Optimizing Chest Compressions for Bradycardia during Neonatal Resuscitation

摘要 出生窒息对全球健康造成巨大负担，每年造成100万新生儿死亡。 目前的建议，由新生儿复苏计划（NRP），以提供外部胸部 当新生儿的心率在提供有效的外部治疗后保持在每分钟60次以下时， 呼吸30秒本方案基于专家意见，而非证据。本提案的目的 确定开始胸部外按压的心率范围，以优化流向大脑的血流 还有心脏新生儿出生时的低心率通常是由于气体交换受损，我们的初步研究表明， 研究表明，当心脏仍在跳动时进行外部胸外按压（CC）可能是有害的。 我们假设，持续的低心率（<60每分钟）的体外呼吸，沿着药物治疗， 肾上腺素，只有在脉搏/心率丧失时才开始体外心脏按压。这种方法 可以改善气体交换，导致更好的大脑和心肌灌注，减少建立一个 心率≥ 100次/分，减少脑和心脏损伤。我们的具体目标将有助于确定 使用早产儿和早产儿开始体外按压的最佳心率截止值（HR 60 - 40或40 - 20 bpm） Lamb模型通过评估： 1.气体交换和血液流向大脑和心脏; 2.当进行胸外按压时固有心跳的丧失以及 达到理想的心率; 3. CC在脑和心脏损伤中的作用。 我们可以直接测量冠状动脉血流量，这在以前没有报道过，这将有助于建立 过渡期心脏正常和异常血流以及进行外胸手术的影响 压缩，这是一个新的观察。本文的研究对于了解目前的方法是否适用于 提供新生儿复苏，这是没有证据为基础的，可以改善。结合使用 血液动力学、生物标志物和成像技术，这些数据可以被转化为指导新生儿 复苏术在产房使用心电图检测心率增加了 提供3倍的胸部按压，如果过度使用，可能会造成更大的伤害。也有可能 早产心动过缓复苏可能需要与足月妊娠不同的治疗方案。是 重要的是要了解目前的做法所涉及的脑和心脏损伤的风险。专注于 在需要时提供胸外按压呼吸，目的是限制心脏和窒息 在每年140万新生儿的复苏过程中，脑损伤将对全球产生重大影响。

ABSTRACT The result of birth asphyxia is a huge burden on global health contributing to 1 million neonatal death each year. The current recommendations by the neonatal resuscitation program (NRP) to provide external chest compressions when a newborn’s heart rate remains below 60 beats per minute after providing effective external breaths for 30 seconds. This protocol is based on expert opinion, but not evidence. The objective of this proposal is to determine the heart rate range for starting external chest compression to optimize blood flow to the brain and the heart. Low heart rate at birth in a newborn is normally due to impaired gas exchange, and our preliminary studies show that performing external chest compressions (CC) could be harmful when the heart is still beating. We hypothesize that continuing external breaths for low heart rate (<60 per minute), along with medications like epinephrine and only initiating external cardiac compressions if there is a loss of pulse/heart rate. This approach could improve gas exchange, leading to better cerebral and myocardial perfusion, reducing time to establish a heart rate of ≥ 100 per minute, and decrease brain and heart injury. Our specific aims will help determine the best heart rate cut-off (HR 60-40 or 40-20bpm) for initiating external compressions using both a preterm and term lamb model by evaluating: 1. Gas exchange and blood flows to brain and heart; 2. The loss of intrinsic heart beat when external chest compressions are performed and time taken to achieve the desired heart rate; 3. The role of CC on cerebral and cardiac injury. We can measure coronary blood flow directly which has not been reported before, which will help establish normal and abnormal blood flow to the heart during transition and the influence of performing external chest compressions, which is a novel observation. The proposed research is significant to find out, if the current method of providing neonatal resuscitation, which is not evidence based, could be improved. Using a combination of hemodynamics, biomarkers and imaging techniques, these data could be translated to direct neonatal resuscitation. Use of electrocardiogram in the delivery room to detect heart rate has increased the frequency of providing chest compressions by 3-fold, and may be causing more damage if over used. It is also possible that resuscitation in preterm bradycardia could require different treatment protocols than at term gestation. It is important to understand the risk of brain and cardiac damage involved with the current practice. Focusing on providing external breaths with chest compressions when needed, with the objective to limit cardiac and asphyxia brain injury will have a great impact globally during resuscitation of 1.4 million newborns each year.