New York, NY -UNS: NYC Health + Hospitals has announced findings from a study published in Anesthesia & Analgesia, demonstrating that deactivating centralized nitrous oxide pipelines significantly reduced anesthetic gas emissions across its 11 acute care hospitals.
The observational study examined 148,762 surgical cases involving general anesthesia between April 2022 and December 2025.
Researchers found that 94.6% of Bellevue Hospital’s nitrous oxide pipeline supply leaked before reaching patients between April 2022 and March 2023. These losses generated approximately 2,136 metric tons of carbon dioxide equivalent (CO₂e), exceeding the annual climate impact of anesthetic gases administered to patients across the entire health system.
Nitrous oxide, commonly known as laughing gas, is a powerful greenhouse gas that remains in the atmosphere for more than a century. Hospital pipeline systems are particularly vulnerable to leakage, resulting in significant environmental impacts and financial waste.
Between June and December 2024, Bellevue, Elmhurst, Jacobi, and North Central Bronx hospitals deactivated their central nitrous oxide pipelines, eliminating associated leakage. Following these changes, the proportion of surgical cases using nitrous oxide at these hospitals decreased from 26.9% to 0.9%. Across all 11 hospitals, emissions from anesthetic gases administered to patients declined by 51%.
Bellevue Hospital had spent $56,200 on bulk nitrous oxide during the baseline year, with only 5.4% reaching patients. The wasted gas produced emissions equivalent to those of approximately 460 passenger cars annually.
Study investigators emphasized that reducing unnecessary anesthetic gas use and preventing leakage can support environmentally sustainable healthcare without compromising patient safety.
The initiative also highlighted the importance of collaboration among anesthesiologists, engineering teams, facilities management, and hospital leadership.
The findings demonstrate how data-driven operational improvements can reduce greenhouse gas emissions, minimize resource waste, and advance sustainability goals across healthcare systems.
