurses’ demographic factors, specialty certification, and years of practice. Results showed a statistically significant relationship between a nurse’s knowledge of safe, correct SCD use and certification in a specialty—but not between the nurse’s SCD knowledge and his or her educational level and years of experience. Clinical observations that demonstrated safe, correct SCD use among nurses were inconsistent for various reasons, including educational deficiencies and incomplete physician orders for SCD.
Based on study results, an educational plan was developed for the nursing staff, and a physician-ordered, nurse-driven protocol was developed at the hospital to ensure safe, correct SCD use. The proposed protocol is shown below.
What you should know about SCD therapy
SCD devices sequentially inflate and deflate air-filled sleeves on the lower extremities. With knee-high sleeves, pressure starts at the ankle and moves toward the knee; pressure is approximately 45 mm Hg at the ankle and 35 mm Hg at the knee. With thigh-high sleeves, pressure at the thigh is 30 mm Hg. Each compression lasts approximately 11 seconds.
SCD therapy mimics muscle activity during ambulation. As the sleeves inflate and deflate, the muscle tightens and relaxes, blood is pushed upward to prevent venous stasis, and venous valves are protected against venous hypertension and continue to function normally. (SCD therapy must continue when the patient is seated in a chair, because sitting doesn’t cause the lower-leg muscle contractions needed to push venous blood upward.)
Choosing and applying sleeves correctly
For safe, effective SCD therapy, select a sleeve of the correct size and apply it properly. Sleeves are sized according to the manufacturer’s recommendations. Determine correct sleeve size by measuring the patient’s extremity with a tape measure; document the result in the patient’s medical record.
To apply the sleeve, follow the manufacturer’s instructions. Generally, these include the following steps and precautions:
- Make sure the ankle lines up with the ankle indication on the sleeve.
- Wrap the sleeve around the patient’s leg and secure it.
- Place two fingers between the patient’s leg and the sleeve to ensure a correct fit.
- Attach the sleeve to the mechanical pump unit.
- To check connections, note the arrows that indicate accurate insertions from sleeve to pump on the pump side and on the patient side of the pump hose.
- Turn on the mechanical pump and confirm it’s working properly.
- Stay with the patient to assess sleeve inflation and deflation through one full cycle.
- Remove the sleeve once every 8 hours to assess skin integrity and neurovascular status of the extremity and to reinforce patient education.
- Know that the sleeve should be removed during bathing and when the patient ambulates.
- Instruct the patient to call for assistance when preparing to ambulate.
- Caution the patient never to ambulate with the sleeve in place due to the risk of falling.
- Make sure the sleeve is removed only for a short time daily.
To improve patient compliance, provide education on SCD therapy. Advise patients to notify nursing staff if they have a concern or question about therapy. Caution them never to remove the sleeves without consulting a nurse.
Patient and nurse collaboration may aid patient compliance in maintaining and continuing SCD therapy. Consider asking the physician or a LIP to discontinue SCD therapy once the patient is ambulating most of the day.
Obstacles to SCD therapy
Research shows that poor patient and nurse compliance is the leading obstacle to VTE prophylaxis with SCD. Patient complaints include sweating or itching from the sleeves, discomfort from sleeve inflation, and dislike of having the sleeves on the legs. Patients frequently remove the sleeves without notifying the nurse; unfortunately, the effects of SCD therapy are short-lived, and patients are at risk for VTE within minutes of discontinuation.
To ease sweating, initiate the cooling system on the SCD pump; to relieve itching, use cornstarch. Some patients complain of discomfort from tight sleeves if they develop edema during their stay; in this case, the sleeve should be resized.
Be aware that knee-length SCDs are as effective as thigh-length SCDs and can improve patient compliance. Also, they’re easier to use and less expensive than thigh-length sleeves.
Poor nurse compliance
Among nurses, the main cause of poor compliance with SCD therapy is lack of education about proper use of this therapy and about VTE pathophysiology. Many nurses have received only limited education on sleeve sizing, application, and duration of SCD therapy. Lack of available equipment also may reduce compliance. Some nurses with high patient workloads fail to reapply SCDs after ambulation, a bath, or assessment. A 2009 study found SCD compliance increased 4% after nursing staff were educated on proper use of SCD.
Nursing: The cornerstone of prevention
Nursing is the cornerstone of VTE prevention. Comprehensive patient education and nursing proficiency in SCD therapy can improve patient care and reduce illnesses and deaths from VTE. Further research and data collection on SCD use in adults are needed to develop educational programs for nurses and patients.
Cathy Moore and Jeanne Nichols-Willey work at Bayhealth Kent General Hospital in Dover, Delaware. Ms. Moore is a clinical nurse specialist and house supervisor; Ms. Nichols-Willey is a clinical nurse specialist. Jennifer Orlosky-Novack is a clinical nurse specialist at Bayhealth Milford Memorial Hospital in Milford, Delaware.
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