Pediatric Anatomy, Physiology, and Pathophysiology Flashcards
What is bronchopulmonary dysplasia?
Bronchopulmonary dysplasia is one of the long-term potential
consequences of the respiratory distress syndrome seen in
premature infants. It is characterized by a chronic disorder of
the lung parenchyma that involves hyperplasia of the smooth
muscle tissue of the airways, peribronchiolar fibrosis, enlarged
alveoli, and abnormalities in the pulmonary vasculature.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 1200.
When does the the anterior fontanelle normally
close? Prior to its closure, what information can be
ascertained by palpating it?
The anterior fontanelle normally closes between 9 and 18
months of age. Palpation of the anterior fontanelle can tell if it
is sunken or bulging. A sunken fontanell can indicate
dehydration while a bulging fontanelle may be indicative of
increased intracranial pressure from causes such as
hydrocephalus, intracranial hemorrhage, infection, or an
increased PaCO2.
Cote CJ, Lerman J, & Anderson BJ. A Practice of Anesthesia
for Infants and Children. 5th Ed. Philadelphia: Elsevier
Saunders; 2013: 10.
How does the resting oxygen consumption of an
infant compare to that of an adult?
The resting oxygen consumption of an infant is much higher
than the rate of an adult, which is why alveolar ventilation (on a
per-kilogram basis) is double that of adults.
Cote CJ, Lerman J, & Anderson BJ. A Practice of Anesthesia
for Infants and Children. 5th Ed. Philadelphia: Elsevier
Saunders; 2013: 127.
What temperature regulation compensatory
mechanisms does the neonate possess? What are
the disadvantages of this?
A normal neonate cannot shiver, increase activity, or
vasoconstrict effectively like an adult can. The only means of
responding to heat loss is nonshivering thermogenesis. A 2-
degree Celsius difference between the skin and core
temperature results in the release of norepinephrine which
stimulates the lipolysis of brown fat. The side effects of
nonshivering thermogenesis are increased oxygen consumption
and the production of ketone bodies and water. This has a
tendency to produce a metabolic acidosis and osmotic diuresis,
both of which are disadvantageous. Every attempt should be
made to regulate the neonate’s core temperature to prevent
nonshivering thermogenesis.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 1199-1200.
What premature neonates are at the highest risk for
postoperative apnea and bradycardia? When is the
risk the highest? What monitoring standards should
you employ?
Postoperative apnea and bradycardia is most likely to occur in
neonates who were premature, those with multiple congenital
anomalies, those with lung disease, and those with a history of
apnea and bradycardia. The risk is highest in the first 4-6 hours
after surgery, but can still occur for up to 12 hours
postoperatively. The conservative approach is to monitor all
infants younger than 60 weeks postconceptual age overnight.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 1200.
How does the presence of fetal hemoglobin affect
the oxyhemoglobin dissociation curve? When does
this change normally resolve?
At full-term, 50% of an infant’s hemoglobin is the fetal form,
which results in a leftward shift in the oxyhemoglobin
dissociation curve. Over the first week of life, the fetal
hemoglobin is replaced with the adult form of hemoglobin which
shifts the curve back to the right.
Cote CJ, Lerman J, & Anderson BJ. A Practice of Anesthesia
for Infants and Children. 5th Ed. Philadelphia: Elsevier
Saunders; 2013: 14.
Infants younger than what postconceptual age have
the greatest associated risk for postanesthetic
respiratory depression?
The greatest risk of postanesthetic respiratory depression
occurs in infants prior to 60 weeks postconceptual age.
Cote CJ, Lerman J, & Anderson BJ. A Practice of Anesthesia
for Infants and Children. 5th Ed. Philadelphia: Elsevier
Saunders; 2013: 14.
What is the difference between periodic breathing
and apnea of prematurity?
Periodic breathing consists of brief, recurrent pauses in
ventilation. Apnea of prematurity, however, is associated with
prolonged ventilatory pauses that are significant enough to
produce arterial hypoxemia and bradycardia. Both are more
common in premature infants.
Cote CJ, Lerman J, & Anderson BJ. A Practice of Anesthesia
for Infants and Children. 5th Ed. Philadelphia: Elsevier
Saunders; 2013: 14.
What would you expect to be the normal respiratory
rate for a newborn? A 6 month old? 12 month old? 5
year old?
The normal respiratory rate for a newborn is about 50
breaths/minute. By 6 months of age, it drops to about 30/min.
By 12 months of age, it is about 24 breaths/min and stays at
about that rate until 5 years of age.
Cote CJ, Lerman J, & Anderson BJ. A Practice of Anesthesia
for Infants and Children. 5th Ed. Philadelphia: Elsevier
Saunders; 2013: 13.
What is ‘transient tachypnea of the newborn’?
Normally, the first breath begins a sequence of expulsion of
pulmonary fluid through the airway and absorption of the fluid
into the lung interstitium and into the lymphatic vessels. In
some children, this removal of the fluid through the interstitium
may be delayed, producing a tachypnea that can last between
24 and 72 hours.
Cote CJ, Lerman J, & Anderson BJ. A Practice of Anesthesia
for Infants and Children. 5th Ed. Philadelphia: Elsevier
Saunders; 2013: 12.
How does alveolar developmenti in a full-term infant
compare to that of adults?
The alveoli don’t begin to truly develop in number until after
birth. They increase in number substantially until about 8 years
of age and in size when the chest wall ceases growing.
Cote CJ, Lerman J, & Anderson BJ. A Practice of Anesthesia
for Infants and Children. 5th Ed. Philadelphia: Elsevier
Saunders; 2013: 12.
Elective surgery on a preterm infant should be
delayed until they reach what postconceptual age?
Elective surgery on a preterm infant should be deferred until the
infant reaches 50 weeks postconceptional age. If surgery must
be performed prior to this time period, it is mandatory that the
infant be monitored with pulse oximetry for 24-48 hours
following surgery. Patients between 50 and 60 weeks
postconceptional age should be monitored closely for at least 2
hours in the postanesthesia care unit.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 898
A healthy 5 year-old is presenting for tonsillectomy.
What diagnostic tests should be performed on this
patient?
None. The current standard states that healthy children
presenting for minor elective procedures be spared the
unnecessary anxiety of blood drawing and have no labwork
performed.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 1231.
A 12-lead ECG of a newborn reveals upright T
waves in all the chest leads. Is this normal?
Yes. The T waves are upright in all chest leads at birth, but
become isoelectric or inverted in leads V1-V4 by one week of
age. They remain isoelectric or inverted until adolescence
when they become upright again. Failure of the V1-V4 T waves
to invert by one week of age can indicate right ventricular
hypertrophy.
Cote CJ, Lerman J, & Anderson BJ. A Practice of Anesthesia
for Infants and Children. 5th Ed. Philadelphia: Elsevier
Saunders; 2013: 15.
How does the normal resting cardiac output of an
infant compare to that of an adult?
A healthy, full-term infant has a cardiac output that is about 2-3
times that of an adult (based on weight)
Cote CJ, Lerman J, & Anderson BJ. A Practice of Anesthesia
for Infants and Children. 5th Ed. Philadelphia: Elsevier
Saunders; 2013: 15.
