Most modern general anesthetics involve the use of inhalation anesthetics. When breathed in adequate concentrations, these medicines create an anesthetic sleep. The most commonly used are desflurane, and isoflurane. Also used are sevoflurane, enflurane and halothane.
These anesthetics are liquid at room temperature and are vaporized in precisely controlled concentrations in a metered stream of oxygen and nitrous oxide (laughing gas.)
They are breathed into the lungs, from there they travel into the bloodstream and on into the brain. When present in adequate concentration in the brain they produce anesthesia. Anesthesia continues as long as that concentration in the blood is maintained. When the inhalation agent is discontinued, the patient breathes it out, brain levels fall and he reawakens.
All inhalation agents have been studied very carefully to be certain that they dont damage any part of the body. Virtually all the inhalation agent is breathed out in a matter of a few hours. Almost none is left behind. This is why anesthesia probably has nothing to do with the way you feel the day after surgery.
Inhalation agents are fluorinated hydrocarbons.