Determining reference data for overnight oximetry in neonates: A pilot study

To determine the variability of overnight oximetry parameters in a group of normal, healthy term infants; to enable the calculation of the number of subjects required to produce reliable reference ranges for neonatal overnight oximetry.

A convenience sample of normal, healthy term neonates was recruited. Each had overnight oximetry using the Masimo SET Radical oximeter (data downloaded using Profox software). The report included the number of oxygen desaturation events (an absolute decrease in SpO₂ of 4 or more), and the duration of oxygen saturations <90%.

21 babies were recruited with data available from 19. 32% were female; 68% born by vaginal delivery; 37% fully breast feeding, 53% bottle and 11% by a combination of both. The mean (SD) GA was 39.2 (0.79) weeks, the mean (SD) BW was 3477 (240) grams. The median (IQR) post-natal age at the time the oximetry recording started was 31 (28-41) hours; four babies were <24 h old. All babies had some desaturation events ranging from 4 to 36 times per hour. On average babies spent 3.0% (SD 2.3) of the time with an SpO₂ < 90% (range 0.12-7.94).

In a cohort of healthy term neonates, as assessed by overnight oximetry, the mean SpO₂ was 97% (SD 1, range 95-99). All neonates had a number of oxygen desaturation events ranging from 4 to 36 per hour. The mean proportion of time spent with oxygen saturations below 90% was around 3%.