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Ultrasound/Imaging

Poster Session 1

(261) Maternal administration of oxygen to predict respiratory morbidities among growth restricted infants

Tuesday, February 13, 2024
10:30 AM – 12:00 PM  
Location: Prince George's Exhibit Hall CDE, Lower Atrium Level
Objective: Maternal hyperoxygenation (MH) decreases the fetal pulmonary vasoreactivity (PVR) and increases the pulmonary blood flow in normally grown fetuses. Considering that fetal growth restriction (FGR) negatively affects the pulmonary development and increases the risk for neonatal respiratory morbidities, we sought to evaluate the role of MH and PVR in identifying newborns at risk for respiratory morbidities among pregnancies complicated by FGR.

Study Design:

Case series where singleton pregnancies complicated by FGR underwent MH testing every 1-2 weeks from enrollment to delivery. The pulsatility index (PI) of the middle branch of the pulmonary arteries (mPA) was obtained by ultrasound as a baseline, during MH, and after 15 minutes of MH. MH consisted of maternal administration of 8 L/min of 100% oxygen through a non-rebreathing face mask. A reactive PVR test was defined as any decrease in mPA-PI during MH compared to baseline. PVR results of newborns requiring respiratory support at delivery or admission to the neonatal intensive care unit (NICU) due to respiratory morbidity (Group I) were compared to those in no need of respiratory support at birth (Group II). Results of the last PVR test prior to delivery were compared with neonatal outcomes.

Results:

Among 32 subjects enrolled from July 2018 to July 2019, 28 participants were eligible for analysis (Group I=12; Group II=16). Among Group I, 7 fetuses had a non-reactive PVR (NR-PVR) test, while 1 fetus in Group II had a NR-PVR test; P=0.008. When subdivided by early (N=23) or late FGR (N=5) FGR, NR-PVR was seen only on the early FGR subgroup.  Sensitivity, specificity, positive (PPV) and negative predictive (NPV) values were 58%, 93%, 87% and 75%, respectively. At 6-mo age, WIDEA-FS was comparable among both groups.

Conclusion:

PVR tested by MH is a non-invasive test with high specificity and PPV in anticipating respiratory morbidity in early FGR when antenatal NR-PVR is observed. PVR by MH does not predict infant outcomes at 6-mo age.