[Cost of VIMA = unit price of sevoflurane X used volume of sevoflurane];

[Cost of TIVA = unit price of propofol X total volume of propofol in the syringe];

[Cost of Propofol Induction and Sevoflurane Maintenance = unit price of propofol X total volume of propofol in the syringe + unit price of sevoflurane X volume of sevoflurane in the syringe].

The total volume of propofol in the syringe was calculated, even if all the anesthetic was not used, because it could not be reused.

The full analysis set was used for the determination of cost of anesthesia.

Loss of consciousness was measured from the time the anesthetic was administered until loss of consciousness (no response to command) occurred. Inhalational induction was induced with sevoflurane via vital capacity induction at 8%. Intravenous induction was induced with propofol at 4 µg/mL via target controlled infusion (TCI). In subjects who received both anesthetic agents, a bolus dose of propofol 1.5 mg/kg was used for induction.

Measured from the time sevoflurane or propofol administration was stopped until the subject's eyes were opened. The investigator tapped the subject on the forehead or shoulder after anesthesia was stopped and asked them to open their eyes. This process was repeated approximately every minute until eye opening occurred.

Time to extubation was measured from the time sevoflurane or propofol administration was stopped until tracheal extubation occurred. Criteria to determine extubation included a train of four stimulus > 0.9 (a method to measure the magnitude and type of neuromuscular block, a ratio of the fourth response to the first one), a tidal volume > 5 mL/kg, minute ventilation > 3 L, a respiratory rate of > 10 breaths/minute, an end tidal carbon dioxide < 45 mmHg, and eye opening has occurred.

Measurement

Time to orientation was measured from the time sevoflurane or propofol administration was stopped until orientation (able to state their name and date of birth).