Global warming potential of inhaled anesthetics: application to clinical use

Desflurane versus sevoflurane anesthesia and postoperative recovery in older adults undergoing minor- to moderate-risk noncardiac surgery - A prospective, randomized, observer-blinded, clinical trial

STUDY OBJECTIVE

The effect of volatile anesthetics on postoperative recovery in older adults is still not entirely clear. Thus, we evaluated the effect of desflurane versus sevoflurane anesthesia on speed of postoperative recovery in older adults eligible for same-day discharge. We further evaluated the incidence of postoperative nausea and vomiting (PONV), bispectral index (BIS) values, and S100B concentrations.

DESIGN

Single-center, prospective, observer-blinded, randomized clinical trial.

SETTING

Operating room.

PATIENTS

190 patients ≥65 years of age and scheduled for minor- to moderate-risk noncardiac surgeries.

INTERVENTIONS

Goal-directed administration of desflurane versus sevoflurane for maintenance of anesthesia with an intraoperative goal of BIS 50 ± 5.

MEASUREMENTS

The primary outcome was the time to anesthesia recovery, which was defined as the time between arrival at the post-anesthesia care unit (PACU) and reaching criteria for discharge from PACU, based on modified Aldrete score ≥ 12 points. Modified Aldrete scores were assessed at PACU arrival and thereafter in five-minute intervals. PONV was evaluated during PACU stay and the first three postoperative days, BIS values were recorded during PACU stay, and S100B values were measured before and after surgery, and on the second postoperative day.

MAIN RESULTS

95 patients were randomized to receive desflurane, and 95 patients to receive sevoflurane. We did not observe a significant difference in median duration of postoperative recovery between the groups (desflurane: 0 min [0;0]; sevoflurane: 0 min [0;0]; p = 0.245). 77 patients (81.1%) in the desflurane group and 84 patients (88.4%) in the sevoflurane group already had Aldrete scores ≥12 points upon arrival at PACU (p = 0.277). There was also no significant difference in the incidences of PONV (p = 0.606), postoperative BIS values (p = 0.197), and postoperative maximum S100B concentrations (p = 0.821) between the groups.

CONCLUSIONS

Despite previous reports, we did not observe significant faster recovery times after desflurane anesthesia. Both volatile anesthetics may be appropriate for same-day discharge in older adults.

Scoping review for the SAGES EAES joint collaborative on sustainability in surgical practice

BACKGROUND

Surgical care in the operating room (OR) contributes one-third of the greenhouse gas (GHG) emissions in healthcare. The European Association of Endoscopic Surgery (EAES) and the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) initiated a joint Task Force to promote sustainability within minimally invasive gastrointestinal surgery.

METHODS

A scoping review was conducted by searching MEDLINE via Ovid, Embase via Elsevier, Cochrane Central Register of Controlled Trials, and Scopus on August 25th, 2023 to identify articles reporting on the impact of gastrointestinal surgical care on the environment. The objectives were to establish the terminology, outcome measures, and scope associated with sustainable surgical practice. Quantitative data were summarized using descriptive statistics.

RESULTS

We screened 22,439 articles to identify 85 articles relevant to anesthesia, general surgical practice, and gastrointestinal surgery. There were 58/85 (68.2%) cohort studies and 12/85 (14.1%) Life Cycle Assessment (LCA) studies. The most commonly measured outcomes were kilograms of carbon dioxide equivalents (kg CO2eq), cost of resource consumption in US dollars or euros, surgical waste in kg, water consumption in liters, and energy consumption in kilowatt-hours. Surgical waste production and the use of anesthetic gases were among the largest contributors to the climate impact of surgical practice. Educational initiatives to educate surgical staff on the climate impact of surgery, recycling programs, and strategies to restrict the use of noxious anesthetic gases had the highest impact in reducing the carbon footprint of surgical care. Establishing green teams with multidisciplinary champions is an effective strategy to initiate a sustainability program in gastrointestinal surgery.

CONCLUSION

This review establishes standard terminology and outcome measures used to define the environmental footprint of surgical practices. Impactful initiatives to achieve sustainability in surgical practice will require education and multidisciplinary collaborations among key stakeholders including surgeons, researchers, operating room staff, hospital managers, industry partners, and policymakers.

Evaluation of Operating Room Staff Awareness of Environmental Sustainability and Medical Waste Management

Objective

This study aims to identify the obstacles to recycling and environmental sustainability habits in a university hospital's operating room (OR) environment in Turkey and lay the groundwork for potential solutions.

