For procedures such as a colonoscopy, an anesthesia known as MAC may be used. MAC is the acronym for monitored anesthesia care. MAC is a term that tends to be used more by medical personnel—but what it translates into for the patient is most closely related to levels 2 and 3 (moderate and deep) sedation.
While some MAC states allow for the patient to retain what is known as room consciousness, there are a classification of drugs known as amnestics (from the word amnesia) which, when used, the patient will have no memory of the procedure. The patient is conscious and able to respond to prompts during the procedure—but he or she will not remember the experience. Why would someone prefer MAC over general? Usually the recovery from MAC sedation is quicker and there is less depression of breathing, heart rate and blood pressure during sedation.