Nutritional Assessment in Preterm Infants: A Practical Approach in the NICU

Abstract

A practical approach for nutritional assessment in preterm infants under intensive care, based on anthropometric measurements and commonly used biochemical markers, is suggested. The choice of anthropometric charts depends on the purpose: Fenton 2013 charts to assess intrauterine growth, an online growth calculator to monitor intra-hospital weight gain, and Intergrowth-21st standards to monitor growth after discharge. Body weight, though largely used, does not inform on body compartment sizes. Mid-upper arm circumference estimates body adiposity and is easy to measure. Body length reflects skeletal growth and fat-free mass, provided it is accurately measured. Head circumference indicates brain growth. Skinfolds estimate reasonably body fat. Weight-to-length ratio, body mass index, and ponderal index can assess body proportionality at birth. These and other derived indices, such as the mid-upper arm circumference to head circumference ratio, could be proxies of body composition but need validation. Low blood urea nitrogen may indicate insufficient protein intake. Prealbumin and retinol binding protein are good markers of current protein status, but they may be affected by non-nutritional factors. The combination of a high serum alkaline phosphatase level and a low serum phosphate level is the best biochemical marker for the early detection of metabolic bone disease.

Customized Human Milk Fortification Based on Measured Human Milk Composition to Improve the Quality of Growth in Very Preterm Infants: A Mixed-Cohort Study Protocol

“…Weight gain velocity (g/kg/day) is calculated using an exponential model [ 51 ]. The same observer (MMC) measures the length and head circumference weekly, according to recommended methods [ 52 , 53 ], to calculate linear and head growth velocities (cm/week). At term, postmenstrual age (around 40 weeks), the fat mass (FM), FFM, %FM, percentage of FFM (%FFM), and FM index (FMI) are assessed using displacement plethysmography (Pea Pod, Cosmed, Italy), as previously described [ 35 ].…”

Enteral Nutrition in Term Infants with Congenital Heart Disease: Knowledge Gaps and Future Directions to Improve Clinical Practice

“…The assessment of the body composition could better correlate with clinical outcomes. Body fat mass can be estimated by mid-upper arm circumference, lean mass by body length, and cerebral growth by head circumference [ 51 ]; a lower adiposity has been associated with a delayed recovery, a prolonged need for mechanical ventilation, and for vasoactive treatments [ 52 ].…”

“…Prealbumin, also known as transthyretin or thyroxine-binding prealbumin, has a half-life life of 24–48 h and thus reflects acute protein intakes. This protein is synthetized by the liver and excreted by the kidneys, so its values may be altered in cases of renal or liver disease [ 51 , 53 ]. Blood urea nitrogen (BUN) may better correlate with protein intake during enteral feeding in clinically stable newborns; however, BUN may be influenced by renal function, hydration status, and amino acid oxidation for energy production in critically ill patients [ 54 ].…”

Catch-up growth and nutritional status of preterms born at a Ugandan tertiary hospital: An Observational study.

“…We enrolled children who were born preterm/LBW; these are a high risk for undernutrition [22] and this may explain the high prevalence of stunting demonstrated by our results. The prevalence of stunting in the children under-5 years based on a Uganda national survey was 29% [23].…”