Research published in anesthesia Nitrous oxide (N₂O), widely used to manage pain during labour.

This study was conducted by a multidisciplinary team of anesthesiologists and midwives from St John’s Hospital, Livingstone, UK and the University of Manchester NHS Foundation Trust, Manchester, UK. The lead author of the study is Dr. Annie Pinder, Fellow in Sustainable Health Care, North West School of Anaesthesia, Manchester, UK. The study was supervised by Dr. Cliff Shelton, Consultant Anesthesiologist at Wythenshawe Hospital and Lancaster University, UK.

All inhalation anesthetic gases commonly used today are greenhouse gases. Equivalent mass of carbon dioxide (CO₂), nitrous oxide has 265 times the global warming potential. Nitrous oxide, the ‘gas and air’ analgesic ingredient, is the most frequently used labor pain reliever in the UK and is available in all birthing settings. Reducing interventions may significantly reduce the environmental impact of this drug.

One way that nitrous oxide’s carbon footprint can be reduced is by using a catalyst to break down (“crack”) the exhaled gas into nitrogen and oxygen. Previous research has established the efficiency of this process, but for it to be really effective, it needs to “capture” as much of the exhaled nitrous oxide as possible so that it can be broken down. It relies on the patient being able to exhale consistently into the mask or mouthpiece.

In this quality improvement project, based on environmental monitoring and staff feedback, the authors evaluated the impact of nitrous oxide cracking technology in the obstetric environment. Nitrous oxide levels were recorded during her last 30 min of 36 simple deliveries. In the first 12 cases, measurements were obtained without the use of technology to establish baselines. The research team then introduced the cracking device and took a stepwise approach to optimize its clinical use. This included using two types of face masks after using the mouthpiece and providing usage tips and feedback to the patient.

As a result, median ambient nitrous oxide levels were 71% lower than baseline with mouthpieces, compared with low-profile facemasks (lightweight facemasks with flexible seals) and optimal usage. 81% lower when combined with coaching.

The authors concluded, “Given that similar reductions in nitrous oxide levels were seen with mouthpieces and discreet face masks, we offer pregnant women the option of either device when using cracking. We suggest that the use of the device is very important given the high degree of cooperation required for the education of pregnant women and their choice. [for the successful use of the technology], and this is consistent with guidelines for selection and individualized care in obstetric services. Future research to better characterize the optimal use of this technology could focus on investigating other types of delivery devices, and examining optimal timing and methods of education. “

The authors say they tried to avoid inflicting “climate guilt” on pregnant women during labor. For example, by making it clear that nitrous oxide-related greenhouse gas emissions are the responsibility of healthcare providers, not patients.

“While feedback from staff was generally positive, some found the technology to be unwieldy. Successful implementation relies on effective staff engagement. It reduces ambient nitrous oxide levels in the obstetric environment, indicating that it has the potential to reduce environmental impacts and occupational exposures.”

Provided by AAGBI