Statistical analysis
The sample size of this study was calculated based on minimal clinically importance difference (MCID) of Spo2. Considering standard deviation (SD) of 4.4%, MCID of 4%, two steps of measurements (before and after), a correlation between measurements of .6, type I error of .05, and 80% power, a sample size of 13 participants per group was calculated [Stata version 13. (Stata, College, Statin, Texas) was used to analyze the data. We reported Means ± SD and frequency counts (%) for continuous and categorical data, respectively. Data normality was checked for all continuous variables using the P-P plot, Q-Q plot, and Shapiro-Wilk test. Analysis of variance and covariance (ANOVA/ANCOVA) was used to determine the differences of all continuous data, with the baseline score included as a covariate (one factor, one covariate) [The number needed to treat (NNT) was calculated using an online calculator for all measures [The study was registered at 