Multiple. The current gases we use are called sevoflurane, Desflurane and isoflurane. The anesthesiologist will choose which one based on many factors. Each one has its own special vaporizer, though old-timers will talk about copper kettles, drop ether, and older explosive gases. Other gases used are nitrous oxide, oxygen and air, with oxygen most flammable by far. We have safety features to protect you.
Oxygen + anesthesia. Several inhalational anesthetics are currently used with similar efficacy: isoflurane, sevoflurane, and desflurane. These are all halogenated anesthetics that are vaporized for inhalational use. These gases are mixed with oxygen and air to a safe concentration as you are monitored for surgery. Nitrous oxide is commonly used by dentists, but used less frequently for general anesthesia.
Volatile Anesthetics. The most typically or commonly used anesthesia gases today are the derivatives of ether, such as isoflurane, sevoflurane and desflurane. Also, nitrous oxide (laughing gas) is still widely used. These gases are administered with oxygen for safe anesthesia. It is important to get to know your anesthesia doctor prior to undergoing surgery and anesthesia.
Depends. There are four main gasses used during anesthesia. These are nitrous oxide, sevoflurane, Desflurane and isoflurane. The last three are very similar in chemical composition, but have some specific elements about them. I prefer isoflurane, but other anesthesiologists might differ. Talk to your anesthesiologist and see what they like to use and why.