Investigating variations and early-life temporal changes in oxygen saturation indices in healthy moderate-late preterm and term infants: a cohort study.

Abstract

Background: Neonatal respiratory system immaturity causes unstable breathing patterns during sleep, resulting in respiratory events and intermittent hypoxaemia (IH). The recent literature correlates frequent respiratory events with adverse early neurodevelopmental outcomes.

Aims: This study investigated 5-week temporal changes in oxygen saturation indices in healthy moderate-late preterm (MLPT) (born between 32+0 weeks and 36+6 weeks of gestation) and term (born between 37+0 weeks and 41+6 weeks of gestation) infants.

Methods: MLPT and term infants' sleeping postductal saturations were measured using nocturnal pulse oximetry at 7 days, 14 days, 21 days, 28 days and 35 days (±3 days) postnatal age. This recorded mean peripheral oxygen saturation (SpO₂), Oxygen Desaturation Indices (ODIs) 3, 4 and 10 (number of desaturations >3%, >4% and >10% per hour) and mean nadir SpO₂ >3%.

Results: 34 infants were studied (17 per group). The groups' median gestations were 35+0 weeks and 39+5 weeks, respectively. Generalised linear mixed modelling indicated increasing mean saturations from 94.98% in week 1 to 96.68% in week 5 (p<0.001) for both groups together, with no significant group differences. MLPT infants' average mean nadir SpO₂ >3% was 89.94% versus 91.55% for term infants (p=0.005), with both groups improving throughout the study (p=0.006). MLPT infants had 2.08 times more ODI3 dips/hour (p<0.001), 2.49 times more ODI4 dips/hour (p<0.001) and 6.66 times more ODI10 dips/hour (p=0.005) than term infants.

Conclusion: This study demonstrated significant differences in IH prevalence and severity between groups. Further research is needed to evaluate IH's impact on neurodevelopmental outcomes in this population.