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Effects of a new device for automated closed loop control of inspired oxygen concentration on fluctuations of arterial and different regional organ tissue oxygen saturations in preterm infants
  1. Marek Gajdos1,
  2. Markus Waitz1,2,
  3. Marc Robin Mendler1,
  4. Wolfgang Braun3,
  5. Helmut Hummler1,4
  1. 1 Divison of Neonatology and Pediatric Intensive Care, Department of Pediatrics, University of Ulm, Ulm, Germany
  2. 2 Division of Neonatology, Department of Pediatrics, University of Giessen, Giessen, Germany
  3. 3 Fritz Stephan Medizintechnik GmbH, Gackenbach, Germany
  4. 4 Division of Neonatology, Department of Pediatrics, Sidra Medical and Research Center, Sidra, Qatar
  1. Correspondence to Dr Marek Gajdos, Divison of Neonatology and Pediatric Intensive Care, Department of Pediatrics, University of Ulm, Ulm 89081, Germany; mark.gajdos{at}


Objective To assess the efficacy of a newly developed system for closed loop control of the fraction of inspired oxygen (FiO2) on variation of arterial (SpO2) and on regional tissue oxygen saturation (StO2) in preterm infants with fluctuations in SpO2.

Design Randomised crossover trial comparing automated (auto) to manual FiO2 adjustment (manual) during two consecutive 24 hours periods using a Sophie infant ventilator (SPO2C).

Setting Tertiary university medical centre.

Patients Twelve very low birthweight infant (VLBWI) (gestational age (median; IQR): (25; 23–26 weeks); birth weight (mean±SD): (667±134 g); postnatal age (mean±SD): (31.5±14 days)).

Main outcome measure Time within SpO2 target range.

Results There was an increase in time within the intended SpO2 target range (88%–96%) during auto as compared with manual mode (77.8%±7.1% vs 68.5%±7.7% (mean±SD), p<0.001) and a decrease in time below the SpO2 target during the auto period (18.1%±6.4% vs 25.6%±7.6%; p<0.01). There was a dramatic reduction in events with an SpO2 <88% with >180 s duration: (2 (0–10) vs 10 (0–37) events, p<0.001) and the need for manual adjustments. The time the infants spent above the intended arterial oxygen range (4.1%±3.8% vs 5.9%±3.6%), median FiO2, mean SpO2 over time and StO2 in the brain, liver and kidney did not differ significantly between the two periods.

Conclusions Closed-loop FiO2 using SPO2C significantly increased time of arterial SpO2 within the intended range in VLBWI and decreased the need for manual adjustments when compared with the routine adjustment by staff members. StO2 was not significantly affected by the mode of oxygen control.

  • neonatology
  • closed loop, oxygen, BPD

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  • Contributors MG (first author) collected data, provided and cared for study patients. MW, MRM and WB (coauthors) served as scientific advisors, reviewed the study proposal. HH served as scientific advisor.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent Parental/guardian consent obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.