Figure 4

Meta-regression plot of PaO2/FiO2 ratio: Meta-regression analysis showing a linear relationship between the reduction in the incidence risk ratio of severe hypoxemia and the increase in PaO2/FiO2 ratio. As the cut-off PaO2/FiO2 ratio reached approximately 250, the upper 95% CI of severe hypoxemia incidence risk ratio equaled to 1 and then the incidence of severe hypoxemia decreased. Circles indicate incidence risk ratios of severe hypoxemia in individual studies, and bubble size is proportional to the precision of individual studies.