# Prophylaxis

Prophylaxis

Prophylactic methods can be divided into mechanical and pharmacological. A variety of  mechanical methods have been tried, but only the use of  graduated elastic compression stockings and external pneumatic compression have been William Morrant Baker , 1839–1896, surgeon, St Bartholomew’s Hospital, London, UK, described these cysts in 1877. - - - - - shown to be worthwhile by reducing the incidence of  throm - bosis. Newer devices, such as electronic nerve stimulators, lack evidence of  e ffi cacy to date. More recent emerging evidence is - casting some doubt on the benefit of  mechanical prophylaxis in surgical patients and ther e are further studies underway . Compression-based prophylactic measures should be avoided in patients with peripheral vascular disease. Pharmacological methods are more e ff ective than mechanical methods at risk reduction, although they carry an increased risk of  bleeding. In the past, low-dose unfractionated heparin was used both intravenously and subcutaneously . In the absence of renal impairment, most centres currently use low-molecular-weight heparin (LMWH) given subcutaneously . This is given once daily , does not require monitoring and has a lower risk of  bleeding complications. Patients who are being admitted for surgery may be graded as low , moderate or high risk for pulmonary embolism and VTE ( Tables 62.5 and 62.6 ). Patients in the medium- or high-risk groups should be considered for pharmacological 

Figure 62.34
An ascending venogram of a deep vein thrombosis seen
as
/f_i
lling defects (arrows) with contrast passing around the thrombus.
Figure 62.35
A computed tomography pulmonary angiogram show
-
ing pulmonary emboli as
/f_i
lling defects (arrow) in the pulmonary artery.
TABLE 62.5
Modi
/f_i
ed Wells criteria for predicting
pulmonary embolism (PE).
Variable
Score
Clinical signs and symptoms of DVT (minimum of leg
3
swelling and pain on palpation of deep veins)
Alternative diagnosis less likely than PE
3
Heart rate >100
/uni00A0
bpm
1.5
Immobilisation >3 days or surgery within past 4 weeks
1.5
Previous DVT or PE
1.5
Haemoptysis
1
Malignancy (treatment or palliation within past 6
1
months)
A score of <4 means PE is unlikely (12.4%); >4 is suggestive of PE
(37.1%).
bpm, beats per minute; DVT, deep vein thrombosis.

/uni25CF /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF prophylaxis with an anticoagulant medication. Recent level 1 evidence suggests that the addition of  mechanical prophylaxis in such patients a ff ords no additional benefit. 

for venous thromboembolism.
Low
Minor surgery <30 minutes; any age; no risk factors
Major surgery >30 minutes; age <40; no other risk factors
Minor trauma or medical illness
Medium
Major surgery; age 40+ or other risk factors
Major medical illness: heart/lung disease, cancer, in
/f_l
ammatory
bowel disease
Major trauma/burns
Minor surgery, trauma, medical illness in patient with previous
DVT, PE or thrombophilia
High
Major orthopaedic surgery or fracture of pelvis, hip, lower limb.
Major abdominal/pelvic surgery for cancer
Major surgery, trauma, medical illness in patient with DVT, PE or
thrombophilia
Lower limb paralysis (e.g. stroke, paraplegia)
Major lower limb amputation
DVT, deep vein thrombosis; PE, pulmonary embolus.