How is CO2e calculated for anesthetic gases?

CO2e is calculated by converting agent mass consumed to kilograms, then multiplying by the agent's 100-year Global Warming Potential (GWP100) from IPCC AR6. Desflurane's GWP100 of 2,540 means 1 kg has the climate impact of 2,540 kg CO2.

Why is desflurane so much worse for the environment?

Desflurane has a GWP100 of 2,540 — roughly 20x higher than sevoflurane (130). At typical clinical settings it produces 10-20x more CO2e per hour.

How is liquid agent consumption calculated?

Via the Universal Gas Law: consumption = (vaporizer% / 100) x flow (L/min) x 60 x MW / (density x 22,400).

Is nitrous oxide calculated differently?

Yes. N2O is a gas so consumption = (vaporizer% / 100) x flow x 60 directly in litres/hr. CO2e uses the ideal gas law to get mass.

Are the default costs accurate?

They are approximate US 2024-2025 hospital averages. Enter your facility's actual costs for the most accurate comparison.

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AnesthesiaFree in-browser calculator

Anesthetic Gas CO2e & Cost Calculator.

Compare cost per hour and carbon footprint (kg CO2e) across volatile anesthetic agents. Adjust flow rates, vaporizer settings, and agent costs for a side-by-side comparison.

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Validated2026-04-08

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Session Settings

Duration (hours)Currency

Sevoflurane

Vaporizer (%)Flow (L/min)Cost ($/mL)

Desflurane

Vaporizer (%)Flow (L/min)Cost ($/mL)

Isoflurane

Nitrous Oxide

Results Summary

Agent	Consumed	Cost	CO2e (kg)
Sevoflurane	14.10 mL	$7.05	2.786
Desflurane	36.74 mL	$44.09	137.193

Desflurane emits 49.2× more CO₂e than Sevoflurane at these settings

Cost vs CO2e

When to use

Comparing environmental and financial cost of anesthetic agent choices
Building a business case for restricting desflurane
Estimating annual CO2e from your OR's gas usage
Teaching residents about environmental impact of agent selection

Do not use for

As a clinical dosing guide
For waste gas exposure calculations
As a substitute for institutional pharmacy cost data

Low flow changes everything

Reducing flow from 2 to 0.5 L/min cuts consumption 75%.

N2O volume dominates

N2O at 60%/2 L/min = ~72 L/hr gas. Moderate GWP x large volume = significant CO2e.

Desflurane's heated vaporizer

Tec 6 draws ~250W — negligible vs. drug cost but worth noting.

Costs vary 10x globally

Sevo ~ $0.50/mL in US, ~$ 0.05/mL in India. Enter your facility's actual costs.

Method

Universal Gas Law for consumption. IPCC AR6 GWP100 values. N2O uses gas-volume formula; volatile liquids use mL-liquid formula.

Validated

Last validated 2026-04-08. Calculations are designed for planning and documentation support; verify procurement decisions against manufacturer specifications or institutional SOPs.

How to cite

How to Cite

ConductScience Anesthetic Gas CO2e & Cost Calculator (v1.0). ConductScience, Inc. 2026. https://conductscience.com/tools/anesthetic-gas-cost-calculator

Sulbaek Andersen MP et al. Br J Anaesth. 2010;105(6):760-766.

IPCC. Climate Change 2021: AR6 WG I. Cambridge University Press.

Sustainable Anesthesia Practices

Volatile anesthetics are potent greenhouse gases vented directly to the atmosphere.

Key strategies: - Avoid desflurane (GWP 20x sevoflurane) - Use low fresh gas flows (0.5-1.0 L/min) - Consider TIVA when appropriate - Track and report agent consumption

Volatile Anesthetic Pharmacology Basics

Four agents compared:

Sevoflurane (MAC 2.0%) — most widely used, GWP100 = 130
Desflurane (MAC 6.0%) — fastest emergence, GWP100 = 2,540
Isoflurane (MAC 1.2%) — lowest cost, GWP100 = 510
Nitrous oxide (MAC ~105%) — carrier/adjuvant, GWP100 = 273

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