Minimizing sevoflurane wastage by sensible use of automated gas control technology in the flow-i workstation: an economic and ecological assessment

The effects of end-tidal controlled low-flow anesthesia on anesthetic agent consumption in elective surgeries: randomized controlled trial

PURPOSE

The environmental impact and cost of volatile anesthetics are significant concerns in modern anesthesia. Automated end-tidal control systems aim to optimize anesthetic delivery by reducing waste and improving efficiency. This study compared the effectiveness of end-tidal controlled (EtControl) low-flow anesthesia to manually controlled (MC) low-flow anesthesia in elective surgeries.

DESIGN

A randomized controlled trial.

METHODS

This study was conducted with 132 ASA Class I-II patients undergoing elective surgeries under general anesthesia. Patients were randomly assigned to the EtControl (n = 66) or MC (n = 66) groups. The primary outcomes included anesthetic agent consumption (mL).

FINDINGS

Anesthetic consumption was similar between the EtControl group (17.9 ± 2.63 mL) and the MC group (18.45 ± 2.44 mL) (p = 0.07). The rate of anesthetic consumption per minute was also comparable (0.120 mL/min vs. 0.127 mL/min; p = 0.514).

CONCLUSIONS

EtControl and MC methods provide comparable safety and sevoflurane consumption during low-flow anesthesia. However, EtControl reduces manual adjustments, enhancing workflow efficiency and cost-effectiveness, with potential implications for reducing environmental impact.

The carbon footprint of general anaesthesia in adult patients: a multicentre observational comparison of intravenous and inhalation anaesthetic strategies in 35,242 procedures

BACKGROUND

General anaesthesia is a significant contributor to healthcare-related greenhouse gas (GHG) emissions. Previous studies have compared non-optimised anaesthesia strategies (desflurane, nitrous oxide, or both) to evaluate the impact of green initiatives on reducing the carbon footprint of anaesthesia. However, modern halogenated anaesthesia techniques, including low fresh gas flow and target-controlled inhalation anaesthesia (TCIA), offer potentially more environmentally friendly alternatives. Thus, we aimed to compare the GHG emissions of total intravenous anaesthesia (TIVA) with these newer techniques.

METHODS

This multicentre study compared GHG emissions per hour of general anaesthesia in adult surgical patients between three anaesthetic strategies: TIVA with propofol, sevoflurane in TCIA mode, and manually optimised sevoflurane. The study was conducted in three French university hospitals, each using one anaesthesia strategy. The quantity of anaesthetic drugs used was obtained from pharmacy procurement records and converted to carbon dioxide equivalents (CO2e). The primary outcome was the total GHG emissions per hour of anaesthesia for each strategy, including sevoflurane, propofol, and syringe consumption.

RESULTS

TCIA, manually optimised sevoflurane, and TIVA strategies were used in 7873, 15 461, and 10 717 anaesthetics, respectively. The carbon footprint of the principal anaesthetic drugs per hour of anaesthesia was significantly lower in the TIVA strategy, at 0.4 kg CO2e per hour, compared with 3.1 kg CO2e per hour in the TCIA strategy and 3.8 kg CO2e per hour in the manually optimised sevoflurane strategy.

CONCLUSIONS

TIVA with propofol was the most effective approach for minimising greenhouse gas emissions in anaesthesia practices. However, if TIVA were used exclusively globally, it could lead to issues such as stock depletion, plastic pollution, and water contamination.

Greenhouse gas impact from medical emissions of halogenated anaesthetic agents: a sales-based estimate

BACKGROUND

Halogenated anaesthetic agents are potent greenhouse gases, but little is known about the trajectory of their use and their greenhouse gas impact on a global level. The primary aim of this study was to estimate the global greenhouse gas impact of halogenated anaesthetic agents over the preceding 10 years.

METHODS

We obtained global medical sales data for sevoflurane, desflurane, isoflurane, halothane, and methoxyflurane from the IQVIA MIDAS database between 2014 and 2023. We calculated their annual greenhouse gas impact, expressed as carbon dioxide equivalents (CO2e), using global warming potential factors for a 100-year period. The effect of using only sevoflurane, the clinically relevant alternative with the lowest impact, was estimated by calculating the volume of sevoflurane that was needed to replace the other agents for a standard anaesthesia using a simulation software (Gas Man).

FINDINGS

The 91 countries in the dataset represented 97·8%, 90·5%, and 66·2% of the population in high-income, upper-middle-income, and low-income or lower-middle-income countries, respectively, and covered 80·0% of the global population in 2023. The greenhouse gas impact of halogenated anaesthetic agents decreased by 27% from 2754 kilotons of CO2e (ktonCO2e) in 2014 to 2005 ktonCO2e in 2023. During the study period, the greenhouse gas impact from desflurane in high-income countries decreased by 52% from 2180 to 1053 ktonCO2e, increased in upper-middle-income countries by 151% from 125 to 313 ktonCO2e, and increased in low-income and lower-middle-income countries by 2281% from 2 to 42 ktonCO2e. By replacing desflurane, isoflurane, and halothane with sevoflurane, the global impact from halogenated anaesthetic agents in 2023 could theoretically have been decreased by 73%.

INTERPRETATION

The global greenhouse gas impact from halogenated anaesthetic agents is falling due to lower use of desflurane in high-income countries. Efforts to reverse the increased use of desflurane in middle-income countries are needed. Replacing desflurane and isoflurane with sevoflurane constitutes an opportunity to markedly reduce the greenhouse gas impact from halogenated anaesthetic agents.

FUNDING

The Thelma Zoega Foundation, The Anna and Edwin Berger Foundation, Region Skåne, and a Swedish Government grant for clinical research within the Swedish National Health Service (ALF).

Sevoflurane consumption pattern by individual anaesthesiologists varies widely despite using the same high-end workstations in the same hospital

Volatile anaesthetics are potent greenhouse gasses but contemporary workstations enable considerable savings while improving patient safety. Institutions may provide this technology to reduce the ecological footprint but proper training and motivation is required to maximize their ecologic and financial benefit. This study aims to compare the sevoflurane consumption of 22 anaesthesiologists in a medium sized hospital 4 years after flow-i workstations (Getinge, Sweden) entered into service, in three airway approaches: intubated patients, laryngeal mask ventilation, and mask anaesthesia. Typical sevoflurane consumption for each anaesthesiologist was defined as the mean cumulative consumption in the chronologically first 50 cases meeting the inclusion criteria for each airway group in 2019. The potential savings, if everyone were to adopt the approach of the more economical anaesthesiologists (15th percentile), was calculated. The CO₂ equivalent emissions were calculated using a GWP₂₀ of 702 and a GWP₁₀₀ of 195. The median [range] consumption after 45 min was 10.9 [7.5-18.4] ml in intubated patients and 9.0 [7.4-15.3] ml in patients with laryngeal mask, and 9.9 [3.4-20.9] ml after 8 min with mask ventilation. This corresponds to a double to six fold consumption between the least and most wasteful approach. The typical CO₂ equivalent emissions (GWP₂₀) per anaesthesiologist varied between 8.0 and 19.6 kg/45 min in intubated airways, between 7.9 and 16.3 kg/45 min in LMA, and between 3.6 and 22.3 kg/8 min in mask ventilation. Despite using the same workstations in the same hospital, the typical sevoflurane consumption differed dramatically between 22 anaesthesiologists. In addition to providing advanced workstations, proper education is required to achieve the behavior change needed to reduce the pollution and financial waste associated with volatile anaesthetics.