Sustainable Anesthesia: State of Knowledge and Practices of Moroccan Anesthesiologists

  

    
Gas 
    
Correct    Response (%) 
  
  

    
Nitrous    oxide 
    
19.8
  
  

    
Desflurane 
    
5
  
  

    
Sevoflurane 
    
8.8
  

Table 5: Knowledge of Atmospheric Lifetimes of Anesthetic Gases.

Change in Practices

Finally, when asked whether they would change their anesthetic gas usage habits based solely on ecological arguments, 76.6% responded positively, indicating a significant openness among Moroccan anesthetists to adopt eco-friendly practices.

These results emphasize the need for ongoing education regarding environmental impacts and sustainable practices within the anesthesia field and underscore the importance of fostering a culture of sustainability among professionals.

Discussion

Surgery performed under general anesthesia produces greenhouse gases, particularly halogenated gases, which have the capacity to absorb and re-emit infrared radiation in the Earth's atmosphere [6,7]. These gases have a much greater Global Warming Potential (GWP) than carbon dioxide (CO2), the most significant anthropogenic greenhouse gas. For instance, desflurane has a GWP of 2540, making it 2500 times more potent than CO2, with a long atmospheric lifetime of 114 years, compared to 14 years for desflurane and 1.1 years for sevoflurane [8]. Therefore, it is recommended to reduce fresh gas flow rates and utilize source capture devices to mitigate anesthesia gas emissions into the atmosphere.

The anesthetic gases employed in the medical field significantly impact the environment. A study conducted by Jane Muret et al. in 2020 [9] indicated that one hour of anesthesia with a fresh gas flow of 1 liter and 30% oxygen concentration equates to driving 10 km in a car with sevoflurane (2.5%) or 376 km with desflurane (5%). When the mixture contains 30% nitrous oxide (N2O), this impact can rise to 77 km for sevoflurane and 443 km for desflurane. Over an 8 hour operating room day, the use of these gases could lead to a journey across France with sevoflurane (from Oujda to Agadir) or even to Moscow with desflurane (from Bouarfa to Lagouira). The environmental impact can be easily calculated based on halogenated gas consumption in an anesthesia department: thus, using a 240 ml desflurane bottle emits 886 kg CO2 equivalents, while a 250 ml sevoflurane bottle emits 44 kg CO2 equivalents [10].

The biodegradation and biotransformation of nitrous oxide are very slow, with its atmospheric half-life estimated at between 100 and 150 years. N2O has an Ozone Depletion Potential (ODP) of 0.016, indicating that it depletes the ozone layer that protects us from ultraviolet radiation from the sun and contributes to the greenhouse effect in conjunction with CO2 [11]. Although it accounts for only 1% to 3% of global N2O emissions [12,13], its use in anesthesia is considered significant as it increases the environmental impact of other anesthetic gases used in conjunction. Indeed, using N2O as a carrier gas Indeed, the use of N2O as a carrier gas increases the CDE20 and CDE100 (CO2 equivalent over 20 and 100 years) values of sevoflurane and isoflurane by 6 and 3 times, respectively. However, eliminating N2O from anesthetic mixtures, combined with reducing fresh gas flow, can reduce greenhouse gas emissions by up to 20 times at 1 MAC per hour [14,15].

Reducing or eliminating nitrous oxide can be achieved through several actions. Firstly, constructing new "N2O-free" operating rooms and technical platforms can completely eliminate the gas. Secondly, removing N2O systems and shutting down existing installations can also reduce exposure to the gas. If the use of N2O must continue, greenhouse gas emissions can be minimized by utilizing very low fresh gas flow rates, either manually or through applications that allow for carbon cost calculation, or by using ventilators that permit target concentration inhalation anesthesia. Additionally, to compensate for the loss of N2O's antihyperalgesic effects, alternatives such as medications (ketamine, regional anesthesia) and nonpharmacological methods (hypnosis) can be considered [16,17]. It is recommended to limit the use of equimolar O2/N2O mixtures outside of technical platforms and to adhere to usage guidelines for painful procedures [18], particularly in emergency departments.

Although the hospital use of nitrous oxide is currently decreasing, its atmospheric emissions remain high, raising questions about its use relative to its benefits [19], and its elimination should be considered. In this regard, the authors Mehdi Hafiani et al. [20] proposed practical actions to organize the definitive cessation of nitrous oxide use and the removal of the N2O circuit. The actions to cease N2O use in hospitals occur in ten steps. First, assess the practices regarding N2O use in the relevant hospital center to raise awareness and mobilize the anesthesia team around sustainable development initiatives. Next, evaluate N2O consumption over a reference period and identify user units in the N2O network. The fluid committee should hold an initial meeting to officially terminate N2O use and establish an action plan leading to the removal of N2O systems and the shutting down of N2O circuits. It is essential to reprogram the hospital's anesthesia ventilators to no longer be dependent on N2O and disconnect all anesthetic ventilators from N2O outlets. A 10-to-15-day trial period with N2O valves shut off should follow, along with monitoring and notifying of any alarms related to this shutdown. The removal of N2O systems must be conducted, followed by sealing and closing the circuit and decommissioning N2O outlets. Finally, it is necessary to evaluate the reduction in greenhouse gas emissions linked to the cessation of N2O use.

Anesthetic gases are released into the atmosphere as patients metabolize only a small fraction of these gases during the procedure, and they are evacuated via the SEGA outlet. To reduce their environmental impact, several actions can be undertaken, including selecting the least polluting gas, reducing or eliminating N2O use, working with the lowest possible fresh gas flow rates, optimizing the delivered fraction of halogenated agents by monitoring anesthesia depth, using concentration-targeted inhalation anesthesia modes, and calculating daily consumption via smartphone applications. Additionally, it is crucial to ensure preventive maintenance of anesthesia systems, adapt localized capture devices, control general ventilation, and provide gas evacuation systems during work facility design. Finally, training and informing staff and ensuring appropriate medical monitoring of pollution levels is essential [19,21,22].

The results of our survey indicate that practitioners have a limited understanding of various concepts related to sustainable development. This underscores the need for measures to reduce the carbon footprint of anesthetic activity and achieve financial savings through appropriate selection of anesthetic gases and optimization of fresh gas flow settings in the operating room. To achieve this goal, it is essential to raise awareness, inform, and train medical and nursing staff on sustainable development in anesthesia. The ultimate aim is to integrate these concepts into daily healthcare practices without compromising care quality or the comfort of healthcare professionals in performing their duties.

Conclusion

Hospitals, particularly operating rooms, bear the responsibility of implementing sustainable development strategies. Anesthetic activities generate a significant amount of waste and pollution due to the use of polluting gases, posing health issues for professionals. Efforts must be made to raise awareness and train staff to integrate sustainable development into their practices without compromising care quality or the comfort of caregivers.

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