Pulmonary Embolism

Question 1

What are the four classifications of PE?

Answer 1

Acute Vs. Chronic

Massive Vs. Submassive

Question 2

What is the difference between the presentation of acute vs. chronic PE?

Answer 2

Acute: symptoms of dyspnea, chest pain, coughing occur immediately after obstruction occurs.

Chronic: symptoms progressively appear over a period of years after obstruction due to pulmonary HTN.

Question 3

What are characteristics of a massive PE?

Answer 3

• hypotension (SBP less than 90mmHg or greater than 40mmHg drop below baseline)
• elevated central venous pressure and JVD
• death results from acute RV failure

Question 4

What criteria defines submassive PE?

Answer 4

Any PE that doesn’t meet the criteria for massive PE

Question 5

Why is Brain Natriuretic Peptide measured in the serum when a patient has a PE?

Answer 5

Predicts RV dysfunction and mortality.

-risk of death increases with increased measured levels

Question 6

Why are serum Troponins measured when a patient presents with a PE?

Answer 6

Can indicate integrity of RV. Elevated levels indicate possible RV infarction

Question 7

Why do smaller PEs have a better prognosis than large ones?

Answer 7

Smaller PEs lodge more distally in the lungs. They result in more chest pain and the patient will present earlier and the situation is resolved sooner.

Question 8

Why does PE result in RV dysfunction or failure?

Answer 8

Once 75% of the pulmonary vasculature is occluded, the RV must generate a systolic pressure of around 50mmHg in order to maintain perfusion. The pulmonary artery reaches pressures around 40mmHg. The RV is not designed for this pressure and eventually fails. The preload in the LV decreases and the LV will eventually fail.

Question 9

Best laboratory test to detect PE..

Answer 9

CT angiography

Question 10

Only diagnostic criteria for PE on CXR.

Answer 10

Hamptons Hump

Question 11

What is necessary in addition to a positive V/Q scan to diagnose PE?

Answer 11

High clinical suspicion based on H and P

Question 12

Spiral CT is not sensitive enough to pick up PE but what else can be picked up with it in the lungs?

Answer 12

Pulmonary Fibrosis or other vascular abnormality

Question 13

What are 3 treatments for PE?

Answer 13

1. Supplemental O2
2. IV fluids (delays progression to HF)
3. Meds (thrombolysis and/or anticoagulation)

Question 14

2 biggest indications for using Thrombolytics in PE.

Answer 14

1. Severe Hypoxemia

2. Large Perfusion Defects

Question 15

What are the 4 absolute contraindications for using thrombolytics?

Answer 15

1. Hx of previous hemorrhagic stroke
2. Active Intracranial Neoplasm
3. Recent intracranial hemorrhage or surgery (within 2 months)
4. Active or recent internal bleeding (within 6 months)

Question 16

What are 4 characteristics of acute respiratory distress syndrome (ARDS)?

Answer 16

1. acute onset
2. bilateral infiltrates
3. no left atrium pressure increase
4. PaO2/FiO2 (pressure of arterial O2 to pressure of fractionated inhaled O2 ratio) less than 200mmHg

• Acute process
• Restrictive process
• Diffuse pulmonary infiltrates
• Shunt hypoxemia

Question 17

What are the 4 characteristics of acute lung injury (ALI)?

Answer 17

1. acute onset
2. bilateral infiltrates
3. no left atrium pressure increase
4. PaO2/FiO2 between 201-300mmHg

Question 18

ALI presents the same as PE. How can the two be differentiated?

Answer 18

CXR will show bilateral infiltrate in ALI not PE