331 - Nil per os days and relationship to adverse in-hospital outcomes among very preterm infants

Publication Number: 3319.331

Katie M.. Strobel, University of Washington School of Medicine, Seattle, WA, United States; Gabriel Byram, Pacific Northwest University of Health Sciences, Yakima, WA, United States; Olivia C. Brandon, University of Washington School of Medicine, Seattle, WA, United States; Sandy Huang, University of Washington School of Medicine, Sammamish, WA, United States; Elizabeth Riffel, St. Joseph's Children's Hospital, Tacoma, WA, United States; John Haddock, St. Joseph Medical Center, Puyallup, WA, United States; Addysen Pulley, University of Washington School of Medicine, Puyallup, WA, United States; Sophia Rodriguez, University of Washington School of Medicine, Kirkland, WA, United States; Clara G.. McAdams, University of Washington School of Medicine, Tacoma, WA, United States; Ineeya Senthilnathan Kayal, University of Washington School of Medicine, Seattle, WA, United States; Virginia Higgins, University of Washington School of Medicine, Edina, MN, United States; Natalie Chapkis, Seattle Children's/ University of Washington, Seattle, WA, United States; Laura A.. Boyce, Seattle Children's, Tacoma, WA, United States; Jill Irvine, university of washington medical center, seattle, WA, United States; Kim Deynaka, St Joseph Medical Center, Tacoma, WA, United States; Robin G. LaGrandeur, University of Washington School of Medicine, Seattle, WA, United States; Sarah Kolnik, University of Washington - Seattle Children's Hospital, Seattle, WA, United States; Krystle Perez, University of Washington School of Medicine, Snohomish, WA, United States; Rebecca Hoban, Seattle Children's, Seattle, WA, United States; Gregory C. Valentine, University of Washington School of Medicine, Tacoma, WA, United States

Background: Very preterm infants (VP) are susceptible to intestinal dysmotility, which often leads to feeding pauses even in the absence of necrotizing enterocolitis (NEC) or spontaneous intestinal perforation (SIP). Understanding the effect of nil per os (NPO) days when NEC or SIP are not present is essential for reducing iatrogenic adverse outcomes.

Objective: To examine how the number of NPO days in the first 28 days in the absence of NEC/SIP relates to morbidities and growth after adjusting for severity of illness markers.

Design/Methods: This is a retrospective study of infants born 22w0d - 31w6d gestational age (GA) without a congenital gastrointestinal anomaly admitted to 2 level III/IV neonatal intensive care units from 2017-2024. Infants who developed NEC, SIP, died prior to discharge, or transferred prior to 36 weeks gestation were excluded. Total NPO days in the first 28 days were evaluated; a sensitivity analysis excluded infants with > 7 NPO days. Outcomes retinopathy of prematurity (ROP) requiring treatment, bronchopulmonary dysplasia (BPD), and late-onset sepsis were analyzed using multivariable logistic regression. Growth outcomes (changes in anthropometric Z-scores from birth to 36 weeks postmenstrual age) and length of stay were evaluated using multivariable linear regression. Covariates included site, GA, fetal growth restriction, pressor use in week 1, antenatal corticosteroids, severe intraventricular hemorrhage, and early-onset sepsis.

Results: Among the 499 infants, the median NPO days during the first 28 days was 1 day (IQR 0-2, Table 1). After adjusting for illness severity, for every NPO day in the first 28 days, there were higher odds of developing BPD (aOR 1.13 [95% CI 1.01, 1.27], p=0.03, Figure 1), findings consistent across sensitivity analyses. No association was found with ROP or late-onset sepsis. Unadjusted analyses showed an inverse relationship between NPO days and linear growth (Figure 2). Each additional NPO day corresponded to a 0.19-SD decrease in adjusted length Z-score (SE 0.069, p=0.001), confirmed in the sensitivity analysis. No relationship was observed between NPO days and weight or head circumference Z-scores. In the sensitivity analysis, there was a trend towards longer length of stay with increasing NPO days (4.2 [2.1], p=0.05).

Conclusion(s): In a cohort of VP infants, days of NPO in the first 28 days were directly associated with risk of BPD and inversely with linear growth. Providers should weigh risks and benefits of holding feeds in the absence of definitive gastrointestinal diagnoses, as NPO itself is associated with adverse outcomes.

Table 1
Fetal growth restriction was identified based on the obstetrician's documentation. Vasopressor use during the first week included dopamine, epinephrine, norepinephrine, vasopressin, and dobutamine. The average total intravenous fluids in the first week were calculated using birth weight. Severe intraventricular hemorrhage was defined as either grade III or IV hemorrhage, occurring unilaterally or bilaterally. Patent ductus arteriosus requiring treatment included medical, surgical, or device closure. Bronchopulmonary dysplasia was defined as Jensen 2019 criteria grade 1 or higher, including oxygen or positive pressure ventilation at 36 weeks postmenstrual age. Continuous variables were compared using Wilcoxon rank sum tests, and nominal variables were compared with Fisher's exact tests.

Figure 1
Adjusted odds ratios for adverse event outcomes. NPO days represent each day of NPO status within the first 28 days. Site and severity of illness markers-including gestational age, fetal growth restriction, pressor use during the first week, antenatal corticosteroids, severe intraventricular hemorrhage, and early-onset sepsis-were included as covariates in the models.

Figure 2.
Unadjusted linear regression of NPO days in the first 28 days and change in length Z-score from birth to 36 weeks postmenstrual age (PMA).