2.2 | Randomization
Before randomization, both written and verbal information was provided to the parents and their consent was obtained. Then the random number corresponding to the number of the research object was generated in the process of SAS9.4procplan. Based on the parity of the random number, the research object was randomly divided into the CIV and IIV groups. Each research object was assigned to the corresponding group using a table randomly numbered in the order of admission to the ICU.