Randomised cross-over study of automated oxygen control for preterm infants receiving nasal high flow

Abstract

ObjectiveTo evaluate a prototype automated controller (IntellO2) of the inspired fraction of oxygen (FiO2) in maintaining a target range of oxygen saturation (SpO2) in preterm babies receiving nasal high flow (HF) via the Vapotherm Precision Flow.DesignProspective two-centre order-randomised cross-over study.SettingNeonatal intensive care units.PatientsPreterm infants receiving HF with FiO2 ≥25%.InterventionAutomated versus manual control of FiO2 to maintain a target SpO2 range of 90%–95% (or 90%–100% if FiO2=21%).Main outcome measuresThe primary outcome measure was per cent of time spent within target SpO2 range. Secondary outcomes included the overall proportion and durations of SpO2 within specified hyperoxic and hypoxic ranges and the number of in-range episodes per hour.ResultsData were analysed from 30 preterm infants with median (IQR) gestation at birth of 26 (24–27) weeks, study age of 29 (18–53) days and study weight 1080 (959–1443) g. The target SpO2 range was achieved 80% of the time on automated (IntellO2) control (IQR 70%–87%) compared with 49% under manual control (IQR 40%–57%; p<0.0001). There were fewer episodes of SpO2 below 80% lasting at least 60 s under automated control (0 (IQR 0–1.25)) compared with manual control (5 (IQR 2.75–14)). There were no differences in the number of episodes per hour of SpO2 above 98% (4.5 (IQR 1.8–8.5) vs 5.5 (IQR 1.9–14); p=0.572) between the study arms.ConclusionsThe IntellO2 automated oxygen controller maintained patients in the target SpO2 range significantly better than manual adjustments in preterm babies receiving HF.Trial registration number NCT02074774.

Closed loop automated oxygen control in neonates—A review

“…Sixteen single or multicentre clinical studies have been undertaken comparing closed loop automated oxygen control to manual oxygen control in neonates to determine whether automating FiO 2 control was associated with a greater target SpO 2 achievement. They consistently demonstrated that closed loop automated oxygen control maintained the patient within their target SpO 2 range a significantly greater proportion of the time than manual control . Closed loop automated oxygen control has been demonstrated to reduce hyperoxic episodes, in one study almost halving the frequency (9.3 to 4.7 episodes per 90 minutes) and the duration (19.3 s‐10.1 s) of hyperoxic episodes and in another study reducing the median percentage time spent with an SpO 2 > 95% from 41.9% to 19.3% ( P < .001) .…”

“…A crossover study found that with automated weaning, infants spent significantly more time with a FiO 2 < 0.25 than with manual control . A further crossover study of automated FiO 2 control versus manual control in infants on nasal cannula oxygen found that, in addition to automated control resulting in a significantly greater proportion of time with saturations within the target range, the automated control also tended to result in a FiO 2 of 21%, whereas manual control resulted in an FiO 2 of 30% . Those results suggest automated control might identify, which patients no longer require supplementary oxygen more quickly.…”

“…Closed loop automated oxygen control has been demonstrated to reduce hyperoxic episodes, in one study almost halving the frequency (9.3 to 4.7 episodes per 90 minutes) and the duration (19.3 s‐10.1 s) of hyperoxic episodes and in another study reducing the median percentage time spent with an SpO 2 > 95% from 41.9% to 19.3% ( P < .001) . A randomised crossover study found that an automated controller resulted in ‘overshoot’ (an exaggerated response to hypoxia leading to hyperoxia) more frequently than manual control, but the resulting episodes of hyperoxia were shorter than similar episodes under manual control …”

“…As before, none of these studies have included term‐born infants. They have also been shown to be effective for infants who were intubated and ventilated, as well as those on non‐invasive respiratory support . In a randomised trial of a closed loop automated oxygen control system for infants on non‐invasive respiratory support, infants on automated control spent a significantly higher proportion of their time within their target saturation range compared to those on manual control (58% versus 33.7% respectively) .…”

Automated control for high‐flow oxygen

“…Machines have been developed that use regular pulse oximetry measurements to modify delivered oxygen concentration automatically to maintain Sp0 2 in the recommended target range (90–95%). Two UK units randomised 30 infants (gestation 24–27 weeks, weight 959–1443 g, age 18–53 days) receiving high‐flow oxygen with Fi0 2 ≥ 25% to commence either manual or automatic control of Fi0 2 . The automatic device, called an Intell0 2 , was set to maintain an Sp0 2 of 93%.…”