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RESP 5017 > 5. Pulmonary Disorders Part 2 (PPHN, MAS, CDH) > Flashcards

5. Pulmonary Disorders Part 2 (PPHN, MAS, CDH) Flashcards

1
Q
  1. what is PPHN?
  2. why does this occur?
  3. does the high PVR affect respiration?
  4. what age does this disease affect?
A
  1. failure of the systemic circulation and pulmonary circulation to convert from fetal circulation to “normal” circulation
  2. due to an increased PVR, with R —> L shunt at the ductus arteriosus and/or foramen ovale in the absence of structural heart disease (normal transition from intrauterine life is disrupted)
  3. elevated PVR causes varying degrees of respiratory distress
  4. mainly term or late-preterm infants
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2
Q
  1. what helps to decrease PVR in normal pulmonary vascular transition? (hint: 11)
  2. at what point does PVR decrease dramatically? when does this continue to fall?
A
  1. expansion of the lung, clearance of fetal ;ung fluid, hyperoxic vasodilation, hypocarbic vasodilation, increase in pH, increase prostaglandin, increase nitric oxide, increase cyclic GMP, increase cyclic AMP, increase adenosine, increase bradykinin
  2. at birth, and continues to fall over next 6 weeks
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3
Q

what are the 3 mechanisms of action of PPHN? what can cause each one?

A
  1. abnormally constricted pulmonary vasculature –> due to parenchymal disease
  2. structurally abnormal pulmonary vasculature –> idiopathic persistent pulmonary hypertension (black lung PPHN)
  3. hypoplastic pulmonary vasculature –> congenital diaphragmatic hernia or pulmonary hypoplasia
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4
Q
  1. what parenchymal disorders cause pulmonary vasoconstriction?
  2. what is normal about the blood vessels? what is abnormal?
  3. what is impaired?
  4. what causes the vasoconstriction? (hint: 6)
  5. what can cause chemical vasoconstrictors to be released?
A
  1. MAS, RDS, pneumonia, sepsis
  2. normal structure but abnormal vaso-reactivity
  3. impairment of normal transition
  4. lung injury, collapse, consolidation, hypoxia, hypercarbic, acidosis
  5. lung injury and hypoxia
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5
Q
  1. what is structurally abnormal pulmonary vasculature also called?
  2. what happens to the vasculature? (hint: 3)
  3. what is lacked at birth?
  4. what may contribute to idiopathic PPHN?
  5. what is the problem with NSAIDS or SSRI’s?
  6. what would a CXR look like?
A
  1. idiopathic persistent PHTN
  2. significant remodeling of pulmonary vasculature, vessel wall thickening, smooth muscle hyperplasia
  3. lack normal pulmonary vasodilation at birth
  4. multiple pathways
  5. NSAIDS–> in utero cause constriction of ductus arteriosus and pulmonary vasculature remodeling
    SSRI’s–> late third trimester associated with PPHN
  6. clear, hyperlucent from lack of blood flow, oligemic “black lung”
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6
Q
  1. what can cause hypoplastic pulmonary vasculature?
  2. what happens during development? what is observed in CDH and hypoplasia?
    3 what is decreased in hypoplasia pulmonary vasculature? what is abnormal?
  3. what is the pulmonary vasoconstriction worsened by? (hint: 3)
A
  1. pulmonary hypoplasia and congenital diaphragmatic hernia
  2. pulmonary arterial system parallels development of the bronchial tree therefore, fewer branches are observed
  3. decreased cross sectional area of pulmonary vasculature and decreased pulmonary blood flow with abnormal muscular hypertrophy of pulmonary arterioles
  4. hypoxia, hypercarbia, and acidosis
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7
Q
  1. what age do we see presentation of PPHN? when does it present in life of a neonate?
  2. what does a CXR depend on?
  3. what is the pre and post ductal SpO2 difference?
  4. what are some clinical presentations/signs at birth? (hint: 8)
A
  1. term or post term, presents at birth within the first 12 hours of life
  2. depends on underlying cause
  3. difference > 10%
  4. respiratory distress, increased WOB, hypoxia, hypercarbia, acidosis, hypotension, tachycardia, enlarged liver
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8
Q

what can be used to diagnose PPHN? (hint: 9)

A

recognize risk factors, excluding other conditions (CHD, RDS, GBS, CDH), clinical picture, CXR dependent on cause, enlarged liver, SpO2 Pre > Post, echo, cardiac catheterization, response to treatment (pH, iNO)

