Background and Aims Manual control of oxygen delivery to premature infants is conducted mainly by NICU nurses. This involves FIO2 adjustments in order to keep the SPO2 within a specific target range (88–92%). Pulse oximeters have alarms set to alert the nurses when SPO2 values are outside the range (85–95%). Our aims were to study FIO2 alteration in terms of magnitude and time outside target immediately before the FIO2 change.
Methods Infants receiving CPAP or ventilation on the Babylog 8000 ventilator (Dec 2010- Apr 2012) were studied. Signals were acquired from oximeters and ventilator using the PowerLab data acquisition system. The 9-minute epoch prior to each FIO2 change: FIO2 increase (ΔPOS) and FIO2 decrease (ΔNEG) were studied.
Results Recordings were obtained from 7 (5 male) infants with mean (± SD) gestation of 26.9 (±1.9) weeks and birthweight 767 (±200) g. 253 FIO2 adjustments were recorded (130 ΔPOS and 123 ΔNEG) from 105 hours of total recording time. Mean (range) magnitude of ΔPOS and ΔNEG was 4.6% (0.5–19.5) and 4.5% (0.5–57.0), respectively. Proportion time spent with low alarm in the 9 minutes before ΔPOS was 50.8%, with 28.4% (±20.2) of time in 80–85%, 15.8%(±16.7) in 70–80% band and 6.6%(±11.3) less than 70% saturation. 22.5% of time was spent with high alarm (before ΔNEG) with 4.3% (±8.7) time SPO2 exceeding 98% and 7.7% (±11.4) in 96–98% band.
Conclusion Nurses were more likely to tolerate low oxygen saturations than high saturations in preterm infants. Mild desaturation episodes (between 80–85%) were often managed conservatively.