Random grouping
In Excel, a column of numbers 1–84 was established as column A. After numbering, column B of 84 corresponding random numbers was generated using a random function. Column A and column B were all selected and sorted in ascending order of column B, so that 84 numbers in column A were randomly arranged, with the first 42 random numbers assigned to the control group and the last 42 random numbers assigned to the intervention group. Then, the 84 randomly numbered cards were sequentially placed into 84 envelopes and the envelopes were ordered. After the patient agreed to participate in this study, the operator opened the envelopes sequentially according to the envelope number and obtained the random number and corresponding grouping. The patient did not know the grouping situation.