There is insufficient evidence to support the purchase, installation and maintenance of volatile anaesthetic gas capture technologies (VCTs) in NHSScotland.

More evidence is required on the capture efficiencies of VCTs when used in clinical settings. Based on two small studies, VCTs have been shown to capture only up to 50% of volatile anaesthetic agent (by mass).

Robust life-cycle assessments are required to define the direct and indirect environmental impact of VCTs. The life-cycle analyses should compare use of VCTs with alternative strategies that take into account current and planned changes to anaesthetic practice.

Further considerations which limit the applicability of VCTs include:

• the recent reductions in the environmental impact of volatile anaesthetic gas emissions within NHSScotland, driven largely by the decommissioning of desflurane
• the lack of agreement on the extent to which the remaining volatile anaesthetic gases contribute to climate change particularly at current atmospheric concentrations.

What were we asked to look at?

The Scottish Government’s Health Infrastructure Division asked SHTG to independently evaluate the use of VCTs in anaesthetic rooms and operating theatres. The intended purpose of VCTs is to reduce anaesthetic volatile gas emissions (greenhouse gases) entering the atmosphere and contributing to global warming and climate change.

Why is this important?

The gases that are used for anaesthetics and pain relief are greenhouse gases, and include the volatile gases desflurane, sevoflurane and isoflurane. Volatile gases are defined as those that evaporate readily at normal temperatures. Reducing the environmental impact of anaesthetic gases has been highlighted by the Scottish Government as a key priority.

Desflurane, isoflurane and sevoflurane are reported as having 100-year time horizon global warming potentials (GWP₁₀₀) that are respectively 2,540, 510 and 130 times more potent than carbon dioxide. Some climate experts suggest these figures are misleading, and that the impact of these gases on climate change is insignificant because the lifetimes of the gases are too short and the concentrations are too low to have a meaningful environmental impact. In NHSScotland an 82% reduction in volatile gas emissions was achieved over the period of 2018/19 to 2021/22 as a result of various mitigation measures (for example, low flow anaesthetic techniques and switching from desflurane to sevoflurane).

An impartial assessment of VCTs was requested to establish whether the purchasing, installation and maintenance of VCTs offers good value for money and whether they provide net environmental benefit.

Referred by

Scottish Government Health Infrastructure Division