The path to climate-neutral anesthesia

Last updated on June 06, 2024 First published on April 03, 2024

They are used to induce unconsciousness, muscle relaxation and insensitivity to pain. At the same time, anesthetic gases are highly potent greenhouse gases. The USZ is committed to a further reduction.

Many people have to undergo surgery in the course of their lives. Modern medicine uses various forms of anesthesia to ensure that people do not feel any pain during the operation. Depending on the type of procedure, the anesthesiologist will suggest regional anesthesia, general anesthesia or analgosedation in order to guide the patient through the surgical procedure without pain. Anesthetic gases are substances that were used at the USZ until a few years ago to produce anesthesia (Greek anaisthesis, “numbness”) during surgical procedures. These gases, also known as inhalation anesthetics, lead to a reversible loss of consciousness in the patient. They work by influencing the central nervous system and inhibiting the transmission of nerve impulses. These include those associated with pain sensations.

“We not only select the best possible anesthesia procedure for our patients, but also always think about the environment.”

Corinna von Deschwanden, Head Physician at the Institute of Anesthesiology

Another advantage is the good controllability of the anesthesia: the patient only remains under general anesthesia for the necessary duration and regains consciousness shortly after the end of the operation. In recent years, however, inhaled anesthetics such as desflurane, sevoflurane, isoflurane or nitrous oxide have been increasingly called into question, particularly in the case of general anesthesia.

15,000 kilometers in seven hours

Inhaled anesthetic gases have a non-negligible disadvantage: desflurane, isoflurane and sevoflurane are strong greenhouse gases and therefore extremely harmful to the environment. Desflurane, for example, is 2540 times, isoflurane 510 times and sevoflurane even 130 times more climate-active than CO². A more concrete comparison: the environmental impact caused by a seven-hour anesthesia with desflurane is roughly equivalent to a 15,000-kilometer drive in a gasoline-powered car.

Hospitals cause greenhouse gas emissions in various areas. The entire healthcare sector accounts for around seven percent of national CO² emissions. In addition to anesthetic gases, medicines and disposable instruments, cooking meals for thousands of people, for example, also produces greenhouse gases. A few years ago, the Department of Medical Technology and Anesthesiology at the USZ set itself the goal of reducing the institute’s ecological footprint. Because the problem of the climatic activity of inhaled anaesthetic gases has been recognized for some time, particular attention has been paid to their use.

Patient at the center

Approximately 30,000 anesthesias are performed at the USZ every year. A variety of different procedures are offered and different anesthetics are used. In addition to safety and the best possible medical care for the patient, the sustainability of the various anesthesia procedures is of great importance in the choice of procedure. There is no “one size fits all” concept in anesthesia at the USZ: the procedure is discussed and coordinated individually with each patient.

More about anesthesia procedures

Implementation even before the directive

Targeted measures were taken on the initiative of the Institute. In addition to desflurane, the most climate-damaging anesthetic gas, the second most harmful, isoflurane, was also banned from the operating theaters at the USZ before 2022. Since the beginning of 2022, there has been a directive in place in anesthesiology that limits the use of climate-damaging anesthetic gases. For example, only sevoflurane is currently used in anesthesia at the USZ. Nitrous oxide, which also has a climate and ozone-damaging effect, has not been administered for over twenty years and is now only used in obstetrics clinics – but even there it is becoming increasingly rare.

Propofol as an alternative

For most operations, intravenous anesthetics such as propofol can be used instead of anesthetic gases. “At the USZ, we made total intravenous anesthesia the standard anesthesia. However, there are certain clearly defined medical indications for which inhaled anesthesia with sevoflurane is still necessary and sensible,” says Corinna von Deschwanden, Head Physician and Sustainability Officer at the Institute of Anesthesiology. Many seriously ill patients are treated at the USZ, which is why anesthesia with Propofol cannot be administered in every case – for example after a long stay in the intensive care unit and long-term sedation with Propofol.

The order for anesthesia with sevoflurane is issued by the responsible senior physician on the basis of the instructions. Since their introduction, consumption of the only remaining anesthetic gas sevoflurane has already been halved by 2022. At the Institute of Anesthesiology, many employees are constantly working towards greater sustainability in anesthesiology.

The reduction or elimination of inhaled anaesthetics is one of several projects: “We are in a process that is far from complete. Completely climate-neutral anesthesia is difficult to achieve,” says Corinna von Deschwanden. The switch to Propofol as the standard anesthetic also requires adjustments to the work processes. For example, the wake-up phase for these patients takes many times longer than with inhaled anesthetic gases. As a result, they need medical care for longer. Decisions relating to sustainability are always multidimensional and usually complex.

More is always possible

Until now, the gases have been removed using the so-called anesthetic gas transport system. It is a copper pipe system that extracts the inhaled anesthetic gases using a hose and discharges them via the roof or façade. In addition to greatly reducing its use, the USZ is also keen to recycle the remaining quantity of inhaled anesthetics and thus further reduce its ecological footprint. “Carbon-based filters are one way of binding these gases and thus recycling them,” says Fabio Tonina. To this end, a market analysis was carried out in which various products were compared. “In the next step, we want to carry out tests,” says the Technical Project Manager for Medical Gas Supply, looking to the future.

Responsible specialist

Corinna Von Deschwanden, MBA, Dr. med.

Senior Attending Physician, Institute of Anesthesiology

Tel. +41 43 253 82 33
Specialties: Transplant anesthesia, Anesthesia in thoracic and visceral surgery

Responsible Department