Lesson 1: Standardizing Care of the Preterm Infant
1.1 The Value of Standardized Feeding Guidelines for Preterm Infants
Picture used with kind permission of Dr. Darius Gruszfeld
Units 1 and 2 of this module have outlined the importance of optimizing the nutritional care of preterm infants, and presented specific nutrient recommendations based on the most current evidence. Often, however, there can be gaps between theory and practice. Preterm infants are frequently medically unstable and require round-the-clock intensive care. Provision of optimal nutritional care can be overshadowed by an infant's acute medical issues. Medical instability and fears of increasing the infant's risk of NEC can sometimes lead to a delay in initiating or advancing enteral feeds.
Early nutrition is so important both for the short and long-term health of preterm infants, that it should be awarded the status of a critical medical issue. As two experts have written:
"Infants born at around 24 completed weeks' gestation are composed of approximately 90% water, with the remainder being protein with virtually no lipid...Protein in organs and muscle represent the largest potential energy 'store' but if catabolized for energy will no longer be functionally available. A typical 500g baby at 24 weeks is only composed of approximately 50g of dry tissue. Even if one third of that protein could be utilized for energy, that still only represents potential energy stores of around 50 kcal, barely enough to meet basal metabolic energy requirements for the first 24h. Delivery of an extremely preterm infant (e.g.<28 weeks' gestation) deserves to be viewed as a nutritional emergency.”
(Embleton & Simmer 2014)
As already mentioned in Unit 1, Lesson 2 of this module, established and standardized feeding guidelines can help optimize the nutritional care of preterm infants in several ways. Nutritional practices vary considerably across different neonatal care centers. Implementation of protocols or processes that have been found effective can have a positive impact on outcomes for premature infants. In a study by Bloom and colleagues differences among neonatal care centers with higher and lower weight gain in very low birth weight (VLBW) infants were analyzed. Processes unique to the centers where higher weight gains were achieved were identified. These "meaningful differences” were provided to the centers where weight gains were lower, resulting in improvements in outcomes at 76% of the sites (Bloom et al. 2003).
Practice variation within individual neonatal care units can also be reduced. Implementation of an evidence-base feeding guideline can lead to more rapid attainment of full enteral feeds and improved growth velocity in preterm infants. Such protocols can provide guidance for managing feeding intolerance or correcting reduced growth velocity as soon as it is detected (Ehrenkranz 2014).
Studies have also shown that the provision of nutritional support is influenced in practice by the clinical status of a preterm infant. In many cases, less nutrition is provided to the sickest of infants who might benefit from it the most. A study by Ehrenkranz and colleagues in 2011 used data from 1366 ELBW infants to demonstrate that the infants who were perceived to be more critically-ill based on their ventilation status at day 7 of life received significantly less nutritional support in the first three weeks of life than their counterparts who were perceived to be more medically stable (Ehrenkranz et al. 2011). At the same time, the risks of adverse outcomes among the infants perceived to be more critically ill were found to be mediated by the total daily energy intake during the first 7 days of life. The adverse outcomes included poorer growth velocity, increased rates of late-onset sepsis, death, moderate or severe bronchopulmonary dysplasia, longer hospital stays, and worse neurodevelopmental outcomes at 18-22 months adjusted gestational age. Therefore, the use of a standardized guideline could minimize the variation in nutritional support and contribute to improved short to mid-term outcomes, particularly in the most fragile infants (Ehrenkranz 2014).
Concerns about NEC loom large in decisions about preterm infant feeding (See unit 1, lesson 2.6 of this module). Here again, standardized feeding guidelines have been shown to be beneficial. A meta-analysis of 6 studies focusing on the incidence of NEC before and after implementation of standardized feeding regimens showed a pooled risk reduction of 87% (Patole & de Klerk 2005). The authors felt that this benefit may have resulted as much from the process of putting a practice standard into place as from the actual details of the practice standards used.
Neonatal nutritionists are vital members of the neonatal care team and can supervise the implementation of standardized nutritional guidelines (Ehrenkranz 2014).
