Reducing patients’ risk of venous thromboembolism
Nurses have an essential role to play in preventing VTE
In this article…
- What is venous thromboembolism?
- Nurses’ roles and responsibilities in preventing VTE
- The importance of educating patients
Huw Rowswell is venous thromboembolism clinical nurse specialist at Plymouth Hospital Trust. Carol Law is VTE education adviser. Both are members of the VTE National Nursing and Midwifery Network.
Rowswell H, Law C (2011) Reducing patients’ risk of venous thromboembolism. Nursing Times; 107: 14, early online publication.
As the largest professional group involved in direct clinical care, nurses have a vital role to play in venous thromboembolism prevention. This article describes the condition and its implications for patients. It discusses how nurses can reduce the risk of harm to patients through risk assessment and thromboprophylaxis, and by educating patients.
Keywords: Venous thromboembolism, Thromboprophylaxis, Pulmonary embolism, Anti-embolic stockings
- This article has been double-blind peer reviewed
5 key points
- Venous thromboembolism is a significant cause of preventable death in patients admitted for medical and surgical care
- VTE can cause long-term complications and morbidity
- Appropriate risk assessment and thromboprophylaxis can reduce mortality by two thirds
- One in three patients who experience deep vein thrombosis will go on to develop post-thrombotic syndrome within five years
- Patients who survive pulmonary embolism may develop pulmonary hypertension - a life-limiting condition
Venous thromboembolism (VTE) is a significant cause of preventable death in patients admitted to hospital for medical and surgical care (House of Commons Health Select Committee, 2005). However, risk assessment and thromboprophylaxis can reduce mortality by two-thirds (Collins et al, 1988).
VTE incorporates deep vein thrombosis (DVT) and pulmonary embolism. Venous thrombosis can be asymptomatic, but most nurses will be familiar with VTE as a DVT in the leg, where it can cause unilateral pain, swelling, warmth and erythema. Although prevalent in the legs, DVT can affect the arms and visceral veins. It is believed to occur due to one or a combination of the following factors, referred to as “Virchow’s triad”:
- Venous stasis; this is caused by immobility, which leads to blood pooling, particularly in the extremities;
- Vein wall injury or dilation; this can result from local trauma from surgery or injury, and it activates clotting by stimulating the release of tissue factor;
- Hypercoaguability, which means the blood clots more easily; this can occur for a number of acquired and genetic reasons, for example thrombophilia (see Discussion, page 15), pregnancy and malignancy (Bonner, 2004).
When part of a deep vein thrombus breaks off, it can enter the circulation, travel through the heart and lodge in a branch of the pulmonary arteries where it is known as a pulmonary embolism. The embolus prevents gas exchange and impedes blood supply to the lung tissue, which can result in rapid-onset chest pain, shortness of breath, haemoptysis, hypoxaemia and syncope.
When assessing patients with suspected pulmonary embolism, nurses should monitor for these symptoms as well as for hypotension, tachypnea and tachycardia. Small pulmonary emboli can be asymptomatic and are sometimes found incidentally. Large pulmonary emboli are a medical emergency and can be instantly fatal (Tapson, 2004).
Venous thromboembolism can cause long-term complications and morbidity, such as post-thrombotic syndrome (PTS). This is a long-term condition in which damage from DVTs results in valve incompetence leading to venous stasis, which clinically manifests as chronic swelling and discomfort in the limb and, in severe cases, venous leg ulcers (Bonner, 2004). The condition can be debilitating and expensive to manage. Kolbach et al (2004) described how one in three patients who experience DVT would develop PTS within five years. Patients who survive pulmonary embolism may develop pulmonary hypertension, which is a life-limiting condition.
Defining best practice
The National Institute for Health and Clinical Excellence (NICE) clinical guideline on reducing the risk of VTE sets out key criteria to be followed to prevent VTE in hospitalised patients (NICE, 2010a). This guidance should be considered in conjunction with the institute’s quality standards for VTE prevention (NICE, 2010b) (Box 1) and the Department of Health (DH) VTE risk assessment tool (DH, 2010a). It should be the basis of all hospital policies and protocols on thromboprophylaxis.
Box 1. VTE prevention quality standard
- All patients, on admission, are assessed for VTE and bleeding risk against the clinical risk assessment criteria set out in the national tool
- Patients/carers are offered verbal and written information on VTE prevention as part of the admission process
- Patients provided with anti-embolism stockings have them fitted and monitored in accordance with NICE guidance
- Patients are reassessed within 24 hours of admission for risk of VTE and bleeding
- Patients assessed to be at risk of VTE are offered VTE prophylaxis in accordance with NICE guidance
- Patients/carers are offered verbal and written information on VTE prevention as part of the discharge process
- Patients are offered extended (post hospital discharge) VTE prophylaxis in accordance with NICE guidance
Source: NICE (2010b)
VTE prevention care pathway
NICE (2010a) has identified a care pathway for all patients admitted to hospital (Fig 1). This gives nurses a framework within which to structure their approach to VTE prevention and to identify their role and responsibilities, particularly in promoting or championing appropriate risk assessment for all patients in their care.
