RT 132 Pulmonary Embolism and Infarction

Terms in this set (44)

Question 1
Define and contrasts thrombosis and embolisms and how they are formed
-Embolus occurs when a blood clot (thrombus) becomes dislodged from veins elsewhere in the body. Blood clot most common source
-Thrombus moves into the pulmomnary arterial circulation: Embolizes
-Thromus is a blood clot, moving is embolism
Question 2
Describe how an embolism travels and where it may lodge
-fragments or detatched thrombosis that occlude a vessel: emboli
-Travels from their point of origin thru bloodstream
-Lodges in another site
-Emboli may be partial or a whole thrombus
-May occur from : Large thrombus, shower of small thrombi
May or may not interfere with right side of heart's ability to perfuse the lungs adequately
Question 3
What could occur if an embolism significantly disrupts pulmonary blood flow?
-Pulmonary infarction. Area of tissue of the lung undergoes necrosis following cessation of blood supply
Question 4
Describe the anatomic alterations that will occur if narcosis occurs following cessation of blood flow to the lung
-Pulmonary infarction can cause alveolar atelectasis
-Interferes with surfactant production
-Hypoventilated alveolus due to pulmonary infarct
-PAO2 near 40 mmHg (clinical manifestation)
-Consolidation
-Tissue necrosis
-Bronchial constriction is rare but could occur
Thrombosis
-Stationary blood clot
-From vein or artery
-Impedes normal circulation
-Most likely formation spot : artery containing fatty deposits, plaques
What can a emboli be composed of?
-Although blood clots are most common. May be composed of debris, cholesterol, air or fat from marrow of fractured bones (solid, liquid or gas)
Question 5
What is the prognosis if an embolism lodges in the pulmonary artery?
-Often fatal. 50,000 americans die of PE annually, 1/3 die in first hour
Question 6
Describe "Saddle embolus"
-When large thrombus embolizes to right side of heart could lodge in the bifurcation of pulmonary artery
-Pulmonary infarction
Question 7
What is the most common cause of maternal death after a live birth?
Pulmonary embolism
Question 8
In overall cases, what percentage of PE are not diagnosed?
-Diagnosis missed in about 70 - 80% of overall cases
Found during autopsy
Question 9
What clinical signs should always raise the question of the possible diagnosis of PE?`
-Dyspnea, Tachypnea, chest pain = classic triad
-Sense of impending doom
-These signs occur in less than 20% of the cases
Question 10
Where do thrombi that cause the most PE's most commonly originate from?
-Blood clots from venous thrombosis
-Most originate from deep veins in lower part of body:
Leg and pelvic veins and hip
Inferior vena cava
Question 11
List and describe the sources of PEs
-Fat particles
-Air
-Amnionic fluid
-Bone marrow
-Tumor Fragments
Question 12
Define DVT and describe its significance in relation to pulmonary embolisms
Deep vein Thrombus: thrombus breaks lose in deep vein
-Usually in lower lef
-Pain noted in this area
-Hot and swollen
-Clot carried through the venous system: right atrium and ventricle
-Lodges in pulmonary arteries or arterioles: pulmonary embolism
How long does it generally take for pulmonary embolism to occur once it originally dislodges?
-This can happen hours or even days after the formation of a clot in the calf veins. It may cause chest pain and shortness of breath
Virchow's Triad
Reference three primary factors associated with formation of DVT
-Venous stasis: slowing or stagnation of blood flow through venins
-Hypercoagulability: Increased tendency of blood to form clots
-Injury to the endothelial cells lining vessels
Question 13
List and describe the risk factors for developing a PE
-Venous stasis
-Trauma
-Hypercoagulation disorders
-Smoking
-Pregnancy
What is venous stasis?
