Nutrition, growth and body composition in preterm infants

The goal of neonatal nutrition in the preterm infant is to achieve postnatal growth and body composition approximating that of a normal fetus of the same postmenstrual age and to obtain a functional outcome comparable to infants born at term. However, in clinical practice such a pattern is seldom achieved, with growth failure and altered body composition being extensively reported. The BabyGrow preterm nutrition study was a longitudinal, prospective, observational study designed to investigate nutrition and growth in 59 preterm infants following the implementation of evidence-based nutrition guidelines in the neonatal unit at Cork University Maternity Hospital. Nutrient delivery was precisely measured during the entire hospital stay and intakes were compared with current international recommendations. Barriers to nutrient delivery were identified across the phases of nutritional support i.e. exclusive parenteral nutrition and transition (establishment of enteral feeds) phases of nutrition and nutritional strategies to optimise nutrient delivery were proposed according to these phases. Growth was measured from birth up to 2 months corrected age and body composition was assessed in terms of fat mass and lean body mass by air displacement plethysmography (PEA POD) at 34 weeks gestation, term corrected age and 2 months corrected age. Anthropometric and body composition data in the preterm cohort were compared with a term reference group from the Cork BASELINE Birth Cohort Study (n=1070) at similar time intervals. The clinical and nutritional determinants of growth and body composition during the neonatal period were reported for the first time. These data have international relevance, informing authoritative agencies developing evidence-based practice guidelines for neonatal nutritional support. In the future, the nutritional management of preterm infants may need to be individualised to consider gestational age, birth weight as well as preterm morbidity.

Improving the care of preterm infants: before, during, and after, stabilisation in the delivery room

Introduction Up to 10% of infants require stabilisation during transition to extrauterine life. Enhanced monitoring of cardiorespiratory parameters during this time may improve stabilisation outcomes. In addition, technology may facilitate improved preparation for delivery room stabilisation as well as NICU procedures, through educational techniques. Aim To improve infant care 1) before birth via improved training, 2) during stabilisation via enhanced physiological monitoring and improved practice, and 3) after delivery, in the neonatal intensive care unit (NICU), via improved procedural care. Methods A multifaceted approach was utilised including; a combination of questionnaire based surveys, mannequin-based investigations, prospective observational investigations, and a randomised controlled trial involving preterm infants less than 32 weeks in the delivery room. Forms of technology utilised included; different types of mannequins including a CO2 producing mannequin, qualitative end tidal CO2 (EtCO2) detectors, a bespoke quantitative EtCO2 detector, and annotated videos of infant stabilisation as well as NICU procedures Results Manual ventilation improved with the use of EtCO2 detection, and was positively assessed by trainees. Quantitative EtCO2 detection in the delivery room is feasible, EtCO2 increased over the first 4 minutes of life in preterm infants, and EtCO2 was higher in preterm infants who were intubated. Current methods of heart rate assessment were found to be unreliable. Electrocardiography (ECG) application warrants further evaluation. Perfusion index (PI) monitoring utilised in the delivery room was feasible. Video recording technology was utilised in several ways. This technology has many potential benefits, including debriefing and coaching in procedural healthcare, and warrants further evaluation. Parents would welcome the introduction of webcams in the NICU. Conclusions I have evaluated new methods of improving infant care before, during, and after stabilisation in the DR. Specifically, I have developed novel educational tools to facilitate training, and evaluated EtCO2, PI, and ECG during infant stabilisation. I have identified barriers in using webcams in the NICU, to now be addressed prior to webcam implementation.

Establishment and development of infant gut microbiota

The nascent gut microbiota at birth is established in concert with numerous developmental parameters. Here, in the INFAMTET study, we chronicled the impact of some factors which are key determinants of the infant gut microbiota, namely; mode of birth, gestational age, and type of feeding. We determined that the aggregated microbiota profile of naturally delivered, initially breastfed infants are relatively stable from one week to six months of age and are not significantly altered by increased duration of breastfeeding. Contrastingly, there is significant development of the microbiota profile of C-section delivered infants, and this development is significantly influenced by breastfeeding duration. Preterm infants, born by either mode of birth, initially have a high proportion of Proteobacteria, and demonstrate significant development of the gut microbiota from week 1 to later time-points. The microbiota is still slightly, but significantly, affected by birth mode at one year of age although no specific genera were found to be significantly altered in relative abundance. By two years of age, there is no effect of either birth mode or gestational age. However this does not preclude the possibility that symptoms developed later in life, which are associated with preterm or C-section birth, are as a result of the early perturbation of the neonatal gut microbiota. It is likely that the combination of relatively low exposure (breast fed), high exposure (formula fed) or delayed exposure (C-section and preterm) to specific antigens and the resulting inflammatory responses, in this crucial window of host-microbiota interaction, influence systemic health of the individual throughout life.