Through Commissioning for Quality and Innovation (CQUIN), the DH has recognised VTE risk assessment as a priority goal and has linked performance to the payment that trusts receive from their commissioners. This requires trusts to audit VTE risk assessment and submit data monthly, which the DH publishes.
The DH has developed a national VTE risk assessment tool to be used by all trusts (DH, 2010). This includes the assessment of both clotting and bleeding risk factors to assist in deciding on thromboprophylaxis that would be appropriate and safe.
The tool requires all patients admitted to hospital to have their mobility assessed. Medical patients whose mobility is not significantly lower than it is normally will not need further VTE assessment or thromboprophylaxis. Other medical and all surgical patients should be assessed for patient-related and admission-related risk factors and, subsequently, bleeding risk factors if pharmacological prophylaxis is indicated.
Day-case patients who meet certain predetermined criteria such as chemotherapy, minor day-case interventions and minor surgery requiring no general anaesthesia are covered under a generic (cohort) risk assessment and are not usually individually assessed. If these patients subsequently require an overnight stay, the risk assessment must then be completed.
Decisions about who should complete risk assessments are made locally. In many trusts, they are initiated by nurses and completed, with a prescription, by doctors. All nurses should be aware of their role and responsibility with regard to VTE risk assessment within their hospital.
Nurses can ensure NICE guidance is followed by prompting reassessment of VTE risk within 24 hours of admission and whenever a patient’s clinical condition changes. This ensures that patients continue to receive appropriate prophylaxis throughout their stay and on discharge.
Risk assessment is essential to ensure all patients admitted to hospital receive appropriate thromboprophylaxis. Nurses must work collaboratively with doctors and pharmacists to make sure appropriate thromboprophylaxis treatments are selected and that contraindications have been considered. They also administer the medication (Box 2) and must ensure patients are well hydrated and encouraged to mobilise as soon as possible.
Box 2. Key considerations in administering thromboprophylaxis
- Technique for administering subcutaneous heparin, identifying contraindications and complications
- Contraindications to and usage of anti-embolic stockings, foot pumps and intermittent pneumatic compression
- Early and effective mobilisation
- Patient education before admission, on admission, during inpatient stay and on discharge
The choice of pharmacological thromboprophylaxis will be based on local policies, the clinical condition and patients’ preferences. NICE (2010a) recommends a choice of fondaparinax sodium, low molecular weight heparin (LMWH) or, for patients with renal failure, unfractionated heparin. As LMWH dosage is based on weight, nurses must ensure that patients are weighed and their weight is documented.
Prophylaxis should start as soon as possible after the risk assessment has been completed and should continue until the patient is no longer at an increased risk of VTE. Nurses should observe patients on chemical thromboprophylaxis for signs of bleeding and bruising, and encourage them to report either.
The correct technique for administering subcutaneous prophylaxis should be followed. A video demonstrating this can be found on the National Nursing and Midwifery Network page of the VTE Exemplar Network website (www.kingsthrombosiscentre.org.uk). To minimise abdominal bruising and discomfort, alternate sites should be used and documented.
Along with prescribers, nurses have a duty to consider whether patients may have cultural, spiritual or ethical objections to the use of heparin, which is porcine. Consent should be sought before administration and, where it is withheld, a synthetic alternative should be offered.
New oral anticoagulants are licensed for elective hip and knee arthroplasty. Rivaroxaban (Xarelto) is a direct factor Xa inhibitor and dabigatran (Pradaxa) is a direct thrombin inhibitor. Either can be given as an alternative to LMWH postoperatively.
NICE (2010a) recommends that certain high-risk groups of patients should continue thromboprophylaxis after discharge. Nurses must check how care will be continued following discharge, and that patients are given information and advice before they are discharged from hospital.
Mechanical VTE prophylaxis includes anti-embolic stockings (knee or thigh length), foot impulse devices and intermittent pneumatic compression devices (thigh or knee-length). The choice of device will depend on the clinical condition, surgical procedure and patient preference (NICE, 2010a).
Nurses play an essential role in ensuring stockings are fitted and maintained appropriately: see the Practice Educator article on page 18 for information on using anti-embolism stockings.
NICE (2010a) says anti-embolic stockings use a passive mechanism to reduce VTE, whereas foot impulse devices and intermittent pneumatic compression devices are active or dynamic methods to reduce the risk.
