WIP 71 - Body Composition Assessment Using Point-Of-Care Ultrasound for Infants Admitted to the Neonatal Intensive Care Unit

Poster Number: WIP 71
Publication Number: WIP 71.2391

Background: Fat-free mass accretion is associated with improved neurodevelopment and metabolic health in preterm infants. Current body composition techniques are not feasible in unstable infants admitted to the neonatal intensive care unit (NICU). In older children and adults ultrasound is routinely used to measure muscle area to guide nutritional management. Determining the utility of point-of-care ultrasound as a body composition assessment tool in NICU infants is important to help guide future nutritional management and optimization of growth for vulnerable premature infants.

Objective: This study aims to assess if ultrasound measurements of rectus femoris and biceps muscle area in infants are feasible, safe, and reliable. This study also aims to investigate the relationship between biceps and rectus femoris muscle area with infant anthropometrics and nutritional intake.

Design/Methods: This is a pilot, prospective observational study recruiting infants from 24-46 weeks admitted to the NICU. Infants have ultrasound measurements, mid-upper arm circumference, mid-thigh circumference, abdominal circumference, and foot length measured every other week. Nutritional prescription and standard anthropometrics are collected weekly.
Three static cross-sectional images of each biceps and rectus femoris muscle are obtained per ultrasound session. For the first twelve subjects, a second neonatologist obtains a single image of each muscle for assessment of inter-rater reliability using intraclass correlation. Images are reviewed by an ultrasound radiologist to ensure accuracy. Muscle cross-sectional area measurements are obtained using polygon tool on Horos image software.
Data analysis will include intraclass-correlation coefficients to assess reliability and linear mixed regression models comparing biceps/rectus femoris muscle area with recorded growth and nutrition parameters. IRB approval has been obtained. To date, 19 sets of ultrasounds and measurements from ten subjects have been obtained. There have been no safety events. Target enrollment by March 2024 is 30 subjects.