Newborn oxygen saturation at mild altitude versus sea level: implications for neonatal screening for critical congenital heart disease.

AIM To determine the normal SpO2 in healthy term newborns at mild altitude (MA, 780 metres) compared with sea level (SL), within the context of universal screening for critical congenital heart disease (CCHD). METHODS We studied 199 (119 at MA and 80 at SL) consecutively born healthy newborns. SpO2 recordings were at 24-72 h using Masimo SET Radical-7 on the right hand and left foot. RESULTS Mean SpO2 was lower at MA compared with SL in the right hand (97.86 ± 1.58 vs 98.28 ± 1.41, p = 0.05) and left foot (98.49 ± 1.35 vs 98.90 ± 1.16, p = 0.03). No infant with SpO2 <95% had CCHD. Extrapolating with predicted regression lines set at 95% CI, a SpO2 cut-off of 95% would result in up to 3.5 times more false-positive screens at MA compared with SL. CONCLUSIONS At MA, SpO2 is approximately 0.4% lower compared with SL. Our study supports the AAP recommendation suggesting algorithm cut-offs may need adjustment in high-altitude nurseries and suggest broadening it to MA as well.