Page 706 - ACCCN's Critical Care Nursing

Paediatric Considerations in Critical Care 683

developed intercostal and accessory muscles. The dia- As the infant liver is not completely mature at birth, glu-
phragm is the most important muscle for infants and coneogenesis is deficient, causing low and unstable blood
children in respiration, with abdominal muscles also sugar level in the first weeks of life. The infant is therefore
13
used. The compliant chest wall prevents generation of reliant on fat stores until normal feeding is established.
high intrathoracic pressures, meaning that infants and Formation of plasma proteins and clotting factors are
young children are unable to significantly increase tidal likely to be inadequate in the first weeks of life, thus all
volume; rather, they increase minute volume by breath- newborns in Australasia are given vitamin K shortly after
ing faster. This means that tachypnoea is a normal birth to prevent bleeding. Blood glucose monitoring and
response to illness in infants and children, and a slowing provision of early nutrition are essential aspects of care,
respiratory rate in children may indicate impending especially for infants. Children normally have increased
collapse rather than clinical improvement. 18,19 metabolic demands to achieve growth but have fewer
energy stores than adults.
Assessing airway patency is important. Talking and crying
indicates that the infant or child is maintaining their own
airway. Adventitious airway noises in children include OTHER SYSTEMS AND CONSIDERATIONS
wheeze, stridor and grunting. In infants, grunting may be The following section presents the paediatric consider-
heard and is an attempt by the baby to produce positive ations of the genitourinary, musculoskeletal and integu-
end-expiratory pressure (PEEP). Infants and children who mentary systems.
are grunting, gasping or unconscious need urgent assess-
ment for possible endotracheal intubation. 19 Genitourinary System
Other observed signs of respiratory distress in infants and The small developing pelvic bones of infants and young
children up to about eight years old include head bobbing children cause adult pelvic organs, such as the bladder,
in infants, nasal flaring, and paradoxical chest movement to be located in the lower abdominal cavity. Urine output
observed in several locations on the chest and known in children is calculated in mL/kg bodyweight/hour.
as recessions. Recessions can be observed at the costal In infants with immature kidney function and limited
margin, or subcostal; between the ribs, or intercostal; at ability to conserve water, urine output should be 1–2 mL/
the sternum, or sternal; and at the trachea, called tracheal kg/h. In the first month of life, infants have the capacity
tug. Oral feeding is difficult for infants in moderate to to concentrate urine to only 1.5 times their plasma osmo-
severe respiratory distress due to limitations associated lality, while adults can concentrate their urine to 3–4
with sucking and breathing at the same time. In addition, times their plasma osmolality. The higher metabolic rate
tachypnoea greater than 60–80 breaths/min may lead to of infants means that they produce twice the acid that an
20
vomiting and aspiration. For these reasons, initial adult will, leading to a tendency to acidosis in critical
22
enteral feeding might not be possible or desirable, so illness. By six months of age, normal urine output
nutrients should be given as parenteral nutrition (PN) should be 1 mL/kg/h, and by adolescence 0.5–1 mL/kg/h
until enteral feeding is tolerated. 21 is considered normal. Catheterisation is generally required
in critically ill infants and children for accurate hourly
Diagnosis of an upper or lower respiratory illness may be measurement of urine output. Where this is not possible,
made, using the history of the symptoms from the parent particularly where small sizes of indwelling catheters are
or the child when age-appropriate, in conjunction with not readily available, weighing nappies will provide an
physical assessment of the child. Assessment of the rate, interim estimate of urine output. Inserting feeding tubes
rhythm, effort and pattern of breathing according to age in place of a urinary catheter is not recommended.
as well as colour and agitation should be undertaken.
Similar to how heart rate is used to increase cardiac
output, children compensate to maintain oxygenation for
some time by breathing more rapidly until they become
fatigued, when they are likely to become hypoxic and Practice tip
ultimately apnoeic. Where catheterisation is not possible, nappies can be weighed
to estimate urine output. Use an indelible marker to record
the dry weight of a disposable nappy on the nappy itself. This
GASTROINTESTINAL TRACT weight is then subtracted from the nappy’s wet weight to give
There are few differences between the child’s and adult’s an estimate of volume, with 1 g equivalent to 1 mL.
gastrointestinal tract outside the neonatal period;
although a palpable liver below the costal margin is a
normal finding. It will be up to 3 cm below the costal
margin in normal infants, decreasing to 1 cm by 4–5 Musculoskeletal System
years of age, and should no longer be palpable in adoles- Children have less developed musculature than adults,
cents. In the neonate, a relative pancreatic amylase defi- with less protection from external forces that collide
ciency means utilisation of starches is less effective. Fats with the child. Conversely, a child’s skeleton is more
are also absorbed less well; the reason why higher- cartila ginous than adults and therefore more pliable. As
fat milks such as cow’s milk are not ideal for infants. a result, rib fractures rarely accompany chest trauma in
23
Protein synthesis and storage is however enhanced in children while lung contusions are common. The skel-
the neonate. 13 eton in children changes from less cartilaginous in