Lung Volume Change Under Apnoeic Oxygenation With Different Flow Rates in Children

Aebli J et al

Pediatric Anesthesia. Published July 18, 2025.
https://doi.org/10.1111/pan.70018

Summary:
This randomized controlled trial evaluated the impact of different flow rates and timing of high-flow nasal oxygen (HFNO) on lung volume loss during apnoea in children under general anesthesia. Using electrical impedance tomography (EIT), the study analyzed oxygenation strategies in 108 pediatric patients.

Key findings:

• Low-flow oxygen (0.2 L/kg/min) was non-inferior to very high-flow (4 L/kg/min) in preventing lung volume loss

• Moderate-flow oxygen (2 L/kg/min) with or without early onset did not meet non-inferiority thresholds

• Lung volume loss occurred rapidly after apnea onset—often within seconds

• Optiflow Switch nasal cannula slightly delayed volume loss but did not prevent it

• HFNO did not generate clinically meaningful airway pressure to prevent atelectasis in children, consistent with previous adult studies

• Regional analysis (anterior vs. posterior lungs) and time-based loss curves showed no significant differences between flow strategies

Conclusion:
Low-flow nasal oxygen is a viable and non-inferior alternative to very high-flow oxygen for pediatric apnoeic oxygenation during anesthesia. Early onset of HFNO may offer slight delay in atelectasis formation, but HFNO does not create enough subglottic pressure to prevent lung collapse.

Reference for SEO:
Aebli J, Bohnenblust V, Koepp-Medina G, et al. High-flow nasal oxygen during apnoea in children under general anesthesia: A randomized controlled trial. Pediatric Anesthesia. 2025. https://doi.org/10.1111/pan.70018

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