Eliminating anaesthetic gas leaks 'significant' for Cork hospital's carbon footprint

CUH decommissions pipe system which delivered inhaled nitrous oxide anaesthetic to machines in surgical theatres, replacing it with a small cylinder of the gas attached to each anaesthetic machine 

Denise O’Brien, Lavina McCarthy, Aisling Lehane, and Aileen Fitzgerald. Front: Patrick Hassett, PJ Murphy, Cathal Flannery, Dr Cathy Burke, and Ruaidhri de Barra at CUH. Picture: Larry Cummins

One of the largest public hospitals in Ireland has finished a major environmental project to eliminate leaks into the atmosphere of a common anaesthetic and potent greenhouse gas.

Cork University Hospital (CUH), which in 2014 became the first Green Flag hospital campus in the world, has decommissioned its decades-old pipe system, which delivered the inhaled anaesthetic, nitrous oxide (N2O), to machines in the surgical theatres, replacing it with a small cylinder of the gas attached to each anaesthetic machine for delivery to the patient as required.

N2O is a potent greenhouse gas with atmospheric warming potential some 300 times that of CO2 and the pipes which deliver it to surgical theatres are prone to leaks, resulting the loss of millions of litres of the gas into the atmosphere, where it can remain for around 100 years.

CUH group chief executive David Donegan said that as well as helping to reduce CUH’s carbon footprint, the pipe-decommissioning project will serve as a template for other Irish hospitals to follow.

We have taken out, unprecedented in Ireland, a medical gas that was piped throughout the whole hospital, the biggest HSE hospital in Ireland.

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“To be able to do that, while still providing the medication at the bedside when it’s needed, and to reduce the emissions to the scale that has been achieved, is another significant contribution to our sustainability agenda," he said.

N2O was one of the earliest and most commonly used general anaesthetics, but its use has waned significantly over the years. 

While still used in maternity hospitals, mixed 50:50 with oxygen to become entonox, commonly known as gas and air, it is rarely used for adult general anaesthetics, with most anaesthetists opting for the more modern, greener option of total intravenous anaesthesia.

Trainee anaesthetist Dr Ola Nordrum, operations officer for Irish Doctors for the Environment (IDE) and a member of the College of Anaesthesiologists of Ireland’s sustainability committee, said research has shown that most N2O delivered to hospitals was being lost through leaks.

“In 2019, total emissions from inhaled anaesthetic agents used across all public hospitals and the majority of private hospitals amounted to almost 18,000 tonnes of CO2 equivalent. The vast majority of emissions were related to N2O use, either as pure N2O [42%] or entonox," he said.

A hybrid theatre at the Cath Lab at Cork University Hospital. Picture: Larry Cummins

IDE has been encouraging hospitals with large N2O usage and large carbon footprints to address these emissions.

Dr Cathy Burke, a consultant gynaecologist at Cork University Maternity Hospital, drove the pipe decommissioning project across the CUH campus, with chief biomedical engineer Nelius O’Sullivan and consultant anaesthetist Dr John Chandler.

CUH engineering officer PJ Murphy in a storage room for gas cylinders.  Picture: Larry Cummins

PJ Murphy and his engineering colleagues decommissioned the pipes, while Denise O’Brien and her biomedical engineering colleagues removed the redundant medical equipment and installed the new gear without disrupting the availability of the surgical theatres.

“We believe that N20 decommissioning in CUH will have a significant effect on the carbon footprint of CUH," said Dr Burke.

“As a hospital with Green Campus status, this achievement will demonstrate our ongoing commitment to green healthcare and we hope will inspire hospitals across the country to do the same as part of achieving the aims of the HSE Climate Action Strategy.”