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9
Q
  1. what do we want to avoid with treating PPHN? why?
  2. what may help if indicated?
  3. what do we want to prevent?
  4. what may help to reduce PVR? describe the 5 importance’s with this strategy.
  5. describe the ventilation strategy according to lung disease (hint; 4)
A
  1. avoid overexpansion of the lung as may worsen pulmonary hypertension because of over distention of alveoli and compression of capillaries
  2. surfactant therapy if indicated
  3. prevention and anticipation of PPHN
  4. oxygenation and ventilation (hyperoxia, SpO2 95%, hyperventilation, alkalosis, hyperventilation VS gentle ventilation with permissive hypercapnia)
  5. optimal lung volume (may need recruitment), conventional, HFOV/HFJV, iNO
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10
Q
  1. what other support may help to maintain systemic blood pressure?
  2. why is adequate sedation/paralysis important?
  3. what infusion may help severe metabolic acidosis?
  4. what else do we want to treat? (hint: 5)
  5. what do we want to make sure to decrease? (hint: 4)
  6. what other treatment strategies should we consider? (hint: 5)
  7. what vasodilators may be helpful?
A
  1. hemodynamic support
  2. stress response leads to catecholamine release which increases PVR and minimize fighting of ventilator
  3. sodium bicarbonate
  4. hypothermia, hypoglycemia, hypocalcemia, anemia and hypovolemia
  5. decrease stimulation, minimize handling, light and sound
  6. broad spectrum antibiotics, adequate nutrition, venous/arterial umbilical cord access, vasodilators, ECMO
  7. PGE2, prostacyclin, tolazoline, adenosine, sildenafil
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11
Q
  1. where is the shunting occurring in PPHN?
  2. what does it mean when shunting is protective?
  3. what does this shunting allow?
  4. where does this relieve pressure in the heart?
A
  1. PDA and foramen ovale
  2. if both close, RS of heart works harder against increased PVR which can cause HF causing a drop in C.O. and oxygenation/delivery to systemic circulation
  3. allows to maintain C.O. and some oxygen delivery to systemic circulation
  4. relieves pressure from the RV
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12
Q

what difference does a shunt at the FO vs PDA make? (this is very long and added it as I thought it was important:)

