Environmental sustainability in healthcare has become an NHS priority. Climate change is now acting as a serious threat to human health globally (Kotcher et al, 2021) and given that the provision of healthcare is a known pollutant (Lenzen et al, 2020), it is imperative that health services lead by example in combating such effects. As an organisation, the NHS has stated that more must be done to meet the targets set out by the 2008 Climate Change Act and that development of current practice is required (Winter, 2019). NHS England set targets in line with the NHS net zero commitment for the NHS carbon footprint to be net zero by 2040, aiming for an 80% reduction in this area by 2028–2032 (NHS England, 2020).
Anaesthetic gases make up 5% of the carbon footprint for acute organisations, with nitrous oxide and desflurane being the greatest culprits for negative climate effect (Charlesworth and Swinton, 2017). A 2020 paper suggested that a vital measure anaesthetists can take is to avoid these anaesthetic gases to limit their carbon footprint (McGain et al, 2020). Nitrous oxide is widely used in childbirth as Entonox, a 50:50 mix of nitrous oxide and oxygen. Improving sustainability in the context of nitrous oxide use requires identifying all relevant factors that influence its use in healthcare settings, specifically in labour wards where Entonox is widely used (Care Quality Commission, 2021).
Identified barriers to Entonox use include its ability to cause side effects such as nausea, vomiting, dizziness and light-headedness (Talebi et al, 2009; Richardson et al, 2019) and the potential for its equipment to make women feel claustrophobic (Richardson et al, 2019). One paper suggested that there has not been enough research on the effect that long-term nitrous oxide exposure can have specifically on those working in labour suites (Koyyalamudi et al, 2016); however, in the past, it has been suggested that long-term exposure to nitrous oxide can cause spontaneous abortion or congenital malformations, alongside difficulties with fertility (Henderson et al, 2003). Another identified barrier is that nitrous oxide has a negative environmental impact resulting in destruction to the ozone layer, with 1kg of nitrous oxide having the same effect as 298kg of carbon dioxide (Ek and Tjus, 2012).
Several facilitators for continued use of Entonox in childbirth have been identified. Entonox offers labouring women something to focus on, acting as an anxiolytic throughout their labour (Richardson et al, 2019). It aligns with some labouring women's birth plan, reduces the need for epidural analgesia and women often consider it part of a ‘natural birth’ (Richardson et al, 2019). It also provides some pain relief for a labouring woman (Talebi et al, 2009; Dammer et al, 2014; Koyyalamudi et al, 2016), is readily available for use and can be initiated without delay (Talebi et al, 2009), allowing for both fast onset and offset of effects. There is also no evidence of it causing harm to a woman or fetus (Talebi et al, 2009), so it is considered to be a safe analgesic. In relation to its occupational impact, the use of scavenging can reduce the negative effects of Entonox for staff (Chessor et al, 2005; Van Der Kooy et al, 2012); however, recent evidence has shown that a double mask is a much more effective scavenging system in terms of staff exposure (Caetano et al, 2021). This tool is not in use in the current system. ‘Cracking’ technology has become available to break down nitrous oxide into its harmless constituents, nitrogen and oxygen. It has been shown to be effective at reducing both its environmental and occupational effects (Pinder et al, 2022) but is not yet in use in this system.
Using the systems engineering initiative for patient safety 2.0 model (Holden et al, 2013), Entonox use was reconceptualised as a healthcare process influenced by a complex interaction of work system factors. Specifically, an interaction of the relevant people, tasks they need to accomplish, tools/technologies they use, their internal environment, the organisation that structures their work and the external environmental influences that shape the whole work system. This human-factors approach has already proved useful in anaesthesia literature (Schnittker et al, 2018).
Using the qualitative methodology of semi-structured interviews, this service evaluation aimed to identify work system factors that act as facilitators or barriers to Entonox use in a Scottish hospital's labour ward, and perceived outcomes for women on the ward, healthcare staff, the organisation and environmental sustainability from the perspective of midwives and an environmental sustainability manager.
Methods
This service evaluation of Entonox use in a Scottish hospital's labour ward used semi-structured interviews with midwives and an environmental sustainability manager. Participants were recruited via email invitation. A total of 10 midwives who use Entonox frequently and one non-clinical manager who had an environmental role and could provide additional depth to the data participated, until data saturation was reached (Hennink et al, 2016).
Data collection
A semi-structured interview is one that has adequate structure to ensure the objectives of a study are addressed, but also has the flexibility for interviewees to give additional insight to the researcher (Galletta and Cross, 2013). Semi-structured interviews require a guide to ensure that the interviewer covers all aspects they wish to explore (Jamshed, 2014), yet the open-ended nature of such questions gives the interviewee the freedom to answer as they wish.
