1.
Which of the following is true regarding endotracheal intubation in
infants and children:
A.
The presence of a Murphy eye side hole provides absolute protection
against obstruction of the endotracheal tube
B. Tube obstruction in infants is as high as 30%
C. Incidence of obstruction with small tubes is similar to the incidence
with large tubes
D. The
endotracheal tube insertion guide is the channel on the straight blade
E. Age is a more reliable determinant of endotracheal tube size than height
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2.
The incidence of subglottic stenosis following intubation in children is
approximately:
A.
5%
B.
10%
C.
15%
D.
20%
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here for answer
3.
Predisposing risk factors for tracheal injury and subglottic stenosis
following tracheal intubation include:
A.
General medical condition of the patient
B. Seizures
C.
Head position
D.
Endotracheal tube material
E.
All of the above
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4.
Regarding post-extubation croup:
A.
Occurs in 50% of children
B. Begins within 18 hours, peaks at 48 hours and resolves by 5 days
C.
Less prevalent in patients with frequent coughing
D.
More prevalent in children 1-4 years of age who have undergone neck
surgery
E. All of the above
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5.
Post extubation croup is most closely associated with which of the
following:
A.
Failure to lubricate the endotracheal tube prior to insertion
B. Failure to use analgesic sprays
C.
Excess humidification
D.
History of upper respiratory infection prior to intubation
E.
Surgery within the neck area
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6.
Regarding tracheostomy:
A.
The highest complication rate occurs in infants
B. Mortality rate of up to 3% has been reported
C.
Complications are higher with emergency tracheostomy compared to
tracheostomy following endotracheal intubation
D.
Airway secretions are increased 24-48 hours following tracheostomy
E. All of the above
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7.
Acute post-operative complications of tracheostomy include:
A.
Subcutaneous emphysema
B. Pneumothorax
C.
Pneumomediastinum
D.
Increased airway secretions
E. All of the above
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8.
Immediate post-operative care of a child with a new tracheostomy include:
A.
Evaluation of a chest radiograph for tube position
B. Evaluation for subcutaneous emphysema
C.
Monitoring for bleeding
D. More frequent suctioning
E. All of the above
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here for answer
9.
Which of the following is/are true pertaining to tracheostomy tubes:
A.
Must measure 0.5 mm smaller in size than the previously used endotracheal
tube
B. Initial tracheostomy change may be done by the bedside nurse
C.
Cuffed tracheostomy tubes are not suitable for infants due to the small
diameter of the airway
D.
All of the above
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10.
A 9-year-old boy with a tracheostomy in place for 8 years is emergently
transferred to the Pediatric Intensive Care Unit because copious amounts of
fresh blood had been noted coming out of the tracheostomy tube.
Regarding the diagnosis and immediate intervention:
A.
A cuffed tracheostomy tube must be passed and the cuff inflated
immediately
B.
Erosion of the thyroid vein is the most likely diagnosis
C.
The patient should be intubated orally and the tracheostomy tube removed
D.
Tracheal granuloma is the most likely diagnosis
E.
All of the above
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answer
11.
A 3-year-old with a tracheostomy for 2-1/2 years is being decanulated.
Immediately following decannulation,
he develops stridor and respiratory
distress. Possible etiologies
include all except:
A.
Tracheal stenosis or granulation tissue
B. An obstructing flap of the posterior tracheal wall
C.
Fusion of vocal cords
D.
Temporary laryngeal abductor failure
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answer
12.
Regarding use of tracheostomy for a prolonged period of time, which of
the following is true:
A.
The tracheostomy tube is placed above the narrowest portion of the airway
in children
B. The tracheostomy stoma frequently needs suture closure
C.
In infants, the tracheostomy tube is plugged prior to decannulation
D.
Bronchoscopy is often indicated prior to decannulation
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answer
13.
Select whether the following statements are true or false regarding a
child with globe injury:
____ A.
Apply the same principles of treatment for closed head injury, i.e.,
complete sedation and relaxation prior to attempts at intubation; one option is
to use thiopental 2-4 mg/kg and vecuronium (0.2-0.25 mg/kg)
____ B. Avoid succinyl choline because it increase intraocular pressure
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answer
14.
Contraindications to nasotracheal intubation include:
A.
A platelet count of 18,000/mm3
B. A prothrombin time of 18 seconds
C.
Fracture of the cribriform plate of the ethmoid bone
D.
All of the above
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answer
15.
Which of the following medication combinations is most appropriate for
intubating a 5 year-old with a closed
head injury who has a capillary
refill of 5 seconds and fractured right femur due to a crushing injury he
sustained
5 hours ago:
A.
Succinyl choline, thiopental and lidocaine
B. Ketamine, succinyl choline, and lidocaine
C.
Vecuronium, lidocaine, and low-dose thiopental
D.
Pancuronium, thiopental and lidocaine
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answer
16.
A 2-year-old male with a history of vomiting and diarrhea for two days is
admitted to the Pediatric ICU from the emergency department.
He appears very lethargic; P 195/min; BP 60/P and capillary refill is 6
seconds. In preparing for tracheal
intubation, which of the following combinations of drugs is best?
A.
Ketamine, vecuronium
B. Thiopental, vecuronium
C.
Thiopental, pancuronium and lidocaine
D.
Thiopental, succinyl choline
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answer
17.
The relationship between helium and the effect on airway resistance is
best described by which of the following:
A.
Helium-O2 mixtures have much lower viscosity than O2-Nitrogen
mixtures
B. Use of oxyhood is highly recommended in children with croup
C.
To minimize airway resistance, helium must be mixed with at least 60%
oxygen
D. When Helium-O2 mixture is administered through the ventilator
direct volume measurements are necessary
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answer
18.
Acute pulmonary edema has been described in children with the relief of
airway obstruction with:
A.
Epiglottis
B. Laryngotracheobronchitis
C.
Laryngospasm
D.
Obstructed endotracheal tube
E.
All of the above
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answer
19.
Bronchopulmonary dysplasia occurs in association with the following
conditions in the neonate:
A.
Pulmonary hypoplasia
B. Hyaline membrane disease
C.
Diaphragmatic hernia
D.
Tracheoesophageal fistula
E.
All of the above
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answer
20.
Risk factors for development of bronchopulmonary dysplasia is/are:
A.
Male sex
B. White race
C.
Birth weight < 750 grams
D.
All of the above
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answer
21.
Factors that promote formation of pulmonary edema include all of the
following except:
A.
More negative pleural pressure
B.
