What Is MAC Anesthesia?

Medically Reviewed by Dan Brennan, MD on June 23, 2021

Also known as monitored anesthesia care or conscious sedation, MAC anesthesia is a type of sedation where you remain aware of your surroundings and stay calm. The anesthetist administers it through an IV into the skin and muscle around the area on which surgery will be performed. You become sedated but can follow instructions with ease. The amount injected is determined by the professional attending to you.

How MAC Anesthesia Is Used During Medical Procedures

MAC anesthesia is commonly used for outpatient diagnostic or therapeutic procedures, meaning it can be used to check for disease or to provide treatment. 

For example, it is used for colonoscopy, which is a test used to check for changes or abnormalities in the large intestines. In such a case, you can go home after the anesthesia has completely worn off.  

Medications used include:

How Does MAC Anesthesia Feel?

The anesthetist will provide a level of sedation ranging from light to heavy. This means that you can be very relaxed or get to a level where you're unaware of what's happening around you. Light sedation means that you can speak, hear things around you, and respond to commands. However, you don't feel any pain and are not anxious about what's happening. With heavy sedation, you’re only able to respond to significant stimulation. You may also fall asleep but will still breathe on your own.

MAC anesthesia differs from general anesthesia because you don’t become subjected to chemical paralysis. You also don’t require assistance with breathing. The service providers will also closely monitor your vitals to ensure they remain in a stable state throughout the procedure. Depending on the dose of anesthesia you receive, you may or may not remember what happened during the surgery.

The service providers need to assess the depth of sedation, as it helps in drug administration. It also prevents awareness or excessive anesthetic depth, thus promoting your safety and early recovery.

What is MAC Anesthesia Used for?

Most surgical procedures (10-30%) incorporate monitored anesthesia care as the first choice of sedation. It’s ideal for quick surgical procedures like:

MAC is based on three fundamental elements and functions: safe sedation, pain control, and anxiety control. The procedure also ensures you’re satisfied during surgical procedures, allowing you to get discharged as soon as possible.

How is Monitoring Done?

MAC anesthesia is a monitored process because of the varying levels of sedation. An anesthesia professional must be present at all times to continuously monitor your vital signs. It’s also crucial that they maintain or adjust the sedation levels as required.

In most cases, this may entail a blood pressure cuff and oxygen level monitoring. Electrodes, or devices that carry electric current, will also be placed on your chest to observe your heart rate and EKG throughout the surgical procedure.

Preoperative evaluation. You will undergo observation before the surgical procedure begins. The evaluation, in this case, is not any different from what you'd experience during general or regional anesthesia. 

Your cooperation is of utmost importance during MAC. As such, in preoperative evaluation, the service provider will evaluate your readiness for the procedure. If they establish that you’re unable to cooperate, general anesthesia may be used instead. However, there are no specific exclusion criteria for MAC, and it can be performed in older or high-risk people.

Communication between you and the anesthesia team is a tool for monitoring sedation levels. It is also used to offer verbal assurance while improving your cooperation. While MAC may be used where you have cardiovascular and respiratory instability, it may not be suitable if you have a persistent cough where microscopic procedures are involved.

Intraoperative monitoring. According to the American Society of Anesthesiologists, monitoring during a surgical procedure is essential. It should be applicable, effective, non-invasive, and economical. A qualified anesthesiologist must be present to continuously monitor your oxygenation, ventilation, temperature, and circulation.

Continuous respiratory monitoring helps to prevent respiratory problems during the infusion of sedatives and analgesics for MAC.

Monitoring consciousness level. Service providers must also evaluate your sedation levels during MAC. In this case, they assess the safety and efficacy of the sedatives using clinical or electrical methods that show the activity of your brain during the procedure. This monitoring is crucial in establishing your level of consciousness as it detects the sedative levels used. Some degree of stimulation is essential during the process to evaluate your level of sedation.

Possible Side Effects of MAC Anesthesia

MAC anesthesia usually presents minimal side effects. However, if you’re allergic to anesthesia, the anesthesiologist will monitor your reaction to the anesthesia upon administration. Some expected side effects include:

In rare cases, severe side effects include:

WebMD Medical Reference



American Society of Anesthesiologists: “Standards for Basic Anesthetic Monitoring.”

Digestion: “Basic Requirements for Monitoring Sedated Patients: Blood Pressure, Pulse Oximetry, and EKG.”

Indian Journal of Anesthesia: “Monitored aneasthesia care: Case for a smarter management.”

Journal of Anaesthesiology Clinical Pharmacology: “Monitored anesthesia care: An overview.”

Korean Circulation Journal: “Monitored Anesthesia Care for Cardiovascular Interventions.”

Korean Journal of Anesthesiology: “Monitored Anesthesia care in and outside the operating room.”

Minerva Anestesiologica: “Monitored anesthesia care.”

Stroke: “Role of Anesthesia for Endovascular Treatment of Ischemic Stroke.”

Systematic Reviews: “Depth of anesthesia monitoring during procedural sedation and analgesia: a systematic review protocol.”

The Internet Journal of Health: “Monitored Anesthesia Care.”

Weill Cornell Medicine: “Types of Anesthesia Care.”

© 2020 WebMD, LLC. All rights reserved.