Randomised crossover trial comparing algorithms and averaging times for automatic oxygen control in preterm infants
Christoph E. Schwarz, Karen B. Kreutzer, Lukas Langanky, Nicole S Wolf, Wolfgang Braun, Marc Paul O’Sullivan, Christian F. Poets, Axel R. Franz
Abstract
Objective Automatic control (SPOC) of the fraction of inspired oxygen (FiO 2 ), based on continuous analysis of pulse oximeter saturation (SpO 2 ), improves the proportion of time preterm infants spend within a specified SpO 2 -target range (Target%). We evaluated if a revised SPOC algorithm (SPOC new , including an upper limit for FiO 2 ) compared to both routine manual control (RMC) and the previously tested algorithm (SPOC old, unrestricted maximum FiO 2 ) increases Target%, and evaluated the effect of the pulse oximeter’s averaging time on controlling the SpO 2 signal during SPOC periods. Design Unblinded, randomised controlled crossover study comparing 2 SPOC algorithms and 2 SpO 2 averaging times in random order: 12 hours SPOC new and 12 hours SPOC old (averaging time 2 s or 8 s for 6 hours each) were compared with 6-hour RMC. A generated list of random numbers was used for allocation sequence. Setting University-affiliated tertiary neonatal intensive care unit, Germany Patients Twenty-four infants on non-invasive respiratory support with FiO 2 >0.21 were analysed (median gestational age at birth, birth weight and age at randomisation were 25.3 weeks, 585 g and 30 days). Main outcome measure Target%. Results Mean (SD) [95% CI] Target% was 56% (9) [52, 59] for RMC versus 69% (9) [65, 72] for SPOC old _ 2s , 70% (7) [67, 73] for SPOC new _ 2s , 71% (8) [68, 74] for SPOC old _ 8s and 72% (8) [69, 75] for SPOC new _ 8s . Conclusions Irrespective of SpO 2 -averaging time, Target% was higher with both SPOC algorithms compared to RMC. Despite limiting the maximum FiO 2 , SPOC new remained significantly better at maintaining SpO 2 within target range compared to RMC. Trial registration NCT03785899