Lung Ultrasound Evaluation of the Impact of Inspired Oxygen Fraction on Atelectasis During Induction of General Anesthesia in Pediatric Patients: A Randomized Controlled Trial.

OBJECTIVE

This study investigated the impact of different inspired oxygen fractions (FiO2) on the development of anesthesia-induced atelectasis in pediatric patients aged one to seven years, utilizing lung ultrasound (LUS) for assessment.

METHODS

In this prospective, randomized controlled trial, 114 pediatric patients with American Society of Anesthesiologists physical status I-II were randomized to receive either 100% FiO2 (n = 57) or 50% FiO2 (n = 57) during anesthesia induction. In the 100% FiO2 group, the inspired oxygen fraction was reduced to 50% after 10 minutes of mechanical ventilation. LUS assessments were conducted at six time points by evaluators blinded to group allocation. The primary outcome was the incidence of clinically significant atelectasis, defined as one or more lung regions exhibiting an LUS score of 2 or higher.

RESULTS

Atelectasis incidence peaked 10 minutes after the initiation of mechanical ventilation and was significantly higher in the 100% FiO2 group (67%) compared with the 50% FiO₂ group (33%; p < 0.001), representing a 51% relative risk reduction. The highest recorded global LUS score was 34% greater in the 100% FiO2 group (12.4 ± 3.1 vs. 8.2 ± 2.6; p < 0.001). Atelectasis affecting gravity-dependent lung regions was also significantly more pronounced in the 100% FiO2 group (p < 0.05). No hypoxemic events were observed in either group.

CONCLUSION

Administration of 50% FiO2 during anesthesia induction in pediatric patients significantly decreased the incidence and severity of atelectasis without compromising oxygenation or safety. These findings support the use of a lower inspired oxygen concentration as a potentially optimal strategy for minimizing anesthesia-related pulmonary complications in this population.