065 - Differences in early cardiovascular physiology between inborn and outborn extremely preterm neonates

Publication Number: 65.4562

Abigail Koski, University of Iowa, Tiffin, IA, United States; Patrick J. McNamara, University of Iowa Stead Family Children's Hospital, IOWA CITY, IA, United States; Danielle R. Rios, University of Iowa Stead Family Children's Hospital, Iowa City, IA, United States

Background: Previous studies have shown the improvement in morbidity and mortality seen when extremely premature infants are born at a tertiary center. Early identification of derangements in cardiovascular physiology in the first 24 hours in extremely preterm infants further enhances neonatal outcomes. The relative contribution of outborn status to abnormal cardiovascular physiology remains unclear.

Objective: To investigate abnormal cardiovascular phenotypes at 24 hours in outborn vs. inborn extremely preterm infants.

Design/Methods: A retrospective chart review was conducted on extremely s admitted within the first 24 postnatal hours to the NICU at University of Iowa between 9/2018 and 5/2023. Groups were identified as inborn or outborn for analysis. Targeted neonatal echocardiography (TNE) is routinely performed in the first 24 hours on patients born at < 27 weeks gestation. Patients were excluded if they had major congenital anomalies or did not receive a TNE during the first postnatal day. The primary outcome was abnormal cardiovascular phenotype at 24 hours. Univariate analysis was used to analyze the groups with respect to maternal characteristics, delivery variables, infant characteristics and clinical variables within the first 24 hours. Significance was set at p< 0.05.

Results: A total of 250 patients were included whose mean birth weight and gestational age were 682 ± 188 grams and 24.6 ± 1.5 weeks, respectively. Of those, 209 were inborn and 41 outborn. Outborn infants had higher birth weight (p < 0.01), lower Apgars at 1 and 5 minutes ( < 0.01), and required more resuscitation with chest compressions (p < 0.01), epinephrine boluses (p < 0.05), and fluid boluses (p < 0.05). Differences in maternal characteristics are shown in Table 1. The rate of abnormal cardiovascular phenotype on TNE at 24 hours was high but with no intergroup difference (p=0.209). In addition, there were no differences in specific types of abnormal physiology between groups.

Conclusion(s): Extremely preterm infants represent a population of significant vulnerability with a high rate of abnormal cardiovascular phenotype at 24 postnatal hours. Although there was no difference in abnormal phenotype between groups, the outborn patients were bigger and had a less favorable perinatal profile. Whether these abnormal cardiovascular phenotypes are modifiable through enhanced perinatal care remains unknown.

Table 1. Demographics and Clinical Variables