A 
PDA = deoxygenated blood to mix with oxygenated blood therefore, pre ductal supplying O2 to the right arm is BEFORE the shunting therefore, increase in O2 where as post ductal down to the feet is where mixing of blood HAS ALREADY OCCURED therefore, decrease in O2 saturation 
FO = shunting across FO does NOT cause a difference in pre or post ductal because shunting is occurring BEFORE mixing of blood therefore, drop in O2 pre and post ductal
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13
Q
  1. what is the equation for the oxygenation index?
  2. what is this equation useful for?
  3. what is considered stable? when should iNO be started? when should ECMO be considered?
A
  1. Oxygenation index = FiO2 x MAP/PaO2
  2. following illness and gives an idea of how sick the patient is
  3. < 10 = stable, > 25 = start iNO, > 40 = consider ECMO
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14
Q
  1. what is the incidence of meconium stained amniotic fluid (MSAF)?
  2. what does the risk increase with?
  3. what age infants do we see this?
  4. what is meconium aspiration syndrome (MAS)?
  5. how often does this occur from MSAF?
  6. what two situations can MAS occur?
A
  1. 10-20% of all deliveries
  2. risk increases with gestational age
  3. most often seen in term or post term infants
  4. aspiration of stained amniotic fluid before, during and after birth causing respiratory distress
  5. 2-6% of infants born through MSAF
  6. occur in utero or with initial postnatal breaths
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15
Q
  1. what is meconium?
  2. can you describe the material?
  3. what does meconium contain?
  4. where do the cells come form that are found in meconium?
  5. what is meconium a great medium for?
A
  1. earliest stools of an infant
  2. odorless, thick, blackish green material
  3. water (75%), with glycoproteins, lipids, and proteins
  4. GI tract, skin, hair, vernix, amniotic fluid, pancreatic enzymes, and bile
  5. great medium for bacterial growth
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16
Q
  1. what causes the passage of meconium in utero? (hint: 2)
  2. what can cause this to occur? (hint: 4)
  3. what does aspiration of meconium occur as a consequence of?
  4. can you describe the pathway of how meconium passage happens when the cause is vagal stimulation?
  5. can you describe the pathway of meconium aspiration when hypoxia is the cause?
A
  1. increased peristalsis and rectal sphincter relaxation
  2. spontaneously in term or post term fetus with mature GI, hypoxia, infection or vagal stimulation produced by hypoxia
  3. consequence of hypoxia-induced gasping
  4. Vagal stimulation –> peristalsis + rectal sphincter relaxation –> meconium passage
  5. hypoxia –> breathing in utero –> aspiration of MSAF into the lungs
17
Q
  1. what does meconium increase the risk of?
  2. who should be present at birth to help with this risk?
  3. what should be done when a baby is born through meconium-stained fluid?
  4. what is not suggested?
  5. what is suggested?
A
  1. baby will require resuscitation after birth
  2. an individual skilled in endotracheal intubation should be present at birth
  3. regular steps of NRP, and clear the mouth and nose of secretions
  4. routine intubation for tracheal suction not suggested
  5. editions of NRP recommended routine endotracheal intubation and suction immediately after birth in an effort to reduce the chance of developing meconium aspiration syndrome
18
Q
  1. how long does it take meconium to migrate to the peripheral portions of the lungs? what causes this to happen?
  2. what cells are responsible for clearing the meconium from the lungs? how long does this take?
  3. can you describe the MAS pathological changes? (hint: 5)
A
  1. 1-2 hours by spontaneous respiratory movements or PPV
  2. macrophages clear the meconium, takes 1-3 weeks
  3. airway obstruction, pulmonary vasoconstriction and persistent pulmonary hypertension, surfactant dysfunction, infection, chemical pneumonitis
19
Q
  1. what does a partial blockage (airway obstruction) do to the lungs? (hint:2)
  2. what phenomenon usually happens and what can this cause?
  3. what happens during the ball valve phenomenon?
  4. what does a complete blockage (airway obstruction) cause?
A
  1. increased airway resistance and hyperinflation
  2. ball valve phenomenon which can cause a potential for air leaks
  3. on inspiration, lower airways open so gas can go past the obstruction but on expiration, the lower airways collapse so air gets trapped and can’t get out
  4. atelectasis
20
Q
  1. what is the main factor that causes pulmonary vasoconstriction and persistent pulmonary hypertension?
  2. what accompanies this?
  3. what is PPHN caused by? (hint: 3)
A
  1. hypoxia induced pulmonary vasoconstriction
  2. accompanied by R –> L shunt through PDA and PFO
  3. muscle hypertrophy, thickening of pulmonary vessels caused by chronic intrauterine hypoxia
    - pulmonary vasoconstriction as a result of hypoxia, hypercarbia or acidosis
    - pulmonary vasoconstriction as a result of lung inflammation
21
Q
  1. what does meconium do to surfactant?
  2. what molecule in meconium causes this affect on surfactant?
  3. what molecule in meconium may affect surfactant? what does this do?
  4. what is the result of the lung from surfactant dysfunction?
A
  1. inactivates surfactant function
  2. free fatty acids in meconium have a higher surface tension than surfactant and may displace it form alveolar surface
  3. bile salts may inhibit surfactant synthesis
  4. diffuse atelectasis, decreased lung volume and poor compliance
22
Q
  1. what is meconium a good environment for?

2. how can infection present as? (hint: 3)

A
  1. good medium for enhancing bacterial growth

2. compound, lung inflammation and infiltrates

23
Q
  1. what is the pH of meconium?
  2. how does chemical pneumonitis affect the airway?
  3. what of meconium can cause a release of chemical mediators? what does this result in?
  4. what 3 things will we see with chemical pneumonitis?
A
  1. 7.10 to 7.20
  2. causes airway irritation
  3. enzymes and bile salts of meconium, resulting in diffuse chemical pneumonitis
  4. alveolar inflammation, edema and inflammatory mediators (circulating)
24
Q

what are the 5 lung characteristics resulting from chemical pneumonitis/MAS?

