8 minute read
Nitrous Oxide: Friend or Foe
from CHF Winter 2022
by MediaEdge
Why this medical gas is a growing climate concern
By Jannik Jensen & Alan Pinkerton
While there are benefits of using nitrous oxide for patients and the healthcare system, the environmental impact is significant.
Nitrous oxide is an analgesic gas used for pain management within maternity, dentistry, emergency, orthopedics, endoscopy, pediatrics, operating rooms and radiology.
The properties of nitrous oxide as a gas make it almost the ideal pharmaceutical. While there are alternative methods of administering pharmaceuticals, such as tablets and intravenous injection, they can take longer to work properly or administer. Nitrous oxide, on the other hand, provides almost immediate pain relief and relaxation when mixed with oxygen and inhaled though a mask or mouthpiece. What’s more, when a patient stops inhaling the gas mixture, the effect wears off quickly leading to a very fast recovery. This is ideal in a busy hospital setting where staff can reduce necessary observation time and move on to the next patient. The gas mixture is also self-administered, delivering benefits like greater control for the patient over their pain relief.
However, the environmental impact of using nitrous oxide means its use in hospitals needs to evolve.
Healthcare is responsible for 4.6 per cent of Canada’s total greenhouse gas emissions, as reported in the Canadian Medical Association Journal, in addition to more than 200,000 tonnes of other pollutants, resulting in 23,000 lives lost annually from disability or early death.
Other sources place Canada among the top 10 worst polluters per capita and in the middle of the pack of Organisation for Economic Co-operation and Development nations in terms of the percentage of emissions from healthcare. And while the United Kingdom has cut health sector emissions by nearly one-fifth since 2007, Canada’s healthcare emissions are increasing.
A small number of medicines account for a large portion of these emissions. There is
significant focus on two such groups — anaesthetic gases and inhalers. Nitrous oxide is one of the most harmful gases in the anaesthetic group.
Nitrous oxide is the third most important greenhouse gas. It is emitted into the atmosphere from both natural sources (approximately 57 per cent) and anthropogenic sources (approximately 43 per cent), including oceans, soils, biomass burning, fertilizer use and various industrial processes. The increase in emissions from 2020 to 2021 was slightly higher than that observed from 2019 to 2020, and higher than the average annual growth rate over the past 10 years, according to the World Meteorological Organization.
This environmental impact came to the attention of politicians and healthcare professionals in Sweden 16 years ago. As a result, they began to capture and destroy nitrous oxide used in healthcare. Hospitals in Sweden use a central destruction unit to destroy nitrous oxide from many different rooms at the same time like those on a ward. Meanwhile, mobile destruction units are used to handle single rooms.
If this technology was applied across the U.K.’s entire health system, it could deliver up to a 75 per cent reduction in nitrous emissions, says the National Health Service. Similar results could be achieved across Canada. In Ontario alone, nitrous oxide use as anaesthesia was responsible for approximately 80,000 tonnes of carbon dioxide in 2015, according to the province’s environmental commissioner.
TOP OZONE-DEPLETING EMISSION
Trapping heat in the atmosphere, known as the greenhouse effect, is a natural and necessary process that enables life on earth. However, in the last century, human activity has rapidly increased the release of greenhouse gases, resulting in an excessive greenhouse effect.
Some gases are extra potent and trap more heat than others; nitrous oxide is one of these. In fact, one kilogram of nitrous oxide is equal to 298 kilograms of carbon dioxide and will remain in the atmosphere for 114 years. Due to this extremely long atmospheric lifetime and high consumption volumes, nitrous oxide has become a major contributor to global warming.
A comparison to the emission of carbon dioxide during a single car trip illustrates the environmental impact of nitrous oxide. The use of nitrous oxide for one hour at one litre per minute has the carbon dioxide equivalency of driving a car for 95 kilometres. Given one litre per minute is almost irrelevant as a clinical dosage — a maternity department, for example, will deliver much higher volumes at normal use — the scale of the issue becomes even more apparent.
