The limits of electronic fetal heart rate monitoring in the prevention of neonatal metabolic acidemia

• Published in: American journal of obstetrics and gynecology 2017-02, Vol.216 (2), p.163.e1-163.e6
• Main Authors: Clark, Steven L., MD, Hamilton, Emily F., MD, Garite, Thomas J., MD, Timmins, Audra, MD, Warrick, Philip A., PhD, Smith, Samuel, MD
• Format: Article
• Language: English
• Subjects: Acidosis - etiology; Acidosis - prevention & control; Adult; Algorithms; Cardiotocography - methods; Case-Control Studies; category II; Cesarean Section; Clinical Decision-Making; Delivery, Obstetric - methods; Extraction, Obstetrical; Female; fetal heart rate monitoring; Heart Rate, Fetal; Humans; Hypoxia - complications; Hypoxia - diagnosis; Infant, Newborn; Infant, Newborn, Diseases - etiology; Infant, Newborn, Diseases - prevention & control; metabolic acidemia; Obstetrics and Gynecology; Pregnancy; Young Adult
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1016/j.ajog.2016.10.009

Background Despite intensive efforts directed at initial training in fetal heart rate interpretation, continuing medical education, board certification/recertification, team training, and the development of specific protocols for the management of abnormal fetal heart rate patterns, the goals of consistently preventing hypoxia-induced fetal metabolic acidemia and neurologic injury remain elusive. Objective The purpose of this study was to validate a recently published algorithm for the management of category II fetal heart rate tracings, to examine reasons for the birth of infants with significant metabolic acidemia despite the use of electronic fetal heart rate monitoring, and to examine critically the limits of electronic fetal heart rate monitoring in the prevention of neonatal metabolic acidemia. Study Design The potential performance of electronic fetal heart rate monitoring under ideal circumstances was evaluated in an outcomes-blinded examination fetal heart rate tracing of infants with metabolic acidemia at birth (base deficit, >12) and matched control infants (base deficit, 12 mM/L. Matched control infants were not demographically different from subjects. In actual practice, operative intervention on the basis of an abnormal fetal heart rate tracings occurred in 36 of 120 fetuses (30.0%) with metabolic acidemia. Based on expert, algorithm-assisted reviews, 55 of 120 patients with acidemia (45.8%) were judged to need operative intervention for abnormal fetal heart rate tracings. This difference was significant ( P =.016). In infants who were born with a base deficit of >12 mM/L in which blinded, algorithm-assisted expert review indicated the need for operative delivery, the decision for delivery would have been made an average of 131 minutes before the actual delivery. The rate of expert intervention for fetal heart rate concerns in the nonacidemic control