Nutrition for ill neonates.

From early in this century, investigators have attempted to determine the optimal nutrient delivery for term infants to promote normal growth and development. In the past 25 years, nutritional investigators have concentrated on the needs of the ideal, healthy preterm infant to try to mimic intrauterine growth and body composition. Although great progress has been made in characterizing the needs of healthy preterm and term infants, the needs of ill, physiologically unstable infants largely have been neglected. The primary reasons for this lack of investigation are the assumption that the needs of ill infants are similar to those of healthy infants and the difficulty of studying metabolic needs in ill infants. The persistent efforts of several groups of investigators and the development of new techniques to study metabolism now have begun to delineate the specific nutritional needs of this particular patient population. Drawing on models generated in the adult surgical intensive care literature of the 1980s makes it possible to try to elucidate the effect of common illnesses and conditions (eg, acute pulmonary disease, bronchopulmonary dysplasia [BPD], congenital heart disease [CHD], sepsis, and surgery) on neonatal metabolism and, therefore, nutritional requirements. The assumption is that changes from the norm in metabolism require alterations in substrate delivery (ie, nutrition). As with adults, it is likely that each illness induces characteristic changes in metabolism. The task for the practitioner is to customize nutritional delivery to fit the specific infant’s needs. We will review current knowledge about the metabolic changes induced by common neonatal illnesses by comparing the nutritional needs of ill infants with the wellestablished standards for healthy newborns. Nutritional needs induced by some diseases have been characterized better than others. For example, there is an extensive literature on the energy (but not the protein) needs of infants who have BPD. The protein and energy needs of infants undergoing surgery have received substantial attention recently. Other aspects of neonatal nutrition, particularly micronutrient requirements, have not been studied specifically in ill compared with healthy infants. Where possible, we have attempted to make specific recommendations for nutrient delivery when such values are available.