Pulmonary embolism Flashcards
Pulmonary embolism (PE)
A condition where a blood clot (thrombus) forms in the pulmonary arteries. This is usually the result of a deep vein thrombosis (DVT) that developed in the legs and travelled (embolised) through the venous system and the right side of the heart to the pulmonary arteries in the lungs. Once they are in the pulmonary arteries they block the blood flow to the lung tissue and create strain on the right side of the heart.
Features of PE
> Pleuritic chest pain > dyspnoea > haemoptysis > tachycardia > tachypnoea
The Wells score
Predicts the risk of a patient presenting with symptoms actually having a DVT or pulmonary embolism.
It considers risk factors such as recent surgery and clinical findings such as tachycardia (heart rate >100) and haemoptysis.
What investigations are carried out for a PE after the well’s score has been calculated?
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Likely: perform a CT pulmonary angiogram
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Unlikely: perform a d-dimer and if positive perform a CTPA
PE Blood gas features
Respiratory alkalosis when an ABG is performed. This is because the high respiratory rate causes them to “blow off” extra CO2. As a result of the low CO2, the blood becomes alkalotic.
Patients with a PE will have a low pO2 whereas patients with hyperventilation syndrome will have a high pO2.
Initial first line management of suspected PE
The initial recommended treatment is apixaban or rivaroxaban. Low molecular weight heparin (LMWH) is an alternative where these are not suitable, or in antiphospholipid syndrome.
It should be started immediately before confirming the diagnosis in patients where DVT or PE is suspected and there is a delay in getting the scan.
Initial first line management of PE in patient with severe renal impairment
if renal impairment is severe (e.g. < 15/min) then LMWH, unfractionated heparin or LMWH followed by a VKA such as warfarin
Initial first line management of PE in patient with antiphospholipid syndrome
if the patient has antiphospholipid syndrome then LMWH followed by a VKA (e.g. warfarin) should be used
What is the length of time anticoagulation should be taken after a PE?
3 Months - longer than this depends on whether it was a provoked or unprovoked PE
Unprovoked should be continued for a further 3 months
Examples of thrombolytic agents used in PE
Involves injecting a fibrinolytic medication (they break down fibrin) that rapidly dissolves clots.
It is only used in patients with a massive PE where the benefits outweigh the risks. Some examples of thrombolytic agents are streptokinase, alteplase and Tenecteplase.
