Supplementary Material for: Cerebral Hemodynamics and Regional Oxygen Metabolism during Ductus Arteriosus Ligation in Preterm Infants

<b><i>Introduction:</i></b> Neurodevelopmental impairment is a growing concern for preterm infants who received surgical ligation of patent ductus arteriosus (PDA). We aimed to explore the cerebral hemodynamics during the critical period of PDA ligation. <b><i>Methods:</i></b> Very-low-birth-weight (VLBW) preterm infants who underwent PDA ligation were prospectively enrolled. Patients were monitored preoperatively and until 72 h post-ligation. Middle cerebral artery (MCA) flow, regional cerebral oxygen saturation (rcSO₂), and cardiac output were measured through Doppler ultrasound, near-infrared spectroscopy, and electrical cardiometry, respectively. Using rcSO₂ &lt;55% indicating cerebral hypoxia, the duration (% of time) and burden (cumulative negative quantity of rsSO₂ &lt;55% × the period [minutes]) were estimated. An abnormal MCA was defined as an MCA flow of &lt;10th percentile of flow velocity or &gt;90th percentile of pulsatility or resistance index. Poor outcomes were defined as in-hospital death or neurologic disorders, either neuroimaging or functional abnormalities, upon discharge. <b><i>Results:</i></b> Thirty-two VLBW infants were examined, and 15 (46.9%) had poor outcomes. Infants with poor outcomes had significantly longer duration of cerebral hypoxia (5.4 [2.2–32.3] vs. 1.8 [0.4–5.6] %, <i>p</i> = 0.033) and worse hypoxic burden (2,118 [684–13,549] vs. 622 [88–1,669] %minutes, <i>p</i> = 0.027). In a linear mixed model, rcSO₂ was positively correlated with arterial saturation (β 0.860, 95% CI: 0.649–1.070) and negatively correlated with abnormal MCA flow (β −5.287, 95% CI: −8.238 to −2.335). <b><i>Conclusion:</i></b> Longer duration of cerebral hypoxia and worse hypoxic burden post-ligation was associated with an increased risk of in-hospital mortality or neurologic disorders upon discharge in VLBW preterm infants.