Optimizing Transition with Delayed Umbilical Cord Clamping and Supplemental Oxygen during Preterm Resuscitation with Perinatal Asphyxia

摘要 早产儿占美国新生儿的10%；这些新生儿都是未成熟的 出生时经常需要帮助呼吸。表面活性物质缺乏，抗氧化剂体系不成熟 需要更长时间的机械通风支持会对肺部造成损害， 其他器官导致发病率和死亡率增加。最近的研究表明， 妊娠28周出生的婴儿在最初使用21%的呼吸机时死亡风险更高。 氧气。较高的死亡率是由于呼吸衰竭，这可能是由于发育不发达。 肺部受损，氧合受损，流向肺部的血流受损。新生儿复苏 由美国儿科学会(AAP)开发的计划(NRP)为 设定目标血氧饱和度目标的临床治疗。最近的一项研究强调了 这些目标的重要性以及未能在5分钟内达到这些目标会导致更高的 死亡率。保持脐带完整的古老做法(附着在胎盘上) 早产儿需要复苏，这可能有助于过渡。 在这项建议中，我们计划研究早产后胎羊的呼吸启动。 低心率(&lt；90/min)，初始含氧量为30%或60%，并根据目标进行滴定的模型 在脐带仍完好无损的情况下进行氧合。我们会把这比作没有 使用相似初始氧浓度(30%或60%)的完整绳索。我们将在以下位置研究这些变化 通过测量氧合、肺和脑血流量以及氧化损伤来实现过渡 这4组。通过这种方式，我们可以比较生理变化和由此产生的氧化 压力标记，以更好地了解在人类早产过渡期间可能发生的事情。 在抑郁早产动物模型中优化脐带完整的初始氧暴露 以受控的方式检查这个问题。脑组织的实时连续测量 血氧饱和度、体肺血流和压力在早产过渡期间的变化将 有助于降低这些婴儿的发病率和死亡率。 与当前新生儿复苏实践的相关性： 产后建立良好的氧气供应是关键，而要实现这一点则更加困难。 早产儿肺部疾病。目前的AAP-NRP指南警惕地保护新生儿免受 靶向血氧饱和度范围和限制高氧暴露的氧化应激损伤 浓度。这一新的方法检查早产羔羊出生时的生理学，以确定 在脐带完整的情况下实现向空气呼吸过渡的最佳需氧量 氧化损伤最小。

ABSTRACT Premature babies account for 10% of births in the United States; these newborn have immature lungs and often need help breathing at birth. Surfactant deficiency, immature antioxidant system and the need for extended mechanical ventilation support can cause damage to the lungs and other organs resulting in increased morbidity and mortality. Recent studies have shown that infants born <28 weeks’ gestation had a higher risk of mortality when initially ventilated with 21% oxygen. The higher mortality was due to respiratory failure, which could be due to underdeveloped lungs, impaired oxygenation and impaired blood flow to the lungs. The Neonatal Resuscitation Program (NRP) developed by the American Academy of Pediatrics (AAP) provides guidelines for clinical treatment that sets target oxygen saturation goals. A recent study emphasized the importance of these target goals and failure to reach these targets by 5 min lead to higher mortality. The ancient practice of keeping the umbilical cord intact (attached to placenta) when a premature baby needs resuscitation could potentially help transition. In this proposal, we plan to study initiation of ventilation following preterm delivery in a fetal lamb model with low heart rate (<90/min), with 30% or 60% initial oxygen and titrate based on target oxygenation while the umbilical cord is still intact. We will compare this to resuscitation without an intact cord using similar initial oxygen concentration (30% or 60%). We will study the changes at transition by measuring oxygenation, pulmonary and cerebral blood flow and oxidative injury in these 4 groups. In this way, we can compare physiologic changes and the resultant oxidative stress markers to better understand what may be happening during the human preterm transition. Optimizing the initial oxygen exposure with an intact cord in a depressed preterm animal model examines this problem in a controlled way. Real-time continuous measurements of cerebral oximetry, systemic and pulmonary flow and pressure variations during the preterm transition will contribute to reducing morbidity and mortality in these babies. Relevance to current practice in neonatal resuscitation: Establishing good oxygen supply following birth is critical and it is more difficult to achieve with premature lung disease. Current AAP-NRP guidelines are vigilant to protect newborns from oxidative stress injury by targeting oxygen saturation ranges and limiting exposure to high oxygen concentrations. This newer approach examines physiology at birth in preterm lambs to establish optimal oxygen requirements with an intact umbilical cord to achieve the transition to air breathing with minimal oxidative damage.