Randomised crossover study on pulse oximeter readings from different sensors in very preterm infants

Abstract

ObjectiveIn extremely preterm infants, different target ranges for pulse oximeter saturation (SpO2) may affect mortality and morbidity. Thus, the impact of technical changes potentially affecting measurements should be assessed. We studied SpO2readings from different sensors for systematic deviations.DesignSingle-centre, randomised, triple crossover study.SettingTertiary neonatal intensive care unit.Patients24 infants, born at <32 weeks’ gestation, with current weight <1500 g and without right-to-left shunt via a patent ductus arteriosus.InterventionsSimultaneous readings from three SpO2sensors (Red Diamond (RD), Photoplethysmography (PPG), Low Noise Cabled Sensors (LNCS)) were logged at 0.5 Hz over 6 hour/infant and compared with LNCS as control using analysis of variance. Sensor position was randomly allocated and rotated every 2 hours. Seven different batches each were used.OutcomesPrimary outcome was the difference in SpO2readings. Secondary outcomes were differences between sensors in the proportion of time within the SpO2-target range (90–95 (100)%).ResultsMean gestational age at birth (±SD) was 274/7(±23/7) weeks, postnatal age 20 (±20) days. 134 hours of recording were analysed. Mean SpO2(±SD) was 94.0% (±3.8; LNCS) versus 92.2% (±4.0; RD; p<0.0001) and 94.5% (±3.9; PPG; p<0.0001), respectively. Mean SpO2difference (95% CI) was −1.8% (−1.9 to −1.8; RD) and 0.5% (0.4 to 0.5; PPG). Proportion of time in target was significantly lower with RD sensors (84.8% vs 91.7%; p=0.0001) and similar with PPG sensors (91.1% vs 91.7%; p=0.63).ConclusionThere were systematic differences in SpO2readings between RD sensors versus LNCS. These findings may impact mortality and morbidity of preterm infants, particularly when aiming for higher SpO2-target ranges (eg, 90–95%).Trial registration numberDRKS00027285.