Table 4

Summary of intervention effects for GHG emissions

StudyOutcomeIntervention type(s)Measurement method and data sourceEffect estimate (%)P valueVote count
Ang et al23CO2e saved per year (tonnes)
  • Education

  • Organisational culture change

  • Reminders

  • Equipment to promote total intravenous anaesthesia

  • Care pathway

‘Translated’ from desflurane and sevoflurane usage data from Department of Pharmacy and case notesNot estimableN/ABeneficial
Chambrin et al41CO2e over 100 years
  • Set up of sustainable anaesthesia groups

  • Education

  • Reminders

Estimated from desflurane and sevoflurane monthly purchase90% reduction<0.01Beneficial
Glenski and Levine26CO2e per year (metric tonnes)
  • Change carbon dioxide absorbers

  • Low-flow Wizard software

  • Education

  • Audit & feedback

  • Reminders

  • Daily huddle board

Estimated from anaesthetics performed per bottle of sevoflurane used per month25% reductionN/ABeneficial
Martinez Ruiz et al28CO2e (units unclear)
  • Anaesthetic gas capture technology to absorb and recycle expelled halogenated anaesthetic gases and recycle them

Determined from use of anaesthetic gases (sevoflurane, desflurane and nitrous oxide) and published estimates of GWP100% reductionN/ABeneficial
Patel and Smith-Steinert42CO2e per year from desflurane use (metric tonnes)
  • Education

  • Removal of desflurane vaporisers

Not reported—assume estimated from retrospective chart review and/or pharmacy records77% reduction (FY19)N/ABeneficial
Richter et al43CO2e per case (tonnes)
  • Education

  • Removal of desflurane vaporisers

Determined from use of anaesthetic gases (sevoflurane and desflurane) and published estimates of GWP68% reductionN/ABeneficial
Tay et al40GWP100 per hour (kg)
  • Replacement of anaesthetic machines to automate control of end-tidal gases

  • Education

Estimated from bottles of each volatile agent used per hour of general anaesthesia44% reduction0.0179Beneficial
Wyssusek et al36CO2e (kg) from 2016 to 2021
  • Education

  • Audit & feedback

  • Gradual removal of desflurane vaporisers

  • Automated control of anaesthetics

  • Default low fresh gas flow settings

Estimated from number of bottles of each volatile agent purchased per month88% reductionN/ABeneficial
Zuegge et al37CO2e emissions per case per fiscal year (kg)
  • Multidisciplinary staff engagement

  • Empowering local champions

  • Education

  • Vaporiser labels

Estimated from number of bottles of each volatile agent purchased per month64% reductionN/ABeneficial
Grimmond et al38CO2e per 1000 patient episodes (kg)
  • Convert from single-use to reusable sharps containers

LCA—process-based attributional84% reductionN/ABeneficial
Labib et al27CO2e per case (kg)
  • Revise appendicectomy surgical set to add reusable and remove rarely used instruments

LCA—cradle to grave62% reductionN/ABeneficial
Neves et al30CO2e per month (kg)
  • Education

  • Audit & feedback

  • Recycling

Estimated from weight of landfill and regulated medical waste32% reduction0.018Beneficial
Riedel33CO2e per 6 months (metric tonnes)
  • Addition of single-stream recycling

  • Education

Estimated from total non-hazardous waste disposal (EPA Waste Reduction Model)Not estimableN/ABeneficial
Wormer et al35CO2e per year (tonnes)
  • Green Operating Room Committee

  • Alcohol-based waterless scrub solutions

  • Recycling and reusing

  • Education

  • Initiative to turn off equipment not in use

  • Donations of unused surgical items

Not reported—assumed to be estimated from electrical energy saved per operating room. Method of GHG emission calculation not reportedNot estimableN/ABeneficial
McAlister et al29CO2e per admission (g)
  • Policy to reduce non-urgent pathology testing

  • Education

LCA—process-based consequential (from previous study)37% reduction<0.001Beneficial
Regan et al32CO2e per year (tonnes)
  • Education

  • Reminder stickers

  • Audit & feedback

  • Incentives

Estimated from number and cost of biochemistry tests orderedNot estimableN/ABeneficial
Wang et al34Total CO2e emissions per patient (kg)
  • Telehealth implementation

  • Established guideline

  • Education

LCA—economic data (prices for services) and process data (quantity of patient travel)9.5% reduction0.019Beneficial
McCarthy et al39CO2e wasted per year (metric tonnes)
  • Education

  • Audit & feedback

Estimated from electrical energy from computers and Picture Archiving and Communication Systems (PACS) left on when not in use4.3% increase*N/ANull 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.