Inhalational anesthesia uses an inhaled gas, usually nitrous oxide, also called nitrous oxide. After the gas is inhaled, it can make the central pain and consciousness lose temporarily so as to play the effect of anesthesia. Many people first use this drug to induce anesthesia during the initial period of entering into intravenous anesthesia because of its quick effect, and it will make people lose consciousness and pain feeling in a short time. However, because of the rapid onset of the effect, the maintenance time will also be very short, and have to use intravenous anesthesia to maintain, so can only be used as an induction of anesthesia, and then get used to the use of intravenous anesthesia can play a role in general anesthesia after the onset of the effect of the drug.