Understanding Anesthesiology - The Global Regional Anesthesia ...

from non-specific stimuli as well as from direct irritation
of the vocal cords by blood or secretions. In order
to avoid laryngospasm, pediatric patients are extubated
either at a deep plane of anesthesia or wide
awake.
The pediatric patient is more prone to hypoxemia than
most adults. Like the obstetric patient, children have a
slightly smaller functional residual capacity (FRC) (Table
19). The FRC acts as a reserve tank of oxygen during
apneic periods. In addition, the pediatric patient
has a markedly increased oxygen consumption which
Table 18 Pediatric ETT sizes
AGE
ETT SIZE
TERM NEWBORN 3.0-3.5
0-12 MONTHS 3.5
1-2 YEARS 4.0
3 YEARS 4.5
4-5 YEARS 5.0
6-8 YEARS 5.5
8-9 YEARS 6.0
10-12 YEARS 6.5
Table 19 Oxygen reserve, delivery and consumption
CHILD
ADULT
FRC (mL/kg) 30 35
Va (mL/kg) 150 60
Va/FRC 5 1.5
VO2 (mL/kg./min) 7.5 3.5
FRC=functional residual capacity, VA =minute alveolar
ventilation, VO2=minute oxygen consumption
is usually maintained with an increased minute ventilation.
The result of both of these factors is that the pediatric
patient will desaturate much more rapidly during
apnea. Adequate pre-oxygenation is key to the airway
management of the pediatric patient.
Cardiovascular
Infants and young children have a heart-rate dependent
cardiac output. This means that with bradycardia,
their stiff left ventricles are unable to increase stroke
volume to maintain cardiac output. This explains why
bradycardia is undesirable in pediatric patients. Curiously,
the pediatric patient is relatively “vagotonic”. In
other words, their vagus nerve is dominant and they
are prone to developing bradycardia in response to cer-
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