Study design and participants
’ systolic blood pressure
RECRUITMENT
This study was approved by the Ethics Committee of Sir Run Shaw Hospital, School of Medicine, Zhejiang University (IRB No. 20200928-30) and all patients who participated in the study signed informed consent before recruitment. The trial was registered prior to patient enrollment at Chinese Clinical Trial Registry (registration number, ChiCTR2000040344; Principal investigator: Gang Chen, date of registration, November 28, 2020), adhered to the applicable CONSORT guidelines, and complied with the Declaration of Helsinki.From December 1, 2020 to January 31, 2021, sixty patients who were aged 60–75, American Society of Anesthesiologists (ASA) Physical Status I or II, with a body mass index (BMI) between 18.5 and 24, with a simplified risk scorePatients were randomly allocated to receive intravenous injection of granisetron (3 mg/3 ml, group G) or saline placebo (3 ml, group C) prepared in a uniform appearance syringe within 30 s half an hour before induction of general anesthesia. Randomization scheme adopting computer-generated random number codes was prepared by statisticians, and other investigators involved in subsequent study were unaware of patient sequence. Patients allocations were kept in opaque, sealed envelopes that were not opened till the participants entered the pre-operating room.Premedication with 0.02 mg/kg intravenous midazolam was given 30 min before induction in the pre-operating room. When patients arrived the operating room, standard monitoring (electrocardiogram, SpOPatients’ systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate, and oxygen saturation were recorded on arrival in operation room (THypotension after induction of anesthesia were defined as a more than 25% decrease in MBP from the baseline level during the observation phase of the study