A
  • increased airway resistance (increase time constants)
  • poor compliance caused by atelectasis, inflammation and surfactant inactivation
  • areas of lung inflation (ball valve phenomenon) and collapse (complete obstruction/poor compliance)
  • intrapulmonary and extrapulmonary shunting
  • poor ventilation-perfusion ratios
25
Q
  1. what are the 3 factors that help to diagnose MAS?
  2. what else can help to further confirm this?
  3. where can “meconium staining” be seen on an infant?
  4. what may postmature infants have evidence of?
  5. what are other findings of MAS? (hint: 6)
  6. what are other clinical features associated with?
    (hint: 2)
A
  1. infant born through meconium-stained fluid, respiratory distress at birth or shortly after, positive radiographic features
  2. suctioning meconium from the ETT
  3. yellow-green stained fingernails, umbilical cord and skin
  4. peeling skin, long fingernails and decreased vernix
  5. tachypnea, retraction, grunting, barrel shaped chest, crackles and wheezes
  6. perinatal asphyxia and PPHN
26
Q
  1. what 3 major factors can be seen through radiographic findings?
  2. what does an increased risk for air leaks refer to?
  3. what are the classic radiological findings of MAS? (hint: 2)
A
  1. diffuse or local linear or patchy infiltrates, consolidation or atelectasis and areas of hyperinflation/underinflation
  2. pneumothorax or pneumomediastinum
  3. diffuse, coarse, patchy infiltrates that may alternate with areas of hyper expansion
27
Q
  1. what do we want to minimize when managing MAS? (hint: 3)
  2. what other support should be provided? why?
  3. with conventional ventilation, what two things should be considered to help clear meconium?
  4. what should be considered when using HFJV?(hint:2) how does HFJV help?
  5. what should we be aware of with HFOV? (hint:2)
  6. what other 3 things should be considered for managing MAS?
A
  1. hypoxia, hypercarbia and acidosis
  2. cardiovascular support to ensure systemic blood pressure and C.O.
  3. long expiratory times and adequate PEEP
  4. low jet rate for prolonged expiratory time and adequate PEEP. The jet functions to help remove meconium.
  5. beware of ball valve effect and risk for air leaks
  6. iNO, appropriate sedation +/- paralysis, treatment of PPHN
28
Q
  1. what are the two ways you can give surfactant therapy?

2. how is a surfactant/normal saline lavage done? what is the goal?

