Prevention Unintentional Mechanical Birth Injuries

该提案的目的是阐明机械性产伤的机制，发生后，产科急诊称为肩难产，并制定切实可行的干预措施，以控制或预防这种伤害，其中一些可能导致终身残疾。肩难产影响了15%的阴道分娩，是一种自然发生的机械性梗阻，其中，在头部分娩后，胎儿的肩部在母亲的耻骨后面受到影响，如果没有临床医生的特殊干预，躯干就无法分娩，临床医生必须采取适当的措施以防止窒息，同时避免对胎儿颈部的过度拉伸。后者可导致骨骼骨折和/或臂丛神经损伤-高达近30%的肩难产的意外结果。 标准的产科操作用于解决肩难产涉及操纵母亲或胎儿。一种操作优于另一种操作的优势尚未得到证实;然而，生物力学方面的考虑支持这样一种假设，即胎儿操作分娩婴儿所需的力比母体操作少20%至30%，如果优先考虑，可以减少损伤的发生率。然而，大多数临床医生不太熟悉胎儿操作， 推迟它们的使用，以利于重复母亲的声音。本研究的目的是证明胎儿在实现肩难产的无创伤解决方面优于母体操作的机械优势，并使临床医生熟悉胎儿操作作为减少和预防新生儿损伤的公共卫生措施。 为了实现这些目标，生物医学工程将通过5个具体目标与临床产科相结合： 1.使用定制设计的肩难产分娩模拟器测量临床医生施加在胎头上的牵引力，并将该力的方向、大小和速率与胎儿颈部伸展、屈曲和旋转、臂丛神经伸展和骨骼骨折相关联; 2.在实验室环境中，客观评估子宫和母体排出力以及不同肩难产操作对临床医生施加的力、胎儿颈部运动参数和臂丛神经牵拉的影响; 3.利用实验室模拟器和测力系统，对临床医生进行肩难产操作的教育计划，并评估其对临床医生估计分娩期间牵引量的能力的影响; 4.测量临床医生在体内施加的牵引力，并将其与实验室得出的力参数进行比较; 5.进行一项小型随机临床试验，比较McRoberts手法（母体手法）和Rubin手法（胎儿手法）后临床医生施加的力。

The objective of this proposal is to elucidate mechanisms involved in mechanical birth injuries that occur following an obstetric emergency known as shoulder dystocia and to develop practical interventions to control or prevent such injuries, some of which can lead to lifelong disability. Affecting up to 15% of vaginal deliveries, shoulder dystocia is a naturally-occurring mechanical obstruction in which, after the head delivers, the fetal shoulders become impacted behind the mother's pubic bone and the trunk cannot deliver without specific intervention by the clinician who must act expediently to prevent asphyxia while simultaneously avoiding undue stretch on the fetal neck. The latter can result in skeletal fractures and/or brachial plexus nerve injury -- unintended outcomes of up to nearly 30% of shoulder dystocias. Standard obstetric maneuvers used to resolve shoulder dystocia involve manipulation of either the mother or the fetus. The superiority of one maneuver over another has not been proven; yet biomechanical considerations support the hypothesis that fetal manipulation requires 20% to 30% less force to deliver the infant than maternal manipulation and, if prioritized, could reduce the incidence of injury. However, most clinicians are less familiar with fetal maneuvers and defer their use in favor of repeating maternal ones. The goals of this research proposal are to demonstrate the mechanical advantage of fetal over maternal manipulation in accomplishing atraumatic resolution of shoulder dystocia and to familiarize clinicians with fetal maneuvers as a public health measure to reduce and prevent neonatal injury. To achieve these objectives, biomedical engineering will be integrated with clinical obstetrics through 5 specific aims: 1. to measure clinician-applied traction on the fetal head using a custom-designed shoulder dystocia birthing simulator and correlate direction, magnitude and rate of this force with fetal neck extension, flexion and rotation, brachial plexus stretch and skeletal fracture; 2. to objectively assess, in a laboratory setting, the effect of uterine and maternal expulsive forces and of different shoulder dystocia maneuvers on clinician-applied force, fetal neck motion parameters and brachial plexus stretch; 3. to conduct an educational program for clinicians on the performance of shoulder dystocia maneuvers, employing the laboratory simulator and force-measuring systems, and assess its effect on clinicians' ability to estimate the amount of traction they apply during delivery; 4. to measure clinician-applied traction in vivo and compare this with laboratory-derived force parameters; 5. to conduct a small, randomized clinical trial comparing clinician-applied forces following McRoberts' maneuver (a maternal manipulation) and following Rubin's maneuver (a fetal manipulation).