Summary & Overview

HCPCS G9654: Monitored Anesthesia Care (MAC)

HCPCS Level II code G9654 denotes Monitored Anesthesia Care (MAC), a service in which anesthesia professionals provide sedation and physiologic monitoring during procedures that require variable levels of anesthetic support. Nationally, MAC is integral to a wide range of outpatient and inpatient procedures performed in ambulatory surgery centers, hospital operating rooms, and other procedural suites; accurate coding ensures clarity about the level of anesthesia oversight provided and supports appropriate claims processing. Key payers in typical analyses include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.

This publication provides a concise overview of HCPCS Level II code G9654, covering clinical context for MAC, payer coverage considerations, common modifiers, and where this service is delivered. Readers will find benchmarks and policy summaries relevant to national reimbursement and coding practice, succinct explanation of clinical scenarios where MAC is indicated, and operational notes for billing teams. Data not available in the input is noted where applicable. The content is intended for clinicians, billing professionals, and policy analysts seeking a national perspective on coding and operational implications for monitored anesthesia care.

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Billing Code Overview

HCPCS Level II code G9654 represents Monitored anesthesia care (MAC). This service involves administration of varying levels of sedation and anesthesia monitoring to support procedures where patient consciousness and physiologic status require anesthetic oversight.

Service type: Monitored anesthesia care
Typical site of service: Procedural settings such as ambulatory surgery centers, hospital operating rooms, and other facility-based procedural suites where anesthesia professionals provide monitoring and sedation support.

Clinical & Coding Specifications

Clinical Context

A 58-year-old patient with poorly controlled hypertension and obstructive sleep apnea presents for an elective endoscopic sinus surgery to treat chronic rhinosinusitis with nasal polyposis. The surgical team anticipates the need for light-to-moderate sedation with potential for rapid conversion to deeper anesthesia if airway or hemodynamic conditions change. Monitored anesthesia care (G9654) is requested: an anesthesia professional provides continuous monitoring of vital signs, administers sedative and analgesic medications titrated to procedural needs, manages the airway as needed, and is immediately available to convert to general anesthesia if indicated. Typical workflow includes pre-procedure assessment by the anesthesia team, placement of standard monitors (noninvasive blood pressure, pulse oximetry, ECG, capnography as indicated), IV access, intra-procedural sedation and physiologic monitoring, and post-procedure recovery and handoff to PACU nursing. Typical site of service is an ambulatory surgery center or hospital outpatient department. Monitored anesthesia care is commonly used for procedures where patient cooperation may be required, airway risk is present, or anesthesia depth may need rapid adjustment, such as endoscopy, ophthalmic surgery, minor orthopedics, and select ENT procedures.

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services	Use when MAC involves substantially greater work (e.g., complex airway management, prolonged hemodynamic instability) beyond typical MAC documented in anesthesia record.
`23`	Unusual anesthesia	Use when general anesthesia was administered instead of MAC due to unforeseen circumstances and MAC-related code remains reported per payer guidance.
`52`	Reduced services	Use when MAC is partially provided but substantially reduced in scope (e.g., procedure aborted early) and documentation supports reduced service.
`53`	Discontinued procedure	Use when MAC was initiated but procedure terminated before completion for patient safety, with documentation of reason.
`54`	Surgical care only	Rare for MAC; use when reporting surgical provider separately and anesthesia care is not included in global surgical package reporting contexts.
`55`	Postoperative management only	Use when anesthesia provider only performs postoperative management distinct from intraoperative MAC services.
`56`	Preoperative management only	Use when anesthesia provider only evaluated and prepared the patient preoperatively without providing intraoperative MAC.
`62`	Two surgeons	Use when two surgeons are required concurrently for the procedure while MAC is provided; documents shared operative responsibility.
`AS`	Medically directed anesthesia (physician)	Use when the physician medically directs multiple anesthesia providers for MAC and meets time/direct supervision rules.
`QK`	Medical direction of two to four CRNAs or anesthetists	Use when physician medically directs multiple qualified anesthesia personnel during MAC and meets documentation and time requirements.

Taxonomy Code	Specialty	Notes
`207L00000X`	Anesthesiology	Primary specialty providing MAC services in hospital and ambulatory settings.
`2080P0207X`	Nurse Anesthetist (CRNA)	Commonly delivers MAC under supervision or direction per facility and payer rules.
`207LP2900X`	Pediatric Anesthesiology	Subspecialty providing MAC for pediatric patients or pediatric procedures requiring specialized management.
`207K00000X`	Pain Management	Anesthesiologists with pain specialty may provide MAC for interventional pain procedures.
`103T00000X`	Otolaryngology	Surgical specialty frequently performing procedures that commonly utilize MAC, coordinating intraoperative sedation.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`J32.9`	Chronic sinusitis, unspecified	Common indication for endoscopic sinus surgery performed under MAC when appropriate.
`H57.11`	Ocular pain	Ophthalmic procedures frequently use MAC for patient comfort and immobility.
`K21.9`	Gastro-esophageal reflux disease without esophagitis	Patients undergoing endoscopy for GERD-related evaluation often receive MAC.
`M25.50`	Pain in unspecified joint	Minor orthopedic procedures or joint injections may be performed with MAC.
`G47.33`	Obstructive sleep apnea (adult)	OSA increases airway risk; MAC planning accounts for potential airway compromise and need for more intensive monitoring.
`I10`	Essential (primary) hypertension	Common comorbidity requiring careful hemodynamic monitoring during MAC.
`Z98.890`	History of bariatric surgery	Altered airway and physiologic considerations influence MAC planning and monitoring.
`F17.200`	Nicotine dependence, unspecified, uncomplicated	Smoking history affects airway reactivity and peri-procedural respiratory risk under MAC.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`00530`	Anesthesia for lower abdomen including hernia repair, not otherwise specified	Example of anesthesia codes for procedures where MAC may be considered an alternative to general anesthesia depending on case complexity and patient factors.
`00100`	Anesthesia for procedures on salivary glands, including biopsy	Illustrates head and neck procedures where MAC is commonly used for local/regional plus sedation.
`00740`	Anesthesia for upper gastrointestinal endoscopic procedures	Endoscopic procedures often use MAC for sedation and airway monitoring; anesthesia services complement endoscopist care.
`00920`	Anesthesia for upper abdomen procedures (laparoscopy)	Larger abdominal procedures may require conversion from MAC to general anesthesia; understanding related anesthesia codes clarifies workflow transitions.
`00400`	Anesthesia for procedures on the lower leg/ankle/foot	Regional blocks with MAC are used in orthopedics; CPT codes for anesthesia in these regions are commonly paired with monitored anesthesia care when sedation is employed.