Raghuraman N, et al. - A randomized, unblinded noninferiority clinical trial was carried out between June 2016 and July 2017 in the labor and delivery ward of a single tertiary care center to test the premise that room air was noninferior to oxygen in improving fetal metabolic status among patients with category II fetal heart tracings. The obtained results demonstrate that intrauterine resuscitation with room air was noninferior to oxygen in improving umbilical artery lactate among patients with category II fetal heart tracings. This trial challenged the effectiveness of a ubiquitous obstetric practice and suggested that room air might be an acceptable alternative to oxygen for category II fetal heart tracings in labor.

Methods

• Participants in the study were women with singleton pregnancies at 37 weeks’ gestational age or more who were admitted for delivery.
• After that, the patients who developed category II tracings in labor that necessitated intrauterine resuscitation were randomized in a 1:1 ratio to room air or oxygen.
• Intention-to-treat were the analyses.
• By nonrebreather facemask until delivery, the oxygen group received 10 L of oxygen per minute.
• Only without a facemask, the room air group was exposed to room air.
• Umbilical artery lactate, a marker of metabolic acidosis and neonatal morbidity was the primary outcome.
• Researchers defined noninferiority as a mean difference between groups of less than 9.0 mg/dL (1.0 mmol/L).
• Other umbilical artery gases, cesarean delivery for nonreassuring fetal status, and operative vaginal delivery were the secondary outcomes.

Results

• According to the findings obtained, out of 705 subjects who met inclusion criteria, 277 (39.3%) were enlisted on admission.
• It was observed that 114 subjects (41.2% of the enrolled patients) developed category II tracings and were randomized to room air (57 patients; 50.0% of the randomized patients) or oxygen (57 patients; 50.0% of the randomized patients) during labor.
• In the modified intention-to-treat analysis, 99 patients (86.8% of the randomized patients) with paired cord gases were involved.
• It was noted that the 99 patients involved 76 African American women (77%); mean (SD) age was 27.3 (6.3) years in the oxygen group and 27.8 (5.3) years in the room air group.
• No difference in umbilical artery lactate between the group on oxygen and the group on room air (mean, 30.6 mg/dL [95% CI, 27.0 to 34.2 mg/dL] vs 31.5 mg/dL [95% CI, 27.9 to 36.0 mg/dL]); P=.69) was found.
• Findings revealed that the mean difference in lactate was 0.9 mg/dL (95% CI, -4.5 to 6.3 mg/dL), which was within the noninferiority margin.
• No difference in other umbilical artery gas components or mode of delivery between groups was found.