O Ajuste Automático da Fração Inspirada de Oxigénio (FiO2) e o Tempo em Normoxémia em Recém-Nascidos Prematuros

Introduction: The challenge of maintaining normoxemia in preterm infants undergoing respiratory support and oxygen therapy has led to the development of closed-loop automatic control systems for FiO2. The aim of this study was to assess the effectiveness of these systems in maintaining SpO2 within a target range (90% - 94%) in preterm neonates receiving supplemental oxygen.Methods: We conducted a single-centre prospective study over a three-year period (2020 - 2023) including preterm infants with a gestational age < 33 weeks who received supplemental oxygen within the first 24 hours of life and either invasive or non-invasive respiratory support. The closed-loop automatic control of FiO2 used was the Predictive Intelligent Control of Oxygenation feature on Fabian® ventilators. Two groups were randomized and compared, one receiving automatic plus manual control of FiO2, and the other receiving routine manual control. Uni- and multivariable regression analyses (linear or Poisson) were used to evaluate the association between the use of closed-loop automatic control of FiO2 and the parameters of manual adjustments, hypoxemia, hyperoxemia, and normoxemia. Results: The study included 89 patients, of which 45 received automatic plus manual control of FiO2 and 44 received routine manual control. The first group required fewer manual adjustments of FiO2, experienced fewer episodes of hypoxemia and hyperoxemia (p < 0.002), and spent more time with SpO2 within the target range (p < 0.001), compared to the second group. After adjustment for confounding, the total time spent in normoxemia was higher when in automatic plus manual control of FiO2 (β = 81.5; 95%CI: 47.9 - 115.2, p < 0.001).Conclusion: The use of closed-loop automatic control of FiO2 seems feasible and was associated with fewer episodes of hypoxia and hyperoxia, thereby maintaining SpO2 within normal limits for longer periods. Additionally, it has been shown to be associated with a reduction in manual interventions.