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Monitored Anesthesia Care (MAC) for Pain Procedures
Most interventional pain procedures need only local anesthetic or light sedation. Some need more: a very anxious patient, serious heart or lung disease, or a longer procedure such as a device implant. In those cases, an anesthesia professional may provide monitored anesthesia care, usually called MAC.
MAC is often confused with nurse-administered "conscious sedation," but the two are different services with different expectations. This article explains what MAC is, how it can be provided safely for pain procedures, and what a physician expert reviews. Our post on sedation safety during interventional pain procedures covers the sedation continuum and patient risk factors; a companion post covers nurse-administered IV moderate sedation.
What MAC is, and what it is not
The American Society of Anesthesiologists (ASA) describes MAC as a specific anesthesia service performed by a qualified anesthesia provider for a diagnostic or therapeutic procedure. In its Statement on Distinguishing Monitored Anesthesia Care ("MAC") from Moderate Sedation/Analgesia (2023), the ASA explains that MAC includes a preprocedure assessment, care during the procedure, and postprocedure management. The provider must be prepared to manage all levels of sedation up to and including general anesthesia.
The statement contrasts this with moderate sedation, where a proceduralist may have divided attention. MAC is not a depth of sedation. What defines it is who provides the care and what that person is prepared to do.
Who provides MAC
Under the ASA statement, MAC is provided by an anesthesia professional, either an anesthesiologist or another anesthesia provider working within the applicable care team model. The ASA Standards for Basic Anesthetic Monitoring (last amended October 2025) state that qualified anesthesia personnel shall be present in the room throughout all monitored anesthesia care. Review questions include who the anesthesia provider was, who (if anyone) was medically directing, and whether the provider was present for the entire case.
Patient selection and depth of sedation in pain procedures
Choosing MAC is a clinical judgment based on the patient's condition, the procedure, and the need for deeper sedation than moderate sedation can safely provide. For pain procedures there is a counterweight: many rely on the patient being able to report pain, paresthesia, or new symptoms. The ASIPP Guidelines for Sedation and Fasting Status of Patients Undergoing Interventional Pain Management Procedures (Kaye and colleagues, Pain Physician, 2019) state that deep sedation or general anesthesia for most interventional procedures is considered unsafe, because the patient cannot communicate acute changes in symptoms. A survey Dr. Urits co-authored (Hasoon and colleagues, Pain Therapy, 2021) found that deep sedation and general anesthesia are used at times during spinal cord stimulator lead placement despite guidance favoring a responsive patient.
An expert asks what depth was planned, why, and whether the patient could communicate when the procedure required it.
Monitoring standards that apply to MAC
The ASA Standards for Basic Anesthetic Monitoring apply to all general anesthetics, regional anesthetics, and monitored anesthesia care. They call for, among other things:
- a quantitative method of assessing oxygenation, such as pulse oximetry, with an audible tone and low-threshold alarm;
- during moderate or deep sedation, continual observation of clinical signs of ventilation, with every effort made to achieve continual monitoring for exhaled carbon dioxide (capnography);
- a continuously displayed electrocardiogram; and
- blood pressure and heart rate determined and evaluated at least every five minutes.
For propofol, the ASA Statement on Safe Use of Propofol (last amended 2024) advises care consistent with deep sedation even when moderate sedation is intended, because depth can change rapidly and there is no reversal agent. An expert should identify the version of each standard in effect on the date of care.
What the closed claims literature shows
The ASA Closed Claims Project has examined MAC specifically. Bhananker and colleagues (Anesthesiology, 2006) compared 121 MAC claims with general and regional anesthesia claims. More than 40% of MAC claims involved death or permanent brain damage. Respiratory depression after an absolute or relative overdose of sedatives or opioids was the most common specific mechanism, and nearly half of those claims were judged preventable by better monitoring, including capnography, improved vigilance, or audible alarms. Analyses of anesthesia outside the operating room (Metzner and colleagues, 2009; Woodward and colleagues, 2017) found these claims often involved MAC and inadequate oxygenation or ventilation.
Operating room fires are a second MAC-related theme. Mehta and colleagues (Anesthesiology, 2013) found that 81% of electrocautery-induced fire claims occurred during MAC, most often during head, neck, or upper chest procedures with oxygen delivered by an open system. This can matter when electrocautery is used near the upper chest or neck, as in some device implants. Closed claims data describe patterns; they do not establish how often injuries occur or whether care in a given case met the standard.
Documentation and records that usually matter
- The preanesthesia evaluation, including airway assessment, sleep apnea screening, medications, and fasting status
- The anesthesia record with drug doses, times, depth of sedation, and vital signs
- Monitor and capnography downloads, including alarm settings where available
- Staffing and supervision records, the procedure note, and any fire-risk assessment
- Recovery notes, discharge criteria, and facility policies in effect on the date of care
Key takeaways
- MAC is an anesthesia service, defined by the provider and their readiness to rescue, not by a depth of sedation.
- For pain procedures, deeper sedation is weighed against the value of a patient who can report symptoms.
- ASA basic monitoring standards, including capnography efforts, apply to MAC.
- Oversedation with respiratory depression and fire are recurring themes in MAC closed claims.
References
- American Society of Anesthesiologists. Statement on Distinguishing Monitored Anesthesia Care ("MAC") from Moderate Sedation/Analgesia (Conscious Sedation). Approved October 18, 2023.
- American Society of Anesthesiologists. Standards for Basic Anesthetic Monitoring. Last amended October 15, 2025.
- American Society of Anesthesiologists. Statement on Safe Use of Propofol. Last amended October 23, 2024.
- Kaye AD, Jones MR, Viswanath O, et al. ASIPP Guidelines for Sedation and Fasting Status of Patients Undergoing Interventional Pain Management Procedures. Pain Physician. 2019;22(3):201-207. PMID:31151329.
- Hasoon J, Urits I, Viswanath O, et al. Percutaneous Spinal Cord Stimulation Lead Placement Under Deep Sedation and General Anesthesia. Pain Ther. 2021;10(2):1719-1730. PMID:34652716.
- Bhananker SM, Posner KL, Cheney FW, et al. Injury and liability associated with monitored anesthesia care: a closed claims analysis. Anesthesiology. 2006;104(2):228-234. PMID:16436839.
- Metzner J, Posner KL, Domino KB. The risk and safety of anesthesia at remote locations: the US closed claims analysis. Curr Opin Anaesthesiol. 2009;22(4):502-508. PMID:19506473.
- Woodward ZG, Urman RD, Domino KB. Safety of Non-Operating Room Anesthesia: A Closed Claims Update. Anesthesiol Clin. 2017;35(4):569-581. PMID:29101947.
- Mehta SP, Bhananker SM, Posner KL, Domino KB. Operating room fires: a closed claims analysis. Anesthesiology. 2013;118(5):1133-1139. PMID:23422795.
Related: Sedation and MAC Cases
Educational information only. Not legal or medical advice.
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