Effect of different fraction of inspired oxygen on development of atelectasis in mechanically ventilated children: A randomized controlled trial

Abstract

Background: The use of high fraction of inspired oxygen (F_I O₂ ) can cause direct pulmonary toxicity and pulmonary complications. The purpose of this study was to evaluate the effect of different F_I O₂ on development of intraoperative atelectasis in mechanically ventilated children using lung ultrasound.

Methods: In this randomized controlled, patient- and sonographer-blinded trial, 86 children (≤6 years) undergoing noncardiac surgery were allocated into a low (n = 43) or high (n = 43) F_I O₂ group. The low F_I O₂ group consistently received 30% air-oxygen mixture during preoxygenation, ultrasound-guided recruitment maneuver, and mechanical ventilation. The high F_I O₂ group received 100% oxygen during preoxygenation and ultrasound-guided recruitment maneuver and 60% air-oxygen mixture during mechanical ventilation. Positive end-expiratory pressure of 5 cm H₂ O was applied in both groups. Lung ultrasound was performed one minute after the start of mechanical ventilation and at the end of surgery in both groups. Primary outcome was significant atelectasis incidence (consolidation score of ≥2 in any region) on the postoperative lung ultrasound. Secondary outcomes included significant atelectasis incidence on the preoperative lung ultrasound, incidences of intra- and postoperative desaturation, and incidences of postoperative fever and postoperative pulmonary complications.

Results: Significant atelectasis incidence on the postoperative lung ultrasound was similar between the low and high F_I O₂ groups (28% vs 37%; Pearson chi-square value = 0.847; P = .357; OR 1.531; 95% CI 0.617-3.800). Significant atelectasis incidence on the preoperative lung ultrasound was also similar between the groups (12% vs 9%; Pearson chi-square value = 0.124; P = .725; OR 0.779; 95% CI 0.194-3.125). There were no statistically significant differences in the other secondary outcomes.

Conclusions: F_I O₂ did not affect significant atelectasis formation in mechanically ventilated children who received ultrasound-guided recruitment maneuver and positive end-expiratory pressure.

Keywords: anesthesia; child; general; oxygen; pulmonary atelectasis; ultrasonography.