Venous thromboembolism (VTE)
Deep venous thrombosis (DVT), pulmonary embolism (PE)
VTE – Epidemiology (BBC 2008).
Pulmonary embolism following DVT kills more than breast cancer, Aids and traffic accidents combined, and 25 times more people than MRSA.
kill more than 25,000 patients in
Many patients who develop clots show signs that something is wrong only after they have been discharged from hospitals.
Disorders of vascular endothelium
Sluggish or abnormal blood flow
Increased blood coagulability
75% of PEs are from leg deep venous thrombosis.
Rare causes include, amniotic fluid, placenta, air, fat, tumour, septic emboli (from endocarditis).
PE affects 20% of surgical patients, 40% of major orthopaedic patients.
DVT and subsequent PE accounts for 10% of in hospital deaths.
Major abdominal or pelvic surgery
Lower limb orthopaedic surgery
Common mode of death in cancer and stroke
Pelvic or abdominal tumours
Risk in late pregnancy and puerperium, caesarean section, pre-eclampsia
Stroke and SCI
Any disabling disease, e.g. COPD, CCF
PMH of VTE
Familial antithrombin deficiency
Other genetic predispositions
Severity varies massively
Clinical features in small / medium PE
Pleuritic chest pain
Clinical features in massive PE
Faintness or collapse
Central chest pain
Some T wave inversion, right BBB
CXR to exclude other pathology, e.g. CCF, pneumonia, pneumothorax, tumour.
Possible raised hemidiaphragm or effusion
Other non-specific changes on CXR.
ABGs, usually reduced PaO2, normal or low PaCO2
D-dimer, tests for a fibrin degradation product
Low D-dimer (<500 ng/ml) has a high negative predictive value
Normal D-dimer does not exclude VTE
CT pulmonary angiogram
Ventilation-perfusion (V/Q) scanning
Echocardiography shows acute dilation in the right heart
CPR in moribund patients may break up an embolism
Maintain O2 sats over 90%
Opiates to relieve pain and distress
IV fluids for hypotension
Anticoagulation, aim for INR of 2.0 – 3.0
SC low molecular weight heparin for at least 5 days and until INR is at least 2
Warfarin probably for 6 months
Thrombolysis when massive and causing shock
Post op cases have a good prognosis
Other groups may be up to 9% recurrence per year
Pulmonary hypertension after 6 week indicates risk of RVF
Possible treatment for life
Post-thrombotic syndrome, which affects many people after a DVT, due to damage to the valves along the length of the vein can lead to chronic venous hypertension.
Consider stopping combined oral contraceptives 4 weeks before elective surgery
Journeys of 3 or more hours in the 4 weeks before elective surgery increases risk
Assess risk in all patients
Inpatients having surgery should be offered thigh-length graduated compression / antiembolic stockings from the time of admission. If full length are not tolerated use knee length.
Ankle 18 mmHg
Mid calf 14 mmHg
Thigh 8 mmHg
Intermittent pneumatic devices or foot impulse devices may be used instead of or as well as stockings.
Use Low Molecular Weight Heparin or Fondaparinux in orthopaedic patients or other patients with high risk. This is as well as mechanical prophylaxis.
Do not allow patients to become dehydrated.
Continue LMWH for 4 weeks after hip fracture surgery.
Regional anaesthesia has a lower risk than general anaesthesia.
Mobilise early after surgery.
Pre discharge teach about S and S of VTE, instruct on correct use of prophylaxis at home and the risks in failing to do so.
Good intra-operative care to minimise effects of muscle relaxation
No leg crossing in bed or on trolleys
Active and passive limb movements
No flying for a while after surgery or VTE
Oily fish, garlic,?aspirin