Background Oxygen under- and overexposure has detrimental effects on preterm infants. Controlling the oxygen saturation manually within strict targets is a notoriously difficult and time consuming task which can be facilitated by automated control.

Aims To evaluate the performance of a closed loop fraction of inspired oxygen (FiO₂) controller based on oxygen saturation (SpO₂) targets when compared to dedicated manual control.

Methods Prematurely delivered lambs (128–132 days of gestation, term 150 d) were intubated and ventilated with volume guaranteed ventilation (Fabian HFO, Acutronic®) adjusted to arterial pCO₂. SpO₂ was measured via pulse oximetry (Radical 7, Masimo®). After a stabilisation period of 30 min, lambs were randomised to three hours of ventilation with automated or manual FiO₂ control (caretaker-lamb ratio 1:1). Saturation targets were 90–95% according to European guidelines. Data is represented as median [IQR].

Results Twenty-two lambs were included, 11 in each group. Time spend within the target range was significantly better when the automated controller was used (93.2% [80.6–98.9%] vs. 84.0% [63.8–89.4%], p₂ adjustments per hour was higher when the automated controller was used (13.0 [3.0–16.4] vs. 5.7 [2.3–9.8], n.s.).

Conclusions Automated FiO₂ control was effective in this model. These results are especially promising as we compared our device to animals receiving 1:1 care in the manual control group. In a clinical setting, the combination of automated control and dedicated caretakers might even be more effective.