Venous Thromboembolism Flashcards
What are the main conditions contained within the umbrella of venous thromboembolism?
DVT and PE.
What should all patient’s admitted to hospital be assessed for?
VTE risk.
When admitted to hospital, which patients may be considered high risk of VTE?
Patients anticipated to have substantially reduced mobility, obese patients, patient’s with malignant disease, patients with a history of VTE, patients with a thrombophilic disorder, patients over 60.
What pharmacological prophylaxis should be offered to patients at high risk of VTE when in hospital?
A low molecular weight heparin, unfractionated heparin (renal failure) or fondaparinux.
How long should pharmacological prophylaxis of VTE in high-risk patients in hospital be continued for?
Until the patient is no longer considered to be at significant risk of VTE.
When should mechanical prophylaxis of VTE be considered for high-risk patients in hospital?
For medical patients in whom pharmacological prophylaxis is contraindicated.
How long should mechanical prophylaxis of VTE in high-risk patients in hospital be continued for?
Until the patient is sufficiently mobile.
What can be considered for mechanical prophylaxis of VTE?
Anti-embolism stockings.
What is the initial pharmacological treatment of DVT and PE?
A low molecular weight heparin or unfractionated heparin IV infusion. Warfarin is usually started at the same time.
How long should a heparin, used for the initial pharmacological treatment of VTE, be continued for?
At least five days and until the INR is greater than or equal to two for at least 24 hours.
How frequently is laboratory monitoring required when a patient is on heparins for VTE treatment?
Preferably on a daily basis.
Can heparins be used in pregnancy and why?
Yes, they do not cross the placenta.
Which heparins are preferred for use in pregnancy and why?
LMWHs as they carry a lower risk of osteoporosis and heparin-induced thrombocytopenia.
When should treatment with heparins be stopped in pregnancy?
At the onset of labour, with speciality advice being sought.
If haemorrhage occurs when a patient is being administered heparins what should be the first action taken?
The heparin should be withdrawn.
If rapid reversal of anticoagulation is required after a patient has been administered heparins, what should be used?
Protamine sulphate (only partially reverses the effects on LMWHs).
What is the difference between unfractionated heparins and LMWHs?
Unfractionated heparins act rapidly but have a short duration of action. LMWHs have a longer duration of action.
Give some examples of LMWHs.
Dalteparin, tinzaparin, enoxaparin.
Why are LMWHs generally preferred?
They carry a reduced risk of heparin-induced thrombocytopenia.
Why are LMWHs generally more convenient?
Less frequent dosing (longer duration of action), reduced requirement for monitoring.
Why are unfractionated heparins preferred for use in those patients with a high risk of bleeding?
Because their effects can be terminated rapidly by stopping the infusion.
How long does it usually take for heparin-induced thrombocytopenia to present?
Five to ten days.
In order to monitor for heparin-induced thrombocytopenia, what should be specifically monitored?
Platelet counts before and during treatment if given for longer than four days.
What signs suggest a patient is suffering from heparin-induced thrombocytopenia?
30% reduction of platelet count, thrombosis, skin allergy.
If heparin-induced thrombocytopenia occurs, what actions should be taken?
The heparin should be stopped and an alternative anticoagulant should be given. One should ensure the platelet count is returned to normal in those who require warfarin.
How can heparins lead to hyperkalaemia?
Heparins inhibit aldosterone secretion which can result in hyperkalaemia.
Which patients are at greater risk of hyperkalaemia when given heparins?
Patients with diabetes mellitus, chronic renal failure, acidosis, raised plasma potassium, taking potassium-sparing drugs.
In patients at a greater risk of hyperkalaemia when using heparins, what should be monitored before and during treatment?
Plasma potassium concentration, especially if treatment is to last for longer than seven days.