Higher pulmonary blood flow
C.
Lower plasma protein
D.
More positive pleural pressure
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answer
22.
Infections likely to predispose the pre-term infant to bronchopulmonary
dysplasia include:
A.
Group B streptococcal infection
B.
Ureaplasma urealyticum
C. Respiratory syncytial virus infection soon after birth
D.
Cytomegalovirus infection
E.
All of the above
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answer
23.
Pulmonary interstitial emphysema promotes:
A.
Pulmonary edema
B.
Hyperinflation
C.
Higher airway resistance
D.
Pneumoperitoneum, pneumopericardium and subcutaneous emphysema
E.
All of the above
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answer
24.
The primary event in the development of pulmonary interstitial emphysema
is:
A.
Subcutaneous emphysema
B. Increased airway resistance
C.
Impaired lymphatic drainage
D.
Epithelial necrosis
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answer
25.
Physiologic changes unique to pre-term infants with bronchopulmonary
dysplasia that places them at higher risk
for respiratory failure is least
likely to include which of the following:
A.
Low intercostal muscle activity during REM sleep
B. Disuse atrophy following prolonged mechanical ventilation
C.
A blunted response to hypoxia
D.
Absence of the peripheral chemoreceptor response
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answer
26.
In infants with bronchopulmonary dysplasia, progressive pulmonary
hypertension can lead to all of the following
except:
A.
Systemic to pulmonary anastomoses with intrapulmonary shunting
B. Increased right ventricular preload
C.
Restriction of right coronary blood flow to diastole
D.
Subendocardial ischemia
E.
Restriction of blood flow through the right coronary artery to systole
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answer
27.
The single most essential drug for infants with bronchopulmonary
dysplasia (BPD) is:
A.
Oxygen
B. Theophylline
C.
Lasix
D.
Furosemide
E.
Caffeine
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answer
28.
Side effects of aerosolized b2
agonist include all except:
A.
Tachycardia
B. Hypokalemia
C.
Impaired mucociliary clearance
D.
Tremor
E. Arrhythmia
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answer
29.
Regarding use of bronchodilators and anti-inflammatory medications in
infants with bronchopulmonary
dysplasia, which of the following statements is
least accurate:
A.
Methylxanthines decrease chemoreceptor sensitivity to CO2
B. Cromolyn Na+, like methylxanthine, has anti-inflammatory effects
C.
Combination of ipatropium bromide and b2
agonist appears more effective than either one alone
D.
Improved mucociliary function is a recognized effect of b2
agonists
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answer
30.
Side effects of methylxanthines include all of the following except:
A.
Hyperglycemia
B. Hypokalemia
C.
Hypothermia
D.
Agitation and seizures
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answer
31.
Which one of the following is the least likely effect of diuretics when
used in patients with bronchopulmonary dysplasia:
A.
Improved pulmonary mechanics
B.
Improved survival
C.
Decreased pulmonary vascular resistance
D.
Improved lymphatic drainage from lungs
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answer
32.
Regarding use of furosemide in bronchopulmonary dysplasia:
A.
Chloride depletion induced by furosemide has been associated with poor
outcome
B. The hypokalemic metabolic alkalosis induced by furosemide can decrease
minute ventilation leading to elevation of PCO2
C.
Furosemide is associated with renal calcification
D.
All of the above
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answer
33.
Advantages of tracheostomy for infants with bronchopulmonary dysplasia
include:
A.
A stable, chronic access to airway
B. A decrease in work of breathing
C.
More freedom of mobility and physical therapy
D.
Pleasant oral stimulation such as nippling
E. All of the above
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answer
34.
Factors which contribute to decreased respiratory muscle capacity
include:
A.
Respiratory acidosis
B. Hyperinflation
C.
Disuse atrophy
D.
All of the above
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answer
35.
In infants with bronchopulmonary dysplasia, factors that may adversely
lead to elevation of CO2 include all of the following except:
A.
Agitation with patient ventilator asynchrony
B. Fever
C.
Hyperalimentation with 68% carbohydrate
D.
Tracheostomy
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answer
36.
Increased dead space contributes significantly to work of breathing.
In a setting of increased dead space, a small increase in CO2
production may require significant increases in minute ventilation for adequate
CO2 elimination. The
ratio of dead space to tidal volume can be improved by:
A.
Allowing patient’s spontaneous respiratory rate to have a higher
contribution to the total
ventilatory support
B. Use of pulmonary vasodilators
C.
Tracheostomy
D.
A and C only
E. A, B and C are true
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answer
37.
In infancy, congenital anomalies are the most common cause of death.
The second most common cause of death in infancy is due to disorders in:
A.
The cardiovascular system
B.
The respiratory system
C.
The central nervous system
D.
The gastrointestinal system
E.
The cardiovascular system
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answer
38.
Whenever lung disease leads to respiratory failure, the most common
mechanism responsible for abnormal gas exchange is:
A.
Ventilation-perfusion mismatch
B.
Diffusion defect
C.
Alveolar hypoventilation
D.
Shunt
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answer
39.
A newborn diagnosed with a left-sided diaphragmatic hernia at the 22nd
week of gestation underwent complete repair on the 1st day of life.
He is on mechanical ventilation and recovering from surgery.
In the ensuing several months, it is expected that:
A.
Progressive branching of airways will occur
B. Progressive regression of airways will occur
C.
Airway branching will occur albeit very slowly over the next few years
D.
Post-natal branching of airways will not occur and left lung hypoplasia
is irreversible
E. The airway branching will continue in the left lung but growth of the
distal airway will lag behind the proximal airway in the 1st five
years of life
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answer
40.
Developmental changes in lungs that predispose the infant to respiratory
failure include all of the following except:
A.
Bronchial cartilage is incomplete and continues to increase in number for
several months. This cartilaginous
deficiency predisposes the infant to dynamic compromise
B. Growth of the distal airway lags behind growth of the proximal airway in
the 1st five years of life
C.
The smaller alveolar size and number predisposes the infant to airway
collapse
D.
Absence of pores of Kohn
E. The presence of canals of Lambert
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here for answer
A.
Pores of Kohn
B.
Canals of Lambert
C.
Both
D.
Neither
41.
____ Appear in
the 2nd year of life
____ Do not
appear until the frontal sinuses start forming
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answer
42.
A 4-year-old (20kg) child is breathing at a rate of 20 bpm.
