486 - The hemodynamic benefits of brief 100% oxygen use during preterm resuscitation with an intact umbilical cord using asphyxiated and non-asphyxiated surfactant deficient ovine model

Poster Number: 486
Publication Number: 486.231

Praveen Chandrasekharan, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Sylvia Gugino, SUNY at Buffalo, Buffalo, NY, United States; Justin Helman, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Bufalo, NY, United States; Nicole Bradley, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Lori Nielsen, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, buffalo, NY, United States; Mausma Bawa, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Andreina Mari, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Depew, NY, United States; Arun Prasath, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Williamsville, NY, United States; Clariss Blanco, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Munmun Rawat, University at Buffalo, Buffalo, NY, United States; Satyan Lakshminrusimha, University of California Davis Children's Hospital, Sacramento, CA, United States

Background: The use of 100% supplemental O2 is not recommended in the resuscitation of preterm neonates due to the risk of systemic oxygen toxicity. A recent meta-analysis suggests that more than 50% of preterm infants are born with a heart rate < 100 bpm. Not achieving an HR of ≥100bpm and saturation (SpO2) of ≥80% by 5 min places a preterm infant at a higher risk of morbidity/mortality. Ventilation with an intact cord improves hemodynamic transition in a preterm neonate. In an asphyxiated preterm neonate, the use of 100% O2 with an intact cord could improve alveolar oxygenation with less systemic toxicity due to buffering by umbilical venous return.

Objective: To study the effect of initiating positive pressure ventilation (PPV) with 100% O2 with and without an intact umbilical cord in asphyxiated and non-asphyxiated preterm lambs.

Design/Methods: Preterm lambs (125-127d gestation) were randomized to 4 groups a) AXDCC - asphyxiated (to HR < 100 bpm) and ventilated with an intact cord, b) AXECC – asphyxiated, early cord clamping and PPV, c) NoAXDCC - non-asphyxiated delayed cord clamping, d) NoAXECC - non-asphyxiated, early cord clamping. The cord clamping is delayed in all DCC groups for 5 min. The primary outcome is the incidence of HR of ≥ 100 bpm and SpO2 of ≥80% by 5 min. The secondary outcomes were measures of gas exchange, hemodynamics, and oxidative stress (oxidized to reduced glutathione ratio in the blood). In all the groups PPV was initiated with 100% O2 for 2 min and titrated proportional to the difference in observed and targeted SpO2 every min.

Results: Asphyxia led to lower PaO2, SpO2, HR and higher PaCO2 at the initiation of PPV. The primary outcome was achieved in 4/7(AXECC), 6/7 (AXDCC), 5/6 (NoAXECC) & 7/7 (NoAXDCC). By 5 min, the preductal SpO2 was higher in DCC groups despite lower O2 exposure compared to other groups (Fig 1B & Fig 2A). Intact cord resuscitation led to lower PaCO2 in asphyxiated lambs along with higher peak pulmonary and carotid flow (Fig 2 & 3). At 5 min, there was no significant difference in oxidized to reduced glutathione ratio between groups (Fig 3).Conclusion(s): In both asphyxiated and non-asphyxiated preterm lambs, initial use of 100% with an intact cord improved hemodynamic and respiratory transition by increasing peak pulmonary blood flow, with lower oxygen exposure, improved ventilation without any change in oxidative stress markers.
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