Intraoperative Fetal Heart Rate (FHR) Monitoring: a Feasibility Study

Overview

Fetal heart rate \[FHR\] monitoring is used widely to assess the well-being of the baby in the delivery period. If it is determined that an urgent cesarean delivery is required because of fetal distress, FHR is discontinued once the mother is in the operating room in order to allow for surgical site preparation. From this point, there is no real-time monitoring that permits assessment of the well-being of the infant. The investigators are evaluating the feasibility of intraoperative FHR monitoring using fetal ECG placed on the mother's upper abdominal wall and the standard acoustic device routinely used. The investigators will compare these to the traditional well-being tests: umbilical arterial blood gas and Apgar score. The first 15 subjects will be recruited from pregnant women who have scheduled induction of labor. The subsequent 40 subjects will be recruited from pregnant women who have scheduled cesarean sections.

Fetal heart rate (FHR) monitoring has become the most widely used assessment of fetal well-being in the peripartum period and the only routinely used method that provides continuous fetal monitoring. Despite a false positive rate for the detection of intrapartum asphyxia leading to cerebral palsy of over 99% \[1-3\] FHR monitoring continues to be the mainstay of peripartum fetal surveillance. FHR monitoring is routinely available in the operating room, where it is typically reassessed in cases of urgent cesarean delivery for fetal distress since it may direct immediate anesthetic and peripartum management. However, despite the ubiquitous use of FHR monitoring in labor and the typical use of FHR monitoring on arrival to the OR, FHR monitoring is universally stopped once anesthesia has been performed in order to allow abdominal skin preparation and for surgery to proceed. From the moment of anesthesia induction until fetal delivery, no real-time data is available that allows assessment of fetal well-being. A few isolated studies and case reports in the 1970s-1980s examined intraoperative FHR monitoring using scalp-clip electrodes during Cesarean deliveries \[4-7\]. None of these studies assessed external FHR monitors or current anesthesia techniques. To the investigators' knowledge no studies since that time have examined FHR monitoring during Cesarean deliveries using external monitoring or spinal anesthesia