The concentration of CO2 in the alveolar gas is estimated to
be 40 torr, whereas the concentration of CO2 in the exhaled gas is
estimated to be 30 torr. Assuming
that the spontaneous tidal volume is 5 ml/kg, the total volume of the anatomic
dead space is:
A.
100 ml
B.
200 ml
C.
300 ml
D.
400 ml
E. 500 ml
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answer
43.
A 3-month-old with bronchiolitis is on mechanical ventilation for
respiratory failure. The arterial
PCO2 is 55 mm Hg whereas the end tidal CO2 on capnography
that is attached to the end of the endotracheal tube is 35 mm Hg.
The infant is being ventilated with a tidal volume of approximately 50 ml
at a rate of 35 bpm. The
physiologic dead space in this patient is:
A.
235 milliliters
B. 345 milliliters
C.
636 milliliters
D.
725 milliliters
E. 125 milliliters
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answer
44.
The physiologic dead space in this infant is:
A.
Normal
B. Slightly increased
C.
Slightly decreased
D.
Cannot be determined from this data
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answer
45.
Infants have a very compliant chest wall and a reduced elastic recoil.
Both these factors lead to higher intrapleural pressure with subsequent
collapse of airways and alveoli in dependent lung regions.
However, functional residual capacity is maintained by:
A.
Expiratory braking
B. Grunting constantly
C.
Increasing closing capacity
D.
Increasing closing volume
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answer
46.
Regarding expiratory braking in infants, all of the following are true
except:
A.
It is decreased during active sleep in premature infants
B. It is increased during active sleep in premature infants
C.
Absence of expiratory braking in premature infants during active sleep
exacerbates loss of O2 stores during apnea
D.
Abolished by anesthesia
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answer
47.
Regarding respiratory physiology, which one of the following statements
is least accurate:
A.
With laminar flow, resistance to flow is proportional to viscosity
B. With turbulent flow, resistance to flow is proportional to density
C.
Specific compliance is the same for adults and children but specific
conductance is higher in children
D.
Peripheral airway resistance in children < 5 years is four fold higher
than in older children or adults
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48.
The above diagrams schematically represent two compartment lung units.
If inflation were interrupted prematurely in the above examples:
A.
Units A & C will have higher volumes of gas
B. Units D & B will contain higher volumes of gas
C.
Units A & C are considered fast units
D.
The pressure within C will be higher than in D
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answer
49.
Regarding developmental changes of pulmonary blood flow and lung
development, all of the following are true
except:
A.
Pulmonary blood flow plays a significant role in the growth of lungs
B. Diaphragmatic hernias adversely affect airway and alveolar development
but not pulmonary vascular development
C.
In the newborn, muscular arteries end at the level of terminal
bronchioles
D.
The onset of congestive heart failure from left to right shunt occurs
earlier in the premature than full term infant
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answer
50.
With regard to pulmonary circulation in infants and children, which one
of the following statements is least accurate:
A.
The hypoxic pulmonary vasoconstriction response is more dramatic in
infants than in the older child
B. During hypoxic pulmonary vasoconstriction, driving pressure increases
much more than flow in the whole lung
C.
Regional hypoxic pulmonary vasoconstriction increases pulmonary vascular
resistance dramatically
D.
Newborns who live at high altitudes have persistent right ventricular
hypertrophy
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answer
51.
Examples of “shunt” include which of the following:
A.
Cyanotic congenital heart disease
B. Bronchial circulation
C.
Thebesian circulation
D.
Blood flow through completely atelectatic lung segments
E. All of the above
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answer
52.
The alveolar air equation: PaO2
= PIO2 – PaCO2 / R
does not make which one of the following assumptions:
A.
There is no inert gas exchange
B. There is no differences in inspired and expired gas volume
C.
Normally more O2 is consumed than CO2 is produced
D.
Normally the amount of O2 consumed and CO2 produced
are the same
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answer
53.
Regarding the oxygen cascade and O2 transport, all of the
following statements are true except:
A.
If the percentage of shunt (QS/QT) is close to zero, the response to
increasing FiO2 is linear
B. An increase in FiO2 will have a negligible effect on PaO2
with a QS/QT of 50%
C.
If cardiac output falls while O2 consumption remains constant,
then mixed venous content must fall
D.
If O2 consumption rises for a constant cardiac output, mixed
venous oxygen content will increase
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answer
54.
The normal newborn exhibits a lower PaO2 than an adult.
The mechanism that contributes least to this phenomenon is:
A.
A right to left shunt through the foramen ovale
B. A right to left shunt through the patent ductus arteriosus
C.
Shunting due to atelectatic areas of the lungs
D.
Low V/Q segments
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answer
55.
The alveolar capillary membrane is the physical barrier that separates
alveolar gas from pulmonary capillary blood and thus acts as a gaseous diffusion
barrier and as a fluid transfer barrier. Statements
that are true in describing this barrier include all of the following except:
A.
Diffusion block is rarely if ever the sole cause of significant hypoxemia
B. Diffusion is measured by diffusing capacity
C.
In practice, diffusing capacity is measured by using the diffusing
capacity for carbon monoxide instead of O2
D.
Transfer factor refers to diffusing capacity in relation to alveolar
ventilation
E. Transfer factor increases with age and height
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answer
56.
The type of hemoglobin and the position of the O2–Hb
dissociation curve play a significant role in O2 delivery to tissues.
All of the following statements are true regarding this topic except:
A.
2,3-DPG lowers O2 affinity to hemoglobin by binding to either b-chain
or g-chain
of the hemoglobin
B. The interaction of 2,3-DPG and g-chain
does not lower O2-Hb affinity to as great an extent as the
interaction of DPG with the b-chain
C.
Hemoglobin-S has a lower P50 than hemoglobin-A
D.
The iron in hemoglobin-F is more resistant to oxidation than the iron in
hemoglobin‑A
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answer
57.
Newborns are particularly susceptible to methamoglobinemia following
exposure to nitrates because:
A.
Of their smaller size
B. Iron in hemoglobin F is less readily oxidized
C.
Of exposure to city water at such an early age
D.
Of the relative deficiency in the enzyme methemoglobin reductase
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answer
58.
Regarding O2 delivery to and O2 consumption by
tissues, which of the following least accurately describes these two processes:
A.
A normal O2 delivery with a resultant normal mixed venous O2
content does not guarantee adequate tissue oxygenation
B. In the newborn, if environmental temperature drops from 33oC
to 31oC, O2 consumption doubles
C.
The normal O2 extraction is 0.25
D.
Resting O2 consumption in a 1-week-old is approximately half
of that for an adult based on kilogram body weight basis
E.
