Fig. 2.

Duration of the successful intubation at the first attempt demonstrated by Kaplan-Meier estimator. Vertical ticks mark the time point when the first intubation attempt failed (censored observation). Kaplan-Meier estimator demonstrates that the intubation time in CVS-V group is consistently shorter than that in the other two groups. And the intubation time in CVS-L is the most inconsistent. The p value was 0.023 by the log-rank test. However, after Sidak’s adjustment for multiple comparisons for the log-rank test, the p values were more than 0.05 between the groups