Fig. 3From: Comparison of the effectiveness of high-flow nasal oxygen vs. standard facemask oxygenation for pre- and apneic oxygenation during anesthesia induction: a systematic review and meta-analysisForest plots of PaO2 in HFNO versus FMV after preoxygenation and after intubation. Subgroup analysis shows the PaO2 after preoxygenation versus after intubation. CI indicates confidence interval; df, degrees of freedom; HFNO, a high-flow nasal oxygen; FMV, facemask ventilation; IV, inverse variance, 02 oxygen, standard deviationBack to article page