-Prolonged bed rest or immobilization
-Prolonged sitting during travel: car, plane, CHF
-Varicose veins
-Thrombophlebitis
Question 14
Define Thrombophlebitis
-Inflammation of a vein
-Caused by or associated with formation of a blood clot
-Increase circumference of the calf
Trauma causing PE
-Bone fractures: pelvis, long bones of lower extremities
-Extensive soft tissue injury
-Postoperative or postpartum states
-Extensive hip or abdominal operations
-Phlegmasia alba dolen puerperarm:
Thrombophlebitis in pelvic veins leading to thrombus in veins of legs
Acute edema especially of leg from venous obstruction usually a thrombosis
Called Milk leg of pregnancy
Types of emboli
-Granuloma: cottom fiber embolus, carelessly wiped needles
-Mustard seed emboli: contaminated heroin
-air emboli: Inadvertantly introduced during IV injection
-Bone marrow embolus: fracture after bone surgery
-Fat emboli: fracture after bone surgery
-amniotic fluid embolus: rare, after difficult labor
Hypercoagulation disorders causing PE
-Oral contraceptives
-Polycythemia
-Multiple myeloma
-Factor V Leidne Mutation: Protein lacking to interact with Factor V, Genetic cause of blood clots,
-Other: obesity, pregnancy, burns, smoking
What are the vital signs of someone with a PE?
-Increased HR: due to hypoxemia/fear/pain
Tachycardia: due to increased rate of lung inflation
-Systemic hypotension: reduced cardiac return and decrease in left ventricular output
-Cyanosis
-Cough and hemoptysis
-Peripheral distention: distended neck veins, swollen and tender liver
-Decreased chest expansion
-Syncope, lighheadedness, confusion:
-Abnormal heart sound
-Crackles, wheezes, pleural friction rub
Why do you become lightheaded and confused during PE?
-Blood flow to brain is diminished
-Due to left ventricular output and systemic BP decreased
Hypoxemia with Pulmonary Embolus
- blood flow reduced or absent distal to obstruction
-Ventilation beyond obstruction is:
Waste or dead space ventilation
No gas exchange occurs( no perfusion)
V/Q ratio high (increased ventilation to perfusion)
In response to a PE a pulmonary infarction may occur
-Condition of dead space reverses eventually
-Causes atelectasis, consolidation and necrosis
-Decreased V/Q ratio occurs
-Bronchial constriction occurs(secondary)
Decreased alveolar ventilation relative to perfusion
Causes pulmonary shunting and venous admixture
-Results in decreased PaO2 and PAO2
What are the ABG of PE?
-Mild: Acute hyperventilation with hypoxemia: increased pH, decreased PaCO2, HCO3(slightly), PaO2
-Severe: Pulmonary embolism and infarction=acute ventilatory failure with hypoxemia: decreased pH, increased PaCO2, HCO3, decreased PaO2
What is the gold standard test for PE?
-Pulmonary Angiogram
Question 15
List and contrast the various diagnostic procedures used for diagnosis of PE and infarcts and list their distinguishing factors
-Chest xray
-EKG
-Ventilation / Perfusion scan (V/Q scan)
-Fast computed tomography scan(CT)
-Pulmonary angiogram
-Fibrinogen test
-Extremity venography
-Duplex ultrasonography (DUS)
-Magnetic Resonance imaging (MRI)
Chest xray with PE
-Often normal
-May be used to rule out : pneumonia and pneumothorax
-May visualize infiltrate or atelectasis or elevated hemi diaphragm
-Increased density in infarcted area: similar to pneumonia
-Hyperradiolucency distal to embolus: Westermarks sign decreased vascularity
-Pulmonary edema: common following fat embolism
-Cor pulmonale may be present
Electrocardiogram with PE
Due to the obstruction of pulmonary blood flow EKG may show:
-Nonspecific ST-T wave changes
-Sinus tachycardia is most common rhythm disturbance: may be in relationship to cor pulmonale. Arterial fibrilation or flutter
-P-pulmonale: Peaked P waves
-NO significant EKG pattern diagnostic of PE
Ventilation / Perfusion scan for PE
-Confirms lungs are normal or there is a high probability of PE: Only reliable in extremes
-Starting to be used less due to more sophisticated testing
-Breathes small amount of radioactive gas
Fast computed tomography scan (CT scan) and PE
-Spiral (Helical) CT scan
-1st choice test for patients suspected of having a pulmonary embolism but not gold standard
-relatively fast and less invasive than a V/Q scan
-eliminates need for invasive pulmonary catheterization
Pulmonary Angiography for PE
-Gold standard test
-Provides a clear image of blood flow in the lung's arteries
-Extremely accurate test to diagnose PTE: invasive and time consuming
-Catheter advanced through right side of heart into pulmonary artery
-Radioopaque dye rapidly injected into pulmonary artery: serial roentgenograms are taken
-PE confirmed by abnormal filling within artery or a cut off at the artery
Dark area appears on the angiogram distal to the embolism
Radioopaque dye is prevented from flowing past obstruction
How do you detect a blood clot in a vein?
