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

Abstract

Objective: In 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 SpO₂ readings from different sensors for systematic deviations.

Design: Single-centre, randomised, triple crossover study.

Setting: Tertiary neonatal intensive care unit.

Patients: 24 infants, born at <32 weeks' gestation, with current weight <1500 g and without right-to-left shunt via a patent ductus arteriosus.

Interventions: Simultaneous readings from three SpO₂ sensors (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.

Outcomes: Primary outcome was the difference in SpO₂ readings. Secondary outcomes were differences between sensors in the proportion of time within the SpO₂-target range (90-95 (100)%).

Results: Mean gestational age at birth (±SD) was 27^4/7 (±2^3/7) 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 SpO₂ difference (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).

Conclusion: There were systematic differences in SpO₂ readings 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 number: DRKS00027285.