Greenhouse gases: the choice of volatile anesthetic does matter

Abstract

To the Editor, Global warming, considered one of the greatest health threats of the 21st century, is linked to greenhouse gas emissions. The major greenhouse gases-carbon dioxide (CO 2), methane, nitrous oxide, and chlorofluorocarbonshave been well studied and regulated. The contributions from the healthcare industry, however, have been largely ignored or excused under the guise of medical necessity. 1 Nevertheless, a considerable portion of hospital waste is generated in the operating room, and anesthesiologists are in an ideal position to take a leadership role to minimize the hospital-related negative environmental impact. Volatile anesthetic drugs are halogenated fluorocarbons and potent greenhouse gases, as measured by their global warming potential (GWP), which is a relative measure of how much heat a given gas traps in the atmosphere compared with a similar mass of CO 2. Because most volatile agents remain in the atmosphere for one to 15 years, 2 the GWP is often expressed over a 20-year time horizon (GWP 20). This value represents the amount of heat trapped by the gas over a 20-year period, compared with a similar mass of CO 2. For example, the GWP 20 values for desflurane, isoflurane, and sevoflurane are 6810, 1800, and 440, respectively. 2 The carbon dioxide equivalent (CDE 20) is the product of the GWP 20 and the quantity of the gas. Colloquially referred to as the ''carbon footprint,''

The future is now—it’s time to rethink the application of the Global Warming Potential to anesthesia

“…To illustrate the impact of inhalational agents, various authors have calculated driving equivalencies using either GWP 20 or GWP 100 values. 7,[16][17][18] The Table is a calculation of driving equivalencies for one day's use (i.e., seven hours of anesthetic delivery) of inhalational agents used at 1 MAC (though with N 2 O at 66%) and variable FGF; GWP 1 was used for the calculations. Desflurane used at 2 LÁmin -1 FGF for seven hours has the same impact as driving a car from the northernmost point of continental Europe accessible by car (North Cape, Norway) to the southernmost city in Africa (Cape Town, South Africa)a 211-hr drive (according to Google Maps).…”

Volatiles or TIVA: Which is the standard of care for pediatric airway procedures? A pro‐con discussion

“…For pregnant operating room staff, there is a higher risk of spontaneous abortion when exposed to WAG, especially nitrous oxide . WAG can be reduced with closed circle systems and low flow anesthesia, but TIVA provides an optimal solution.…”

“…The effect of sevoflurane on the environment will remain until degradation occurs, which can take up to 15 years. The effects of nitrous oxide are much longer, at 114 years . It is clear that anesthetists need to be part of “Greening the Operating Room.”…”

Re-defining the 3R’s (reduce, refine, and replace) of sustainability to minimize the environmental impact of inhalational anesthetic agents

“…A report from Vancouver showed how education within the department led to a substantial shift away from desflurane to sevoflurane, which over a fiveyear period led to a 66% reduction in GHG emissions. 15 Replacement of inhaled anesthetics with other alternative modes of anesthesia should be actively considered when feasible. Regional anesthesia is an elegant modality to reduce or to avoid general anesthesia and can potentially play an important role in the ''greening'' of anesthesia.…”