Physiologic and Psychological Considerations
Surgery generates a neuroendocrine stress response in neonates,
infants, and children,[6]
[90]
resulting in undesirable alterations of the metabolic state and immune function.
[91]
Epidural anesthesia diminishes or even suppresses
this stress response[92]
[93]
and is well tolerated in children. Central blocks do not affect left ventricular
function[94]
and are virtually free of measurable
hemodynamic effects, at least up to the age of 8 years. A well-designed study[95]
evaluated systemic and pulmonary hemodynamic changes during epidural anesthesia in
children. The investigators did not find any change in regard to mean blood pressure,
end-diastolic diameter of the left ventricle, ejection fraction of the left ventricle,
and mean velocity circumferential fiber shortening. Pulmonary Doppler flow velocity
decreased during epidural anesthesia, probably because of an increase in the pulmonary
arterial resistance. Preloading with saline is not recommended in children, and
even in adolescents, fluid therapy or injection of vasoactive agents is rarely required.
Children are frightened by the new environmental conditions in
the operating room,[96]
and most of them cannot
cope with their anxiety. They feel abandoned by their parents and threatened by
the strangers who intend to use needles, which they fear. Even if they wish to cooperate,
they do not have a complete body image until the age of 10 years, which does not
let them clearly distinguish between adjacent parts of their body such as forearm
and arm. They usually cannot understand the concept of paresthesia and that of differential
block (i.e., "touch" is not "pain"). Localization of nerve trunks and anatomic spaces
has to be done by physical means such as electrical stimulation or loss-of-resistance
(LOR) techniques, which do not depend on the patient's cooperation. Therefore, sedation
or, preferably, light general anesthesia before any block is desirable because most
of these patients are healthy and express the desire to be unconscious during surgery.
Regional anesthesia has important psychological effects on the
patient, the parents, and the medical team. A pain-free postoperative course improves
the morale of the patient, the parents, and the nurses. The surgeon is happy to
examine a calm, alert, and manageable patient in the postoperative period. Occasionally,
regional anesthesia can result in negative psychological effects; persistence of
motor and even sensory block during the postoperative course may be frightening to
some children, especially those between 3 and 5 years of age, and sometimes to their
parents. This anxiety can be reduced by friendly environmental conditions and precise
preoperative explanations about the expected course of events during the postoperative
period. In any case, a motor block must be avoided when not absolutely required
for surgery.
