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ORIGINAL RESEARCH article

Front. Med.

Sec. Intensive Care Medicine and Anesthesiology

FiO₂ Requirements During General Anesthesia with Dual-Lung Ventilation: A Prospective Pilot Study

  • 1. Department of Anesthesiology, Hangzhou Fuyang Hospital of Traditional Chinese Medicine, Hangzhou, China

  • 2. The Forth Clinical Medical College, Zhejiang Chinese Medicine University(Hangzhou First People's Hospital), Hangzhou, China

  • 3. Zhejiang Provincial People's Hospital, Hangzhou, China

  • 4. Department of Anesthesiology, Hangzhou Women's Hospital (Hangzhou Maternity and Child Health Care Hospital, Zhejiang Chinese Medical University), Hangzhou, China

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Abstract

Abstract Background: Hyperoxemia and prolonged oxygen exposure were common during general anesthesia. However, the relationship between FiO2 and PaO2 in patients undergoing general anesthesia with dual lung ventilation remained unclear. This prospective pilot study aimed to explore this relationship. Methods: A cohort of 50 patients was recruited for this self-controlled, prospective pilot study. A standardized volume-controlled ventilation strategy was applied, with FiO2 initially set to 0.3 immediately after tracheal intubation. FiO2 was then increased in steps of 0.1 until it reached 0.6, followed by an increase to 0.8. Each FiO2 step was maintained for at least 30 minutes before blood samples were drawn for blood gas analysis at each point. Results: Rmcorr analyses revealed a significant correlation between FiO2 and PaO2 (P <0.001). The correlation coefficient (r) was 0.967 and Model convergence was robust, with a gradient value of 0.00003. At an FiO₂ of 40%, 78.0% of patients maintained PaO₂ between 100–200 mmHg, while more than 68.0% exceeded 200 mmHg at 50% FiO₂ levels. Rmcorr analysis revealed a weak but statistically significant correlation between FiO₂ and PaO₂/FiO₂ (r = 0.290; P <0.001). Conclusions: A significant linear correlation was identified between FiO₂ and PaO₂ during general anesthesia with dual-lung ventilation. In this prospective pilot study, our findings suggested that maintaining 40% FiO₂ was generally sufficient for most patients to achieve PaO₂ levels of 100–200 mmHg, unless specific clinical conditions require otherwise. Importantly, FiO₂ need not exceed 50% in most patients undergoing general anesthesia with dual-lung ventilation.

Summary

Keywords

general anesthesia, Inspiratory oxygen fraction, oxygen exposure, oxygen saturation, Partial pressure of oxygen, Ventilation

Received

05 January 2026

Accepted

09 February 2026

Copyright

© 2026 Sun, Chen, Wang, Wang, Liu, Cheng and ZHOU. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Zhen-feng ZHOU

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