Binene V, Panauwe D, Kauna R, et al. - In the present study, the researchers sought to determine reference values for oxygen saturation (SpO ₂) among healthy children younger than 5 years living at moderately high altitude in Papua New Guinea, as well as other factors that influence oxygen saturation levels. During immunisation clinic visits, 266 well children living at 1810–2630 m above sea level were examined, and SpO ₂ was measured using pulse oximetry. The reference range for healthy children living in Papua New Guinea's highlands was established. Other factors, in addition to altitude, are linked to lower SpO ₂. 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, such as if their 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. Further research is needed to determine the clinical significance of these findings.