PE Flashcards
PERC rule:
Used to stop work up in someone already low risk (Wells)
If PERC negative, pretest prob is <2%
Not valid in pregnancy
————-
ie.
Consider PE
Apply Wells
Found low/<15%
Apply PERC
If neg, stop.
Wells Criteria for PE: scores and pretest probability
2 TIER:
4 or less = ‘unlikely’ = 3%
5+ = ‘likely’ = 28%
3 TIER
CXR in PE:
Normal in most
Useful for:
- DDX
- Decision if VQ option
PE:
Hampton Hump
—> Semicircular peripheral
Focal lucency/ oligaemia (Westermark)
Prominent pulmonary artery (Fleishner)
ECG in PE:
Sinus tachycardia
RV strain
—> TWI/STD V1-3
RBBB
RAD
S1Q3T3
—> only 10%
ECG changes poor prognostic factor
Imaging modalities in PE:
CTPA
- Sensitivity high 90s (segmental +)
-Can miss small, subsegmental (but so will all Ix, and significance unclear)
VQ scan
- Safe in dye allergy, renal failure, pregnancy
- Ineffective in lung disease
—> 50% equivocal!!
—> Not appropriate if ANY CXR abnormality
- Not definitive: gives probability only
—> High prob = 85% risk (will inappropriately anticoag 15%*)
—> If prob doesn’t match risk profile, needs further Ix
- Availability
- Nuclear suites remote from ED
*VQ SPECT
- Combo VQ and low dose CT
- Probably performs similarly to CTPA but studies incomplete
Echo
- Used at bedside in UNSTABLE patients
- Exclude DDx (eg. tamponade, valve failure)
- Will only diagnose massive PE
MRI angio
- A bit shit. Misses even segmental sometimes.
Pulmonary angiography
- Gold standard but impractical
Significance of single, subsegmental PE:
Trunk/ segmental/ subsegmental
PESI score:
PE Severity Index
Determines mortality risk
In general, I and II okay for outpatient Mx.
*Excludes renal failure and significant comorbidity
Classification of PE:
Massive
Submassive
Non-massive
MASSIVE
SBP <90 (or SHOCKED)
SUBMASSIVE
Not shocked, but
Trop rise or RV dysfunction
NON MASSIVE
Nil above features
Management of massive PE:
By definition, unstable
- High PVR (PE + hypoxia)
- RV dilation and strain
- RV bows into LV and reduces LV output
- Shock
Oxygen. Avoid tubing if at all possible.
Avoid intubation.
Early norad
AVOID FLUIDS- will further distend the strained and overloaded RV.
__________________
Thrombolysis
ALTEPLASE 100mg over 2 hours (10mg as bolus)
Or, embolectomy- catheter or surgical
- If lysis contraindicated, or fails.
- Surg unstable, rad if stable
—> VA ECMO/ bypass
Thrombophilia screen
Commence heparin infusion
Anticoagulation in PE:
TAKE THROMBOPHILIA SCREEN FIRST
UF heparin
80units/kg stat, then 18units/kg/hr
- Target APTT 60-80
OR
Enoxaparin
1.5mg/kg SC daily or 1mg/kg SC BD
- Max dose as per 100kg (ie. 150g daily)
AND
Warfarin
- Start at same time as heparin
- Continue 3-6mo
- INR 2-3
OR
DOAC
____________
UFH and LMWH equal options.
Unless robust and stable, UFH as first dose to allow for reversal.
Don’t wait for imaging if unwell
If patient has been lysed, start UFH (and warfarin) straight after.
PE in pregnancy:
ISSUES
Symptom crossover (dyspnoea, tachy)
D-dimer elevated after 1st trimester
Wells/ PERC arent validated
Radiation risk to mum, fetus
Risk of PE is higher
D-DIMER
Rises from T2 to 6 weeks PP
Still useful T1, and useful if NEGATIVE
DIAGNOSTIC APPROACH
Still use Wells to risk stratify
-Low- RO with Ddimer
-Mod/high (or Ddimer +):
1- CXR
If no alternative Dx:
2- Bilat LL doppler
If +, treat as PE
If -, image lungs
3- CTPA/ VQ
- Based on normal/abn CXR
- CTPA more rad to mum, VQ more rad to baby On balance, mum’s CTPA risk > baby’s VQ risk.
- Attenuate with: breast/ belly shield, IDC to drain contrast, Q component only.
ANTICOAGULATION
All heparins fine
UF heparin infusion for labour
No NOAC
Warfarin safe for breastfeeding (but not early PP)
Continue 6 months total, at least 6 weeks PP
Long term sequelae of PE
Pulmonary hypertension
Pulmonary infarct
‘Post PE syndrome’ (dyspnoea, SOBOE)
RV dysfunction
