Study | Outcome | Intervention type(s) | Measurement method and data source | Effect estimate (%) | P value | Vote count |
Ang et al 23 | CO2e saved per year (tonnes) |
| ‘Translated’ from desflurane and sevoflurane usage data from Department of Pharmacy and case notes | Not estimable | N/A | Beneficial |
Chambrin et al 41 | CO2e over 100 years |
| Estimated from desflurane and sevoflurane monthly purchase | 90% reduction | <0.01 | Beneficial |
Glenski and Levine26 | CO2e per year (metric tonnes) |
| Estimated from anaesthetics performed per bottle of sevoflurane used per month | 25% reduction | N/A | Beneficial |
Martinez Ruiz et al 28 | CO2e (units unclear) |
| Determined from use of anaesthetic gases (sevoflurane, desflurane and nitrous oxide) and published estimates of GWP | 100% reduction | N/A | Beneficial |
Patel and Smith-Steinert42 | CO2e per year from desflurane use (metric tonnes) |
| Not reported—assume estimated from retrospective chart review and/or pharmacy records | 77% reduction (FY19) | N/A | Beneficial |
Richter et al 43 | CO2e per case (tonnes) |
| Determined from use of anaesthetic gases (sevoflurane and desflurane) and published estimates of GWP | 68% reduction | N/A | Beneficial |
Tay et al 40 | GWP100 per hour (kg) |
| Estimated from bottles of each volatile agent used per hour of general anaesthesia | 44% reduction | 0.0179 | Beneficial |
Wyssusek et al 36 | CO2e (kg) from 2016 to 2021 |
| Estimated from number of bottles of each volatile agent purchased per month | 88% reduction | N/A | Beneficial |
Zuegge et al 37 | CO2e emissions per case per fiscal year (kg) |
| Estimated from number of bottles of each volatile agent purchased per month | 64% reduction | N/A | Beneficial |
Grimmond et al 38 | CO2e per 1000 patient episodes (kg) |
| LCA—process-based attributional | 84% reduction | N/A | Beneficial |
Labib et al 27 | CO2e per case (kg) |
| LCA—cradle to grave | 62% reduction | N/A | Beneficial |
Neves et al 30 | CO2e per month (kg) |
| Estimated from weight of landfill and regulated medical waste | 32% reduction | 0.018 | Beneficial |
Riedel33 | CO2e per 6 months (metric tonnes) |
| Estimated from total non-hazardous waste disposal (EPA Waste Reduction Model) | Not estimable | N/A | Beneficial |
Wormer et al 35 | CO2e per year (tonnes) |
| Not reported—assumed to be estimated from electrical energy saved per operating room. Method of GHG emission calculation not reported | Not estimable | N/A | Beneficial |
McAlister et al 29 | CO2e per admission (g) |
| LCA—process-based consequential (from previous study) | 37% reduction | <0.001 | Beneficial |
Regan et al 32 | CO2e per year (tonnes) |
| Estimated from number and cost of biochemistry tests ordered | Not estimable | N/A | Beneficial |
Wang et al 34 | Total CO2e emissions per patient (kg) |
| LCA—economic data (prices for services) and process data (quantity of patient travel) | 9.5% reduction | 0.019 | Beneficial |
McCarthy et al 39 | CO2e wasted per year (metric tonnes) |
| Estimated from electrical energy from computers and Picture Archiving and Communication Systems (PACS) left on when not in use | 4.3% increase* | N/A | Null effect |
Intervention targets anaesthesia, waste disposal, unnecessary testing or energy use.
Effect estimates reported at end of intervention or closest point.
Carter et al, Epstein et al and Pinder et al did not report effect on GHG emissions.
*Calculated from reported number of machines left switched on multiplied by number of hours left on overnight and at weekends multiplied by energy consumption of machine.
CO2e, carbon dioxide equivalent; EPA, Environment Protection Agency; GHG, greenhouse gas; GWP100, 100-year global warming potential; LCA, life cycle assessment; N/A, not applicable.