VTE is largely preventable in many cases. VTE is a term which includes PE and DVT. It doesn’t have ot be symptomatic.
DVT is most common in the lower leg, although it can occur further up or in the arms. It can be caused by several factors; they form Virchow’s triad:
- Pooling of blood (venous stasis) which occurs mainly in the extremities and is largely caused by immobility/inactivity
- Injury or dilation of the vein wall which releases tissue factor and enables clotting
- Hypercoaguability – increased ability for clotting – this may occur for a variety of reasons.
If any, or two, or all of the above factors are present the patient is at risk of VTE.
The thrombus becomes an embolus when it detaches and occludes a smaller vessel elsewhere, sometimes in the lung (PE). This prevents gaseous exchange, impeding the lung tissue’s blood supply which can cause chest pain, syncope, hypoxia, haemoptysis and shortness of breath. It is therefore important to monitory respiratory rate for tachpnea, tachycardia, and hypotension as PEs can be fatal.
Post-thrombotic syndrome (PTS) is cuased when a DVT causes long-term damage to venous values, this causes venous stasis which in turn increases the likelihood of developing a further DVT, causes erythema and swelling to the affected limb, discomfort, and sometimes venous leg ulcers. A third of DVT patients develop PTS.
On admission to hospital, all patients should be screened for their risk of developing TE and their care planned accordingly. This may involve anti-embolism stockings. Subcutaneous heparin, intermittent pneumatic compression (IPC), mobilisation as soon as possible or hydration.
Pharmacological prophylazis may involve low molecular weight heparin (LMMWH) fondaparinaz sodium, or if the patient has renal failure unfractionated heparin. Prophylaxis should begin as soon as possible and continue until the patient is no longer at the increased risk of VTE. As with all pharmacological thromboprophylaxis, the patient should be monitored for signs of bleeding/bruising. This needs to be documented and reported.