The connection between healthcare systems and climate change was reported in The Lancet in 2018. The study concluded climate change is expected to influence the environment, leading to increases in conditions like cardiovascular and pulmonary disease, undernutrition, diarrhea and vector-borne disease. The social consequences from this scenario would be the loss of habitation, mass migration and poverty, which could also result in violent conflicts.
N2O PACKS A PUNCH
In most countries, nitrous oxide programs have exposure limits for healthcare professionals. Known as threshold limits, they describe how much exhaled gas staff are allowed to be exposed to. These also apply in Canada, meaning that alongside a high room air exchange rate, inhaled and exhaled gas from patients should be controlled in a closed system. To that end, exhaled gas should be captured by an exhalation hose and moved away from where it may affect staff. This process of collection and removal is called scavenging.
Although the effects of exposure to nitrous oxide are still uncertain and the literature is inconclusive, they include headache, dizziness and loss of concentration. These possible effects are not in the best interests of the healthcare professional or patient who expects total focus on the procedure.
t The central destruction unit also accommodates multiple treatment room setups, offering caregivers an optimal method of reducing work environment risks and greenhouse gas emissions. The unit also combines minimal energy consumption with ease of use and operates at an efficiency level above 99 per cent.
SCANDINAVIA KNOW-HOW
In Scandinavia, the use of closed systems for delivering nitrous oxide gas mixes to patients, and capturing and destroying the gas locally, as well as threshold limits for staff exposure are governed by national guidelines. Hospitals have technicians and work environment specialists that make sure guidelines are correct and followed. Medical equipment is used for inhalation and exhalation and captured via pipeline systems, which are designed by hospital gas system contractors. The exhaled gas from patients goes to a medical gas terminal unit in the treatment room. From there, a gas evacuation pipeline transports it to a mechanical services room. Each hospital has a central destruction unit in place, as there are many rooms that support the nitrous oxide program.
In the same hospital, there may be a pediatric and an emergency department supporting patients with nitrous oxide. In this case, there is no gas evacuating pipeline. The amount of nitrous oxide used is small by both volume and frequency, so this hospital would use the mobile destruction unit.
In Sweden, all hospitals with a nitrous oxide program are aware of the solutions for capturing and destroying the gas. Given even a small volume of nitrous oxide leads to a very high carbon dioxide emission value, failure to install the solution would result in a heavy local carbon dioxide footprint. For example, Copenhagen’s largest
As the demand for constant sanitation of high traffic environments continues to rise, so does the need for efficiency and effectiveness in killing bacteria on surfaces.
DEFENSETM
T E C H N O L O G Y
KILLS BACTERIA
Laboratory testing has shown that when cleaned regularly this surface:
• Reduces bacteria contamination, achieving 99.9% reduction within 2 hours of exposure. • Delivers continuous and ongoing antibacterial action. • Helps inhibit the buildup and growth of bacteria within 2 hours of exposure between routine cleaning and sanitizing steps.
For more information on Copper DefenseTM technology deltafaucet.ca/copper-defense
public and teaching hospital, Rigshospitalet, calculated that nitrous oxide use for its maternity department in 2018 was 4,514 kilograms. Determining the carbon dioxide equivalency by multiplying by 298 means the department alone emitted the equivalent of 1,345,172 tonnes of carbon dioxide.
The environmental case is compelling. By installing a central destruction unit connected to the gas evacuation system, 99 per cent of these carbon dioxide emissions are removed from the hospital’s nitrous oxide program. Compared to other possible carbon dioxide emissions solutions, this technology requires a relatively small investment to deliver a beneficial impact on the hospital’s total carbon footprint.
CSA Z7396.1, Medical Gas Pipeline Systems, recommends that every healthcare facility conduct a review of the use, benefit, cost and environmental impact of piped nitrous oxide to determine whether a pipeline is appropriate and, if deemed necessary, whether measures can be taken to reduce the permeation of nitrous oxide into the atmosphere. For example, pipeline valves could be closed except during periods of use.
As Canada continues its pursuit of a zero-emissions healthcare system, the lessons from Scandinavia will prove invaluable.
