We added the data using FiO2 ROC curve. The area under the curve for FiO2 ROC curve was smaller than the area under the curve for oxygen flow. In addition, the cut-off value for FiO2 corresponded to the cut-off for the oxygen flow rate, so the two groups in Table 3 would be similar.
Results When comparing different oxygen delivery methods, isn't it more appropriate to compare FiO2 rather than oxygen flow rate?