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Flashcards in FN: DVT Deck (18):
1

epi

DVTs occurs in 25% of surgical patients

2

Risk factors: pathophysiology

Virchows triad

3

Virchows triad

Blood contents
Blood flow
Vessel wall

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Blood contents

1. Surgery - raised platelets and raised fibrinogen
2. Dehydration
3. Malignancy
4. Increasing age

5

Blood flow

- surgery
- Immobility
- Obesity

6

Vessel wall

Damage to veins: esp. pelvic veins
Previous VTE

7

Signs

- Peak incidence @ 5-10d post-op
- 65% of belo knee DVTs are asymptomatic
- Calf warmth, tenderness, erythema, swelling
- Mild pyrexia
- Pitting oedema

8

Differential

Cellulitits
Ruptured baker cyst

9

Investigations

- D-dimers: sensitive but not specific
- Compression US (clot will be incompressible)
- Thromobophilia screen

10

Do a thrombophilia screen if:

- no precipitating factors
- Recurrent DVT
- Family Hx

11

Diagnosis

1. Assess probability using Wells score
2. Low-probability - perform D-dimers
3. Med/high probaility - compression US

12

Low probability results of D-dimer

Negative - excludes DVT
Positive - compression US

13

Rx

Anticoagulate
- therapeutic LMWH: enoxaparin 1.5mg/kg/24h SC
- Start warfarin using Tait model: 5mg OD for first 4 d
- Stop LMWH when INR 2.5

14

Duration of anticoagulation

below knee: 6-12 wks
Above knee: 3-6 months
On-going cause: indefinitie

15

Graduated compression stockings

Consider for prevention of post-phlebitic syndrome

16

Preventing DVT pre-op

- pre-op VTE risk assessment
- TED stockings
- Aggressive optimization: esp. hydration
-Stop OCP 4wks pre-op

17

Intra-op prevention

1. Minimize length of surgery
2. Use minimal access surgery where possible
3. Intermittent pneumatic compression boots

18

Post-op prevention

1. LMWH
2. Early mobilization
3. Good analgesia
4. Physio
5. Adequate hydration

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