Mechanism of reduction of newborn metabolic acidemia following application of a rule-based 5-category color-coded fetal heart rate management framework

J Matern Fetal Neonatal Med. 2015 Sep;28(13):1608-13. doi: 10.3109/14767058.2014.963044.

Abstract

Abstracts Objective: We have reported a 7-fold reduction in newborn umbilical arterial (UA) metabolic acidemia after adoption of a rule-based 5-category color-coded fetal heart rate (FHR) management framework. We sought evidence for the relationship being causal by detailed analysis of FHR characteristics and acid-base status before and after training.

Methods: Rates of UA pH and base excess (BE) were determined over a 5-year period in a single Japanese hospital, serving mainly low-risk patients, with 3907 deliveries. We compared results in the 2 years before and after a 6-month training period in the FHR management system. We used a previously published classification schema, which was linked to management guidelines.

Results: After the training period, there was an increase in the percentage of normal patterns (23%), and a decrease in variable decelerations (14%), late decelerations (8%) and prolonged decelerations (12%) in the last 60 min of labor compared to the pre-training period. There was also a significant reduction in mean UA pH and BE in the groups with decelerations after introduction of the FHR management framework.

Conclusions: The adoption of this FHR management system was associated with a reduction of decelerations and metabolic acidemia, without a change in cesarean or vacuum delivery rates. These results suggest that the obstetrical providers were able to better select for intervention those patients destined to develop more severe acidemia, demonstrating a possible causal relationship between the management system and reduced decelerations and metabolic acidemia.

Keywords: Fetal BE; fetal heart rate; fetal pH.

MeSH terms

  • Acidosis / congenital*
  • Acidosis / physiopathology
  • Acidosis / therapy*
  • Blood Gas Analysis
  • Cardiotocography / methods*
  • Cardiotocography / standards*
  • Clinical Coding / methods*
  • Color
  • Female
  • Fetal Blood / chemistry
  • Fetal Blood / metabolism
  • Heart Rate, Fetal / physiology*
  • Hospitals, Maternity / organization & administration
  • Humans
  • Hydrogen-Ion Concentration
  • Infant, Newborn
  • Pregnancy
  • Severity of Illness Index