Characteristics of Deliveries Resulting in Neonatal Hypoxic Ischemic
Encephalopathy: A Multi-Centred Retrospective Case Series
Abstract
OBJECTIVE: To characterize clinical management of deliveries resulting
in neonatal hypoxic ischemic encephalopathy. DESIGN: Retrospective case
series SETTING: Three academic referral medical centers in the United
States POPULATION: All neonates ≥35 weeks’ gestation with HIE based on
cord blood pH<7.0, base deficit of ≥12.0mmol/L, along with
relevant radiological, laboratory, and clinical findings. METHODS:
Clinical management was characterized based on whether (i)delivery
occurred within 120 minutes of presentation, (ii)delivery occurred due
to a sentinel event such as cord prolapse or uterine rupture, and
(iii)the fetal heart rate tracing(FHR) demonstrated variability,
accelerations, or both upon presentation and in the half hour before
delivery. MAIN OUTCOME MEASURES: Relationship of mode of delivery to FHR
tracing characteristics at delivery. Obstetric outcomes, labour course
and management were analysed. RESULTS: Of 144,904 deliveries, 102
maternal-newborn dyads met criteria. Of these, 19 delivered within 120
of minutes of presentation and four further women experienced a sentinel
event. Of the remaining 79, 66(84%) had a FHR tracing on presentation
that demonstrated variability, accelerations or both. Of these 66 cases,
27 had a fetal heart tracing that demonstrated variability,
accelerations or both in the 30 minutes preceding delivery. CONCLUSION:
Approximately two-thirds of cases of HIE occurred in cases where the FHR
tracing initially demonstrated variability, accelerations, or both,
without a sentinel event and without a condition requiring delivery
within 120 minutes of presentation. Of these >40% had
variability, accelerations, or both in the half hour before delivery.
This suggests additional insights are required to prevent some cases of
HIE.