453 - Transitional Physiology and Interventions During Delivery Room Resuscitation of Newborns with d-Transposition of the Great Arteries

Publication Number: 1435.453

Alyssa R. Thomas, Brigham and Women's Hospital, SOUTH BOSTON, MA, United States; Anna Bostwick, Childrens Hospital of Philadelphia, Philadelphia, PA, United States; Leny Mathew, Children's Hospital of Philadelphia, Philadelphia, PA, United States; Rebecca Josowitz, Children's Hospital of Philadelphia, Philadelphia, MD, United States; Anne Ades, Childrens Hospital of Philadelphia, Philadelphia, PA, United States; Tom Reynolds, Children's Hospital of Philadelphia, Philadelphia, PA, United States; Elizabeth Foglia, Children's Hospital of Philadelphia, Swarthmore, PA, United States

Background: Newborns with critical congenital heart disease (CCHD) are a high-risk population yet remain largely excluded from delivery room (DR) resuscitation guidelines. Among these, dextro-transposition of the great arteries (d-TGA) poses a unique challenge, as systemic oxygen delivery depends on intracardiac mixing of parallel circulations. When mixing is inadequate, infants may rapidly decompensate. Early physiology remains difficult to predict, and evidence to guide interpretation of postnatal data such as SpO2 trends is limited.

Objective: To characterize early oxygenation trajectories and resuscitation practices in d-TGA newborns and assess whether ventricular septal anatomy modifies transitional physiology or intervention patterns.

Design/Methods: Single center cohort study of newborns with prenatally diagnosed d-TGA born between 2012-2025 (IRB #21-018553, exempt); infants < 37 weeks' gestation, with DR palliative care, or other major anomalies were excluded. Data were abstracted from a clinical database including vital sign data. Infant and resuscitation characteristics were compared between d-TGA-intact ventricular septum (IVS) and d-TGA-ventricular septal defect (VSD) using Student's t-test or Chi-square tests. Generalized Additive Models for Location Scale and Shape (GAMLSS) estimated the 3rd, 25th, 50th, 75th and 97th centiles of preductal SpO2 over the first 60 minutes after birth using discrete SpO2 data and high-frequency pulse oximetry recordings when available (Moberg CNS, 3-sec intervals).

Results: Of 212 infants (110 IVS and 102 VSD; mean gestation 39.2 weeks), 80% received DR respiratory support. DR intubation was more frequent in IVS (64.5%) vs VSD (44.1%, p=0.003); median time to intubation was similar (IVS 23.5 vs VSD 22 min, p=0.57). Among intubated patients, 94.8% received sedation/neuromuscular blockade. There were 209 infants with discrete SpO2 data and 43 with high frequency data. Mean SpO2 was lower in IVS at 5 min (IVS: 60%, VSD: 67%, p=0.013), 15 min (IVS: 70%, VSD: 77%, p=0.029) and 20 min (IVS: 71%, VSD: 78%, p=0.004). By 10 min, 43.1% of IVS vs 64% of VSD reached 70% SpO2 (p=0.004); by 15 min, 35.8% of IVS vs 67% of VSD reached 75% SpO2 (p=0.001).

Conclusion(s): Leveraging a large clinical-physiologic dataset, this study defines early oxygenation trajectories and DR interventions in d-TGA newborns. Infants with IVS required more respiratory support and showed delayed oxygenation compared with VSD, suggesting that ventricular septal anatomy may modify early transition. These findings may inform DR management and guideline development for CCHD resuscitation.

Table 1. D-TGA demographics and interventions
Demographic data and delivery room interventions in newborns with d-TGA

Table 2. Preductal SpO2 up to 60 minutes in d-TGA newborns
Median, 25th, and 75th percentile values for SpO2 for all newborns with d-TGA and divided into ventricular anatomic subtypes (IVS and VSD) in the first 60 minutes after birth.

Figure 1. 3rd-97th Percentile curves of SpO2 among d-TGA newborns with VSD or IVS.
Figure 1. 3rd-97th Percentile curves of SpO2 among d-TGA newborns with VSD or IVS in the first 60 minutes after birth.