In the perioperative arena, the terms “MAC” (monitored anesthesia care) and “sedation” are used interchangeably; however, they are not the same. The term MAC has nothing to do with levels of sedation (minimal, moderate, deep, and general anesthesia).
As described by the American Society of Anesthesiologists (ASA):
Monitored Anesthesia Care (MAC) does not describe the continuum of depth of sedation, rather it describes “a specific anesthesia service in which an anesthesiologist has been requested to participate in the care of a patient undergoing a diagnostic or therapeutic procedure.”
The ASA has also released the “Continuum of Depth of Sedation: Definition of General Anesthesia and Levels of Sedation/Analgesia.”
There is no “right” medication or dose for any given situation either. For example, one can run a propofol infusion at varying doses to achieve any of the aforementioned levels of sedation. Personally, I use agents like propofol, remifentanil, ketamine, fentanyl, midazolam and dexmedetomidine for MAC cases. The MAC provider must be prepared to convert to a general anesthetic at any point during the procedure and rescue the airway from compromise.
Take home message: the depth of sedation is defined by the patient’s responsiveness to stimuli and how his/her cardiopulmonary status is affected.
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