BACKGROUND: Children who are critically ill frequently experience inadequate nutrition, resulting in changes in body composition. We investigated the nutrition status and body composition changes among children with prolonged stays in the pediatric intensive care unit (PICU), utilizing midupper arm circumference (MUAC), and triceps skinfold thickness (TSF) measurements. METHODS: A single-center prospective cohort study monitored nutrition support for children admitted to the PICU for over 6 days. MUAC and TSF were measured at admission and every other day through the 15th day of the PICU stay. Target energy was caculated using the Schofield formula without stress correction, and recommended protein intake was set at 1.5 g/(kg/d). Factors influencing changes in anthropometry were analyzed through pairwise correlation and regression analysis. RESULTS: Sixty children with a median PICU stay of 9 days were included. MUAC decreased by 2.53% in the first week and by 7.42% over 2 weeks. During the first week, average energy and protein intakes were only 53.0% and 41.3% of recommended levels, respectively. Decreases in MUAC correlated with mean cumulative energy deficits (1 week: r = 0.310 [P = 0.016]
2 weeks: r = 0.504 [P = 0.023]) and mean cumulative protein deficits (1 week: r = 0.304 [P = 0.018]). CONCLUSIONS: Many children with longer PICU stays did not met energy and protein recommendations. Decreases in MUAC were associated with deficits in energy and protein intake. Monitoring MUAC is a valuable tool for assessing nutrition support adequacy in children with longer PICU stays.