Nitrous oxide (N2O) is an ozone-depleting greenhouse gas that lingers in the atmosphere for over a hundred years. Much of the climate impact of medical N2O 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 N2O piped supply system, substituting it with a portable supply system within the operating room (OR) complex. At the preintervention phase, we gathered N2O 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 N2O’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 N2O systemic consumption (as estimated using monthly procurement data) and a 66% reduction in the number of general anesthesia cases using N2O (as captured by snapshot audits). The project will enable annual carbon savings of 307 tonnes of carbon dioxide equivalents (CO2e) and annual financial savings of CAD 7,620.

This quality improvement project shows that substantial reduction in N2O systemic consumption in an OR complex is possible through changing the N2O 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 N2O, thereby withdrawing N2O altogether. This project can be replicated at other centres to collectively reduce the greenhouse gas effect of N2O in clinical care.