Monitored anesthesia care (MAC), also known as twilight anesthesia, is a type of anesthesia where sedatives are provided to keep the patient calm while allowing the patient to remain awake and responsive. It is used in conjunction with local or regional anesthesia. A trained anesthesiologist administers MAC and is present throughout the procedure to look out for the welfare of the patient. After the procedure is over, the anesthesiologist will allow the patient to regain full awareness and assess the patient for pain.
There are a number of settings where monitored anesthesia care may be desired. In some procedures, it is necessary for the patient to be awake and able to respond to commands. In others, a patient may be endangered by general anesthesia, making it an unsafe choice. For minor procedures and many dental surgeries, monitored anesthesia care can be used to keep the patient comfortable during the procedure without exposing the patient to the risks of general anesthesia.
This anesthesia technique cannot be used alone. When provided with sedatives, patients can still experience pain. The sedatives address anxiety and discomfort. Local or regional anesthesia is needed to prevent the patient from feeling pain. MAC can also include the use of drugs designed to induce amnesia so the patient will not remember the procedure after it took place. This can be desirable in cases where patients might develop nightmares or other problems after surgery.
If a patient is a good candidate for a combination of monitored anesthesia care and local or regional anesthesia, the anesthesiologist will meet with the patient before the surgery to identify any risk factors and develop an anesthesia plan. When it is time for the surgery, medications will be introduced through an intravenous line and the patient's vital signs will be monitored on hospital equipment. The anesthesiologist and surgeon may talk to the patient during the procedure and the patient will be assessed for signs of stress reactions and other complications, with medications adjusted as needed.
There are fewer risks associated with monitored anesthesia care. Because patients breathe independently during the procedure, artificial ventilation does not have to be used, reducing the risks of damage to the lungs. Complications associated with the heart and other organs are less common, and patients are less prone to adverse reactions to anesthesia. Intensive monitoring is provided throughout the procedure to identify and address any issues that develop during the surgery.