Objective Automatic control (SPOC) of the fraction of inspired oxygen (FiO2), based on continuous analysis of pulse oximeter saturation (SpO2), improves the proportion of time preterm infants spend within a specified SpO2-target range (Target%). We evaluated if a revised SPOC algorithm (SPOCnew, including an upper limit for FiO2) compared to both routine manual control (RMC) and the previously tested algorithm (SPOCold, unrestricted maximum FiO2) increases Target%, and evaluated the effect of the pulse oximeter’s averaging time on controlling the SpO2 signal during SPOC periods.
Design Unblinded, randomised controlled crossover study comparing 2 SPOC algorithms and 2 SpO2 averaging times in random order: 12 hours SPOCnew and 12 hours SPOCold (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 FiO2 >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 SPOCold_2s, 70% (7) [67, 73] for SPOCnew_2s, 71% (8) [68, 74] for SPOCold_8s and 72% (8) [69, 75] for SPOCnew_8s.
Conclusions Irrespective of SpO2-averaging time, Target% was higher with both SPOC algorithms compared to RMC. Despite limiting the maximum FiO2, SPOCnew remained significantly better at maintaining SpO2 within target range compared to RMC.
Trial registration NCT03785899
Data availability statement
Data are available on reasonable request. Additional data will be made available on reasonable request.
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Contributors CES conceptualised and designed the study, received the research grant, supervised and participated in biosignal processing, and performed statistical analyses, coordinated, performed and supervised patient recruitment and data collection, is responsible as guarantor, and drafted the initial and the revised manuscript. KBK conducted patient recruitment and data collection, evaluated the analyses and critically reviewed the manuscript. LL conducted patient recruitment and data collection and critically reviewed the manuscript. NSW conducted patient recruitment and data collection and critically reviewed the manuscript. WB performed biosignal processing and critically reviewed the manuscript. MPO’S was involved in statistical analysis and critically reviewed the manuscript. CFP critically reviewed the study design and the manuscript. ARF led the study team, received the research grant, conceptualised and designed the study, supervised biosignal and statistical analyses, is responsible as guarantor, and revised the draft of the manuscript. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.
Funding This study was supported by a research grant from Fritz Stephan GmbH (Gackenbach, Germany).
Disclaimer The granting company had no impact on the study design and data analysis.
Competing interests The University of Tübingen holds a patent on the CLAC algorithm for automated oxygen control and have a licensing agreement with Löwenstein Medical in relation to this algorithm. ARF and CFP are supported by a grant from the German Ministry of Research and Education for conducting the FiO2 Controller study on medium-term effects of closed-loop automated control of FiO2. CES, ARF and CFP also received a research grant from Löwenstein Medical, Bad Ems, Germany. WB is an employee of Fritz Stephan GmbH. CFP received speaker honoraria from Masimo Inc. The other authors declare no competing interests.
Provenance and peer review Not commissioned; externally peer reviewed.
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