The question guides used in this service evaluation were based on the factors in the systems engineering initiative for patient safety framework to gain an insight into the entire system. The questions focused on the use of Entonox by midwives, their use of alternative analgesics, their perceptions of women's experiences with Entonox and factors that influenced their use of Entonox for women in labour. Midwives were also asked about their knowledge regarding the safety of Entonox, including its environmental and occupational impacts, alongside their understanding of sustainability in healthcare. The non-clinical manager was asked about their role in nitrous oxide waste management and their knowledge of its environmental impact, along with their opinion on the reduction of its use. They were also questioned on their understanding of sustainability in healthcare overall.
Interviews were conducted in a private room of the labour suite during January and February 2021 and lasted 14–30 minutes. The interviews were recorded using a recording device, in order that transcription and analysis could follow. Following transcription, the recordings were deleted and the transcriptions were anonymised. Each anonymised interview transcript was given a numerical identity and then kept on a password protected OneDrive account.
Data analysis
Thematic analysis was used on the datasets (Alhojailan and Ibrahim, 2012). The researcher used deductive analysis (Braun and Clarke, 2006), coding the factors of the systems engineering framework as initial themes from which were found sub-themes. This was done using inductive analysis, a data-driven form of analysis (Braun and Clarke, 2006). Inter-rater reliability was used to review the levels of agreement between researchers, to reduce bias from a single researcher. A kappa score based on the number of observations that aligned from both researchers was calculated using a ‘kappa calculator’ (Landis and Koch, 1977). The kappa score for this thematic analysis was 0.725, which can be interpreted as ‘substantial agreement.’
Ethical considerations
Clinical governance approval was gained from the Theatres, Anaesthesia and Critical Care Clinical Governance Group in the studied NHS Board to permit staff interviews (NHS Tayside database number 71). Informed consent was obtained prior to each interview, using a participant information sheet and a consent form.
Results
The relevant work system factors that influence Entonox use and its impact on outcomes are summarised in Figures 1 and 2, under themes and their relevant subthemes.
All participant midwives were familiar with Entonox and used it regularly, but their knowledge of occupational risks was mixed. Four midwives had no knowledge and six had some knowledge of the potential effects, with variable levels of understanding. Four midwives shared knowledge of potential health issues resulting from occupational exposure to Entonox. None knew of the risks in great detail, but all mentioned either fertility or miscarriage as potential outcomes of exposure. For midwives of reproductive age, these distal outcomes were likely to act as undesirable consequences when considering the use of Entonox.
‘I think there's effects possibly for staff. I think there was risk of miscarriage and things in female staff.’
Midwife 2
The participants' knowledge of nitrous oxide's environmental impact was extremely limited, with none of the midwives having knowledge of its negative effects. One midwife in particular was disappointed that she had never thought of the associated environmental risks, as she considered herself to be very environmentally conscious. Eight midwives acknowledged maternal preference as an important factor towards the use of Entonox.
‘It's all about women having a choice.’
Midwife 10
Nine of the midwives stated that women have the ability to follow instructions appropriately and all midwives acknowledged that the administration of Entonox is very straightforward, as it is always available for use and takes very little time to set up. With regards to tasks involving sustainability, the manager stated that the message that saving the environment is an important matter that should involve everyone is one that needs to be shared, and that environmental initiatives should be pitched to financial teams in a positive light.
Four midwives mentioned that Entonox is a good starting point but that women will often require further analgesia throughout their labour.
‘Entonox is good for the first part of labour but as it progresses it's not always so good.’
Midwife 2
Six midwives highlighted Entonox as a tool that gives the labouring woman something else to focus on, which can help women to cope with the pain of contractions.
‘I wonder is it actually a pain relief or coping mechanism to get through a breathing technique, it's a distraction technique.’
Midwife 3
All midwives stated that they considered Entonox a safe drug. A contributing factor to their assurance of its safety was its short-lasting effects; as soon as a woman stops breathing it in, the effects are gone. When asked about their thoughts on introducing a mask for Entonox delivery, to reduce environmental and occupational risks, the midwives' responses were mixed. Some felt negatively towards a larger mask because of its perceived restrictive nature, which could make women feel claustrophobic, taking away from the natural process of birth and making their labour feel more medicalised. Alternative analgesics were discussed with all midwives, with four midwives observing that analgesics can be used in combination with one another. This can increase the effectiveness of pain relief and the addition of another analgesic could reduce the volume of Entonox required.
None of the midwives mentioned specific organisational training on the use of Entonox, or the guidelines that exist and are expected to be adhered to. All 11 participants were asked what they knew about environmental sustainability in healthcare. Two stated that they did not know anything about it.
‘It's not really something that's discussed to be perfectly honest, so I could not say that I know an awful lot, which is probably really bad actually.’
