Estimates CO₂ equivalent emissions from volatile anesthetic agents and propofol TIVA
N₂O MAC ≈ 105% — cannot reach 1 MAC alone. Uses same FGF, duration, cases/day, and OR days/year as volatile above. GWP-100 = GWP-20 = 273 (IPCC AR6).
Duration, cases/day, and OR days/year are shared from above. Propofol 1% (10 mg/mL). Drug emission factors: Sherman et al. 2012 / McGain et al. 2020. Consumable factors: McGain et al. 2020 (syringe 52 g, TIVA set 118 g, stopcock 22 g, giving set 118 g CO₂e).
| Agent | GWP-100 | GWP-20 | Atm. lifetime | MAC (%) | Source |
|---|---|---|---|---|---|
| Desflurane | 2,540 | 6,350 | 14 yr | 6.0 | Sulbaek Andersen 2012 / Ryan BJA 2022 |
| Isoflurane | 510 | 1,230 | 3.2 yr | 1.15 | Sulbaek Andersen 2012 / Ryan BJA 2022 |
| Nitrous oxide | 273 | 273 | 114 yr | ~105 | IPCC AR6 (2021) |
| Sevoflurane | 127 | 349 | 1.1 yr | 2.0 | Sulbaek Andersen 2021 / Ryan BJA 2022 |
| Propofol — 50 mL vial | 645 g/g | N/A | N/A | McGain et al. 2020 | |
| Propofol — 20 mL ampoule | 890 g/g | N/A | N/A | Sherman et al. 2012 | |
| 50 mL syringe | 52 g/unit | N/A | N/A | McGain et al. 2020 | |
| IV extension / TIVA set | 118 g/unit | N/A | N/A | McGain et al. 2020 | |
| 3-way stopcock | 22 g/unit | N/A | N/A | McGain et al. 2020 |
Volatile: (FGF × dial% × duration) → vapor volume (L) → mass (kg) × selected GWP × atmospheric release fraction.
TIVA drug: (bolus mg/kg + infusion mg/kg/hr × duration) × weight → total propofol (g) × emission factor (g CO₂e/g) ÷ 1000.
Propofol emission factors are cradle-to-grave LCA including synthesis (lipid emulsion base), sterilisation, packaging, cold-chain transport, and clinical waste disposal. Consumable factors cover raw material extraction, manufacture, and incineration.