Nutritional and Metabolic Studies in Term and Preterm Infants

Medicine, Nutrition

Forsyth, James Stewart

University:University of Glasgow

关键词: Medicine, Nutrition;   

Others  :  http://theses.gla.ac.uk/75209/1/13815366.pdf

来源: University of Glasgow

【 摘 要 】

NUTRITIONAL AND METABOLIC STUDIES IN TERM AND PRETERM INFANTS. SUMMARY The nutritional management of the newborn infant continues to be plagued by fundamental issues which are the subject of much confusion and contradiction. There is not only an urgent need to clarify these issues, but also a need to widen our knowledge and understanding of many aspects of infant nutrition especially that relating to the preterm infant. This Thesis considers nutritional issues in both term and preterm infants. The issues addressed in the term infant are first, the aetiology of the condition breast milk jaundice, and second, whether the practice of early solid feeding is harmful to the infant. The studies in the preterm infant are aimed at providing nutritional data on the sick ventilated infant. MEASUREMENT OF ENERGY EXPENDITURE AND NUTRIENT UTILISATION IN VENTILATOR-DEPENDENT VERY LOW BIRTHWEIGHT INFANTS. With neurodevelopmental outcome of very low birth weight infants being adversly affected by inadequate nutrition during the first few weeks of life, there is an urgent need for more specific nutritional data on the sick VLBW ventilator-dependent infant. To date there is no calorimetry data on these infants because of technical difficulties relating to the practice of using continuous flow ventilators for neonatal ventilation. With differences in gas concentrations between inspiratory and expiratory circuits being so small, a system of considerable accuracy and precision is required. INVESTIGATION OF THE AETIOLOGY OF BREAST MILK JAUNDICE The aetiology of breast milk jaundice, an unconjugated hyperbilirubinaemia occurring in approximately 2-4% of breast fed infants, remains uncertain. It has been suggested that elevated free fatty acid concentrations within the breast milk inhibit hepatic glucuronyl transferase activity and their presence is the consequence of the activity of an abnormal lipase which has the chemical characteristics of bile salt-stimulated lipase but does not require prior stimulation by bile salts. For this conclusion to be drawn it was assumed that bile salts were not present in breast milk. There being no studies to support this assumption an investigation of breast milk for the presence of bile salts was undertaken. A STUDY TO DETERMINE IF EARLY SOLID FEEDING IS HARMFUL TO THE INFANT. Despite the professional advice that solid foods should not be introduced before 3 months of age the OPCS survey of 1980 showed that 56% of infants were introduced to solids before this time and the proportion increased to 62% when the survey was repeated in 1985. The reasons put forward for discouraging the premature introduction of solids include the possible risk of excessive weight gain, vulnerability of the gut to infection, and increased susceptibility to the development of allergic disease. A prospective clinical study was undertaken to determine the influence of the early introduction of solid foods on weight gain, the risk of gastro-intestinal disease and the risk of allergic disorders during the first 2 years of life. Special consideration was given to design and methodology, in particular, sample size, accuracy of feeding data, definition of outcomes, data collection and potential confounding variables. In this study 9.7% of infants were commenced on solids before 8 weeks and 4 9.4% between 8 and 12 weeks of age. Solids were introduced earlier in infants who were male, who were from lower socio-economic groups and who were bottle fed. After adjustment for confounding variables the introduction of solids before 13 weeks of age was associated with increased weight gain in infants at 8, 13 26 and 52 weeks but not at 104 weeks. Before and after adjustments for confounding factors, the incidence of gastro-intestinal infection was not influenced by the timing of the introduction of solids. Similarly, the early introduction of solids was not associated with an increased incidence of napkin dermatitis or wheeze. The incidence of eczema was increased at two years in infants who received solids between 8-12 weeks. There was increased incidence of respiratory illness at 14-26 weeks, and persistent cough at 14-26 and 27-39 weeks in early solid feeding infants.(Abstract shortened by ProQuest.).