Oxygen saturation reference ranges and factors affecting SpO2 among children living at altitude

Abstract

AimsTo determine reference values for oxygen saturation (SpO2) among healthy children younger than 5 years living at moderately high altitude in Papua New Guinea and to determine other factors that influence oxygen saturation levels.Methods266 well children living at 1810–2630 m above sea level were examined during immunisation clinic visits, and SpO2 was measured by pulse oximetry. Potential risk factors for hypoxaemia were recorded and analysed by multivariable analysis.ResultsThe median SpO2 was 95% (IQR 93%–97%), with a normal range of 89%–99% (2.5–97.5 centiles). On multivariable analysis, younger children, children of parents who smoked, those asleep and babies carried in bilums, a traditional carry bag made of wool or string, had significantly lower SpO2.ConclusionThe reference range for healthy children living in the highlands of Papua New Guinea was established. Besides altitude, other factors are associated with lower SpO2. Some higher-risk infants (preterm, very low birth weight, recurrent acute lower respiratory infection or chronic respiratory problem) may be more prone to hypoxaemia if they have additive risk factors: if parents smoke or they are allowed to sleep a bilum, as their baseline oxygen saturation may be significantly lower, or their respiratory drive or respiratory function is impaired. These findings need further research to determine the clinical importance.