Electron transfer requires a minimum of 1 mm Hg of O2 for the
mitochondria to properly utilize O2
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answer
59.
Mixed venous PO2 is
least dependent on which of the following factors:
A.
Oxygen delivery (DO2)
B. Circulatory distribution
C.
Inferior vena cava pressure
D.
P50
E. Oxygen consumption (VO2)
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answer
60.
With regard to neural and humoral control of respirations, which of the
following options is not true:
A.
Carotid bodies respond to falling PaO2 in an exponential
fashion
B. Peripheral chemoreceptors respond to falling SaO2 in an
exponential fashion
C.
Central chemoreceptors respond to increasing PaCO2 in a linear
fashion
D.
Hypoxia increases the slope of the minute ventilation curve in response
to increasing CO2
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answer
61.
There are a number of pulmonary receptors that modulate breathing; true
statements pertaining to this include all of the following except:
A.
Chemical or mechanical stimulation of the oropharynx lead to apnea and
bradycardia
B. Stimulation of laryngeal receptors produces cough and wheezing in
experimental animals
C.
Excess interstitial fluid results in bradycardia, hypotension and even
apnea via stimulation of juxtacapillary receptors
D.
Laryngeal and bronchial receptors respond to CO2 in an
exponential fashion
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answer
62.
The resting PaCO2 in the neonate is 33-34 torr as opposed to
40 torr in the older child or adult. Which
one of the following statements least accurately explains the reason for this
phenomenon:
A.
The O2 demand for the young infant is double of that for the
adult based on a kilogram per kilogram body weight basis
B. The lower CO2 is the result of higher minute ventilation
required to meet the increased O2 demand
C.
The CO2 response curve is shifted to the left
D.
The CO2 response curve is shifted to the right
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answer
63.
Chemical and neural control of respirations in the preterm infant differ
from that of the full-term infant. All
of
the following statements are true except:
A.
In preterm infants with periodic breathing, the CO2 response
curve is shifted to the right
B.
The PaCO2 is closer to 40 torr as in adults
C.
The CO2 response is flatter than in the term infant
D.
Premature infants do not have carotid bodies
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answer
64.
The reason for the progressive reduction in total respiratory system
compliance with age is:
A.
Individual variations of the operator performing the test
B. A progressive reduction in lung compliance with age
C.
A progressive increase in airway resistance with age
D.
A progressive reduction in chest wall compliance with age
E. None of the above
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65.
The majority of tidal breathing in the infant takes place in the range of
closing capacity. All of the
following
statements pertaining to this phenomenon are true except:
A.
This increases the risk of atelectasis
B. This is because of the very low elastic recoil pressure of the newborn
chest wall
C.
Closing capacity refers to the volume of the lung below the functional
residual capacity at which the alveoli and airways in the dependent regions of
the lung close
D.
All of the above
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answer
66.
The highly compliant chest wall of the infant:
A.
Means that the infant must generate more pressure and perform more work
to move the same tidal volume
B.
Is clinically manifested as retractions
C.
Is responsible for respiratory muscle fatigue and ultimate apnea, with
any respiratory distress
D.
All of the above
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answer
67.
When infants are confronted with the need to increase work of breathing
because of underlying
pulmonary disease, a certain percentage of them will
fatigue and ultimately develop apnea. Which
one of the
following is a contributing factor:
A.
Functional residual capacity is much greater than closing capacity in
infants
B.
The small tidal volume in infants
C.
The highly compliant chest wall
D.
The CO2 response curve of infants is shifted to the right
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answer
68.
Infants and newborns are more susceptible to diaphragmatic muscle fatigue
because:
A.
Closing volume is lower than in adults
B.
Of smaller residual volume
C.
Of abundant sarcoplasmic reticulum in the muscle fibers of the diaphragm
D.
Of the long contraction-relaxation time of diaphragmatic muscle fibers
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answer
69.
In the face of prolonged respiratory distress, some infants develop
fatigue and apnea. The reasons
for this phenomenon include all of the following except:
A.
These infants are unable to recruit intercostal muscle activity
B.
Rapid chest wall distortion with respiratory distress prematurely
terminates inspiration
C.
The young infant cannot compensate for this respiratory load during
active sleep
D.
The short contraction-relaxation time of the respiratory muscles
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answer
70.
Which of the following statements inaccurately describes apnea in infants
and children:
A.
Premature infants less than 60 weeks conception are at risk of
life-threatening apnea following general anesthesia
B.
Aminophylline helps apnea by significantly altering the pH and PaCO2
around the respiratory center
C.
The association between apnea and gastroesophageal reflux is well
accepted
D.
Children with obstructive sleep apnea due to adenotonsillar hypertrophy,
may have deranged central control of respiration post-operatively due to
increased opioid activity in the cerebrospinal fluid
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answer
71.
Cervical spine injury below C5 in an infant will not result in:
A.
Ineffective cough
B.
Chest wall retraction with each contraction of the diaphragm
C.
Mucus plugging
D.
Respiratory failure
E.
Decreased work of breathing
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answer
72.
Unilateral phrenic nerve paralysis is clinically more significant in
infants and young children compared
to adults because of all of the following
except:
A.
Hemi-diaphragmatic paralysis in this age group is equivalent to massive
flail chest in an adult
B.
Of the excessively compliant chest wall of the young child
C.
Of the poor ability of intercostal muscles to stabilize the chest wall in
the young infant
D.
Less compliant chest wall of the young child
E.
With inspiration the ipsilateral intercostal muscles and the paralyzed
diaphragm are sucked in
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answer
73.
Airway resistance would appear to be the most direct measurement of
airway obstruction. It is not used
as frequently as tests of forced expiration in children because:
A.
It requires use of plethysmography
B.
It is not as accurate as FEV1
C.
Physiologically important changes in pulmonary airways can be obscured by
less important changes in the upper airway which may be responsible for 50% of
airway resistance
D.
None of the above
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answer
74.
Match the statements to the curves in the figure above.
____
Alveolar PO2
____
Arterial PCO2
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answer
75.
Which of the following does not increase the likelihood of having West
“Zone 1” in the lungs:
A.
Mechanical positive pressure ventilation with hyperinflation
B.
A pulmonary artery occlusion pressure of 22 mm Hg
C.
Pulmonary embolism
D.
A capillary refill of 6 seconds in the lower extremity
Click here for
answer
76.
Regarding West “Zone 4” of the lung, which of the following is true:
A.
