A cohort study reporting normal oximetry values in healthy infants under 4 months of age using Masimo technology

Abstract

ObjectiveTo determine sleeping saturation indices in healthy infants using a modern pulse oximeter with motion artefact extraction technology.DesignProspective cohort.SettingHome.SubjectsHealthy term infants.InterventionNocturnal pulse oximetry at home at 1 month of age (Recording 1) and repeated at age 3–4 months (Recording 2). Parents documented sleep times. Visi-Download software (Stowood Scientific) analysed data with artefact and wake periods removed.Main outcome measuresSaturations (SAT50), desaturation index >4% (DI4) and >3% (DI3) from baseline/hour, delta index 12 s (DI12s), minimum saturations (SATmin), percentage time with saturations below 90% and 92%.ResultsForty-five babies were studied at 1 month and 38 babies at 3–4 months. Mean (CI) SAT50, DI4, DI3, DI12s and SATmin (CI) were 97.05 (96.59 to 97.52), 16.16 (13.72 to 18.59), 25.41 (22.00 to 28.82), 0.96 (0.88 to 1.04) and 80.4% (78.8% to 82.0%) at 1 month, respectively, and 97.65 (97.19 to 98.12), 8.12 (6.46 to 9.77), 13.92 (11.38 to 16.47), 0.72 (0.65 to 0.78) and 84.7% (83.3% to 86.1%) at 3–4 months. Median (CI) percentage times with saturations below 90% and 92% were 0.39 (0.26 to 0.55) and 0.82 (0.60 to 1.23), respectively, at 1 month and 0.11 (0.06 to 0.20) and 0.25 (0.17 to 0.44) at 3–4 months. For paired samples (n=32) DI4 (P=0.006), DI3 (P=0.03), DI12s (P=0.001), percentage time with saturations below 90% (P=0.001) and 92% (P=0.000) all fell significantly and SATmin (P=0.004) rose between the two recordings.ConclusionDesaturation indices are substantially higher in young infants than older children where a DI4 over 4 is considered abnormal. These decrease by 3–4 months of age but still remain elevated compared with older children.