RESUMO
Pulse oximetry (SpO2) is essential for guiding oxygen therapy in preterm infants. Data on SpO2 values before discharge are limited. OBJECTIVE: To establish SpO2 values in asymptomatic premature infants at 34, 35, and 36 weeks of postmenstrual age (PMA). SUBJECTS AND METHOD: Longitudinal, multicen ter study carried out from May 2018 to May 2019 in three neonatal intensive care units in Santiago, Chile (altitude 579 m) which included premature infants born ≤ 32 weeks of gestational age, healthy, with clinical stability, and without respiratory morbidity at the moment of the study or until dis charge. The following parameters were analyzed: mean accumulated SpO2 and SD, minimum SpO2 value, SpO2 time percentage < 90%, SpO2 time percentage < 80%, DI4, and DI80. Continuous over night SpO2 was obtained with Masimo Radical-7 or Rad-8 (USA), mean artifact-free-recording-time (AFRT) ≥ 6 hours. RESULTS: 101 SpO2 recordings were registered in 44, 33, and 24 studies at 34, 35, and 36 weeks of PMA, respectively, from 62 preterm infants, twenty-eight (45%) were male, median gestational age at birth 30 weeks (range 26-32), and median birth weight 1480 g (range 785-2700g). Oximetry variables were mean AFRT (± SD) 8.6 (± 1.5) hours; median mean SpO2 96.9% (range 93.3-99.3%); median minimum SpO2 74% (range 51-89%); median time of SpO2 < 90% 2% (range 0-10.6%); median time of SpO2 < 80% 0.1% (range 0-1.3%); median desaturation event ≥ 4% (DI4) within ≥ 10 seconds per hour sampled 15 (range 3.5-62.5); and median desaturation event <80% (DI80) 0.58 (range 0-10.8). We found no differences in SpO2 values between the different PMA wee ks. CONCLUSIONS: We described SpO2 values in very preterm infants, asymptomatic at 34-36 PMA weeks. These values could be used as a reference for guiding oxygen therapy.