Blood flow in this zone is regulated by the gradient between pulmonary
artery pressure and pulmonary venous pressure
B.
Blood flow in this zone is regulated by the gradient between pulmonary
artery pressure and alveolar pressure
C.
Transduction of fluid across the capillary barrier exceeds the rate of
lymphatic drainage from the lungs
D.
Zone 4 blood flow exceeds Zone 3 blood flow
Click here for
answer
77.
In the pulmonary circulation, active vasoconstriction occurs when:
A.
Cardiac output decreases and pulmonary artery pressure increases or
remains constant
B.
Cardiac output increases and pulmonary artery pressure is constant
C.
Cardiac output decreases and pulmonary artery pressure decreases
D.
All of the above
Click
here for answer
A.
Generalized hypoxic pulmonary vasoconstriction
B.
Regional hypoxic pulmonary vasoconstriction
C.
Both
D.
Neither
78.
____ Result(s) in
elevation of pulmonary artery pressure
____ Protective
mechanism(s) for the host
Click here for
answer
79.
Compliance is the relationship between changes in volume (rV)
for a given change in the distending pressure
(rP).
Regarding this relationship, all of the following statements are true
except:
A.
Compliance of the lungs is determined by rV
and the difference between alveolar pressure
and pleural pressure
B. Compliance of the chest wall is determined by rV
and the difference between alveolar pressure and ambient pressure
C.
Compliance of the total respiratory system is determined by rV
and the difference between alveolar pressure and the ambient pressure
D.
Chest wall compliance is the rV
divided by the difference between pleural pressure and the ambient pressure
Click here for
answer
80.
Conditions associated with decreased total respiratory system compliance
due to increased elastic recoil of
the lungs include all of the following
except:
A.
Adult Respiratory Distress Syndrome (ARDS)
B. Pneumocystis carinae pneumonia
C.
Pulmonary edema due to severe mitral stenosis with circulatory failure
D.
Near-drowning
E. Bronchiolitis
Click here for
answer

81.
Please refer to the above diagram to answer the following questions:
A. The
decrease in pressure from A to B is due to redistribution of gas into more
compliant alveoli
B. This diagram indicates that dynamic compliance is greater than static
compliance
C.
The diagram indicates that static compliance is greater than dynamic
compliance
D.
A and C are true statements
Click here for
answer
82.
Conditions associated with decreased total respiratory system compliance
include all of the following except:
A.
Thermal injury of the lower respiratory tract
B. Erect posture
C.
Atelectasis
D.
Abdominal distention
E. High positive end-expiratory pressure
Click here for
answer
83.
All of the following statements about airway resistance in children are
true except:
A.
Airway resistance accounts for less than 50% of total non-elastic
resistance
B. With laminar flow, the pressure drop down the airway is proportional to
the flow rate
C.
With turbulent flow, the pressure drop down the airway is proportional to
the square of the flow rate
D.
Peripheral airways account for 50% of total airway resistance in children
younger than 5 years
E. Airway resistance increases with increased flow and decreased functional
residual capacity
Click here for
answer
84.
The time constant (t) describes the time required for the lung
compartments to achieve a change in volume following the application or
withdrawal of a constant distending pressure and is the product of compliance
and resistance. Regarding this
concept, which of the following statements is most accurate?
A.
Time constant is expressed in terms of flow in liters per second
B. When a constant pressure is applied to the mouth, the component
overcoming air flow resistance is maximal at first and declines exponentially
C.
When a constant pressure is applied to the mouth the pressure required to
overcome compliance is maximal initially and decreases exponentially
D.
Mathematically, 63% of lung inflation or deflation occurs within 3 time
constants
Click here for
answer
85.
An 8-year-old male with post-traumatic ARDS is being ventilated with a
pressure limited “mode “ of ventilation with an inspiratory time of 1
second, SIMV of 20 bpm, PIP of 30 cm H2O and PEEP of 8 cm H2O.
The chest radiograph has shown significant improvement over the past 24
hours, and FiO2 has been decreased from 0.7 to 0.55.
Failure to decrease the inspiratory time may result in all of the
following except:
A.
Decreased venous return
B. Decreased physiologic dead space
C.
Auto PEEP
D.
Pneumomediastinum
Click here for
answer
Answers
1.
E
The Murphy eye side hole does not provide protection against obstruction
of the endotracheal tube. The
incidence of tube obstruction is approximately 5% in the pediatric population,
and approximately 80% of tube obstructions occur in endotracheal tubes which are
3.5 mm in diameter or smaller. The
channel on the straight blade is the visual pathway for the person performing
the intubation. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition;
pp 59-64)
2.
A
Subglottic stenosis occurs in 2-6% of pediatric patients following
tracheal intubation. (Parkin JL, et al. Ann Otolaryngology, 1976; 85:673)
3.
E
All are true. (Rogers, MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition; pp 65-76)
4-5.
D, E
Post-extubation croup occurs in approximately 5% and usually resolves in
24 hours. It is more common in patients with frequent coughing episodes
and in patients who move more frequently while intubated. It has been shown to be more prevalent in children 1-4 years
or age, particularly in association with any type of surgery in the head/neck
area. (Kemper, et al.
Critical Care Medicine, 1991; 19:352)
6-8.
E, E, E
The mortality rate (MR) for tracheostomy is 1-3%.
The MR and complications are highest in infants.
Following tracheostomy there appears to be an increase in airway
secretions for 24-48 hours during which time the patient will need frequent
suctioning. The patient will also need to be evaluated for possible air
leak, such as subcutaneous emphysema or pneumomediastinum and monitoring for
post-operative bleeding. (Zeifouni
A, et al. J Otolaryngology, 1993;
22:431-434; Crysdale, WS. Ann
OtoRhinolaryngology, 1988; 97:493)
9.
C
The tracheostomy tubes, in fact, may measure 0.5 mm larger than the
previously used endotracheal tube because the site of insertion is below the
cricoid cartilage. The initial change of the tracheostomy tube must be done with
the surgeon in attendance as a precaution against complications.
(Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition;
pp 72-73)
10.
A
This is a rare complication of prolonged tracheostomy, and it is most
likely due to erosion of the innominate artery.
Under these circumstances, a cuffed tracheostomy tube should be passed
beyond the site of bleeding and immediately inflated.
(Crysdale WS. Ann
Otorhinolaryngology, 1988; 97:493-499)
11.
B
An anterior (and not a posterior) tracheal flap at the operation site for
tracheostomy is one of the etiologies of obstruction following decannulation.
