Per-protocol analysis
A total of 225 patients were included in the intention-to-treat analysis. In per-protocol analysis, data are analyzed only for those patients who completely adhere to the treatment protocol. In the capnography group, two were excluded from the program analysis because they received midazolam and no oxygen supplementation. In the standard group, two patients were excluded from the program analysis because they received midazolam and etomidate instead of propofol. Thus, 221 participants were included in the per-protocol analysis. The results of statistical analysis for the per-protocol set were consistent with those of the intention-to-treat analysis. The results of the per-protocol analysis are reported in the Supplementary Material.