Clinical evaluation of a novel adaptive algorithm for automated control of oxygen therapy in preterm infants on non-invasive respiratory support.

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.