The Maternity Unit at Copenhagen’s Hvidovre Hospital has recently reintroduced nitrous oxide to support women in labour pain, having ceased using it a decade ago due to concerns over potential health risks to staff. Denmark has since, however, developed new safety protocols for N2O use, and with the gas a highly effective analgesic, the hospital wanted to reintroduce it, but needed to address its substantial climate footprint. Jannik Jensen, Global Product manager at Medclair, and his colleague, R&D manager, Olesya Nikonova, explain how a Medclair central nitrous oxide destruction system met the brief
Nitrous oxide (N2O) gas was first synthesised in 1772 by English natural philosopher and chemist, Joseph Priestley. Its first use as an anaesthetic gas in the treatment of a patient was when dentist, Horace Wells, assisted by Gardner Quincy Colton and John Mankey Riggs, demonstrated its pain relief during a dental extraction on 11 December 1844.1 Today nitrous oxide is widely used globally in a variety of healthcare settings – ranging from dentists’ surgeries to Accident & Emergency Departments, paediatric, orthopaedic, ambulance, and Maternity units. All share the need for fast, safe, and effective pain relief during short procedures, and equally a rapid wearing off of the effects when surgery or other clinical procedures are complete. The economics of using N2O also make it an attractive proposition for healthcare providers compared with other options. Consequently, nitrous oxide is widely used in healthcare facilities in many countries – including the UK, Sweden, Norway, Finland, Australia, New Zealand, the US, and France
One significant drawback of N2O, however, is its carbon footprint – with 1 kg of N2O equivalent to 298 kg of CO2. Nitrous oxide alone contributes 2% of the total NHS England carbon footprint, and 75% of its total anaesthetic gas footprint. As a result, the NHS has a publicly stated aim of reducing its nitrous oxide emissions by 75% as part of the service’s wider goal of reducing greenhouse gas emissions by 80% within the next 7-11 years, and achieving ‘Net Zero’ by 2040.
A long-established form of pain relief
The Maternity Department at Copenhagen’s Hvidovre Hospital, which is not only one of Denmark, but also Scandinavia’s, biggest and busiest, had been using nitrous oxide for pain relief for women in labour for some years, when, a decade ago, it took the decision to withdrew its use. Dorte Dahl, head Midwife at the Department of Obstetrics and Gynaecology, Hvidovre Hospital, explained: “Giving birth is not always a short procedure – it can be a lengthy one, with high pain intensity. Women will use a lot of nitrous oxide in these scenarios, which in turn gives rise to our two biggest concerns over the gas’s use today – staff being exposed to the gas, and its high global warming potential. We in fact stopped using nitrous oxide 10 years ago due to concerns about staff being exposed, over time, to high levels of the gas. Staff safety is naturally one of our highest priorities, and we were not prepared to expose our staff to any excess risk. Subsequently, however, obstetricians, anaesthetists, midwives, medical technicians, and environmental specialists in Denmark developed a national protocol on how to use the gas safely in terms of exposure levels to staff. The protocol gives updated advice on its safe use, on the need for additional training, and on how to capture and destroy exhaled gas before it is released into the atmopshere.2 None of these protocols, of course, existed at the time when, reluctantly, we took the decision to stop using N2O.”
Demand from patients and nursing staff
Dorte Dahl continued: “The decision to reintroduce nitrous oxide in our Maternity Department here was a result of demand from both women in labour and Maternity staff, and with the new protocols in place, all the Maternity Departments in Denmark now offer the anaesthetic gas to women in labour.” One midwife at Hvidovre Hospital said: “How hampered I felt as a midwife before we got the nitrous oxide back – and what a big difference it made to my daily work to have the gas as a tool in the midwifery toolbox when women are in pain.”
Dorte Dahl added: “Nitrous oxide use is clearly highly valued by both patients and staff. When we look at our statistics for nitrous oxide pain relief, about 80% of all women at the hospital use it during labour. Some women use it briefly; others throughout the birth. Some use it while lying in bed, others in the bathtub or sitting on a ball next to the bed. One of the gas’s biggest advantages is that fact that patients can self-administer it.” One woman said following labour: “The nitrous oxide was the most important thing during my labour. Both the midwife and my husband were of great support, but the greatest support was the gas.”
Nitrous oxide’s climate impact
Nitrous oxide thus has major benefits for both women in labour and the staff caring for them. However, as previously discussed, it has a major climate footprint, and in fact the impact of four hours of intermittent use of nitrous oxide mixed with oxygen equates to that of driving 1,400 kms in a car.3 The ability to capture and destroy exhaled nitrous oxide thus not only protects staff in, say, a Maternity unit, from the effects of over-exposure, but also helps reduce global warning by preventing release of the gas to atmosphere – factors that are now clearly recognised in many countries. The environmental problem of nitrous oxide in obstetrics is indeed recognised both in the October 2020 NHSE/I publication, Delivering a ‘Net Zero’ National Health Service, 4 and in an article titled ‘Cracking the environmental problem of nitrous oxide in obstetrics’, published in the journal, Anaesthesia in March this year.5 The latter says: ‘The shared responsibility for the environment relies on us as clinicians to endorse this technique, and on our patients to embrace it. The introduction of a system which reduces the environmental impact of nitrous oxide, enabling women to choose pain relief without concerns they are harming the planet, is a medical advance that justifies a place in delivery units across the UK.
