Pulmonary Circulation Disorders - Exam 2 Flashcards
What is the MC source of PEs? What do fat PEs arise from? What do septic emboli arise from?
thrombus arising from the deep veins of the lower extremities
long bone fractures
acute infective endocarditis
_______ occurs most often when small emboli lodge distally where there is a little collateral blood flow
infarction
What are the 3 pathophysiological response from pulmonary vascular obstruction?
infarction
impaired gas exchange leading to hypoxia
cardiovascular compromise
What does impaired gas exchange leading to hypoxia lead to?
altered ventilation to perfusion ratio
Inflammation → Surfactant dysfunction → Atelectasis → Functional intrapulmonary shunting
Stimulation of the respiratory drive → hypocapnia and respiratory alkalosis
What is the pathophys behind cardiovascular compromise?
Obstruction of the vascular bed → Increased pulmonary vascular resistance → Right heart and intraventricular septal strain
Less blood returning to the left ventricle → Reduced cardiac output → Hypotension
**What is Virchow’s triangle? What does it increase your risk for?
venous stasis
injury to the vessel wall
hypercoagulability
increased risk for PE
What are the risk factors for venous stasis?
immobility
hyperviscosity
increased central venous pressures (low cardiac output states and pregnancy)
What are the risk factors for hypercoagulability?
medications
disease: malignancy or surgery
inherited gene defects: factor V leiden, protein C, S and antithrombin deficiency, prothrombin gene mutation, hyperhomocysteinemia, antiphospholipid antibodies
What is the MC inherited gene defect that leads to hypercoagulability?
Factor V leiden
What are the MC s/s of PE? What does significant pain indicate? _____ is the most reliable physical exam finding
dyspnea, pleuritic chest pain, cough
small PEs that result in infarction
tachypnea
What are s/s of DVT?
Lower leg pain or “charley horse” in the calf
Associated symptoms DVT: swelling, warmth and/or erythema
What is the scale of Wells criteria for PE tell you? **What are the ranges of the scale?
determines the pre-test probability of the s/s being a PE
Determine “pre-test” probability
>6 points = high risk (78.4%)
2–6 points = moderate risk (27.8%)
<2 points = low risk (3.4%)
When are the PERC rules used? What are the PERC rules? **What does it stand for?
PERC rules are only used if Well’s risk is low risk
PERC Rules (Pulmonary Embolism Rule-Out Criteria)
What do you do if the pt is low risk and no PERC rules criteria are met?
no testing is needed
What do you do if the pt is low risk and there is at least 1 positive PERC rule?
move on to plasma D-dimer
Normal → no imaging
Elevated d-dimer → imaging
What do you do if the pt is intermediate risk?
D- dimer
Normal → no imaging
Elevated d-dimer → imaging
What do you do if the pt is high risk?
Imaging (no D-dimer)
What does a positive D-dimer indicate? What is normal?
A protein fragment from a broken down blood clot
normal is less than 500 ng/ml
**What is the equation for age adjusted d-dimer? What age do you need to adjust?
Adults over age 50 use an age-adjusted threshold (age × 10 ng/mL)
T/F: All elevated d-dimer are diagnostic for a PE/DVT
False!!! there are lots of false positive aka non-PE reasons why the d-dimer would be elevated
What are some reasons why the d-dimer would be elevated?
age >50 years, recent surgery or trauma, acute illness, PREGNANCY or postpartum state, rheumatologic disease, renal dysfunction and sickle cell disease
What is the first line imaging modality in PE? Does it require contrast? What will the radiologist report find?
CTA
YES! requires IV contrast (need to order BUN/Cr before)
**positive filling defect
What are the cautions for a CTA?
pregnancy, metformin and allergy to contrast dye
What is the preferred imaging of choice for PE when a pt is pregnant? Name some additional indications.
V/Q scan
pregnancy, renal insufficiency or adverse reaction to contrast
When a PE is present, what will the V/Q results say?
PE is likely when there is reduced perfusion with normal ventilation
** _____ is the gold standard for diagnosing PE. When is it indicate?
pulmonary angiography
Indicated when there is high pre-test probability and inconclusive CTA results
____ and ____ are elevated in up to 25-50% of patients. What are they related to?
troponin and BNP
related to size of PE causing acute right ventricular myocardial stretch
**What are the MC EKG findings associated with PE?
sinus tachycardia
non-specific ST segment and T-wave changes affecting R precordial leads V1-3 +/- V4
S1Q3T3 pattern +/- new incomplete RBBB
**What are 2 rare CXR findings that are associated with PEs?
westermark’s sign and hampton’s hump
**______ is an area of lung oligemia, usually from complete lobar artery obstruction
Westermark’s sign
**______ is a dome-shaped dense opacification in the periphery of the lung - indicative of pulmonary infarction
Hampton’s hump
Why is a lower extremity venous doppler ordered?
to look for evidence of DVT and helps to determine the etiology of the PE
What qualifies as a high risk PE?
hypotension (SBP < 90 mmHg for > 15 minutes)
drop in SBP > 40 mmHg below baseline
hypotension requiring vasopressors
causing a cardiac arrest
What qualifies as an intermediate risk PE?
Hemodynamic stability with signs of R sided heart strain/dysfunction via CTA, echo, elevated troponin or BNP.
aka right heart strain
What qualifies as a low-risk PE?
Normotension without signs of right ventricular dysfunction
aka no signs of right heart strain