OBJECTIVE: To evaluate the efficacy of automatic oxygen control (A-FiO2) in reducing the extremes of oxygen saturations (SpO2<80% and SpO2>98%) in preterm infants on high-flow nasal cannula (HFNC) respiratory support using Vapotherm Precision Flow. DESIGN: A parallel-arm randomised controlled trial. SETTING: A level-III neonatal intensive care unit. PATIENTS: Preterm infants born <33 (23+0 to 32+6) weeks receiving HFNC as respiratory support. INTERVENTIONS: A-FiO2 versus manual (M-FiO2) oxygen control during the full course of HFNC support. OUTCOMES: The primary outcome of this study is percentage of time spent in extreme oxygen saturations (<80% and >98%) in preterm infants when receiving HFNC as respiratory support. Secondary outcomes were time with SpO2 between 90% and 95% plus time >95% without supplemental oxygen. RESULTS: 60 infants were randomised equally to either A-FiO2 or M-FiO2 arm. Their baseline characteristics were comparable. They spent a median of 5.3 (IQR: 2.0-8.4) and 6.5 (IQR: 2.9-13.7) days in the study, A-FiO2 and M-FiO2, respectively. The percentage of time spent in SpO2<80% (median of 0.4% (0.1%-0.8%) vs 1.6% (0.6%-2.6%), p=0.002) and >98% (median 0.2% (0.1%-0.9%) vs 1.9% (0.7%-4%), p<0.001) were significantly lower in A-FiO2 compared with M-FiO2. The difference in median percentage of time in target range between the two arms was 26% (81% (74%-93%) in A-FiO2 vs 55% (48%-72%) in M-FiO2). CONCLUSION: A-FiO2 was associated with statistically significant reduction in the percentage of time spent in extremes of saturation when compared with M-FiO2 in preterm infants receiving HFNC. TRIAL REGISTRATION NUMBER: NCT04687618.
