ABG 44 · Low Flow Inhalational General Anesthesia

Steward: ABG QCDR | Collection Type: QCDR Measure | First Performance Year: 2023 2026 Status: Approved by CMS for the 2026 MIPS performance period.

MEASURE DESCRIPTION

Percentage of patients aged 18 years or older who undergo an elective procedure lasting 30 minutes or longer requiring inhalational general anesthesia and who, during the maintenance phase of the anesthetic, have a total fresh gas flow less than or equal to 1 L/min (less than or equal to 2 L/min for sevoflurane).

NQS DOMAIN / MEANINGFUL MEASURES AREA

Efficient Use of Healthcare Resources / Clinical Process and Effectiveness

MEASURE TYPE: Process (classified as Efficiency in the CMS benchmark file) HIGH PRIORITY STATUS: Yes | HIGH PRIORITY TYPE: Efficiency INVERSE MEASURE: No | RISK ADJUSTED: No NUMBER OF PERFORMANCE RATES: 1 CARE SETTING: All settings TELEHEALTH: No REPORTING OPTIONS: MVP and Traditional MIPS

2026 BENCHMARK

National average performance rate: 95.52%. Historical benchmark. Not topped out. Not 7-point capped.

Reading this benchmark: the top half of the distribution is compressed into less than one percentage point. Moving from 99.2% to 99.6% is worth three deciles. This is a measure where marginal effort pays disproportionately, and where a small number of high-flow cases costs real points.

INSTRUCTIONS

Report each time a patient undergoes an elective procedure in which inhalational general anesthesia is used. It is anticipated that qualified anesthesia providers and eligible clinicians who provide denominator-eligible services will submit this measure.

Measure reporting via the QCDR: CPT codes, patient demographics, and registry codes identify patients in the denominator. The measure must capture both the surgical and the related anesthesia CPT code. G-codes and registry codes capture the numerator.

DENOMINATOR

All patients aged 18 years or older who undergo an elective procedure lasting 30 minutes or longer requiring inhalational general anesthesia. (ABG code 1095)

Denominator Criteria (Eligible Cases): - Patients aged 18 years and older - AND Elective procedure (G9643) - AND Patient receives inhalational general anesthesia (11A96) - AND Procedure lasts 30 minutes or longer (11A97) - AND Patient encounter during the reporting period matching the measure's ASA anesthesia CPT list (251 codes; the full list appears at the end of this measure)

DENOMINATOR EXCEPTIONS

Patient or technical reason exists for not providing low flow inhalational anesthesia, for example a flow meter not capable of generating low flows, a hypermetabolic patient, or lack of CO2 absorbents without KOH and low concentrations of NaOH. (AQI code 12A00; ABG code 1096)

NUMERATOR

Patients who, during the maintenance phase of the anesthetic, have a total fresh gas flow less than or equal to 1 L/min (less than or equal to 2 L/min for sevoflurane).

Numerator Definitions: - Inhalational general anesthesia is the use of at least one inhalational anesthetic gas (halothane, isoflurane, desflurane, sevoflurane, nitrous oxide) as the primary mode of anesthesia for the procedure. - Maintenance phase is the portion of the case in which Stage III surgical anesthesia (unconsciousness, amnesia, immobility, unresponsiveness to surgical stimulation) is achieved at a safe anesthetic depth while maintaining respiratory and hemodynamic stability. It falls between induction and emergence. - Fresh gas flow (FGF) is the combined admixture of medical gases (air, oxygen, nitrous oxide) and volatile anesthetics as set by the anesthesia provider.

Numerator Quality-Data Coding Options:

Performance Met: Total FGF reduced to ≤ 1 L/min (≤ 2 L/min for sevoflurane) for the duration of the maintenance phase (AQI 11A98; ABG 1097)

OR

Performance Not Met: Total FGF greater than 1 L/min (greater than 2 L/min for sevoflurane) for the duration of the maintenance phase (AQI 11A99; ABG 1098)

RATIONALE

Managing fresh gas flow to reduce environmental contamination. In a circle anesthesia system, any anesthetic gases and vapors entering the scavenging system flow through the hospital vacuum system and are ultimately vented to the atmosphere. Total fresh gas flow determines the volume entering the scavenging system per minute. Whenever fresh gas flow exceeds the patient's requirement, gases and vapors enter the scavenging system and contaminate the atmosphere. Choosing the minimal total fresh gas flow minimizes that impact. The effect of a single case is small, but every practitioner can make a meaningful difference across the thousands of procedures in a career.

Described by Foldes in 1952, reducing fresh gas flow below 1 L/min during an anesthetic is both safe and effective, and delivers benefits to the patient, cost savings to the facility, and reduced environmental harm:

• Sevoflurane, isoflurane, and desflurane have global warming potentials two to three orders of magnitude higher than CO2.
• Nitrous oxide contributes significantly to both global warming and ozone depletion.
• Roughly 5% of the carbon footprint of the British National Health Service is attributable to exhaled anesthetic agents.
• Atmospheric lifetimes vary widely: 1 to 5 years for sevoflurane, 3 to 6 years for isoflurane, 9 to 21 years for desflurane, and 114 years for nitrous oxide.
• Conservation of heat and moisture within the breathing system is an added patient benefit, particularly when humidifier connection filters are not used.
• Low flow anesthesia produces cost savings even after accounting for increased CO2 absorber consumption, especially with sevoflurane and desflurane. One simulation of 1 L/min FGF across all agents predicted a 48% reduction in volatile anesthetic costs at a tertiary hospital.

Clinical recommendation: Set fresh gas flow during inhalational anesthesia to less than 1 L/min (less than 2 L/min for sevoflurane) during the maintenance phase of a general anesthetic case greater than 30 minutes in duration.

Reference: Greening the Operating Room and Perioperative Arena: Environmental Sustainability for Anesthesia Practice. Task Force on Environmental Sustainability, Committee on Equipment and Facilities, American Society of Anesthesiologists.

RELEVANT FIELDS (Graphium capture)

- ASA CPT code - Date of birth / patient age - Inhalational agent used - Anesthesia start and end time - Emergency status - Fresh gas flow during maintenance

REPORTING CODES

DENOMINATOR CPT CODES

A case must carry one of the codes below to enter this measure's denominator. The other denominator criteria above still apply - a matching code makes a case eligible for consideration, not automatically countable.

251 anesthesia CPT codes:

Source: 2026 AQI NACOR QCDR Measure Book. CPT copyright American Medical Association.