Neonatal Resuscitation with Intact Cord (NRIC)

描述（由申请人提供）：早产儿有脑出血的风险，被称为脑室内出血（IVH），这通常会导致发育迟缓或其他神经系统问题，如脑瘫。将出生后夹住脐带的时间延迟30-60秒已被证明可减少体外受精，并已成为早产婴儿分娩的标准护理。然而，延迟脐带夹紧（DCC）并不能减少严重IVH，这可能是由于存在严重IVH风险的婴儿胎盘输血不足所致。最近的一项研究（Bhatt等人）比较了DCC和立即脐带夹紧（ICC）在通气羔羊中的作用，发现DCC可以防止颈动脉压力的快速增加，同时增加肺血流量（PBF）。大多数有严重IVH风险的婴儿（受损和极早产婴儿）是通过剖宫产出生的，因此没有获得通过产道的好处，这有助于新生儿肺部的液体清除并增加PBF。先前的研究表明，对于C/S出生的婴儿，DCC的胎盘输血（通过血细胞比容水平）不理想。在DCC过程中，通过通气打开早产儿的肺，可以增加胎盘输血，从而改善PBF，促进生理过渡。通风

DESCRIPTION (provided by applicant): Premature babies are at risk for bleeding in their brain, referred to as intraventricular hemorrhage (IVH), which often results in developmental delays or other neurological problems such as cerebral palsy. Delaying the time at which the umbilical cord is clamped after birth by 30-60 seconds has been shown to reduce IVH and has become the standard of care in the delivery of preterm infants. However, delayed cord clamping (DCC) does not reduce severe IVH, which may be due to inadequate placental transfusion in infants at risk for severe IVH. A recent study (Bhatt et al.) compared DCC to immediate cord clamping (ICC) in ventilated lambs and found DCC prevented a rapid increase in carotid artery pressure while increasing pulmonary blood flow (PBF) to the lungs. The majority of infants at risk for severe IVH (compromised and extremely premature infants) are born by cesarean section (C/S) and therefore do not receive the benefit of passage through the birth canal, which facilitates fluid clearance from the newborn lungs and increases PBF. Previous studies have demonstrated suboptimal placental transfusion (via hematocrit levels) from DCC for infants born by C/S. Opening the premature infant's lungs with ventilation during DCC could increase placental transfusion, thereby improving PBF and facilitating physiological transition. Ventilation during the period of DCC in the delivery room is not currently practiced. A sterile T-piece will be used to achieve lung recruitment simultaneously with placental transfusion from DCC. We will test the hypothesis that a simple sterile ventilation circuit (with which we have extensive experience) can be employed with no impediment to obstetrical care and provide benefit to the premature infant during DCC. Specific Aims: 1) Compare the volume of placental transfusion with ventilation during delayed cord clamping (V-DCC) to delayed cord clamping alone (DCC) between infants born by C/S or vaginal delivery (VD). 2) Compare the physiological changes in the first 6 hours of life (HOL) between infants born by C/S or VD randomized to V-DCC or to DCC alone. 3) Compare the clinical outcomes between infants born by either C/S or VD, randomized to V-DCC or to DCC alone. 4) Compare the effects of mode of delivery on volume of placental transfusion, physiological changes, and clinical outcomes between all 4 groups. Design: This is a blinded randomized controlled clinical trial. Both groups will receive the same resuscitation interventions once the umbilical cord is clamped. Brain oxygenation and cardiac output will be continuously measured beginning in the delivery room until 6 HOL. An early heart ultrasound will be performed (<6 HOL) to measure systemic blood flow and detect fetal shunts. Adequacy of placental transfusion will be assessed by 12 HOL hematocrit. Clinicians will be blinded to whether the infant did or did not receive ventilation during DCC. This will be the first blinded randomized study to evaluate the effect of ventilation on DCC in very preterm infants delivered by C/S with a comparison group of VD preterm infants randomized to the same interventions.