Study design and participants
INSULIN RESISTANCE
Gastric emptying and insulin resistance index were two primary outcomes in this study. We assumed the sample size based on the two outcomes respectively through setting the parameters of 90% power, 5% of a type 1 error, 10% of missing rate, and equivalent cases. In our pre-experiment, the mean of gastric volume (GV) 2 h after oral liquid in both groups are 38 ml, the combined standard deviation of the two groups was 10 ml, and the non-inferiority margin was -6 ml. Each group would need 48 patients using non-inferiority tests for two means in term of gastric emptying. According to previous study [This prospective, randomized and controlled study was approved from Ethics Committees of the Qingdao Municipal Hospital (XCJJ No. 014 (fast) in 2020), and registered in the center of Chinese Clinical Trial Registry (ChiCTR2000039939). Written informed consent was obtained from participating hospitalization patients. A total of 110 patients between January 2021 and August 2021 in the hepatobiliary surgery of Qingdao Municipal Hospital was enrolled in the study who were divided into two groups: oral-water group (group C) and oral-EHR solution group (group E). The inclusion criteria were as follows: patients undergoing elective laparoscopic cholecystectomy before 12 am; 18–64 years old; American society of anesthesiologists (ASA) classification of grade I or II and cardiac function of grade I or II; body mass index (BMI) between 19–30 kg/m