A
  1. replace surfactant inactivated by meconium or surfactant/normal saline lavage
  2. 1/2 surfactant and 1/2 normal saline is instilled then suctioned, followed by surfactant replacement dose and can continue to repeat lavage
    Goal is to clear meconium from the airways and alveoli
29
Q
  1. CDH occurs 1 in every how many births?
  2. what is a left side CDH called? what herniates? what percentage of neonates develop this?
  3. what is a right sided CDH called? what herniates? what percentage develop this?
  4. which CDH has the highest mortality?
  5. are bilateral defects common? what is the fatality?
  6. what percentage of CDH patients have a congenital heart defect? what about chromosomal abnormality?
  7. what percentage of newborns present after newborn period with CDH?
A
  1. 1 in every 2500-5000 births
  2. foramen of Bochdalek where the small and large bowel herniate, 90% of CDH
  3. foramen of Morgagni, where the liver and portion of the large bowel herniate, 10% of CDH
  4. right sided CDH has higher mortality rates
  5. not common, usually fatal
  6. 20% have congenital heart defect, 5-16% have chromosomal abnormality
  7. small amount of patients
30
Q
  1. what week during gestation is the diaphragm developed? what causes this to form?
  2. what happens if this fails to close?
  3. what does this diaphragmatic defect allow? what structures is developing during this time?
  4. what causes greater effects on the developing lung?
A
  1. 8th-10th week gestation, caused by the fusion of the pleura in the chest and peritoneum in the abdomen
  2. abdominal content will herniate into the pleural cavity
  3. allows abdominal organs (intestines, stomach, liver and spleen) to herniate into chest cavity at a critical stage during the time of bronchial and pulmonary artery branching
  4. larger defects and earlier herniation
31
Q
  1. when is an ultrasound done to observe if CDH is present? what can be seen during an ultrasound?
  2. what other additional findings can be seen?
  3. what predictors of fetal lung volume help to calculate severity and outcome?
A
  1. 16-24 weeks, with left sided CDH - fluid filled stomach within the lower thorax and with right sided CDH - more difficult to diagnose because liver has similar density to fetal lungs
  2. polyhydramnios, small abdominal circumference, mediastinal or cardiac shift away from the side of hernia
  3. Lung to head ratio (LHR) - measurement of other lung in comparison with head circumference, providing an indirect assessment of degree of pulmonary hypoplasia and severity
    - three dimensional ultrasonography, MRI, evaluation of extend of herniated abdominal contents
32
Q
  1. what is a fetal tracheal occlusion? what does this help to do? (hint: 2)
  2. when is this surgical intervention performed?
  3. when during gestation is the tracheal balloon removed?
A
  1. intratracheal balloons placed by fetoscopy
  2. trap fetal fluid in the lung and increase lung growth and lung growth is stimulated as retained fetal lung fluid provides gentle distention of lung tissue
  3. severe defects due to good outcomes in less sever defects without added risk of fetoscopy and potential for preterm delivery
  4. 36 weeks gestation
33
Q
  1. how does an infant present with CDH? (hint: 6)
A
  • scaphoid abdomen and barrel chest
  • respiratory distress –> tachypnea, cyanosis, retractions, hypercarbia and acidosis
  • mediastinal shift towards unaffected side
  • shift of heart sounds
  • decrease breath sounds to the affected side
  • possible bowl sounds in chest
34
Q
  1. why does CDH cause pulmonary hypoplasia? (hint: 4)
  2. why does CDH cause pulmonary hypertension? (hint: 2)
  3. why is reduced lung compliance present? (hint: 1)
  4. what is there a risk for with CDH? (hint: 4)
A
  1. compression during development, fewer bronchial generation and alveoli, lung volumes reduced as much as 50%, hypoplastic lungs contain fewer airways, vessels and alveoli
  2. anatomic reduction in capillary number, pulmonary artery hypertrophy, precipitated by hypoxia, hypercapnia, acidosis and accompanying R-L shunt
  3. due to abdominal content causing lung compression
  4. volutrauma, barotrauma, oxygen toxicity, chronic lung disease
35
Q
  1. during delivery, what can swallowed air lead to with CDH infants?
  2. should the infant be intubated? what else should be inserted?
  3. what should be avoided?
  4. if the infant is born vigorous, what may be done initially?
A
  1. intestinal distention worsening lung compression causing increased respiratory distress
  2. YES! and a large NG tube should be inserted
  3. bag mask ventilation to avoid gas in abdomen and further lung compression
  4. insert IV, NG and pre-medicate to allow for easier intubation and less chance of hypoxia and acidosis
36
Q

what else should be done to manage/treat a CDH infant? (hint: 7)

A
  • pre/post ductal SpO2 to assess degree of R-L shunt at PDA and PPHN
  • sedation +/- paralysis
  • minimal handling
  • hemodynamic support to maintain BP and C.O. and minimize R-L shunting
  • echo to evaluate for heart defects, assess cardiac function and determine presence of pulmonary hypertension
  • management of pulmonary hypertension
  • ECMO (less common)
37
Q
  1. what should be minimized during ventilation of CDH?
  2. what do we want to ensure is adequate? what should be low?
  3. what two types of ventilation are commonly used?
    4 what other method may help to treat the pulmonary hypertension?
A
  1. minimize lung injury
  2. adequate gas exchange to avoid hypoxia and acidosis. Low tidal volumes due to severe lung hypoplasia and compression
  3. HFJV or HFOV
  4. iNO
38
Q
  1. how long should a patient be stabilized before attempting CDH repair?
  2. what does the repair NOT reverse?
  3. what usually happens post surgery?
  4. how is the repair generally done?
  5. what is not routinely indicated? what should instead be done?
  6. can this repair be done during HFV?
A
  1. 7-10 days
  2. pulmonary hypertension or hypoplasia
  3. patients often deteriorate before they get better
  4. small incision in upper abdomen, organs then pulled down and a stitch/synthetic patch used to close the diaphragm
  5. chest tubes, should allow air/fluid to resorb as the hypoplastic lung naturally expands in thoracic space
  6. yes!
39
Q
  1. what percentage of CDH survivors develop long-term pulmonary sequelae? what are some examples of what can happen?
  2. what do these long term effects depend on?(hint: 2)
  3. what 3 disorders do infants often deal with having CDH?
A
  1. 50% - includes chronic lung diseases, reactive airway disease, recurrent respiratory infections, and PPH
  2. degree of pulmonary underdevelopment and iatrogenic injury from mechanical ventilation
  3. GERD, feeding difficulties, failure to thrive

RESP 5017 (19 decks)

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