In the air: the environmental impact of medical gases

Our Medical Gas Portfolio Manager Michael Ell examines the environmental impact of medical gases in the context of recent trends and developments.

As with all areas of life, all we can be sure of is change. The world of medical gases is no different, not only in the technical development of medical gas plants and equipment but also developments in medical equipment such as patient ventilators.

There are other changes not always so concrete or visible notably the power of public opinion backed by scientific evidence leading to the requirement to reduce the emission of greenhouse gases.

The current HTM 02-01 standard was published in 2006 14 years ago! Much of the content remains as relevant now as it was in 2006, however there are increasing difficulties in the application of Table 11 which provides guidelines on the types of gas and numbers of terminal units provided to different clinical areas.

Taking firstly the developments in patient ventilator technology and the introduction of ventilators with a self-contained turbine drawing air via a hepa filter means that medical air supplies are not required. However, the need for reliable electrical supply to the patient area is critical. This technology has become available over the recent years and speaking with colleagues in medical engineering, medical engineering departments are purchasing  these newer turbine driven ventilators when replacing  ventilators.

It should be noted that some ventilators have the option of being medical air driven or electrically driven and that medical air may be required for the delivery of nebulised medicines. Therefore, care needs to be taken should the medical gas committee decide to reduce the number of medical air outlets.

Additionally the diversified flow calculations for medical air could be reviewed to accommodate the reduced requirements for medical air flow rates.

Another area where there has been a significant change is that of surgical power tools. Historically these were driven by Surgical air at 7 bar - the developments in battery technology now means that many of these tools are available as portable battery operated.

In the case of medical air and surgical air there is a potential for resource reduction.

The requirement to reduce greenhouse gases is now well documented and we tend to think of this as an energy related issue. Nitrous oxide and volatile anaesthetic agents also contribute to the health care carbon foot print.

There are two points to bear in mind when considering the impact of different gases:

  • GWP Global warming potential comparative to CO2
  • TPL tropospheric life time - the time the gas takes to break down

Desflurane, an  anaesthetic agent, is has a GWP of 2540 with just 250ml being equivalent  to nearly a tonne of Carbon or driving diesel car for close to 5000 miles.

Other anaesthetic agents such as Isoflurane and sevoflurane also have an GWP impact. How these impacts are managed rest with the clinical and medical teams whereas Nitrous oxide is a joint effort both by the clinical teams and estates.

Nitrous oxide has a GWP of 298 and a TPL of 110 years. The high TPL is of concern and one of the reasons that the amount of Nitrous oxide in the atmosphere has increased by about 16% since the pre industrial period. Emissions from healthcare activities are relatively small compared with emissions from agriculture and burning of fossil fuels, healthcare estates teams responsible for medical gas pipe systems should ensure that there is minimal leakage from Nitrous oxide and Entonox systems.

It is, of course, important that training is consistent with the current published standards and guidance. Here at Eastwood Park training is evidenced based with a high percentage of practical content within the courses, worked examples and exercises refer to the information within HTM 02-01 for diversified flow rates and gases supplied to healthcare areas. Nevertheless, it is important to acknowledge the above points that we are aware of the larger picture and the potential future changes to guidance.