Pulmonary Embolus Flashcards
What is the definition of pulmonary embolism
Common, serious, and potentially fatal complication of thrombus formation within the deep venous circulations
What conditions are “two manifestations of the same disease process”
- Pulmonary embolism
- Deep venous thrombus
What is the estimated annual incidence of PE in the US
300,000 cases
*most cases not disposed antemortem
*less than 10% of patients with fatal PEs had treatment for them
*90% did not
What is the mortality rate for patients with PE who did not receive treatment
30%
What must you do when suspecting someone with a PE
Be vigilant, have a systematic approach for understanding risk factors, diagnosis, and to begin therapy
*do not miss diagnosis
What are accurate diagnosis and effective therapy do for mortality rates?
Effective therapy (anti coagulation)
*Will be a reduction in mortality rate 2-8% (vs 30%)
What is Virchows triad
- Venous stasis
- Injury to vessel wall
- Hypercoagulability
*causes for PE
What are the risk factors for PE (THROMBOSIS)
T: trauma, travel, thromnopillia
H: hypercoagulable state, hormone replacement therapy
R: recreational drugs
O: old age
M: malignancy
B: birth control pills
O: obesity
S: surgery
I: immobilization, iatrogenic
S: serious illnesses
What is venous stasis and what can cause it?
Blood that is not flowing as it should
1. Immobility
*prolonged bed rest
2. Major surgery
3. Increased central venous pressure
*pregnancy
*low cardiac output states
4. Hyper-viscosity/hematologic disorder
*polycythemia
What are some causes of “injury to (vessel) wall”
- History of DVT
- Orthopedic surgery
- Trauma
- Central venous catheters
- Chemotherapeutic agents
What can cause hypercoagulability (acquired)
- Medications
*oral contraceptives
*hormone replacement therapy - Pregnancy
- Dehydration
- Nephrotic syndrome
- Sepsis
What types of cancers can cause hypercoagulability (acquired)
Highest risk
*adenocarcinoma
*pancreas
*prostate
*breast
*ovary
Intermediate risk
*lung
*GU
*colon
What can cause hypercoagulability (inherited)
- Most common inherited cause factor V Leiden
- Methylenetetrahydrofolate reductase (MTHFR) deficiency
- Protein C, S deficiency
What is factor V Leiden deficiency
- Causes resistance to activated protein C
*protein C inactivates factor V
*patients are more likely to clot - Seen in 20-40% of idiopathic venous thrombosis
What is MTHFR deficiency
- Most common genetic cause of elevated levels of homocysteine in plasma
What is the most common place for a PE to develop
- Thrombus from lower extremity deep veins
*proximal DVT up to 60% will have PE
*20% of calf veins can travel to popliteal and iliofemoral
**many substance can embolize, and travel to the luminary circulation
What are other things that can break off and become emboli
- Septic emboli (acute infections)
- Fat (long bone fractures)
- Amniotic fluid (Active labor)
- Air
- Foreign bodies
- Parasite eggs
Majority of patients with a symptomatic PE where has the DVT come from?
- 50-70% will have confirmed lower extremity DVT
*will get lodged in the pulmonary artery
*blood will get sticky and grow a clot, leading to occlusion
What is a PEARL of PE
- Documentation of a DVT in a patient with a suspected PE establishes need for treatment
*may preclude further diagnostics
What does a PE increase the likelihood of
- Acutely increases pulmonary vascular resistance
*physical obstruction of the vascular bed
*vasoconstriction from neurohumoral reflexes - Physiologic dead space results in hypoxemia
*due to right to left shunting, decreased cardiac output and surfactant depletion from atelectasis
What does a PE lead to
Increase in wheezing and in effort of breathing
*risk of acute RV failure (massive thrombus possible)
Where is a PE most likely to get stuck
- Right / left pulmonary artery
*if stuck in the bifurcation called a saddle
What are the signs and symptoms of aPE
Findings are fairly sensitive, not specific
1. Dyspnea
2. Painful inspiration
3. Tachycardia
4. Tachypnea
5. Pleuritic chest pain
6. Hemoptysis
What symptoms can a massive PE lead to
- Syncope
- Hypotension
- PEA
Why can diagnosing a PE be difficult
- Depends on the size of the embolus and the cardiopulmonary status of the patient
*pre-existing comorbidities greatly affect the PE’s S/sx - Signs are non-specific
*no single symptoms or sign or combination of clinical findings is specific findings is specific to confirm a PE
What must you do the diagnosis a PE
- Must establish pre-diagnostic study probability
What is an initial approach to diagnose a PE
- Use clinical likelihood of pulmonary embolus or venous thromboembolism derived from clinical prediction rule and results of diagnostic tests
What are the three type of decision that can be made about the diagnosis of a PE
- Confirmed venous thromboembolism
*either DVT or PE - Exclude venous thromboembolism with enough evidence and the patient may discontinue anticogaultion
- Additional testing needed for confirmation
What happens when a patient has a score of <4 and meets ALL of the following criteria
- Age <50
- HR <100bpm
- Oxyhemoglobin saturation on room air >95%
- No prior history of venous thromboembolism
- No recent trauma or surgery requiring hospitalization
- No presenting hemoptysis
- No estrogen therapy
- No unilateral leg swelling
*PE can be excluded (low risk PT)