PE

Question 1

What is a PE?

Answer 1

Blood clot that is lodged in pulmonary artery tree

Increased pulmonary vascular resistance, V/Q mismatch and possibly reduced pulmonary blood flow

Question 2

What is the most common source of PE?

Answer 2

Proximal leg thrombus

Question 3

Does a negative doppler US r/o DVT?

Answer 3

No, US is not reliable for calf vein DVTs (low risk for embolizing)

But 15% risk that calf vein DVTs can extend proximally and become dangerous (can serially US for 2 weeks)

Question 4

When to worry about PE after surgery?

Answer 4

Fever, sudden dyspnea, chest pain or collapse 1-2 WEEKS after surgery

Question 5

What is Virchow’s triad?

Answer 5

Venous stasis
Endothelial damage
Hypercoagulable state

Question 6

RFs for venous stasis?

Answer 6

Immobilization
Obesity, CHF
Chronic venous insufficiency

Question 7

RFs for endothelial cell damage?

Answer 7

Post-op injury

Trauma

Question 8

RFs for hypercoagulable states?

Answer 8

Malignancy, cancer treatment
Exogenous estrogen (OCP, HRT)
Pregnancy, post-partum
Prior history of DVT, PE, FHx
Coagulopathy
Increasing age

Question 9

When to order a d-dimer?

Answer 9

Need to ensure hospital uses 2nd or higher generation assay that has high sensitivity

Test is used for negative predictive value (negative result rules out PE in settings low clinical probability)

Does NOT rule in PE

Question 10

ABG findings for PE?

Answer 10

Acute respiratory alkalosis

But some patients may have normal acid-base status and may not be hypoxemic or hypocarbic

Question 11

ECG findings for PE?

Answer 11

SINUS TACHYCARDIA***

RV strain
RV hypertrophy
RBBB
R axis deviation
RA hypertrophy

S1Q3T3

Question 12

CXR findings in PE?

Answer 12

Atelectasis (ischemia leads to dysfunctional Type II alveolar cells, leading to reduced surfactant and lung collapse)

Small pleural effusion
Normal CXR

Question 13

What are classic but rare CXR findings for PE?

Answer 13

Westermark’s sign (plump proximal arger with distal oligemia)

Hampton’s hump (peripheral pleural based density representing pulmonary infarct)

Question 14

When is a d-dimer not necessary?

Answer 14

Any prior probability for PE that is NOT low

Question 15

Why is a leg doppler preferred as initial imaging?

Answer 15

Presence of DVT has same clinical significant as PE because they have the same treatment

Question 16

When to consider V/Q scan?

Answer 16

Young, healthy females with no history of CHF or lung disease due to lower dose of radiation (decreased risk of breast CA)

Question 17

How to interpret results of V/Q scan?

Answer 17

Low probability/normal: rules out PE

High probability: most likely means PE present

Intermediate: follow up with CTPA

Question 18

How to interpret results of CTPA?

Answer 18

Sensitive and specific for PE

Question 19

How long to serially doppler a leg for a calf vein DVT?

Answer 19

If a calf vein DVT has not extended proximally by 7-10 days in an untreated ambulatory patient, they will not extend after that time

Question 20

Treatment for PE?

Answer 20

Admit for observation, O2 if hypoxemic or dyspneic, analgesia for chest pain (narcotic or acetaminophen)

Acute anticoagulation: LMWH
Long term anticoagulation: Warfarin (start at the same time as LMWH, overlap for at least 5 days and until INR in target range of 2-3 for at least 2 days)

Question 21

When to thrombolyse via IV?

Answer 21

Massive PE (hypotension or clinical RH failure) and no contraindications

IV: hastens resolution of PE but may not improve survival and doubles risk of major bleeding

Catheter-directed thrombolysis by interventional radiologist works better than IV therapy, fewer contraindications

Question 22

Duration of long term anticoagulation?

Answer 22

If reversible cause for PE (surgery, injury, pregnancy, etc.), then warfarin for 3-6 months

Indefinite anticoagulation if ongoing major risk factor (CA, antiphospholipid antibody, etc)

Question 23

What is Well’s criteria for PE?

Answer 23

3: signs/symptoms of DVT
3: no alternate dx
1. 5: prior PE/DVT
1. 5: immobilization or surgery 100)
1: hemoptysis
1: malignancy