Randomization and blinding
The study participants were randomly allocated to receive one of the following three NS doses: 0.1 mL/kg, 0.3 mL/kg, and 0.5 mL/kg (simple randomization) based on the TBW. Following the sample size estimation, the research investigator (TK) created a random allocation table in a 1:1:1 ratio via STATA 17.0® (StataCorp, College Station, TX, USA). Two data managers (YS, TY) consecutively allocated the participants into the three NS dose groups using the random allocation table. The data managers (YS, TY) wrote the allocated NS dose information on a small piece of paper, which was then wrapped with aluminum foil and concealed in an envelope.