Midwife 9
Five midwives mentioned that they believe Entonox is safe because the organisation portrays it that way and that the scavenging systems in place are there to mitigate risks. Eight midwives acknowledged the existence of scavenging systems. Three stated that they remembered the arrival of these systems, as there had previously been nothing. No midwives mentioned the protocol that states that it is their responsibility to ensure that the Entonox delivery environment is safe.
All 10 midwives stated that womens' experience of Entonox can be variable. They reported that some women greatly appreciate the availability of Entonox and saw no negatives, meanwhile others experience side effects, highlighting the unpredictable nature of Entonox.
Midwives' opinions on whether they thought women would be deterred from using Entonox based on knowledge of its risks were mixed. Half of the interviewed midwives believed that there was potential for women to be deterred based on occupational risks, whereas the others thought that they would not.
‘You know if you're in pain during labour, there's not very many women who would say “well I'm worried about you, so I'll not take it”…I think women would still continue to use it.’
Midwife 10
Seven midwives stated that they did not think that women would be deterred from using Entonox based on environmental issues or that only a minority would.
‘I'm not sure, it depends on how much of an impact.’
Midwife 7
Eight midwives stated that they were satisfied with Entonox as a pain relief, while one stated that they were unsure of their satisfaction, as they believe that it helps but feel that it is sometimes more of a distraction than an effective pain relief. Generally, good satisfaction from the midwives suggested that Entonox was seen as a favourable tool in the system.
In response to whether knowledge of occupational risks would deter them from using Entonox for the women in their care, the responses were mixed. Five midwives indicated that occupational risks would not deter them from using Entonox, two said that it would depend on what the risk was and three stated that if there was a risk to them then it would deter them from wishing to use Entonox.
‘If I knew there was occupational risks, or any risk towards it, then of course.’
Midwife 8
With regards to the environmental impact of Entonox, four midwives stated that knowledge of this would not deter them from using Entonox and four stated that it would potentially deter them but they required further information. One midwife said that it probably would, while another said that it would definitely deter them.
‘Yes, saving the environment's pretty important, however labour pain is horrific, so I wouldn't let that deter me from giving it to somebody.’
Midwife 3
When asked about their opinions on a reduction in Entonox use, eight midwives highlighted that its reduction would create difficulty, with five highlighting that there is no alternative that is as quick and easy to use. One stressed the issue of taking the choice away from women. The manager expressed their view that anything that had less of an environmental impact would be a good thing, but they were aware of sensitivities to do with taking away the availability of Entonox from labouring women. Overall, the midwives' perception was that it would be an undesirable outcome to reduce the use of Entonox, despite being desirable for the environment and their own health.
Six participants illustrated the negative effect that they felt the NHS had on the environment. Their points included the volume of waste accumulated, the lack of sustainability, the negative impact that anaesthetic gases have on environmental health and the undesirable outcomes on the external environment. Two participants mentioned the need to consider other ways in which the hospital's environmental impact could be reduced.
“From an environmental perspective there are things that we should be doing that we aren't doing in the room.’
Midwife 6
‘Anaesthetic gases is not included in that report [from Scottish government about mitigating risk]… but we know that they don't have a good impact.’ Non-clinical manager
Discussion
While this service evaluation identified both barriers and facilitators for Entonox use, it appears that in the current system, according to midwives and the environmental sustainability manager, the facilitators outweigh the barriers. An important facilitator identified from the interviews was that Entonox is always readily available and extremely straightforward to set up, allowing for immediate use, which mirrors the findings of Talebi et al (2009). According to the present study's participants, Entonox is perceived well by both women and midwives, reflecting available quantitative literature (Bradfield et al, 2022), which found high maternal satisfaction with Entonox. This contentment with Entonox would likely make it difficult to remove it as a tool. The importance of autonomy is a concept that was illustrated in both the present service evaluation and the literature (Richardson et al, 2019), as the choice of analgesics would be reduced if Entonox were to be discouraged. Therefore, it is evident that the importance of maternal choice acts as a significant stimulus for the continued use of Entonox.
Side effects of Entonox, such as nausea, vomiting and dizziness, were discussed by interviewees and are included in the literature (Talebi et al, 2009; Dammer et al, 2014; Koyyalamudi et al, 2016), suggesting that they could act as a barrier to the continued use of Entonox. However, the interviewees in the present evaluation stated that should these effects occur, they tend to dissipate quickly and do not have a long-lasting effect; therefore, it is unlikely that knowledge of these would prevent a woman from wishing to try Entonox as an analgesic.
