The levels of anesthesiology and the ability to block sensation range from local anesthesia to general anesthesia, with several levels in-between. Determination of which anesthesia, or combinations of anesthesia that are more expansive than a local anesthesia, need to be made by an anesthesiologist. This is why a patient will go through PAT (pre-admissions teaching) prior to a surgical or endoscopic procedure. The total evaluation regarding type of procedure, choice and volume of anesthesia drug, patient general health, patient age and genetics, and patient input as to what they would prefer (if possible) are all taken into consideration.