S2 Ch 2 Pulm 3-6

Front 1

544. 5 sources of PE?

Back 1

1. Fat embolism (long bone fractures)
2. Amniotic fluid embolism during or after delivery
3. Air embolism (trauma to thorax, indwelling venous/arterial lines)
4. Septic embolism (IV drug use)
5. Schistosomiasis.

Front 2

545. Risk factors for DVT/PE?

Back 2

a. Age >60
b. Malignancy
c. Prior hx of DVT/PE
d. Hereditary hypercoagulable states (factor V Leiden, protein C and S deficiency, antithrombin III deficiency)
e. Prolonged immobilization or bed rest, long-distance travel.
f. Cardiac disease, especially CHF
g. Obesity
h. Nephrotic syndrome
i. Major surgery, esp pelvic surgery (orthopedic procedures)
j. Major trauma
k. Pregnancy, oestrogen use (oral contraceptives).

Front 3

546. From where do most PEs arise?

Back 3

a. From thromboses in the deep veins of the lower extremities above the knee (iliofemoral DVT).
b. Pulmonary emboli can also arise from the deep veins of the pelvis.
c. Although calf vein thrombi have a low incidence of Embolizing to the lungs in many patients these thrombi progress into proximal veins, increasing incidence of PE.
d. Upper extremity DVT is a rare source of emboli (it may be seen IV drug abusers).

Front 4

547. Pathophysiology of PE?

Back 4

a. Emboli block a portion of the pulmonary vasculature, leading to increased pulmonary vascular resistance, pulmonary artery pressure, and right ventricular pressure.
b. If it is severe (large blockage), Acute cor pulmonale may result.
c. Blood flow decreases in some areas of the lung- dead space is created in areas of belonging which there is ventilation but no perfusion
d. The resulting hypoxemia and Hypercarbia drive respiratory effort, which leads to tachypnea
e. If the size of the dead space is large (Large PE), clinical signs are moreover (SOB, tachypnea).

Front 5

548. Course and prognosis of PE?

Back 5

a. Most often, PE is clinically silent.
b. Recurrences are common, which can lead to development of chronic pulmonary hypertension and chronic cor pulmonale.
c. When PE is undiagnosed, mortality approaches 30%.
d. A significant number of cases are undiagnosed (as many as 50%)
e. When PE is diagnosed, mortality is 10% for 60 min.
f. Of those who survived the initial event, approximately 30% of patients will die of a recurrent PE if left untreated!!!!!

Front 6

549. Symptoms of PE (frequency per the PIOPED study)?

Back 6

a. Dyspnea (73%)
b. Pleuritic chest pain (66%)
c. Cough (37%)
d. Hemoptysis (13%)
e. Note that only 1/3 of patients with PE will have signs and symptoms of the DVT.
f. Syncope seen in large PE

Front 7

550. Signs of PE (frequency per the PIOPED study)?

Back 7

a. Tachypnea (70%)
b. Rales (51%)
c. Tachycardia (30%)
d. S4 (24%)
e. ↑d P2 (23%)
f. Shock with rapid circulatory collapse in massive PE
g. Other signs: low grade fever, ↓d breath sounds, dullness on percussion

Front 8

551. Utility of ABG for PE diagnosis?

Back 8

a. AVG levels are not diagnostic for PE
b. PaO2 and paCO2 are low (the latter due to hyperventilation) and pH is high.
c. Thus, there is typically a respiratory alkalosis
d. The A-a gradient is usually elevated
e. A normal A-a gradient PE less likely, they cannot be relied on to exclude the diagnosis

Front 9

552. CXR with PE?

Back 9

a. Usually normal
b. Atelectasis or pleural effusion may be present
c. The main usefulness is in excluding alternative diagnoses

Front 10

553. 2 Classic radiographic signs for PE?

Back 10

1. Hampton’s hump
2. Westermark’s sign
b. These are rarely present

Front 11

554. Utility of venous duplex ultrasound of lower extremities- what should you do with a positive result?

Back 11

a. If there is a positive results, treat with IV heparin.
b. Treatment DVT is the same as for PE
c. This test is very helpful when positive, but of little value when negative!

Front 12

555. Utility of V/Q scan for PE?

Back 12

a. Traditionally, with most common test used when PE is suspected
b. But has been replaced by helical CT as the initial study choice in many medical centres.
c. Plays important role in diagnosis when there is a contraindication to helical CT or in centres which are inexperienced performing helical CT scans.

Front 13

556. When may the V/Q scan be particularly useful in the diagnosis of PE?!?!?

Back 13

a. When the CXR is clear and when there is no underlying cardiopulmonary disease!!

Front 14

557. Interpretation of V/Q scan results?

Back 14

a. Can lead a normal, low probability, intermediate probability, or high probability (treatment guidelines based on PIOPED study)

Front 15

558. Significance of a normal V/Q scan?

Back 15

a. Virtually rules out PE- no further testing is needed.
b. But a V/Q scan is almost never “normal” anyone

Front 16

559. Significance of a high probability V/Q scan?

Back 16

a. Has a very high sensitivity for PE
b. Treat with heparin