[Perioperative infusion therapy in children]

An incorrect fluid therapy can lead to serious complications considerably more rapidly in children, especially in newborns and infants, than in adults. The pediatric patient has a limited range of compensation for maintenance of fluid and electrolyte balance. Precise knowledge of the physiological age-dependent fluid balance, i.e. the large extracellular space, the developing renal function, the increased metabolism, the acid-base state, the electrolyte balance with the relatively higher sodium and chloride requirements must be the basis of an adequate fluid therapy. The basic fluid requirement (normal fluid and electrolyte requirement) varies with age and is influenced considerably by environmental conditions, body temperature and metabolism. For substitution of this basic fluid requirement one-third to one-half strength electrolyte solution in 5% dextrose is used, the amount depending on age. The perioperative fluid requirement, however, has to be calculated with due consideration for the characteristic changes in fluid and electrolyte balance during anaesthesia and surgery, the preoperative fasting period, drug effects of anesthetics, hormonal changes and ventilation; it is higher than the basic fluid requirement (infants 6-8 ml.kg-1.h-1, toddlers 4-6 ml.kg.h-1, schoolchildren 2-4 ml.kg-1.h-1). For intraoperative fluid therapy infusions with an increased sodium concentration (70-100 mmol/l) or Ringer's lactate (Na+ = 130 mmol/l) must be used. On no account must electrolyte-free solutions, e.g., 5-10% glucose, be used intraoperatively, as they can lead to water intoxication. The third-space requirements compensate for the additional losses by drainage, third-space deficits by evaporation and gastric and enteral secretions.(ABSTRACT TRUNCATED AT 250 WORDS)