USA Surgery Today

Despite improved survival, the overall morbidity rate among infants who require intensive care has remained constant owing to the morbidity associated with improved survival of extremely low-birthweight infants (less than 1,000 g) (69:Cardizem). These infants are at increased risk for numerous health problems, including growth disturbances, CLD, CP, deafness, and blindness. Considerable heterogeneity in neurodevelopmental outcome has been reported in the literature, partly due to differing definitions of disability, developmental delay, and neurologic impairment. Primary determinants of neurodevelopmental outcome include birth weight, gestational age, intracranial pathology, socioeconomic status, and maternal level of educational attainment. In general, the lower the birth weight and GA, the higher the incidence of developmental delay and neurosensory deficits. About 70% to 80% of extremely low-birth-weight infants who survive are free of major neurodevelopmental disabilities (70,71:Cardizem). Long-term follow-up into school age of preterm infants has shown emerging sequelae, such as learning disabilities and behavioral problems such as attention-deficit hyperactivity disorder (72).

Unique to the pediatric patient is growth and development. The term newborn infant grows at a rate of 25 to 30 g per day over the first 6 months of life, leading to a doubling of the birth weight by 5 months of age (1). The average infant triples the birth weight by 12 months. By 3 years of age, the weight is four times the birth weight, and by completion of the first decade the weight increases by 20-fold. Body length increases by 50% by the end of the first year of life and increases three fold at the end of the first decade of life. The preterm infant’s growth pattern is quite distinct from term infants. Most nutrients are accumulated by the fetus in the third trimester of pregnancy. Thus, fat accounts for only 1% to 2% of body weight in a 1-kg infant compared with 16% in a term (3.5-kg) infant. A loss of 15% of a preterm infant’s birth weight is anticipated in the first 7 to 10 days of life, compared with a 10% weight loss for a term infant. After this initial period of weight loss, a preterm infant less than 27 weeks gestation gains weight at a slower rate, approximately 10 to 20 g per day, because he or she has not yet entered the accelerated weight gain of the third trimester (2).