], we estimated that the difference between CVP in the continuous IRVF pattern group and discontinuous pattern group was 5 mmHg, and the common standard deviation of CVP in both groups was 5 mmHg. A total of 32 patients were required to confirm the difference between CVP in the IRVF groups with a 2-sided alpha level of 0.05 and power of 80%. Patients were enrolled until the size of both groups reached to at least 16.
Characteristics are presented using median and interquartile range or mean and standard deviation for continuous variables, and frequencies and proportions for categorical variables. For differences in characteristics between the continuous and discontinuous groups, the Mann–Whitneytest was used for continuous variables, and Fisher's exact test was used for categorical variables.