Venous Thromboembolism(VTE)
Fibrinogen test
-Increased levels of protein fibrinogen
Component of the blood clotting process
Normal results more significant than abnormal: many conditions increase it
Normal will rule out VTE
Used to supplement other diagnostic tests
Extremity Venography
-Complex and invasive
-Catheter into vein of arm or leg
-Contrast dye injected into vein: makes it visible on xray
-Can dectect DVT: has been replaced by duplex ultrasonography
Duplex Ultrasonography (DUS)
-Noninvasive
-High frequency sound waves to detect blood clots in thigh veins
-Painless
-30 minutes
-Sensitive to detect DVT above the knee: insensitive below the knee
Magnetic Resonance Imaging (MRI)
-Used for individuals whose kidneys may be harmed by dyes
-women who are pregnant
Question 17
In sequence, describe the general care of a patient that presents with or is suspected of, having a pulmonary edema
-Admit to hospital
-Oxygen
-Fast acting Anticoagulant: prevents existing clots from growing and stops new clots from forming. Heparin
-Follow with a slow acting anticoagulant: Warfarin(oral)
Coumadin
Inactivates vitamin K clotting factors
Monitored by prothrombin time (PT)
-Do not give aspirin or other antiinflammatory drugs (advil, motrin) if alrealdy on above meds
Question 18a
Identify and differentiate between types of HEPARIN and Thrombolytic agents
Heparin
-Unfractionated heparin IV
was main therapy, frequent monitoring, bleeding
monitored by partial thromboplastin time PTT
-Recent and now more currently used
Low molecular weight heparin (LMWH)
Given subcuatanous: lovenox
Shown to be safer and more effective
Prophylaxis of DVT and PE
cost effective
-Both inhibit platelet aggregation but does not dissolve clots
Question 18b
Identify and differentiate between types of Heparin and THROMBOLYTIC agents
Clot Busters --- dissolves clots
Beneficial in treating PE
-Fibrinolytic agents: destroys fibrin and blood clots
Natural resolution from out own body could occur - fibrinolysis
Streptokinase
Tissue plasminogen activator (enzyme)(TPA)
Limited use due to risk of bleeding
-Tissue plasminogen activators
activase - alteplase
-May be used in conjuction with heparin
Question 19
List and contrast the preventative measures used to decrease the incidence of pulmonary embolisms
-Graduated compression stockings - tight fitting elastic stocking
Squeeze patients legs
Helps veins and leg muscles move blood efficiently
Safe, simple and inexpensive
Utilized in DVT pathway
Heparin much more effective if used with stocking
-Greenfield Filter: placed in inferior vena cava to catch clots
Question 20
Describe what a greenfield filter is used for
-Its a filter that is placed in the inferior vena cava to keep clots from moving into pulmonary artery
What are respiratory care protocols for someone with a pulmonary embolus?
-Oxygen: wasted dead space ventilation, may be refractory to oxygen
-Aerosolized medication protocol: rarely needed (bronchodilator)
-Mechanical ventilation:acute ventilatory failure
-Last resort: surgical removal of blood clots: high mortality rate
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