Is the intravenous anesthetic needed for the entire surgery (mainentance for general anesthesia)?

They also use a gas mask.

Is intravenous general anesthesia for induction only or… it is needed for mainentance?

General anesthesia.

(Intravenous is just the induction or it is needed for the entire mainentance? Because they ALSO give a mainentence anesthetic with a gas mask. I want to ask if the intravenous anesthetic is also needed for the entire surgery? Together with the gas mask anesthesia. They place a needle with an induction in the wrist, arm or hand (intravenous). My question is: one needs to be receiving this intravenous anesthesia for the entire procedure?)