FiO₂ requirements during general anesthesia with dual-lung ventilation: a prospective pilot study

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.

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 min before blood samples were drawn for blood gas analysis at each point.

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 and 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).

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.

http://www.chictr.org.cn, identifier ChiCTR2500095383.