Presentation (CTI)

OBJECTIVES: This study aims to recontextualize climate impact calculations for Inhaled Anaesthetic Gases to reflect the expected realistic impact on the environment based on known Radiative Efficiencies and derived atmospheric concentration.
METHODS: The model is an Excel-based assessment of widely used gases in Inhaled Anesthesia across two scenarios; comparing the impacts of Isoflurane, Sevoflurane, Desflurane, and Nitrous Oxide respectively, during a typical hour of maintenance Anaesthesia. We account for variations in practice in vaporizer settings (Volume Concentration %) and Fresh Gas Flow (L/ min). We compare the following scenarios. 1) Outcomes derived from a clinical theoretical publication plus inputs from widely cited literature. 2) Outcomes derived from expert opinion, the latest observable data reported by the Intergovernmental Panel on Climate Change, and published literature.
RESULTS: Considering outcomes, in scenario 1, a typical hour in Maintenance Anaesthesia is calculated to yield the following Radiative Forcing; Isoflurane (515.62x10^-12 W m -2), Sevoflurane (320.25x10^-12 W m -2), Desflurane (202.76x10^-12 W m -2), and Nitrous Oxide (0.11x10^-12 W m -2). Under inputs from expert opinion and the latest data in scenario 2, we calculated the following yields per hour; Isoflurane (522.95x10^-12 W m -2), Sevoflurane (441.59x10^-12 W m -2), Desflurane (878.99x10^-12 W m -2), and Nitrous Oxide (0.19x10^-12 W m -2). In comparison with Carbon Dioxide, Inhaled Anaesthetics provide incrementally insignificant contributions to Climate Change; notably, impacts such as +/-0.20 W m -2 remain insignificant. Only Nitrous Oxide remains a realistic concern due to its Atmospheric Lifetime.
CONCLUSIONS: We present a novel method that can aid Hospital Administrators, Physicians, and policy makers refocus needed efforts to mitigate their climate impact by appraising the actual impact, in real terms, of Inhaled Anaesthetics. Moving discourse towards realistic impacts, centers discussions on the best / safest combination of drugs for the patient, returning decision-making to the physician.