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A cohort study reporting normal oximetry values in healthy infants under 4 months of age using Masimo technology
  1. Hazel J Evans1,
  2. Anne S Karunatilleke2,
  3. Sarah Grantham-Hill1,2,
  4. Johanna C Gavlak1
  1. 1 Department of Respiratory Paediatrics, Southampton Children’s Hospital, Southampton University Hospital NHS Foundation Trust, Southampton, Hampshire, UK
  2. 2 Faculty of Medicine, University of Southampton, Southampton, UK
  1. Correspondence to Dr Hazel J Evans, Department of Respiratory Paediatrics, Southampton Children’s Hospital, Southampton University NHS Trust, Southampton SO16 6YD, UK; hazel.evans{at}


Objective To determine sleeping saturation indices in healthy infants using a modern pulse oximeter with motion artefact extraction technology.

Design Prospective cohort.

Setting Home.

Subjects Healthy term infants.

Intervention Nocturnal 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 measures Saturations (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%.

Results Forty-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.

Conclusion Desaturation 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.

  • respiratory

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  • Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval Southampton REC (14/SC/0016).

  • Provenance and peer review Not commissioned; externally peer reviewed.