Objective To evaluate the performance of a novel rapidly responsive proportional-integral-derivative (PID) algorithm for automated oxygen control in preterm infants with respiratory insufficiency.
Design Interventional study of a 4-hour period of automated oxygen control compared with combined data from two flanking periods of manual control (4 hours each).
Setting Neonatal intensive care unit.
Participants Preterm infants (n=20) on non-invasive respiratory support and supplemental oxygen, with oxygen saturation (SpO2) target range 90%–94% (manual control) and 91%–95% (automated control). Median gestation at birth 27.5 weeks (IQR 26–30 weeks), postnatal age 8.0 (1.8–34) days.
Intervention Automated oxygen control using a standalone device, receiving SpO2 input from a standard oximeter and computing alterations to oxygen concentration that were actuated with a modified blender. The PID algorithm was enhanced to avoid iatrogenic hyperoxaemia and adapt to the severity of lung dysfunction.
Main outcome measure Proportion of time in the SpO2 target range, or above target range when in air.
Results Automated oxygen control resulted in more time in the target range or above in air (manual 56 (48–63)% vs automated 81 (76–90)%, p<0.001) and less time at both extremes of oxygenation. Prolonged episodes of hypoxaemia and hyperoxaemia were virtually eliminated. The control algorithm showed benefit in every infant. Manual changes to oxygen therapy were infrequent during automated control (0.24/hour vs 2.3/hour during manual control), and oxygen requirements were unchanged (automated control period 27%, manual 27% and 26%, p>0.05).
Conclusions The novel PID algorithm was very effective for automated oxygen control in preterm infants, and deserves further investigation.
- Intensive Care
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Correction notice This paper has been amended since it was published Online First. References 17 and 18 were in the wrong order.
Acknowledgements We thank the clinical staff of the Royal Hobart Hospital Neonatal and Paediatric Intensive Care Unit and the parents of participating infants for their cooperation and engagement in this study.
Contributors GKP: conducted the study, compiled and analysed the data (with PAD), co-wrote the first draft of the manuscript (with PAD) and approved the final version. KIW: co-conceived the study (with PAD, TJG), reviewed and edited the manuscript and approved the final version. SKMA: assisted with study conduct, reviewed and edited the manuscript and approved the final version. OSF, RJ: identified enhancements to the automated control algorithm, reviewed and edited the manuscript and approved the final version. TJG: conceived the algorithm (with PAD) and this study (with PAD, KW), oversaw its conduct, reviewed and edited the manuscript and approved the final version. PAD: conceived the algorithm (with TJG) and this study (with TJG, KW), oversaw its conduct, co-wrote the first draft of the manuscript (with GKP) and approved the final version.
Funding Supported by a starter grant (12-019) from the Royal Hobart Hospital Research Foundation.
Competing interests The University of Tasmania and Royal Hobart Hospital have jointly lodged a provisional patent application concerning automated control of inspired oxygen concentration in the newborn infant.
Ethics approval University of Tasmania Human Research Ethics Committee.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Original study data available for sharing on request.
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