Is faster better? A randomised crossover study comparing algorithms for closed-loop automatic oxygen control

Abstract

ObjectiveClosed-loop automatic control (CLAC) of the fractional inspired oxygen (FiO2) improved oxygen administration to preterm infants on respiratory support. We investigated whether a revised CLAC algorithm (CLACfast, ≤2 FiO2 adjustments/min), compared with routine manual control (RMConly), increased the proportion of time with arterial haemoglobin oxygen saturation measured by pulse oximetry within prespecified target ranges (Target%) while not being inferior to the original algorithm (CLACslow: ≤0.3 FiO2 adjustments/min).DesignUnblinded randomised controlled crossover study comparing three modes of FiO2 control in random order for 8 hours each: RMC supported by CLACfast was compared with RMConly and RMC supported by CLACslow. A computer-generated list of random numbers using a block size of six was used for the allocation sequence.SettingTwo German tertiary university neonatal intensive care units.PatientsOf 23 randomised patients, 19 were analysed (mean±SD gestational age 27±2 weeks; age at randomisation 24±10 days) on non-invasive (n=18) or invasive (n=1) respiratory support at FiO2 >0.21.Main outcome measureTarget%.ResultsMean±SD [95% CI] Target% was 68%±11% [65% to 71%] for CLACfast versus 65%±11% [61% to 68%] for CLACslow versus 58%±11% [55% to 62%] for RMConly. Prespecified hypothesis tests of: (A) superiority of CLACfast versus RMConly and (B) non-inferiority of CLACfast versus CLACslow with margin of 5% yielded one-sided p values of <0.001 for both comparisons.ConclusionsThis revised and faster CLAC algorithm was still superior to routine care in infants on respiratory support and not inferior to a previously tested slower algorithm.Trial registration numberNCT03163108.