Evaluation of an Initiative to Decrease the Use of Oxygen Supplementation for Category II Fetal Heart Rate Tracings

To examine compliance with a guideline to reduce exposure to supplemental oxygen for category II fetal heart rate (FHR) tracings in normally oxygenated laboring patients.

All patients in labor in an urban academic medical center from January 1 to July 31, 2020 were assessed. The preintervention group included those who delivered from January 1 to March 19, 2020. On March 20, 2020, a new guideline took effect that recommended no maternal supplemental oxygen for category II FHR tracings. The postintervention group delivered from March 20 to July 31, 2020. Exclusion criteria were planned cesarean delivery, multiple gestations, delivery at less than 24 weeks of gestation, intrauterine fetal death, and patients who received supplemental oxygen for an oxygen saturation lower than 95%. The primary outcome was the percentage of patients who received oxygen in labor analyzed by control charts and the rules of special cause variation. Chi-squared and t tests were used for secondary outcome assessment. P<.05 was considered significant.

A total of 1,333 patients were included, 474 patients in the preintervention group and 859 in the postintervention group. Oxygen was administered to 22.6% of patients before guideline implementation, compared with 0.6% after the guideline. Special cause variation was detected with an 8-point shift starting the month that the guideline was implemented, indicating statistical significance. There were no differences in any studied secondary maternal or fetal outcomes, although our statistical power to detect differences in infrequent outcomes was limited.

This quality-improvement study demonstrated significant adherence to the guideline that supplemental oxygen would no longer be given to patients with category II FHR tracings in the absence of maternal hypoxemia, with no significant change in maternal or perinatal outcomes.