Percentage of pediatric cases < 18 years old with a mean fresh gas flow (FGF) equal to or less than a weight-based threshold during the induction phase of anesthesia.

Halogenated agents and nitrous oxide leaking or vented into the atmosphere are environmental pollutants and potent greenhouse gases.  Nitrous oxide and halogenated agents containing chlorine, such as isoflurane, can deplete the ozone. Reducing fresh gas flows can decrease environmental impact, limit healthcare workers’ exposure, and reduce cost of anesthesia without compromising patient care. Low flow anesthesia can be applied throughout the anesthetic. In pediatric anesthesia, utilizing a weight-based FGF threshold during the induction phase can be done safely and effectively, based on patient’s minute ventilation and minimizing rebreathing.^1-5

Induction Start to Intubation. If none, then  Induction End

Pediatric cases where halogenated hydrocarbons and/or nitrous oxide were administered during the induction phase of anesthesia

• Age ≥ 18 years 
• Cases without a valid weight documented
• Cases without fresh gas flow data documented during induction 
• Cases in which halogenated hydrocarbons or nitrous oxide are not used during induction 

Mean FGF equal to, or less than the weight-based max FGF (L/min) during the induction period of anesthesia (see other measure build details)

• Values for flows and gases will be assessed and considered artifact if within the Halogenated Anesthetic Gases Used range
• If there are no fresh gas flows documented on the case or the variables are mapped to the incorrect MPOG concept, the case will be excluded.
• If Fresh Gas Flow Total (MPOG Concept ID: 3214) is documented for the case, this concept will be used to determine success in the setting of halogenated agents or nitrous oxide use.
• If Fresh Gas Flow Total (MPOG Concept ID: 3214) is not documented for the case, MPOG will calculate Fresh Gas Flow: Flows Oxygen (ID: 3215) + Flows Air (ID: 3220) + Flows Nitrous Oxide (ID: 3225)
  • When calculating the mean Fresh Gas Flow, the sum of all flows will be added and divided by the total number of minutes that have both a documented gas flow and valid inhalational gas value. See Appendix for how minutes are included before calculating mean fresh gas flow.
    • If inspiratory % is not documented, expiratory % will be used

Weight Based Thresholds:

Table: Glenski et al 2022. “Low Flow Anesthesia in Pediatric Patients.”

Weight-based FGF Inhalational Induction Calculation (Derivation for FGF values in Table Above):

FGF induction >/= Minute Ventilation 

• Minute Ventilation (V_E)= Vt x RR

Simplified calculation for FGF Induction:

• Set FGF to exceed minute ventilation (V_E) for open circuit conditions: 

• 150 mL x weight (kg), where VE~120 ml/kg estimate based upon VCO2 from Brody’s equation:
  • VCO2 = 5.56x(Wt in Kgs)^1.05
  • Approximation: VCO2 = 6 x Wt in Kgs
  • Fraction of CO2 in the alveolus
  • FACO2 ~ 0.05 at sea level
  • Minute Ventilation = VCO2/FACO2 ~ (6 x Wt in Kgs)/0.05 ~ 120 x Wt in Kgs

• Values on table calculated based on 150mL x Weight (kg)

*This measure will include valid MPOG cases defined by the Is Valid Case phenotype.

Not applicable

Provider(s) signed in during the induction period of anesthesia

1. Feldman JM, Lockman J, Yaster M. “Remembering the Classics: The Art of Low Flow Anesthesia.” Pediatric Anesthesia Article of the Day. March 28 2022. <https://ronlitman.substack.com/p/remembering-the-classic-the-art-of>.
2. Feldman JM: Managing fresh gas flow to reduce environmental contamination. Anesth Analg 2012; 114:1093–101
3. Glenski T, Narayanasamy S. “Low Flow Anesthesia in Pediatric Patients.” SPA One Pagers. August 2021.
4. American Society of Anesthesiologists’ Task Force on Environmental Sustainability Committee on Equipment and Facilities. Greening the operating room. http://www.asahq.org/resources/resources-from-asacommittees/environmental-sustainability. 
5. Varughese, Shane MD; Ahmed, Raza MD. Environmental and Occupational Considerations of Anesthesia: A Narrative Review and Update. Anesthesia & Analgesia: October 2021 - Volume 133 - Issue 4 - p 826-835 doi: 10.1213/ANE.0000000000005504