Pulse oximetry: what's normal in the newborn nursery?

The objective of this study was to establish normal values for pulse oximetry saturation (POS) in healthy newborn infants in the nursery. POS values were obtained from the right (R) hand and R foot at admission, 24 hr, and at discharge. The following information was recorded: postnatal age, activity state, gender, gestational age (GA), birth weight (BW), mode of delivery (MOD), and Apgar scores. Charts were reviewed and follow-up information was obtained for newborns with measurements < or =92%. The study group consisted of a convenience sample of newborn infants, excluding those on supplemental oxygen. Seven hundred eighteen patients were studied: 51% males, 28% cesarean sections, gestational age 39.3+/-1.6 weeks (mean +/- SD), birth weight 3370+/-550 g, and median Apgar scores 8 and 9. The mean POS was 97.2 +/-1.6%, and the median value was 97%. Only postnatal age and activity state affected POS significantly. POS increased 0.17% per 24 hr in the nursery (P = 0. 0001). POS values obtained while the infants were fussy and crying were lower compared to measurements obtained while sleeping [mean decreases: 0.44% while fussy (P = 0.001), 0.98% while crying (P = 0.0001)]. We conclude that newborns in the nursery have an overall mean POS of 97.2% (+/-2 SD: 94-100%). Mean POS values increase to a small degree with increasing postnatal age. Fussy and crying newborns have lower POS values compared to quiet and sleeping newborns. These reference data can be used in the evaluation of POS measurements in symptomatic newborn infants.