The words tijera and tijeras can be used interchangeably in Spanish to refer to a single pair of scissors.
Both IV sedation (twilight) and general anesthesia are used commonly for cosmetic or plastic surgery. Regardless of technique, the patient's vital signs must be monitored, which include but not limited to heart rate, blood pressure, and breathing rate.
Neither drug is very pain-relieving and yet, together, they lead to an extremely effective sedation that approximates complete anesthesia. When administered as an overdose as part of euthanasia, a complete anesthesia results (no pain can be felt).