While knowledge of the occupational risks of Entonox was limited among the present study's midwife participants, it became apparent that the risks could discourage Entonox use from a staff perspective but would not act as a barrier to all. None of the interviewed midwives had knowledge of the environmental effects of Entonox; this is not wholly surprising, given that there is no UK-based research similar to that of Ek and Tjus (2012). This research, which was conducted in Sweden, investigated the use of destruction units to split nitrous oxide back into nitrogen and oxygen. This allowed the continued use of Entonox as a labour analgesic, while limiting the negative environmental impact of nitrous oxide. The present study's participants believed that knowledge of such effects was unlikely to deter women from wishing to use Entonox, but that it could act as a barrier to some midwives. Further research would be useful to gain information on womens' attitudes towards Entonox with regards to its environmental effects.
With regards to sustainability more generally, the midwives' analysis of environmental sustainability culture in the organisation overwhelmingly revealed poor results. The fact that one midwife knew nothing, as they felt sustainability was not something that was discussed, indicates that these are not conversations that are occurring between the organisation and its staff. The manager commented that it was ‘not the nearest shark to the boat’, a poignant point that relates to the finding that people are not treating climate change like the emergency that it is (Gills and Morgan, 2020) and are not striving to achieve the targets set in legislature, as was recommended by the NHS Sustainable Development Unit (2009). It could be inferred from the present study's participants' comments that the environmental impact of Entonox is unlikely to act as a major barrier to its continued use in the organisation, and therefore that more could be done to limit its effect.
All midwives in the present study stated that their experience suggested Entonox is an extremely safe drug. While one study (Talebi et al, 2009) noted that Entonox is a safe drug for a woman and fetus, Westberg et al (2008) highlighted health risks that exist from exposure to nitrous oxide. More research needs to be undertaken specifically to investigate the true safety of Entonox, in order to educate staff on the risks it poses.
There are alternative labour analgesics to Entonox and while, when questioned, the participating midwives were generally satisfied with these, there is not a directly comparable alternative to Entonox that is as quick, easy and safe to use. This led the midwives to believe that it would be unfavourable to limit the use of Entonox, aligning with a Swedish study that, having sought to mitigate the impacts of nitrous oxide, concluded that a significant reduction in its use was unlikely (Ek and Tjus, 2012). However, it is important to note that there is an identical suggestion for considering other pain relief methods, in conjunction with Entonox, both in the literature (Koyyalamudi et al, 2016) and in the results of the present study's interviews. This combination of analgesics should be given greater consideration in the future, with the ambition of risk mitigation and a decrease in the volume of Entonox required.
Limitations
This was a qualitative service evaluation in one locality. A service evaluation by its nature does not aim to achieve transferability given its application to the locality, and therefore this is not seen as a limitation.
One limitation was the focus on midwives only, with no further consideration of the needs of labouring women and their families or the perceptions of other team members, such as obstetricians and anaesthetists. Accounting for all relevant stakeholders in the system is beneficial (Morris, 2002), as it produces a fuller picture of the issues involved and ways to rectify them in the future. Finally, each interview was conducted during the busy working day for healthcare workers, which may have limited their responses as they did not have an abundance of time (Alamri, 2019).
Recommendations
This research highlights that considering reducing Entonox use must account for the current system's configuration and understand the changes required to make modifications both possible and sustainable. Based on the present study's findings, the authors' recommendations include improving midwives' knowledge of the environmental impact of Entonox and of potential alternatives. If a reduction in Entonox usage is unlikely or impossible, as was inferred by the interviewees' responses, the use of a scavenging mask would improve occupational risks and the addition of a destruction unit would reduce the environmental impact. Therefore, this is a tool that could be used in the UK, to allow the use of Entonox to continue with a less significant environmental effect.
Conclusions
In the current system, facilitators outweigh the barriers for continued Entonox use and the midwives in the present study's locality were satisfied with Entonox as an analgesic in labour. Technology advances should be used to improve its safety profile. If Entonox use is to be decreased or eventually halted in midwifery practice, further work is required to tackle the system factors identified in ways that would allow a system change to more sustainable analgesic solutions in labour.
Key points
- Nitrous oxide is a greenhouse gas widely used as Entonox in childbirth, creating a negative environmental impact.
- Midwives are satisfied with the use of Entonox because of its ease of use and safety for both a labouring woman and her fetus.
- Midwives would find it difficult to implement a reduction in Entonox use without an alternative that is as easy to use.
- Recommendations have been given to decrease the carbon footprint created by labour suites in relation to Entonox, such as catalytic cracking.
CPD reflective questions
- What is your understanding of sustainability in healthcare?
- How can you try to reduce your carbon footprint at work?
- To what extent do you think that Entonox is an effective pain relief for women in labour?
- What do you think about the potential for a reduction in Entonox use, as an outcome for women?
- If possible, how could you implement a reduction in its use, while still giving women the best care?