Delivering a ‘Net Zero’ National Health Service - An Environmental Impact Assessment of Nitrous Oxide (Entonox) - Usage in the Medical Sector

Abstract

Nitrous oxide (N2O), commonly known as Entonox when used for medical purposes, plays a pivotal role in pain management and anaesthesia in the healthcare sector. However, its usage has raised concerns about its environmental impact.

This Environmental Impact Assessment (EIA) explores the ecological consequences of N2O utilisation in the medical sector, considering its production, administration, staff wellbeing, leak mitigation and waste management.

The assessment evaluates potential measures to mitigate its environmental footprint and emphasises the importance of sustainable practices.

Introduction

Nitrous Oxide (N2O), a colourless and odourless gas, is widely employed in the medical sector for its analgesic and anaesthetic properties. Commonly marketed as Entonox, it is administered to patients to alleviate pain and induce a state of conscious sedation. While the medical benefits of Entonox are well-established, its environmental impact, specifically its contribution to greenhouse gas emissions and ozone layer depletion, has come under scrutiny.

This Environmental Impact Assessment aims to evaluate the environmental consequences of Entonox usage in the medical sector, with a focus on its administration and waste management. The assessment also discusses potential mitigation strategies to reduce its environmental footprint.

Production of Nitrous Oxide

?Nitrous Oxide is primarily produced by the thermal decomposition of ammonium nitrate (NH4NO3) or ammonium nitrate-based fertilizers. This process yields N2O and other by-products, such as water and nitrogen gas. The primary environmental concern during production is the release of N2O into the atmosphere, as it is a potent greenhouse gas.

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Greenhouse Gas Emissions

?N2O is a known greenhouse gas, with a global warming potential significantly greater than carbon dioxide (CO2) (approximately x 298) as well as being the largest ozone depleting gas emitted by human activities based on ODP-weighted emissions. The production of nitrous oxide, therefore, contributes to greenhouse gas emissions, leading to serious concerns about its role in global climate change.

?Mitigation Measures:

• ?Improved production processes to reduce N2O emissions.
• Carbon capture and utilisation techniques to capture N2O during production.

Administration of Entonox

Clinical Use

Entonox is commonly used for pain management during labour and in dental procedures, Burns ICU, Endoscopy theatres, Paediatrics, A&E Departments and for minor medical interventions. Its administration is typically through a mask or mouthpiece, enabling patients to inhale the gas mixed with oxygen.

Entonox has a rapid uptake, is not metabolised (less than 0.004%) by the body and the patient recovers from an equally rapid washout. Patients are fit to leave hospital without concern as soon as they are able, due to the speed of recovery from Entonox as an anaesthesia.

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Environmental Impact

The environmental impact of Entonox administration is mainly associated with the venting of exhaled gases into the atmosphere and disposal of empty cylinders (still containing 20 Bar - circa 8.6% remaining unused) along with potential gas leaks in the medical gas pipeline during usage. The release of nitrous oxide into the atmosphere contributes to greenhouse gas emissions, affecting air quality and climate as well as concerns of over exposure by staff.

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Mitigation Measures:

• Improved cylinder recycling and disposal protocols – via a CDU Venting facility. (Central Destruction Unit)
• Regular maintenance and monitoring of gas administration equipment to prevent leaks via MedGasScan. (Acoustic Scan)
• Implementation of efficient gas scavenging systems to reduce environmental emissions and to process nitrous oxide and Entonox, making it safe to vent to atmosphere in the natural gas form of Nitrogen and Oxygen. - via a CDU plant installation (Central Destruction Unit)

Staff Wellbeing

100ppm of Nitrous Oxide is the maximum permitted exposure level to be detected over an 8-hour shift.

?Adverse health effects from over-exposure may include:

• ?decreased mental performance, audio-visual ability, and manual dexterity.
• addiction from repeated administration or exposure to nitrous oxide/
• megaloblastic anaemia and neurological toxic effects (myelopathy) due to inactivation of vitamin B12.
• prolonged exposure may result in bowel distension, middle ear damage and rupture of ear drums.
• Agranulocytosis.
• reduced fertility where they have been repeatedly exposed to levels of nitrous oxide above the specified occupational exposure limits in inadequately ventilated rooms.

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Mitigation Measures:

?It is recommended to take advantage of a personal Nitrous Oxide Detector to measure staff levels on a personal level rather than a per room level. A personal Nitrous Oxide Detector (NOD) allows staff to record their own exposure levels throughout their shift is recommended via a Medclair AB NOD (Nitrous oxide detector.)

Waste Management

Empty Cylinders

The disposal of empty Entonox cylinders is a crucial aspect of waste management. These cylinders may contain residual N2O (circa 20 Bar or approximately 8.6%), posing environmental risks if returned to supplier and vented to atmosphere thereby not being not handled appropriately. A CDU venting facility on site is capable of extracting, breaking down and venting Nitrogen and Oxygen to atmosphere allowing for a completely and safely depleted cylinder to be returned to the supplier.

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Environmental Impact

Improper disposal of cylinders can lead to N2O leakage into the atmosphere, exacerbating the greenhouse gas problem.

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Mitigation Measures:

• ?Proper disposal and recycling of non-empty cylinders to prevent N2O emissions from being vented to atmosphere via a CDU Venting Facility on site

Conclusion

The environmental impact assessment of Entonox (Nitrous Oxide) usage in the medical sector reveals that its production, administration, and waste management have distinct environmental consequences. The primary concern is the release of N2O, a potent greenhouse gas, into the atmosphere, which contributes to global warming and climate change.

To mitigate these environmental impacts, it is essential to implement sustainable practices within the medical sector, including:

• ?Improved production processes to reduce N2O emissions during manufacture.
• Strict monitoring and maintenance of gas administration equipment to prevent leaks.
• Establish a method of controlling, managing and disposing of exhaled Nitrous Oxide / Entonox
• Proper disposal and recycling of empty cylinders.

By adopting these measures, the medical sector can continue to benefit from the therapeutic properties of Entonox while minimising its negative environmental footprint. The importance of balancing medical needs with ecological responsibility cannot be overstated in the context of global environmental challenges.

BeaconMedaes UK are working with the NHS to provide a full #Sustainability solution for the #NHS medical gases under Scope 1 - Anaesthetic Gases and are able to provide a turnkey solution that can:

• Mitigate gas losses due to leaks with regular MedGasScan (Acoustic Scanning) of the medical gas pipelines.
• Can design, plan and establish a dedicated venting facility on site to empty all Nitrous Oxide and Entonox cylinders to ensure that the suppliers are not venting unused or retained Nitrous Oxide or Entonox in cylinders returned to depot.
• Can design, supply, install the pipeline and CDU as well as service and maintain a dedicated Nitrous Oxide and Entonox control system which breaks the gas down to its natural and harmless states of Nitrogen and Oxygen.
• Full Asset Management and reporting via MyMedGas
• Further Consideration needs to be given to #Desflurane, #Isoflurane and #Sevoflurane which will be covered under a separate article on "Managing Volatile / Halogenated Anaesthetic Gases in Operating Theatres"

BeaconMedaes are working alongside the NHS to assist in their drive towards a "Net Zero" NHS.

Full information on the available solutions can be obtained by contacting:

Paul Owen

UK National Sustainability Manager

BeaconMedaes

[email protected]

or by clicking on: https://link.v1ce.co.uk/paulowen/518331

or by clicking "View my portfolio" on the profile header: www.dhirubhai.net/in/paul-owen-beaconmedaes