ABSTRACT
Background Hypoxemia is a critical condition that relates to respiratory disease. The use of pulse oximeters for measuring peripheral oxygen saturation (SpO2) to guide oxygen therapy and treat hypoxemia is largely established for children living at low altitudes. However, at higher altitudes above 2000 m a.s.l., no clear abnormal SpO2 thresholds and recommendations for oxygen delivery are available.
Objective Our aim was to provide a plausible model for the calculation of abnormal SpO2 thresholds for altitudes between 0 m a.s.l. and 4000 m a.s.l. that takes into account physiological adaptation to these altitudes.
Methods We analysed the altitude sensitivity of oxygen transport parameters, and we created an altitude-adaptive SpO2 model based on the oxygen cascade. We derived an altitude-adaptive abnormal SpO2 threshold from known changes in the abnormal range. We compared our model and threshold with a previously proposed statistically derived model to two empirical datasets containing pulse oximetry data that were recorded from Peruvian children living at altitudes up to 4500 m a.s.l.
Results Our altitude-adaptive SpO2 model describes the empirical pulse oximetry data, and provides an altitude-adaptive threshold that conservatively estimates abnormal SpO2.
Conclusion We propose a digital model to calculate the abnormal SpO2 threshold for children living at altitude. Since the model takes into account realistic physiological changes, the output of the model is easily reproducible. Such a model could be used in decision support systems to help practitioners adjust oxygen administration for children living at altitudes above 2000 m a.s.l..