Other etiologies include: fusion
of vocal cords, granuloma and temporary adductor failure.
(Carter P, et al. Ann Otorhinolaryngology, 1983; 92:398-401; Sasaki CT, et al.
Ann J. Dis Child, 1978; 132:266-269)
12.
D
Tracheostomy tubes are not plugged prior to decannulation, as this may
increase the airway resistance significantly, and a tracheostomy stoma is
usually left to heal on its own. Plastic
tracheostomy tubes have been associated with less evidence of stricture and
subsequent tracheal stenosis. Tracheostomy
tubes are placed below the cricoid cartilage.
(Sasaki CT. Am J. Dis Child,
1978; 132:266-269)
13.
T, T
The same principles applied for tracheal intubation in a patient with
closed head injury should be applied here.
(Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition;
pp 65-68)
14.
D
Contraindications to nasotracheal intubation include bleeding diatheses
and suspicion of basilar skull fracture. (Rogers MC, et al.
Textbook of Pediatric Intensive Care, 3rd Edition; pp 65-68)
15.
C
In a patient with closed head injury, one should avoid ketamine because
it increases intracranial pressure, possibly through a cholinergic mechanism.
In a setting of hypotension and shock, thiopental, particularly in the
usual dose of 2-4 mg should be avoided because it may potentiate hypotension
which might be detrimental to the patient.
Vecuronium seems to cause minimal hemodynamic disturbances, and
therefore, in combination with lidocaine and low-dose (1-2 mg/kg) thiopental
would be the most appropriate combination in this patient.
(Rogers MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition; pp 63-70)
16.
A
In a patient with hypovolemia or shock, ketamine seems to be the most
appropriate choice because it is a cardiorespiratory stimulant; along with
vecuronium, which is associated with minimal hemodynamic disturbances would be
most the most appropriate combination. (Rogers MC, et al.
Textbook of Pediatric Intensive Care, 3rd Edition; pp 63-70)
17.
D
With turbulent airflow, the resistance to airflow is proportionate to
density. A helium-O2
mixture has a lower density than an O2-nitrogen mixture.
This leads to a reduced resistance to airflow.
Use of an oxyhood is not recommended since helium tends to separate as a
layer at the top of the oxyhood. It
usually is given through a tight fitting face mask.
As the concentration of helium decreases to < 60%, it becomes less and
less effective. The ventilator
transducer is calibrated with an air-O2 mixture, and therefore, with
a helium-O2 mixture, the tidal volume may not be accurate, unless it
is measured directly. (Kemper KJ.
Critical Care Medicine, 1991; 19:356; Ellean C.
J Pediatrics, 1993; 122:132-135)
18.
E
The theory is that increased negative interstitial pressure is a
contributing factor to the development of pulmonary edema in association with
upper airway obstruction. To further review theories that explain the development of
pulmonary edema in children with croup and epiglottitis, see the following
references. (Travis KW, et al.
Pediatr 1977; 59:695; Lichtenstein S.
Fed Proc 1975; 34:436)
19-20.
E, E
Children who develop hyaline membrane disease or have pulmonary
hypoplasia due to a wide variety of reasons including diaphragmatic hernia,
children with tracheoesophageal fistula, and those who develop early neonatal
infections due to but not limited to group B streptococcal infection, ureaplasma,
respiratory syncytial virus, or cytomegalovirus, seem to be at a higher risk of
developing bronchopulmonary dysplasia. Other
risk factors include male sex, white race, and a birth weight of less than 750
grams. One of the factors that is considered the best predictor of
development of bronchopulmonary dysplasia is the need for oxygen therapy at 36
weeks chronological age. (Kennedy
KA. Seminars Perinatol, 1993;
17:247)
21.
D
Negative rather than positive pleural pressure has a tendency to promote
formation of pulmonary edema. All
other factors in the question tend to promote pulmonary edema.
(Robin ED. N. Engl J Med,
1973; 288:239)
22.
E.
Refer to answer #19-20.
23-24.
E, D
Air within the connective tissue sheath leads to compression of the
surrounding peripheral airway with subsequent increased airway resistance and
hyperinflation. Impaired lymphatic
drainage promotes pulmonary edema. Once
extra-alveolar air develops, it may dissect into the subcutaneous space and
mediastinum. Further extension into
the pericardium and peritoneum may occur. The
primary event appears to be epithelial necrosis.
(Watts, JL. Pediatr 1977;
60:273; Hansen TN. Clin Perinatol
1984; 11:653)
25.
D
Infants with bronchopulmonary dysplasia (BPD) have been shown to have a
blunted arousal response to hypoxia. Increased
chest wall compliance places these infants at a mechanical disadvantage,
particularly during periods of decreased or low intercostal muscle activity such
as during rapid eye movement during sleep.
The peripheral chemoreceptors are intact in these babies.
Prolonged ventilatory support may lead to disuse atrophy of respiratory
muscles. (Gray M.
Pediatr 1988; 82:59; Knosely AS. J Pediatr 1988; 113:1074)
26.
E
Normally, the blood flow through the right coronary artery occurs during
both diastole and systole as opposed to restriction of flow during diastole with
the left coronary artery. In
infants with bronchopulmonary dysplasia with the development of pulmonary
hypertension and particularly with progressive pulmonary hypertension, the blood
flow through the right coronary artery becomes limited to diastole as right
ventricular pressure and volume increase. (Berman
W. Pediatrics, 1982; 70:708)
27.
A
Infants with BPD have been shown to develop a significant reduction in
pulmonary vascular resistance in response to low flow oxygen therapy.
Acute, recurrent hypoxia precipitated by a variety of factors such as
handling, feeding, or infection may precipitate pulmonary hypertension or
pulmonary hypertensive crises with sudden death.
(Long, LA. Pediatrics, 1980;
65:203; Grag M. Pediatrics, 1988;
81:635)
28-30.
C, C, C
Improved mucociliary clearance is a recognized effect of b2-agonists.
Methylxanthines increase chemoreceptor sensitivity to carbon dioxide and
induce hyperthermia rather than hypothermia.
(Santa-Cruz R. Am Review of
Resp Dis 1974; 109:458; Aranda JV. Clin
Perinatol, 1979; 6:87)
31-32.
D, D
Diuretics cause decreased transvascular efflux of fluid in the lung.
Recognized side effects of furosemide include chloride depletion,
metabolic alkalosis, renal calcification, and ototoxicity.
