Preoperative Anxiolysis With Intravenous Midazolam on Intraoperative Sevoflurane Gas Consumption

The Effect of Preoperative Anxiolysis With Intravenous Midazolam on Intraoperative Sevoflurane Gas Consumption: A Prospective Randomized Controlled Study

This prospective, randomized, double-blind, placebo-controlled study is performed after obtaining written informed consent of patients who are scheduled for elective general surgery. After the admission to the preoperative unit 30 minutes before the surgery, The preoperative anxiety of patients is evaluated by The State-Trait Anxiety Inventory (STAI). Patients are randomly assigned to one of two groups in a 1:1 ratio by a computer-generated list. Patients receive midazolam IV at 0.04 mg/kg (group M) and an equal volume of saline IV (group C, control group). Anesthesia is induced with 2mg/kg of IV propofol. At a dose of 0.6 mg/kg, IV rocuronium bromide is given for neuromuscular blockade. Anesthesia is maintained at 2% sevoflurane. At the end of the surgery, anesthesia is terminated and the awake patients are extubated.

An equal depth of anesthesia is achieved by evaluating an entropy value of 40-50 during the operation. Heart rate, blood pressure, the amount of sevoflurane consumed (ml), end-tidal sevoflurane concentration (%), sevoflurane MAC, inspiratory sevoflurane (%) are recorded at baseline and 15-minute intervals.

Inclusion Criteria:

• American Society of Anesthesiologists physical status 1 and 2
• patients who are scheduled for elective surgery
• BMI <30

Exclusion Criteria:

• history of psychiatric disease
• use of psychotropic medications
• neurological disorders
• cancer
• chronic pain
• cardiovascular, respiratory, and hepatic diseases.