VTE Prevention — Deep Vein Thrombosis Guide for Student Nurses

Why VTE prevention matters

Venous thromboembolism (VTE) is a collective term for deep vein thrombosis (DVT) and pulmonary embolism (PE). A DVT forms when a blood clot develops in a deep vein — most commonly in the calf, thigh, or pelvis. When that clot breaks off and travels to the lungs, it becomes a PE.

The numbers are stark. According to NICE (CG92/NG89) and the Department of Health, VTE causes around 25,000 preventable deaths per year in NHS hospitals. That is more than road traffic accidents, breast cancer, and AIDS combined. The vast majority of these deaths are preventable with basic nursing interventions that start with risk assessment and end with consistent prophylaxis on every shift.

As a student nurse, your job in VTE prevention includes: confirming risk assessments are documented, applying and sizing TED stockings correctly, monitoring anticoagulant administration, encouraging early mobilisation, and recognising the signs of DVT and PE before they become fatal.

VTE risk factors on surgical wards

VTE risk is cumulative — more risk factors mean higher risk. NICE NG89 and the Department of Health VTE Risk Assessment Tool group these into patient-related and admission-related factors.

Patient-related risk factors

• Age >60: Venous tone decreases with age; clotting factors increase.
• Obesity (BMI >30): Increases venous stasis and inflammatory markers.
• Previous VTE: Strong independent predictor — significantly increases lifetime risk.
• Active cancer: Malignancy activates coagulation; chemotherapy adds additional risk.
• Hormonal therapy: Combined oral contraceptive pill and HRT increase clotting factor production.
• Pregnancy or recent delivery: Increased coagulability; compression of pelvic veins.
• Thrombophilia: Factor V Leiden, antiphospholipid syndrome, protein C/S deficiency.
• Dehydration: Increased blood viscosity; common post-operatively.
• Varicose veins with phlebitis: Pre-existing venous disease.

Admission-related risk factors

• Surgical procedure >90 minutes: Prolonged immobility; activation of coagulation cascade.
• Lower limb orthopaedic surgery: Hip and knee replacements carry very high VTE risk.
• Pelvic or abdominal surgery: Iliac vein compression; disruption of pelvic vasculature.
• Immobility / bed rest: Venous stasis is the central mechanism for DVT formation — Virchow's Triad.
• Acute illness with reduced mobility: Pneumonia, MI, stroke — all reduce ambulation.
• Central venous catheter: Upper limb DVT risk with PICC lines or CVCs.
• Dehydration / sepsis: Hypovolaemia increases blood viscosity.

VTE risk assessment tools

All adult patients admitted to hospital in the UK and Ireland must have a formal VTE risk assessment documented on admission and reassessed after any significant clinical change (e.g., new diagnosis, return from theatre, change in mobility status).

Department of Health VTE Risk Assessment Tool

The Department of Health (England) VTE Risk Assessment Tool is the national standard. It classifies patients as higher risk or lower risk and combines this with a bleeding risk assessment to determine the appropriate prophylaxis plan.

NICE CG92 (2010, updated as NG89) provides the full clinical guideline. The key principle is: risk assess on admission, document it, communicate the plan clearly, and reassess regularly — especially after surgery or a change in clinical condition.

VTE prophylaxis: stockings, IPC, and LMWH

VTE prophylaxis combines mechanical methods (stockings, compression devices) with pharmacological treatment (LMWH injections). Both are often used together for higher-risk patients.

How to apply TED stockings correctly

Incorrectly applied stockings are one of the most common nursing errors on surgical wards — and they can cause pressure injuries or actually worsen venous return if applied too loosely or rolled down at the top.

1. Measure the patient first. Measure ankle circumference and leg length (heel to knee for below-knee, heel to upper thigh for thigh-length). Match to the manufacturer's sizing chart — never guess.
2. Apply in the morning before the patient gets up or within 15–30 minutes of lying down, when legs are least swollen.
3. Turn the stocking inside out to the heel. Place the foot section over the patient's foot and heel, then roll upward — do not bunch or pull from the top.
4. Check the heel pocket is correctly positioned over the heel, not above or below.
5. Smooth out any wrinkles. Creases concentrate pressure and cause tissue injury in hours.
6. Inspect twice daily. Remove for 30 minutes, check skin for redness, blistering, or blanching, particularly over the heel and Achilles tendon.

Signs of DVT and PE to escalate immediately

Despite prophylaxis, VTE can still occur — especially in high-risk patients. Knowing the signs and escalating promptly can save a patient's life.

Signs of DVT

DVT most commonly affects the calf (distal) or thigh/popliteal vein (proximal). Proximal DVTs are more dangerous as clots are larger and more likely to embolise.

• Calf or thigh pain — often described as aching, cramping, or tightness
• Unilateral leg swelling — compare both legs; even 2cm difference is significant
• Warmth and redness over the affected area
• Homan's sign — dorsiflexion of foot causes calf pain (low sensitivity, not reliable in isolation)
• Pitting oedema in affected limb
• Dilated superficial veins in the affected leg

Signs of PE — escalate immediately

PE presents on a spectrum from mild (small clot, peripheral) to massive (large central clot, cardiovascular collapse). Any suspicion of PE is a medical emergency.

6 common mistakes student nurses make with VTE prevention

These are the patterns seen most frequently on surgical wards. Recognising them helps you avoid them.

1. Applying TED stockings without measuring

Grabbing the first pair of stockings in the bay without measuring the patient first. Too large = no compression. Too small = tourniquet effect. Incorrect heel positioning = pressure injury within hours. Always measure ankle circumference and leg length against the sizing chart before applying.

2. Forgetting to reassess after surgery

VTE risk assessment is not a one-time admission task. NICE NG89 requires reassessment after any significant clinical change — including return from theatre. A patient who was low risk pre-operatively may become high risk after a 2-hour procedure. Check the chart and escalate if there's no post-op reassessment.

3. Allowing stockings to roll down

A stocking that has rolled down to the mid-calf creates a tourniquet band that actively impairs venous return — the exact opposite of the intended effect. Check stocking position on every round. If they won't stay up, check sizing and repositioning technique.

4. Missing LMWH doses without escalating

A patient refuses their LMWH injection, or it's omitted because they're nil by mouth or going to theatre. Every omission should be documented in the medication administration record (MAR) with a reason code, and the prescriber should be notified. Missed doses are a patient safety event — treat them as such.

5. Applying stockings when they're contraindicated

TED stockings are contraindicated in peripheral arterial disease (ankle-brachial pressure index <0.8), severe oedema that doesn't reduce with limb elevation, fragile or damaged skin, and active DVT (compression may dislodge the clot). If a patient has any of these conditions and stockings have been prescribed, query it with your mentor or the prescriber.

6. Not documenting mobilisation attempts

Early mobilisation is prophylaxis. If you encouraged a patient to sit out of bed and they declined, document it. If they mobilised for 10 minutes, document it. This creates a clinical record that a physio, doctor, or senior nurse can act on — and it demonstrates that VTE prevention is an active process, not just a checkbox at admission.

VTE prevention quick reference

Here's a condensed reference for the key decision points you'll encounter every shift on a surgical ward.

VTE prevention is not a single intervention — it's a bundle. Every element matters. Missing one — a skipped injection, incorrectly sized stockings, no mobilisation encouragement — increases risk. The students who understand this are the ones who make a difference on the ward.

For more on monitoring post-operative patients, see our guide to post-op observations. For pre-operative safety checks, read our pre-op preparation guide.