Some of these factors have been implicated in poor growth and poor
outcome in infants with BPD. (Perlman
JM. Pediatr, 1986; 77:212; Hurnagle KG. Pediatr, 1982; 70:360)
33-35.
E, D, D
Respiratory acidosis, hyperinflation, and disuse atrophy from prolonged
mechanical ventilation and tracheal intubation has been associated with
decreased respiratory muscle capacity. Advantages
of tracheostomy include: a stable
airway with more freedom of mobility and oral stimulation.
Tracheostomy decreases anatomic dead space and therefore is unlikely to
lead to elevation of carbon dioxide. It
also decreases work of breathing partly through the same mechanism. (Rogers MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition; pp 183-186)
36.
D
Use of pulmonary vasodilators would lead to ventilation-perfusion
mismatch which is likely to increase the dead space.
Allowing the patient’s spontaneous respiratory rate to have a higher
contribution to the total ventilatory support while on mechanical ventilation
will decrease dead space, as does tracheostomy.
(Rogers MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition; pp 183-186)
37.
B
Self explanatory. (Rogers
MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition;
pp 97-98)
38.
A
Diffusion defect as the only cause of gas exchange abnormalities is
extremely rare. (Rogers MC, et al.
Textbook of Pediatric Intensive Care, 3rd Edition; pp 97-98)
39.
D
Diaphragmatic hernia, if not detected and corrected before 16 weeks of
gestation, will lead to irreversible changes in the lung, in this case, the left
lung, which is expected to remain hypoplastic.
(Rogers MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition; pp 105-106)
40.
E
Canals of Lambert do not develop until approximately 6 years of age.
(Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition;
pp 105-106)
41.
A, B
The intra-alveolar Pores of Kohn do not develop until after 2 years of
age. (Rogers MC, et al. Textbook of
Pediatric Intensive Care, 3rd Edition; pp 105-106)
42.
E
Dead space ventilation = alveolar ventilation ´
(alveolar CO2 – exhaled CO2) ¸ alveolar CO2. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition;
pp 107-108)
43.
C
Dead space ventilation = (arterial CO2 – exhaled CO2)
¸ arterial CO2
´
alveolar ventilation. (Rogers MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition; pp 107-108)
44.
B
The normal ratio of dead space ventilation to alveolar ventilation is 0.3
or less. (Rogers MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition; pp 107-108)
45-47.
A, B, C
Expiratory braking refers to the increase in airway resistance in the
upper airway during exhalation, which leads to an increase in end expiratory
lung volume. This would lead to an
increase in functional residual capacity (FRC).
It is decreased during active sleep because it is arousal dependent.
Specific compliance and specific conductance are the same for adults and
children. (Kosch PC, Stark AR.
Dynamic Maintenance of End-Expiratory Volume in Full-Term Infants.
J Appl Physiology, 1984; 57:1126-1133)
48.
B
Time constant = resistance ´
compliance. It is a dimensionless
number. Whenever one of the
components of the time constant (i.e., either the resistance or the compliance)
increases, the movement of air from one lung unit to another would be prolonged,
leading to an increase in time constant. Therefore,
applying these principles in the diagram, since the resistance in the airway
leading to unit A is increased, and the compliance of unit C is also increased,
these two units will contain less volume of gas when inflation is interrupted
prematurely. (Rogers MC, et al. Textbook
of Pediatric Intensive Care, 3rd Edition; pp 104-106)
49.
B
Diaphragmatic hernia adversely affects the pulmonary vasculature and lead
to pulmonary hypoplasia if it is not corrected before 16 weeks of intrauterine
life. (Please see Answer #40)
50.
C
Regional or localized hypoxic pulmonary vasoconstriction does not
increase pulmonary vascular resistance significantly. (Rogers MC, et al.
Textbook of Pediatric Intensive Care, 3rd Edition; pp 106-112)
51.
E
All statements are examples of a shunt. (Rogers MC, et al.
Textbook of Pediatric Intensive Care, 3rd Edition; pp 110-112)
52.
D
The alveolar air exchange equation makes all of the above assumptions.
(Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition;
pp 110-111)
53.
D
Cardiac output equals oxygen consumption divided by arteriovenous oxygen
content difference, and therefore, if oxygen consumption increases for a
constant cardiac output, the mixed venous oxygen content must decrease. (Rogers
MC, et al. Textbook of Pediatric
Intensive Care, 3rd Edition; pp 108-109)
54.
D
This is the major mechanism (i.e., low V/Q segments) in adults. (Rogers
MC, et al. Textbook of Pediatric
Intensive Care, 3rd Edition; pp 111-112)
55.
E
Transfer factor decreases with age. (Rogers MC, et al.
Textbook of Pediatric Intensive Care, 3rd Edition; pp 112-113)
56.
D
Hemoglobin-F is more easily oxidizable compared to hemoglobin-A.
(Martin H, et al. Formation
of Ferrihemoglobin in isolated human hemoglobin types by sodium nitrite. Nature, 1963; 200:898-900)
57.
D
Neonates and young infants are more susceptible to the development of
methemoglobinemia because 1) the iron in HbF is oxidized more readily; and 2)
the young infant is relatively deficient in the enzyme, methemoglobin reductáse.
When the levels of methemoglobin exceed 30-40%, cyanosis and symptoms of
decreased O2 transport are noted. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition;
pp 114-116)
58.
D
Resting oxygen consumption in a 1-week-old infant is 3 times that of an
adult based on the body weight per kilogram. (Rogers MC, et al.
Textbook of Pediatric Intensive Care, 3rd Edition; pp 118)
59.
C
O2 consumption (VO2) =
Cardiac Output
CaO2 – CVO2
Where CaO2
=
arterial O2 content
CVO2 = mixed venous O2
content
O2 delivery (DO2)
= Q
x CaO2 (where
Q = Cardiac Output)
CaO2 =
Hb (grams%) x
1.34 x
O2 saturation
+ PaO2
x 0.003
Therefore alterations in cardiac output or peripheral circulatory
disturbances (that alter blood flow at the capillary level) will affect O2
consumption. P50 affects
the unloading of O2 from Hb. The
higher the P50, the more the unloading of O2 to tissue.
(Rogers MC, et al. Textbook of
Pediatric Intensive Care, 3rd Edition; p 118)
60.
B
Peripheral chemoreceptors respond to a falling oxygen saturation in a
linear fashion by increasing the inspired minute ventilation.
There is an exponential increase in minute ventilation as PaO2 falls,
particularly at PaO2 < 60 torr. (Berger
AJ, et al. New Engl J Med, 1977;
297:194-198)
61.
