Week One - Case Two Flashcards
what is a pulmonary embolism most common secondary to
a VTE from another source that becomes dislodged, flows via bloodstream, through the right side of the heart and gets lodged into the pulmonary circulation
what is the mortality rate of PE with VTE if there is no haemodynamic instability
<5%
what is the mortality rate of a PE with VTE if shock is present
30%
what is the mortality rate of a PE with VTE if cardiac arrest happens
70%
what are the risk factors for a PE
age
Malignancy
Infection
Family history
Immobility
Bed rest >24 hours
Immobility >48 hours
Plaster of Paris over limbs
pregnancy - oestrogen (4 weeks after birth)
Previous DVT
Trauma or surgery
Dehydration
Smoking
Congestive heart failure
Antithrombin and protein C
deficiency
Obesity
Varicose veins
what are the signs of a PE
Pyrexia
Cyanosis
Tachypnoea
Tachycardia
Hypotension
Raised JVP
Pleural rub
Pleural effusion
Look for signs that could indicate a cause – e.g. DVT, recent surgery, air travel –
Atrial fibrillation (rare)
what percentage of people have tachypnoea with a PE
90% of patients have RR>16
what percentage of people have tachycardia with a PE
45%
what percentage of people have hypotension with a PE
25%
what are the most common symptoms of a PE
Pleuritic chest pain (pain worse on inspiration) –75% of patients
Breathlessness –85% of patients
Cough –50% of patients
Haemoptysis – as a result of pulmonary infarct –30% of patients
Dizziness / pre-syncope –15% of patients
Syncope (loss of consciousness/fainting) –15% of patients
Non-pleuritic chest pain – 15% of patients
what is the first symptom to occur
shortness of breath occurs within seconds and pain develops later
what is the PERC score used for diagnosis
stands for pulmonary embolism rule-out criteria
it is useful to rule out PE in low risk patients
what happens if patient’s PERC score is 0
there is less than 2% chance of PE
how is PERC score scored
Each factor below gives a score of 1. All factors must be negative for a negative PERC score. Any positive factor results in the need for further work up (move onto the Well’s Score)
Age >50
HR >100
SaO2 on room air <95%
Unilateral leg swelling
Haemoptysis
Recent surgery or trauma
Previous PE or DVT
Exogenous Oestrogen
what is the Well’s Score for PE
this can stratify patients as low risk or high risk.
what should happen with low and high risk patients
with high risk patients you should proceed straight to imaging
in low risk patients you should consider a D dimer test
look up the scores used in the Wells Score
what is the traditional interpretation used of Well’s Score
Score >6.0 — High (probability 59%)
Score 2.0 to 6.0 — Moderate (probability 29%)
Score <2.0 — Low (probability 15%)
what is the alternative interpretation of the Well’s Score
Score > 4 — PE likely. Consider diagnostic imaging.
Score 4 or less — PE unlikely. Consider D-dimer to rule out PE.
what is D dimer
a fibrin deviation product - and as such, levels are raised by the presence of a blood clot in the circulation
what does a negative D-dimer plus a low Well’s score mean
that PE or DVT is extremely unlikely
when should a D dimer only be used
should only be used as a rule out test in low probability cases - based on the Well’s scoreb
what does a positive D-dimer test in a low probability case indicate
the need for further investigation
what should you do with a high probability case
skip the D dimer and go straight to imaging