Pulmonary Embolism Part 1 Flashcards
— refers to the obstruction of the —– or one of its branches by a —- (or thrombi) that originate(s) somewhere in the — or in the —.
Pulmonary embolism (PE), pulmonary artery, thrombus, venous system, right side of the heart
Most commonly, PE is due to a
dislodged or fragmented DVT
other types of emboli that may be implicated:
air, fat, amniotic fluid, and septic
PE is describe as an —- of the outflow tract of the main pulmonary artery or of the — of the pulmonary arteries
occlusion
bifurcation
Multiple small emboli can lodge in the terminal pulmonary arterioles, producing
multiple small infarctions of the lungs
pulmonary infarction causes — of part of the lung
Ischemic necrosis
When a thrombus completely or partially obstructs a pulmonary artery or its branches, the
alveolar dead space is increased
a reaction that compounds the ventilation–perfusion (V./Q.) imbalance that ensues.
increase in pulmonary vascular resistance
hemodynamic consequences
increased pulmonary vascular
resistance
The hemodynamic consequences are increased pulmonary vascular resistance due to the
regional vasoconstriction and reduced size of the pulmonary vascular bed.
When the work requirements of the right ventricle exceed its capacity, right ventricular failure occurs, leading to a
decrease in cardiac output
decrease in systemic blood pressure
development of shock
Clinical manifestations
depend on the size of the thrombus and the area of the pulmonary artery occluded by the thrombus.
*Nonspecific
*Dyspnea
*Chest pain
*anxiety
*fever
*tachycardia
*apprehension
*cough
*diaphoresis
*hemoptysis
*syncope
*Tachypnea
Obstruction of the pulmonary artery can result
pronounced dyspnea
sudden substernal pain
rapid and weak pulse
shock
syncope
sudden death
is the most frequent symptom; the duration and intensity of the — depend on the extent of embolization.
Dyspnea
is common and is usually sudden and pleuritic in origin; however, it may be substernal and may mimic angina
Chest pain
The most frequent sign is
Tachypnea
In many instances, PE causes few signs and symptoms, whereas in other instances, it mimics various other
cardiopulmonary disorders
Assessment and Diagnostic Findings
Initial:
*Chest x-ray
*ECG
*Pulse oximetry
*ABG analysis
*D-dimer assay
*MDCTA/pulmonary arteriogram/V./Q. scan
is usually normal but may show infiltrates, atelectasis, elevation of the diaphragm on the affected side, or a pleural effusion. It is most helpful in excluding other possible causes.
Chest x-ray
most frequent ECG abnormality is
Sinus tachycardia
nonspecific ST-T wave abnormalities
If an arterial blood gas analysis is performed, it may show
Hypoxemia and hypocapnia
may be normal even in the presence of PE
ABG measurements
is the criterion standard for diagnosing PE
MDCTA
can be performed quickly and provides the advantage of high-quality visualization of the lung parenchyma
MDCTA
is considered a reasonable alternative diagnostic method if MDCTA is not available
Pulmonary angiography
allows for direct visualization under fluoroscopy of the arterial obstruction and accurate assessment of the perfusion deficit.
Pulmonary angiogram
continues to be used to diagnose PE, especially in
facilities that do not use pulmonary angiography or do not have access to MDCTA
V./Q. scan
is minimally invasive and requires IV administration of a contrast agent
V./Q. scan
This scan evaluates different regions of the lung (—-) and allows comparisons of the percentage of V./Q. in each area
upper, middle, lower
This test has a high sensitivity but is not as accurate as an MDCTA or pulmonary angiogram
V./Q. scan
Medical Mgt revolves around whether the patient is diagnosed with a
hemodynamically unstable PE (also called a massive PE) or a stable PE.
hemodynamically unstable PE, which comprises a life-threatening emergency, may evidence
hypotension
tachycardia
confusion
cardiovascular collapse
Medical Management of Unstable Pulmonary Embolism
*stabilize the cardiopulmonary system
*Emergent measures
*Thrombolytic therapy with t-PA
*surgical embolectomy
*inferior vena cava (IVC) filter
A sudden increase in pulmonary resistance increases the work of the right ventricle, which can cause
acute right-sided heart failure with cardiogenic shock
are initiated to improve respiratory and cardiovascular status
Emergent measures
After emergency measures have been initiated, the treatment goal is to — the existing embolus and prevent new ones from forming
Lyse (dissolve)
is used in treating unstable PE, particularly in patients who are severely compromised (hypotensive & Hypoxemia)
Thrombolytic therapy with t-PA or other agents such as RETEPLASE
lyses the thrombi or emboli quickly and restores hemodynamic functioning of the pulmonary circulation, thereby reducing pulmonary hypertension and improving perfusion, oxygenation, and cardiac output.
Thrombolytic therapy
Contraindications to thrombolytic therapy include having
*had a stroke within the past 2 months
*other active intracranial processes
*active bleeding
*surgery within 10 days of the thrombotic event
*recent labor and delivery
*trauma
*severe hypertension.
Significant in thrombolytic therapy
Risk for bleeding
These are obtained Before thrombolytic therapy is started
INR
aPTT
hematocrit
platelet
is stopped prior to administration of a thrombolytic agent
Any anticoagulant
During therapy, all but essential invasive procedures are avoided because of
Potential bleeding
Is initiated After the thrombolytic infusion is completed (which varies in duration according to the agent used),
maintenance anticoagulation therapy
is rarely performed but may be indicated if there are contraindications to thrombolytic therapy
Surgical embolectomy
can be performed using catheters or surgically.
Embolectomy
Surgical removal must be performed by a
cardiovascular surgical team with the patient on cardiopulmonary bypass
May be inserted for patients who have recurrent PE despite therapeutic anticoagulation,
inferior vena cava (IVC) filter
are not recommended for the initial treatment of patients with PE and should not be used in patients receiving anticoagulants
IVC filters
provides a screen in the IVC, allowing blood to flow unobstructed while large emboli from the pelvis or lower extremities are blocked or fragmented before reaching the lung.
IVC filter
