NORMAL OXYGEN PRE- AND POST-DUCTAL SATURATION IN HEALTHY NEWBORNS AT 3400 METERS ABOVE SEA LEVEL

Abstract

Introduction: Oxygen saturation is not uniform across all altitudes above sea level and is known to be inversely proportional to altitude, making it necessary to determine normal values for each specific altitude. Applying currently recommended saturation thresholds for screening critical congenital heart disease at high altitudes leads to an overestimation of suspected cases. Objective: To establish normal preductal and postductal oxygen saturation values in healthy newborns at 3400 meters of altitude and recommend new cutoff points for suspected critical congenital heart disease at this altitude. Methods: Observational study of 1193 healthy newborns at the Hospital Nacional Adolfo Guevara Velasco EsSalud. Preductal and postductal SpO₂ were measured between 24 and 48 hours of age. Mean, median, mode, range, standard deviation, and percentiles were calculated. Preductal and postductal oxygen saturations were compared using paired t-tests and Wilcoxon tests. Results: The mean preductal SpO₂ was 91.02% (SD 2.47), and the mean postductal SpO₂ was 91.01% (SD 2.38). The median was 91% for both preductal and postductal SpO₂. The mode was 90% for both preductal and postductal SpO₂. The preductal SpO₂ range was 84% to 100%, and the postductal SpO₂ range was 85% to 100%. The 3rd percentile was 88% for both preductal and postductal SpO₂, and the 97th percentile was 96% for both. Conclusion: We found lower preductal and postductal SpO₂ values and propose a significantly lower cutoff point for suspected critical congenital heart disease at this altitude.