Intermittent pneumatic compression devices work by applying inflatable garments around either the whole leg or the calf. These are inflated by a pneumatic pump with intermittent air cycles inflating and deflating chambers of the garment to enhance venous return and stimulate fibrinolytic activity (Morris and Woodcock, 2004).
Foot impulse devices can be used on immobile patients to simulate walking by increasing venous return and reducing stasis by compressing the venous plexus and producing a pulsatile flow.
It is important that both devices are fitted correctly.
Hydration and mobilisation
It is thought that dehydration predisposes patients to venous thromboembolism, so keeping them well hydrated is an important mode of thromboprophylaxis (NICE, 2010a). Nurses can achieve this by keeping accurate fluid balance charts and communicating with patients and medical teams.
Immobility is also a risk factor for VTE as the lack of normal venous calf pump function leads to venous stasis (NICE, 2010a). Early mobilisation and leg exercises are effective ways to prevent stasis of blood and subsequent VTE (NICE, 2010a). Nurses can promote mobilisation and leg exercises by educating patients and collaborating with physiotherapists.
The VTE expert working group highlighted the need for education to empower patients to become involved in their own VTE prevention programme (DH, 2007); this was reinforced by NICE (2010b).
Providing verbal and written information before and on admission can help to minimise the risk by encouraging mobility and adequate hydration and prompting patients to question whether prophylaxis has been prescribed. During and after patients’ stay, education should help promote adherence with chemical and mechanical prophylaxis and should be supplemented with written information (NICE, 2010b).
Patients should also be given information on discharge about the signs and symptoms of VTE and the importance of seeking medical attention should these occur. In much the same way as the Clean Your Hands campaign empowered patients to question health professionals about handwashing, patient education and information should prompt them to ask about VTE prophylaxis and risk assessment.
Roles and responsibilities
The NMC code states nurses should provide a high standard of practice and care at all times based on the best available evidence (NMC, 2008). The nurse’s role is to ensure patients in their care are receiving appropriate thromboprophylaxis based on individual risk assessment. If nurses identify a problem, such as a patient not being prescribed appropriate prophylaxis, the NMC instructs them to raise the issue with an appropriate individual (NMC, 2007).
It is the nurse’s responsibility to ensure VTE care plans or pathways are maintained and include documentation of the VTE risk assessment findings and the selection and evaluation of thromboprophylaxis modalities. Hydration status and level of mobilisation should also be recorded.
NICE highlights that treatment and care should take into account patients’ individual needs and preferences. It also states that good communication is essential, supported by evidence-based information, to allow patients to reach informed decisions about their care (NICE, 2010a).
As the largest professional group involved in direct clinical care and the only group with 24-hour patient contact, nurses are in an ideal position to help to make this happen and have a vital part to play in VTE assessment and effective prophylaxis.
Bonner L (2004) The prevention and treatment of deep vein thrombosis.Nursing Times; 100: 29, 38-42.
Collins R et al (1988) Reduction in fatal pulmonary embolism and venous thrombosis by perioperative administration of subcutaneous heparin: overview of results of randomised trials in general, orthopaedic and urologic surgery. New England Journal of Medicine; 318: 18, 1162-1173.
Department of Health (2010) Venous Thromboembolism (VTE) Risk Assessment. London: DH.
Department of Health (2007) Report of the Independent Working Group on the Prevention of Venous Thromboembolism in Hospitalised Patients. London: DH.
House of Commons Health Select Committee (2005) Inquiry into the Prevention of VTE in Hospitalised Patients. London: HoC.
Kolbach DN et al (2004) Non-pharmaceutical measures for prevention of post-thrombotic syndrome. Cochrane Database of Systematic Reviews; Issue 3. tinyurl.com/post-thrombotic-syndrome
Morris RJ, Woodcock JP (2004) Evidence-based compression: prevention of stasis and deep vein thrombosis. Annals of Surgery; 239: 162-171.
National Institute for Health and Clinical Excellence (2010a) Venous Thromboembolism – Reducing the Risk. Reducing the Risk of Venous Thromboembolism (Deep Vein Thrombosis and Pulmonary Embolism) in Patients Admitted to Hospital. London: NICE.
National Institute for Health and Clinical Excellence (2010b) Quality Standards Programme VenousThromboembolism Prevention. London: NICE.
Nursing and Midwifery Council (2008) The Code - Standards of Conduct, Performance and Ethics for Nurses and Midwives. London: NMC.
Nursing and Midwifery Council (2007) Standards for Medicines Management. London: NMC.
Tapson VF (2004) Acute pulmonary embolism. Cardiology Clinics; 22: 353-365.