Nutritional intakes over time and perioperative nutrition in extremely preterm infants

Abstract

Background: Despite improvements in nutrition practice during the last decades, problems still exist in meeting estimated nutritional needs, especially for extremely preterm (EPT) infants. Today, it is still not known how optimal nutrition and growth will hold in the future. The objectives of this thesis were i) to investigate changes over time regarding nutrition practice in Stockholm and the associations on growth and morbidities such as bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP), and ii) to investigate perioperative nutrition surrounding ductal ligation for patent ductus arteriosus (PDA) of EPT infants born in Sweden.

Methods: This is a population based study of EPT infants born in Sweden before 27 completed gestational weeks between 2004 and 2011 and who survived >24 h (n=489). Detailed nutritional data retrieved from hospital records including all fluid intakes supplied intravenously and enterally together with anthropometrical data were retrospectively registered in Nutrium, a nutrition calculating software. Comprehensive data on cohort characteristics, neonatal morbidity and mortality were obtained from the Extremely Preterm Infants in Sweden Study (EXPRESS) and the Swedish National Quality register.

Results: Nutritional intakes in Stockholm have increased continuously over time during 2004 to 2011and growth improved significantly during later years compared to year-group 2004-2005, (Paper I). The enteral feed advancement and time to full feeds during the year-group 2008-2009 were faster compared to all other years. During the years 2010 to 2011, the proportion of parenteral nutrition was larger and median time to full feeds decreased compared to all other years. Initial growth restriction was reduced by higher energy and protein intake the first week and lower risk of BPD and ROP was associated with higher energy intake the first month, (Paper II). The estimated absolute risk of BPD and ROP decreased when energy intake on days 7 to 27 increased from 110 to 120 and 120 to 130 kcal/kg/d. Reduced risk of BPD was associated with higher energy- and protein intake despite critical illness (>10 days mechanical ventilation), which was not the case in ROP. Perioperative nutrition surrounding ductal ligation for PDA is suboptimal in Sweden, (Paper III). Energy, protein and fat intake were not improved on the third day post-surgery compared to the third day prior surgery. Moreover, protein intake during postneonatal period (> 28 days) was significantly lower in infants undergoing ductal ligation compared to those operated between days 7 and 27. Nutritional intakes between NICUs in Sweden differed, particularly regarding intakes of total, enteral and parenteral fluids, (Paper IV). On the day of ductal ligation, nutritional intakes at all NICUs were lower compared to the other perioperative days.

Conclusions: This thesis highlights the importance of neonatal nutrition. Increased nutritional intake during the first postnatal week and month are associated with reduced initial growth restriction and morbidity. We conclude that there is room for improvement regarding nutritional intakes and growth in general and surrounding perioperative week in particular. More research is needed to investigate the special nutritional needs of vulnerable, ill EPT infants.