(Click here to return to the Pediatric
Surgery @ Brown Home Page)
SURGICAL ISSUES IN INFANTS
Infants with surgical problems frequently present with fluid
losses and are variably dehydrated. This is where you need to
think about the physiology of the congenital anomaly. Remember
your goals in providing fluid therapy: replace losses, provide
for maintenance requirements and estimate ongoing losses. For
instance, there is not much reason to suspect that an infant
promptly diagnosed with esophageal atresia /TEF is tremendously
dehydrated ( remember he/she just came off placental bypass and
hasnt needed to depend on GI absorption yet.
This is where it is important to assess the individual
patient and not make cookbook decisions and this is where experience
is essential. Still, you can start by making educated guesses
and frequently reassessing the outcomes of your intervention.
These measures will be those of adequate perfusion - heart rate,
blood pressure, capillary refill, skin color and most importantly
urine output. This requires attention to detail and a lot of
number crunching. Inadequate perfusion is as treacherous as fluid
overloading. Remember, the ductus arteriosus is supposed
to close postnatally, triggered by the reduced resistance in
the pulmonary bed. Simplistically, think of sudden excess fluid
as resulting in a full pulmonary bed, triggering shunting, which
unless reversed leads to hypoxemia and worsens the pulmonary
hypertension. Therefore, be careful about the rate of bolusing
fluids and anticipate losses so that the baby doesnt face
repeated sudden volume expansion.
| In contrast, the infant with gastroschisis
has an immediate potential for significant fluid losses - in
patients with relatively normal looking bowel surfaces that are
immediately enclosed, those losses are probably less significant
that in infants with a weeping/inflamed serosal surface.
These examples give you a baseline appreciation for the
variability in neonatal fluid management and hopefully will stimulate
curiosity about the individual physiologic concerns. They also
point out that babies can be categorized as euvolemic, mildly
dehydrated or significantly dehydrated and that general principles
can then be applied. Thinking of volumes per unit body weight
is much more meaningful in this instance than speaking in terms
of total fluid rates or volumes.
|| Some infants, such as diaphragmatic hernia
(CDH) babies, are set-ups for pulmonary hypertension. Although
they need an adequate circulating volume for good perfusion and
the avoidance of metabolic acidosis, this is often balanced with
some inotropic support from dopamine or dobutamine to artificially
keep systemic arterial pressures and -resistance greater than
their pulmonary coutnerparts and avoid ductal shunting.
here to return to Hasbro Children's Hospital Surgery Handbook