8. Pulmonary Embolism Flashcards
A pulmonary embolism (PE) is a ___
partial or complete obstruction of the pulmonary capillary bed by a blood clot or another substance such as fat, air, amniotic fluid, or a foreign material, with a disruption of blood flow to an area of the lung.
Massive PE
> 50% occlusion
Submassive PE
< 50% occlusion
80 - 90% result from ___
DVT
Although a pulmonary embolism may be the result of a variety of causes, ____
venous thromboembolism (VTE) is the primary cause. VTE and a fat embolism are the 2 types of embolism that are most likely to be covered on exam. Refer to Table 4-12 for the risk factors for VTE and Figure 4-13 for the pathophysiology of PE.
Strong Risk factors for VTE
-Fracture (hip or leg)
-Hip or knee replacement
-Major trauma
-Spinal Cord injury
Moderate Risk Factors for VTE
-Arthroscopic knee surgery
-Central venous lines
-Chemotherapy
-HF or Resp Failure
-Hormone Replacement Therapy
-Malignancy
-Oral contraceptives
-Stroke
-Pregnancy, postpartum
-Previous VTE
Weak Risk Factors for VTE
-Bed rest > 3 days
-Prolonged sitting
-Increasing age
-Laparoscopic surgery
-Obesity
-Pregnancy, antepartum
-Varicose veins
Pathophys of PE
Clot in Pulmonary Vasculature
–>decreased perfusion of blood
–>Local release of biochemical substances
–>Local lung constriction
–>Atelectasis
–>Pulmonary infarction (not fatal)
or
Clot in Pulmonary Vasculature
–>decreased perfusion of blood
–>V/Q mismatch
–>decreased pulmonary perfusion
–>If pulmonary perfusion < 50%
–>Pulmonary artery pressure increases
–>Right Ventricle Failure
–> decreased cardiac output, BP
(may be fatal)
Signs and symptoms of most PEs
-Dyspnea, Tachypnea
-tachycardia, chest pain
-Right-sided S3 or S4 heart sounds
-Anxiety, apprehension
-Cough, hemoptysis, crackles
-syncope
-Petechiae (fat emboli)
-low-grade fever
-respiratory alkalosis
-positive D-dimer
Signs and symptoms of Massive PEs
-Hypoxemia
-Hypotension
-EKG changes - RBBB, Right axis deviation on the ECG,
tall peaked P-waves in lead II, RV strain
pattern, ST elevation in V1 & V2
-Cardiopulmonary arrest – PEA
-Elevated BNP (due to right ventricular wall stress)
Types of PE
*Venous thromboembolism - DVT
*Fat emboli - long bone, pelvic fx
-Air emboli - surgery, IV lines
-Catheter embolization
-RA/LA or RV embolus - AFib/flutter (left atrial leading to
stroke is more common)
-Amnioti fluid embolism (rare) - amniocentesis, abruptio
placenta, or abortion
-Tumor emboli - malignancy causes an increase in
thrombin
-Septic emboli - bacterial/viral
Diagnosis of PE
-Pulmonary angiography - GOLD STANDARD
-V/Q Scan: “high” probability , “low” probability, not
definitive
-High-speed CT scan
-D-dimer: good rule-out test: if positive, it means that a clot is present in the body; therefore if symptoms ARE due to PE, expect a D-dimer to be positive
-Venous Doppler (helps with source)
Note: ~2/3 of PE never get
diagnosed!
- A PE will increase
alveolar dead space **