D
Laryngeal and bronchial receptors respond to increasing CO2 in a linear
fashion. (Berger AJ, et al.
New Engl J Med, 1977; 297:194-198)
62.
D
The carbon dioxide response curve which relates alveolar CO2
to alveolar ventilation is shifted to the left in the neonate.
(Rigatto H. Apnea.
Pediatr Clin North Am, 1982; 29:1105)
63.
D
Preterm infants have a characteristic breathing pattern referred to as
periodic breathing (i.e., pauses in respirations lasting 5-10 seconds).
Due to the higher O2 demand, newborn infants compensate by
having a higher minute ventilation and a shift in CO2 response curve
to the left. The carotid bodies are
present in preterm infants. (Rigatto
H. Apnea Pediatr Clin North Am,
1982; 29:1105)
64.
D
Total respiratory system compliance equals lung compliance plus chest
wall compliance. With age, there is a progressive reduction in chest wall
compliance which accounts for a reduction in the total respiratory system
compliance. (Sharp JT, et al.
Total respiratory compliance in infants and children.
J Appl Physiology, 1970; 29:775-780)
65-67.
D, D, C
Closing capacity (CC) is the lung volume below the functional residual
capacity (FRC) where alveoli in dependent lung regions have a tendency to
collapse.
In infants, CC is often equal to or greater than FRC, and therefore,
tidal breathing often takes place in the range of CC.
This phenomenon is due to the very low elastic recoil of the chest and it
increases the risk of atelectasis. (Smith
CA. The Physiology of the Newborn
Infant. Springfield, IL, 1976; pp
206-207)
68-69. D, D
This may result in ischemia of respiratory muscles at a high respiratory
rate. Low levels of sarcoplasmic
reticulum in fetal diaphragmatic muscle has been observed.
(Maxwell LC, et al. Development
of histo…. J Appl Physiol, 1083;
54:551)
70.
B
Babies who were born prematurely continue to be at high risk of apnea
post-operatively (following general anesthesia) and therefore, should be
monitored for 24-48 hours after anesthesia.
Aminophylline will increase breathing without significantly altering the
CO2 and pH around the respiratory center.
Patients with adenotonsillar hypertrophy who undergo surgical resection
may be admitted to the PICU because of airway obstruction from post-operative
edema or sometimes due to decreased ventilatory drive after anesthesia. The increased opioid activity found in the spinal fluid in
these patients may be a contributing factor to decreased ventilatory drive noted
perioperatively. (Kurth CD, et al.
Post-operative apnea in preterm infants, Anesthesiol, 1987; 66:483;
Gislason T, et al. Chest 1989;
96:250; Lavaher S. Thorax, 1989;
44:121)
71.
E
Work of breathing is increased due to chest wall distortion secondary to
instability of the chest wall. (Robotham
JL. Crit Care Med, 1979; 7:563)
72.
D
The more compliant chest wall of the young child contributes to the
clinical
manifestation of diaphragmatic paralysis. (Rogers MC, et al.
Textbook of Pediatric
Intensive Care, 3rd Edition; pp 123,
247)
73.
C
The upper airway contributes, to a much higher degree, to total
respiratory resistance in children than in adults.
This may mask the physiologically more important airway resistance.
(Cook LD, et al. J Clin
Investigate, 1957; 36:440)
74.
B, A
The relationship between alveolar ventilation and both PaO2
and PaCO2 are non-linear, as depicted on the graph.
(Benumof J. Respiratory
Physiology and Respiratory Function During Anesthesia, IN; Miller RD.
Anesthesia, Churchill, Livingstone, NY
1981; pp 699)
75.
B
West Zone I occurs when ventilation is wasted.
Alveolar pressure remains constant, whereas pulmonary artery pressure
tends to increase from apex to base in the erect posture.
Hyperinflation, pulmonary embolus, and shock all lead to a decrease in
pulmonary blood flow with consequent wasting of ventilation. (Benumof J. Respiratory Physiology and Respiratory Function During
Anesthesia, IN; Miller RD. Anesthesia,
Churchill, Livingstone, NY 1981; pp
699)
76.
C
The so-called West Zone 4 of the lung develops when there is interstitial
edema, and under those circumstances, there will be less transduction of fluid
across the capillary membrane. (Benumof J.
Respiratory Physiology and Respiratory Function During Anesthesia, IN;
Miller RD. Anesthesia, Churchill,
Livingstone, NY 1981; pp 699)
77.
A
Pressure = Flow ´
Resistance (i.e., mean pulmonary pressure = CO x pulmonary vascular resistance).
(Rogers MC, et al. Textbook
of Pediatric Intensive Care, 2nd Edition; pp 138)
78.
A, B
Regional hypoxic pulmonary vasoconstriction does not result in
significant elevation of pulmonary artery pressure, and it seems to be a
protective mechanism for the host. (Fishman AP. Civc
Research, 1976; 38:221)
79-80.
B, E
Compliance of the chest wall is described in option D.
Bronchiolitis primarily affects the airway. (Rogers MC, et al. Textbook
of Pediatric Intensive Care, 2nd Edition, 1992; pp 138-139)
81.
B
Dynamic compliance is smaller than static compliance because dynamic
compliance is equal to the change in volume divided by peak inspiratory pressure
minus PEEP, as opposed static compliance which equals volume divided by plateau
pressure minus PEEP. Since peak
inspiratory pressure is greater than the plateau pressure, the dynamic
compliance would be smaller than the static compliance. (Rogers MC, et al.
Textbook of Pediatric Intensive Care, 2nd Edition, 1992; pp
138-139)
82.
B
All other conditions are associated with decreased compliance. (Rogers
MC, et al. Textbook of Pediatric
Intensive Care, 2nd Edition, 1992; pp 138-139)
83.
A
In fact, airway resistance accounts for more than 80% of non-elastic
resistance. (Rogers MC, et al. Textbook
of Pediatric Intensive Care, 2nd Edition, 1992; pp 140-142)
84.
B
Time constant is the product of compliance and resistance, and therefore,
it is a dimensionless number. Mathematically,
63% of lung inflation or deflation occurs with one
time constant. (Rogers MC, et al. Textbook
of Pediatric Intensive Care, 2nd Edition, 1992; pp 142-143)
85.
B
Hyperinflation leads to increased physiologic dead space. (Rogers MC, et
al. Textbook of Pediatric Intensive
Care, 2nd Edition, 1992; pp 142-143)
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