Law Rachel G, Koh Wen Jun, Poh Pei Kee, Htet Nay Myo, Ng Su Wei Bryan, Liu Eugene Hern Choon, Ang King Sin
Department of Anaesthesia, National University Hospital, 5 Lower Kent Ridge Rd., Singapore, 119074, Singapore.
Department of Anaesthesia, National University Hospital, Singapore, Singapore.
Can J Anaesth. 2025 Jun 30. doi: 10.1007/s12630-025-03003-4.
Nitrous oxide (NO) is an ozone-depleting greenhouse gas that lingers in the atmosphere for over a hundred years. Much of the climate impact of medical NO is due to systemic central pipeline losses even before it reaches the patients. Health care systems around the world are changing the way it is supplied to decrease wastage to a minimum.
We conducted a quality improvement project at National University Hospital Singapore with the aim to deactivate the central NO piped supply system, substituting it with a portable supply system within the operating room (OR) complex. At the preintervention phase, we gathered NO monthly procurement data and evaluated our system and clinical practices. Following this, we carried out three sequential Plan-Do-Study-Act cycles: the first to raise awareness and understanding of NO's significant leaks and climate impact, the second to disconnect central piped supply from the anesthesia machines, and the third to fully cease the central piped supply system and transition to using portable cylinder supply in ORs.
We achieved a 96% reduction in NO systemic consumption (as estimated using monthly procurement data) and a 66% reduction in the number of general anesthesia cases using NO (as captured by snapshot audits). The project will enable annual carbon savings of 307 tonnes of carbon dioxide equivalents (COe) and annual financial savings of CAD 7,620.
This quality improvement project shows that substantial reduction in NO systemic consumption in an OR complex is possible through changing the NO supply from a central piped supply system to small cylinders directly mounted on anesthesia machines. Next steps would include shifting institutional clinical practice towards using alternatives to NO, thereby withdrawing NO altogether. This project can be replicated at other centres to collectively reduce the greenhouse gas effect of NO in clinical care.
一氧化二氮（N₂O）是一种消耗臭氧层的温室气体，会在大气中留存一百多年。医用N₂O对气候的影响，很大一部分是由于其在到达患者之前，通过中央管道系统造成的系统性损耗。世界各地的医疗系统正在改变其供应方式，以将浪费降至最低。
我们在新加坡国立大学医院开展了一项质量改进项目，旨在停用中央管道供应的N₂O系统，在手术室（OR）综合区域内用便携式供应系统取而代之。在干预前阶段，我们收集了N₂O的月度采购数据，并评估了我们的系统和临床实践。在此之后，我们进行了三个连续的计划 - 执行 - 研究 - 行动循环：第一个循环是提高对N₂O大量泄漏及其气候影响的认识和理解；第二个循环是将中央管道供应与麻醉机断开连接；第三个循环是完全停止中央管道供应系统，并在手术室过渡到使用便携式气瓶供应。
我们实现了N₂O系统消耗量降低96%（根据月度采购数据估算），以及使用N₂O的全身麻醉病例数减少66%（通过快照审核获取）。该项目每年将节省307吨二氧化碳当量（CO₂e）的碳排放量，并节省7620加元的年度财务支出。
这项质量改进项目表明，通过将N₂O的供应从中央管道供应系统改为直接安装在麻醉机上的小气瓶，可以在手术室综合区域大幅减少N₂O的系统消耗量。下一步将包括促使机构临床实践转向使用N₂O的替代品，从而完全停用N₂O。该项目可以在其他中心复制，以共同减少临床护理中N₂O的温室气体效应。