Use in Swedish healthcare since 2004
This brings us on to our nitrous oxide destruction technology; in fact such technology has been used in Swedish healthcare since 2004,6 Swedish politicians having become aware of the carbon footprint of nitrous oxide from the gas’s use in Maternity settings. Medclair Research and Development manager, Olesya Nikonova, explains: “The technology that our nitrous oxide destruction systems use is based around the direct catalytic decomposition reaction of N2O gas into air (nitrogen and oxygen). This catalytic reaction is an exothermic reaction, meaning that additional heat (energy) is released when the N2O molecule is split into N2 and O2. Medclair equipment is designed in such a way that additional energy is used to reduce the system’s energy consumption and give an even lower CO2 footprint.”
The installation at Hvidovre Hospital
The £355,000 Medclair central nitrous oxide destruction system installed at Hvidovre Hospital includes a nitrous oxide manifold system, pipe installation, and outlets in 14 birthing rooms. There is anaesthetic gas scavenging equipment in all rooms, with gas evacuation pipework to one AGS pump, which removes nitrous oxide from all rooms to a single central nitrous oxide destruction unit that eliminates nitrous oxide to air.
The plant has an expected lifetime of over 10 years, over which it is expected to capture and destroy exhaled N2O from around 56,000 patients, at an approximate cost of £6 per patient. It is expected to destroy a volume of 2,000 kg of nitrous oxide per year, which – in terms of carbon footprint reduction – equates to removing almost 600 tons of CO2
Hvidovre Hospital’s Maternity Department supports the birth of around 7,000 babies every year, with an average of 19 babies born there each day. While securing sufficient access to 14 birthing rooms to install the pipework, gas outlets, and gas evacuation equipment associated with the Medclair system could have proven challenging, Dorte Dahl explains that in fact the installation of the entire system was easily managed. She said: “We only had to close two birthing rooms at a time, and in some months, none at all. The installation is now complete in all 14 birthing rooms, and we are very excited about it.”
A first in Denmark
Hvidovre Hospital is the first hospital to install the technology in Denmark. Dorte Dahl said: “Our climate is a concern to us all, and with the central destruction technology installed, both the staff and the women patients here can now use nitrous oxide with a clear conscience. The project’s completion was a fantastic day for all involved – those funding the system, the Estates team, Maternity staff, local politicians, and industry partners, but most importantly the women.”
The Medclair technology can either be supplied as a central nitrous oxide destruction unit serving a number of rooms connected to one unit (as at Hvidovre Hospital), or as a mobile unit ideal for smaller healthcare settings where no gas evacuating outlets are available.
The central nitrous oxide destruction technology generates constant readings on its performance, measuring the energy in kWh used to destroy the nitrous oxide, and the volume of the gas destroyed.
Jannik Jensen
Jannik Jensen is Global Product manager at Medclair. He qualified as an Intensive Care Nurse in 1998 from the Nursing School at the University Hospital of Copenhagen, and spent 10 years in intensive care nursing. He then embarked on a career in medical gas, leading the nitrous oxide programmes in Scandinavia for a global gas company for 13 years. He has represented Medclair since March 2021, working with healthcare systems around the world to reduce their carbon footprint from nitrous oxide use.
Olesya Nikonova
Olesya Nikonova is Research & Development manager at Medclair AB. She has a PhD in Chemistry from the Swedish Agricultural University Uppsala. She has experience in nanochemistry, as well as Sol-Gel technology of functional materials. She has represented Medclair AB since October 2021.
Dorte Dahl
Dorte Dahl is Head Midwife at the Department of Obstetrics and Gynaecology at Hvidovre Hospital in Copenhagen. She qualified as a midwife in 2001, and has many years’ management experience, and was involved in the project, ‘Implementing Safe Births’. In 2017, she was nominated for ‘Manager of the Year’ by her team.
References
1 Erving HW (1933). The Discoverer of Anæsthesia: Dr. Horace Wells of Hartford. Yale J Biol Med 1933 May; 5(5):421-30.
2 Albrectsen C, Kiel M, Kappendrup L, Thomsen L et al. Lattergas som smertelindring ved fødsler. Dansk Obstetrisk DInitrogenoxid-ved-fødsler.pdf (dasaim.dk)
3 Pearson F, Evans E. Nitrous oxide in maternity: what’s all the gassing about? Association of Anaesthetists. https:// tinyurl.com/573c5myf
4 Delivering a ‘Net Zero’ National Health Service, NHSE/I, October 2020. https:// tinyurl.com/5n6z6466. Pages 31-35.
5 Lucas DN, Wong R, Kearsley R. ‘Cracking’ the environmental problem of nitrous oxide in obstetrics. Anaesthesia 2023 Mar; 78 (3): 288-293. https://pubmed.ncbi.nlm. nih.gov/36351439/ 6 Ek M, Tjus K. Destruction of Medical N2O in Sweden. Greenhouse Gases – Capturing, Utilization and Reduction. IVL Swedish Environmental Research Institute, 2012. https://tinyurl. com/4mzt6e3k