Statistical analyses
To calculate the sample size, we performed a preliminary experiment with 20 patients in each group (60 patients in total), and the first-pass intubation success rate in each group was 75% in Group VL, 95% in Group VS, and 90% in Group FV. With The data were analyzed using SPSS 26.0 statistical software. Continuous variables, such as the basic characteristics of patients, are expressed as the mean ± standard deviation. Comparisons of measurement data were performed using the 