Anesthetics commonly used in medical, dental and veterinary surgery have global warming potential (GWP) ranging from 130 to 2,540 times greater than carbon dioxide (CO2), but are largely overlooked when greenhouse gas (GHG) emissions are officially tallied. The gases — desflurane, isoflurane and sevoflurane — are not among the 31 listed in Ontario’s GHG emissions reporting regulation. Nor are health care facilities asked to account for anesthetics in the carbon emissions calculations that public sector entities must make as part of their mandated energy conservation and demand management plans.
“The optics aren’t good,” reflects Roger Holliss, director of engineering at St. Mary’s General Hospital in Kitchener, Ontario, and past president of the Ontario chapter of the Canadian Healthcare Engineering Society (CHES). “Emissions related to natural gas, regardless of the size of the hospital, have to be reported, but anesthetic gases are exempted. Others in Ontario who have an obligation to report look at health care and see that it’s granted this exemption.”
A study published in December 2017 in the international medical journal and news digest, The Lancet Planetary Health, highlights the kind of insight that reporting might reveal. Participating hospitals in Vancouver and Minnesota that relied predominantly on desflurane (GWP 2,540) recorded emissions from anesthetics of more than 2,000 tonnes of CO2 equivalent annually. Their counterpart in the United Kingdom, which uses desflurane sparingly due to its higher cost, had anesthetic related emissions of 211 tonnes CO2 equivalent even though it handled a larger volume of surgical cases over the course of the year.
“We have been working on a fact sheet on greening the anesthetic gas system,” advises Linda Varangu, executive director of the Canadian Coalition for Green Health Care. “There is more than one option for facilities to take — reducing the use, substitutions of lower-GWP anesthetics, capture and recycling. It all takes time and education to get the word out.”
Health and safety priorities
Regulators have historically viewed anesthetic from an occupational health and safety perspective. Requirements for air filtration and containment are set out in widely referenced standards such as CAN/CSA Z5359 for anesthetic and respiratory equipment. And that’s with good reason.
“If it (anesthetic gas) was allowed to circulate in the air in the operating room, it would eventually put the surgical team to sleep,” explains Dusanka Filipovic, president and vice chair of Blue-Zone Technologies Ltd., which manufactures and distributes systems for capturing and recovering waste anesthetics. “It causes impairment that would be something like drinking and driving.”
The 2016 update of the CSA standard is the first version to include an informative appendix addressing measures to mitigate emissions to the environment. More illustrative of convention, instructions from the U.S. Occupational Safety & Health Administration advise: “An effective anesthetic gas scavenging system traps waste gases at the site of overflow from the breathing circuit and disposes these gases to the outside atmosphere.”
That, too, could be problematic depending on where the vent to the outdoors is located. The gas is heavier than air and will drop to lower surfaces before it is dispersed. “If there are workers on the rooftop, they could be directly exposed to these gases,” Filipovic warns.
A call for incentives
The Environmental Commissioner of Ontario, Dianne Saxe, has now turned her attention to the practice and is recommending that funds derived from the provincial cap-and-trade system be used to support more sustainable alternatives. “Unfortunately, Ontario has not been collecting any data on the amount of anesthetics used in the province, nor the rate of adoption of gas capture technologies. Perhaps more importantly, it does not provide any economic incentive for health care facilities to embrace these rather practical methods to reduce emissions,” she observed in her annual progress report, released in late January.
Thus far, the Ontario government has channelled funds earmarked for reducing GHG emissions into the Hospital Energy Efficiency Program (HEEP), which, as the name suggests, is solely focused on incentives to promote energy efficiency. Like Commissioner Saxe, CHES Ontario has asked for expanded criteria that would include systems to control and recover high-GWP anesthetic gases, and has received positive feedback from the Ministry of Health and Long-term Care.
“It has been on the radar and it’s actually moved up on the list of things that they talk about rolling into HEEP,” Holliss reports.
A sizable minority of Ontario hospitals, pegged at about 25 per cent, have already installed recovery systems. (Two Canadian companies, Blue-Zone and Class 1 Inc., are the predominant suppliers of the technology.) At Sunnybrook Health Sciences Centre in Toronto, for example, internal estimates attribute approximately 780 tonnes of annual emission reductions to the recapture of anesthetic gas, representing 4 per cent of annual emissions at the vast campus.
“Sunnybrook is a Canadian leader in anesthetic gas capture, having partnered with Blue-Zone for the last 13 years,” says Michael Lithgow, the hospital’s manager of energy and climate change. “It is part of our Earth Matters Program to foster environmental awareness and provide leadership in energy efficiency, pollution prevention and waste management. That all supports our broader mandate to prevent future health risks.”
Sunnybrook is currently a voluntary participant in Ontario’s cap-and-trade market — an option open to entities with annual emissions of 10,000 to 25,000 tonnes of CO2 equivalent — so there is also potential to claim or sell resulting GHG reductions as carbon offsets. In future, this possibility could help more health care operators with the business case for anesthetic gas recovery systems.
“Certainly, that would take the edge off the cost,” Holliss says. “It would also depend on where the hospital stands in the grand scheme of the 10,000-tonne threshold.”
Regardless, the investment could be a proactive strategy ahead of inevitable requirements to control emissions. “The day is coming soon when hospitals in Ontario are going to be asked to do this,” Holliss predicts.
Awareness supports sustainable choices
For smaller scale practitioners like dentists and veterinarians, less capital-intensive strategies will likely be the preferred option — and that aligns with the Canadian Green Health Care Coalition’s philosophy. “Reducing the use or substituting means we would have less to vent, or capture and treat,” Varangu reiterates.
The good news, perhaps, is that the most environmentally damaging anesthetic gas, desflurane, is also the costliest. In comparing the three participating hospitals, The Lancet study notes that “higher surgical case volumes can be done at a fraction of the cost” when isoflurane (GWP 510) or sevoflurane (GWP 130) are substituted.
“Preferential use of alternative anesthetic agents or strategies (e.g. regional techniques, total intravenous anesthesia) has the potential to dramatically reduce theatre greenhouse gas emissions,” it states. “A lack of awareness regarding the environmental impacts of anesthetic choices is believed to be the greatest barrier to widespread implementation of low-carbon practices.”
Accordingly, the Environmental Commissioner has raised the issue with good timing for the professional standards body for Ontario dentists. It is in the process of a regular review of its standard of practice for sedation and general anesthesia.
“Although we have guidelines dealing with anesthesia and guidelines regarding environmental hazards in amalgam waste, we were not previously aware of concerns being raised about the environmental impact of anesthetic gases,” says Kevin Marsh, director of communications with the Royal College of Dental Surgeons of Ontario. “This will be brought to the attention of our working group.”
Barbara Carss is editor-in-chief of Canadian Property Management.