216 - Effects of Persistent pulmonary hypertension of the newborn on cerebral oxygenation in neonates with neonatal encephalopathy

Poster Number: 216
Publication Number: 216.519

Background: Persistent pulmonary hypertension of the newborn (PPHN) affects systemic oxygenation and may worsen brain injury in neonates with neonatal encephalopathy (NE).

Objective: To evaluate the impact of PPHN on cerebral regional oxygenation (crSO2), as measured with near-infrared spectroscopy (NIRS), in neonates with NE treated with therapeutic hypothermia (TH).

Design/Methods: We retrospectively evaluated neonates with NE in our institution, between 2018-2022, comparing neonates with vs without PPHN. Overall, 164 (76%) neonates were analyzed, including 19 (12%) neonates with PPHN and 145 (88%) neonates without.
crSO2 was expressed as the mean of the 24-hour recording, within the first, second and third day of hypothermia, the rewarming period, and the period after rewarming. Weeke score was applied for the evaluation of the brain magnetic resonance imaging (MRI).
To adjust for the severity of NE, we calculated the predicted probability based on meconium-stained amniotic fluid, Apgar score at 10 minutes, umbilical arterial pH, the initial aEEG pattern, and the highest NE score, and a propensity score matching was performed between neonates with and without PPHN, with nearest neighbor and caliper set to 0.2. Linear regression analysis was then performed to evaluate the impact of PPHN on crSO2 and total MRI injury score, adjusted for the predicted probability.

Results: Neonatal characteristics and outcomes are depicted in Table 1. During the first 3 phases of hypothermia, no differences were recorded in crSO2 between PPHN and non-PPHN groups; however, neonates with PPHN had significantly higher crSO2 during the rewarming period, and the period after rewarming compared to the non-PPHN group (87±6 vs 80±6, p=0.001, and 87±5 vs 80±7, p=0.008, respectively), (Figure 1). Also, neonates with PPHN had a significantly higher total MRI injury score [7(2-19) vs 1(0-3), p< 0.001].
After adjusting for the predicted probability, PPHN was significantly associated with higher cerebral rSO2 on the rewarming period (b 6.89, 95%CI 3.10-10.68, p=0.001) and the period after rewarming (b 9.92, 95%CI 1.17-18.67, p=0.029), and the total MRI injury score (b 6.64, 95%CI 0.36-12.92, p=0.039), (Table 2).

Conclusion(s): PPHN was associated with higher cerebral crSO2 during and after the rewarming periods, and worse brain MRI injury score, indicating a significant impact of PPHN on brain injury in neonates with NE undergoing TH.