ch 20 pulmonary embolism

Question 1

definition of pulmonary embolism

Answer 1

obstruction of the pulmonary artery or one of its branches

Question 2

what is an embolus

Answer 2

clot that travels through the bloodstream from its vessel of origin to lodge in smaller vessel obstructing flow

Question 3

possible sources

Answer 3

fat, air, bone marrow, tumor fragments, blood clots

Question 4

what is the most common source of emboli

Answer 4

blood clot

Question 5

where does it usually orgiinate

Answer 5

in deep veins of leg or pelvic area

Question 6

where does the emboli travel to

Answer 6

back to heart through the venous system and lodges in pulmonary artery

Question 7

why does a clot usually form

Answer 7

stagnation of blood flow, prolonged bed rest, immobility from trauma, surgery, paralysis, or pain

Question 8

examples of predisposing factors

Answer 8

long travel
CHF
varicose veins
thrombophlebitis
traumatic injury

Question 9

in terms of traumatic injury what should be looked at carefuilly

Answer 9

bone fractures from pelvis and long bones of lower extremities and extensive injury to soft tissure

Question 10

hyper coagulation disorders that cause embolism

Answer 10

oral contracetpives, polycythemia, multiple myeloma

Question 11

what does the blockage result in

Answer 11

dead space ventilation (ventilation w/o perfusion)

which causes a high v/q mismatch

Question 12

what causes high v/q mismatch

Answer 12

dead space

Question 13

what causes low v/q mismatch

Answer 13

shunt

Question 14

what is the initial v/q ratio response and what does it lead to

Answer 14

a high ratio is initial and it leads to low v/q mismatch

Question 15

what causes the change from high to low v/q mismacth

Answer 15

activation of serotonin, histamine, and prostaglandin

Question 16

what is caused by the release of serotonin, histamine, and prostaglandin

Answer 16

alveolar atelectasis, alveolar consolidation, bronchoconstriciton, shunting

Question 17

what causes approx 10% of cases

Answer 17

infarction

Question 18

what dictates the pathophysiology

Answer 18

size of thromboembolism

Question 19

what determines the impact on the cardiovascular system

Answer 19

size and number of pulmonary embolism

Question 20

where is the reduction of cardiac output seen

Answer 20

on the systemic side

Question 21

what heart effects are seen in pulmonary side

Answer 21

pulmonary hypertension and increased right ventricular workload

Question 22

what heart effects are seen in systemic side

Answer 22

systemic hypotension from decreased blood flow entering left ventricle

Question 23

how does the body attempt to compensate for the systemic side

Answer 23

increased heart reate

Question 24

what are the most common symptoms of pulmonary embolism

Answer 24

dyspnea
tachypnea
pleuritic c'est pain
cough
tachycardia
hypotension

Question 25

additional findings include

Answer 25

abnormal heart sounds distended neck veins swollen and tender liver right ventricular heave or lift and distention

Question 26

chest ausculation

Answer 26

inspiratory crackles and wheezes | pleural friction rub

Question 27

when is pleural friction rub most common

Answer 27

when pulmonary infarction involves the pleura

Question 28

what is seen in mild to moderate pulmonary emboli ABG

Answer 28

acute alveolar hyperventilation with hypoxemia

Question 29

what is seen in severe pulmonary embolism with infarction

Answer 29

acute ventilatory failure with hypoxemia

Question 30

what happens when tissue hypoxia is severe enough to produce lactic acid

Answer 30

the pH and HCO3 will be lower than expected for a particular paco2

Question 31

increased or decreases shunt fraction qs/qt

Answer 31

increased

Question 32

i/d oxygen delivery

Answer 32

decreased

Question 33

i/d oxygen extraction ratio

Answer 33

increased

Question 34

what is normal oxygen extraction ratio

Answer 34

normal

Question 35

i/d svo2

Answer 35

decreased

Question 36

i/d central venous pressure (cvp)

Answer 36

increased

Question 37

i/d pulmonary artery pressure (pap)

Answer 37

increased

Question 38

what is normal pulmonary artery pressure

Answer 38

no greater than 25/10 mmhg

Question 39

what is normal mean pulmonary artery pressure

Answer 39

15 mmhg

Question 40

what is normal mean pulmonary artery pressure for patients with the embolism

Answer 40

excess of 20mmhg

Question 41

what are the 3 major mechanisms that contribute to pulmonary hypertension

Answer 41

1. decreased cross sectional area of the pulmonary vascular system 2. vasoconstriction induced by humoral agents 3. vasoconstriction induced by alveolar hypoxia

Question 42

are there specific findings for pulmonary embolus in x-ray

Answer 42

no

Question 43

if there is infarction what is seen in xray

Answer 43

increased alveolar density in infarcted areas, appearing similar to pneumonia

Question 44

what may happen to X-ray with cardiovascular response

Answer 44

dilation of pulmonary artery & right ventricular enlargement may cause X-ray to appear similar to pulmonary edema

Question 45

what is a ventilation test

Answer 45

patient breaths in xenon gas to test ventilation

Question 46

what is perfusion test

Answer 46

intravenous injection of radiolabled particles (iodine or technetium) goes through right heart into pulmonary vascular system. if blood flow is decreased or absent past embolus fewer particles are present in that area

Question 47

what is the gold standard used to confirm the presence of pulmonary embolism

Answer 47

pulmonary angiography

Question 48

what is a pulmonary angiography

Answer 48

catheter is advanced into right heart and radio opaque die is injected into artery and X-rays are taken

Question 49

how is a pulmonary embolism confirmed with pulmonary angiography

Answer 49

dark area appears on angiogram distal to emboli bc radiopaque material is prevented from flowing past obstruction

Question 50

does this procure have risks

Answer 50

none unless: 1. severe pulmonary hypertension greater than 45mmhg 2. patient is in shock or allergic to contrast medium

Question 51

what is the best treatment

Answer 51

prevention by avoiding venous stasis

Question 52

what are other ways to treat with prevention

Answer 52

low - dose heparin given subcutaneously tightfitting stockings pneumatic stockings or boots active or passive leg movements

Question 53

when are fibrinolytic agents only used and why

Answer 53

due to excessive risk of bleeding they are only used when hemodynamic instability is severe

Question 54

respiratory care treatment protocols

Answer 54

oxygen therapy aerosolized medications mechanical ventilation