Methods

A questionnaire was used to measure current views among the 140 OR staff members aged 20-54 years. The survey assessed awareness and behaviors of recycling at home and in the OR, as well as awareness of environmentally safe anaesthesia practices.

Results

Half of the participants believed that ORs significantly affected their carbon footprint, and most agreed that these environmental effects could be reduced. The primary barriers to recycling were inadequate knowledge, negative staff attitudes and insufficient services. Notably, 76% of participants paid attention to segregating OR waste, yet many lacked formal education about the environmental impact of their practices. Approximately 89% agreed that the environmental effects of ORs could be further reduced, with education being a critical need.

Conclusion

The healthcare sector's contribution to carbon emissions and waste production is significant, especially in ORs. The lack of education regarding ecological implications is concerning. Implementing standardized training programs and enhancing recycling services can substantially reduce the environmental impact of ORs, highlighting the need for a more sustainable healthcare system.

Improving sustainability and mitigating the environmental impacts of anaesthesia and surgery: a narrative review

Climate change, environmental degradation, and biodiversity loss are adversely affecting human health and exacerbating existing inequities, intensifying pressures on already strained health systems. Paradoxically, healthcare is a high-polluting industry, responsible for 4.6% of global greenhouse gas emissions and a similar proportion of air pollutants. Perioperative services are among the most resource-intensive healthcare services and are responsible for some unique pollutants. Opportunities exist to mitigate pollution throughout the entire continuum of perioperative care, including those that occur upstream of the operating room in the process of patient selection and optimisation, delivery of anaesthesia and surgery, and the postoperative recovery period. Within a patient-centred, holistic approach, clinicians can advocate for healthy public policies that modify the determinants of surgical illness, can engage in shared decision-making to ensure appropriate clinical decisions, and can be stewards of healthcare resources. Innovation and collaboration are required to redesign clinical care pathways and processes, optimise logistical systems, and address facility emissions. The results will extend beyond the reduction of public health damages from healthcare pollution to the provision of higher value, higher quality, patient-centred care.

Promoting behavioural change by educating anaesthetists about the environmental impact of inhalational anaesthetic agents: A systematic review

Of the total carbon footprint of Australia, 7% is attributed to healthcare. In the UK, inhalational agents make up 5% of the healthcare carbon footprint. This systematic review aims to determine which methods of education about the environmental impact of inhalational anaesthetic agents can be utilised to promote behaviour change, reducing the anaesthetic-related carbon footprint. This systematic review sourced records from CINAHL, EMBASE, ERIC, JBI and MEDLINE from 1970 to March 2022. The search identified 589 records, 13 of which met eligibility criteria after the screening process, in which 10 of these records were conference abstracts. Education curricula focused on inhalational agent choice (69%), lowering the fresh gas flow during maintenance anaesthesia (69%), encouraging alternatives such as total intravenous anaesthesia (23%) and/or switching off the gas on transfer (8%). The most common teaching techniques utilised in education curricula were didactic lectures (85%), visual prompts (54%), emails (46%), and conversation forums (31%). All but one study reported a positive relationship between teaching sessions and behavioural change resulting in lower inhalational anaesthetic use by participants and their organisations, reducing healthcare-associated emissions. This systematic review has demonstrated that single education sessions as well as multi-focused, multimodal education curricula on the topic of greener anaesthesia can be beneficial in promoting behavioural change.

Doping Strategy of Monolayer MoS2 to Realize the Monitoring of Environmental Concentration of Desflurane: A First-Principles Study

Desflurane is a new volatile inhalation anesthetic that is widely used in medical operation. However, various diseases can be caused by chronic exposure to desflurane, which is also a greenhouse gas. Therefore, it is urgent to find a suitable method for monitoring desflurane. In this paper, the process of doping of Pd, Pt, and Ni on the MoS2 surface is simulated to determine the stability of the doping structure based on first-principles. The adsorption properties and sensing properties of Pd-MoS2, Pt-MoS2, and Ni-MoS2 on desflurane are explored by parameters including independent gradient model based on Hirshfeld partition (IGMH), electron localization function (ELF), and density of states (DOS), sensibility, and recovery time, subsequently. The doping results show that the three doping systems (Pd-MoS2, Pt-MoS2, and Ni-MoS2) are structurally stable, and the chemical bonds are formed with MoS2. The adsorption results show the best chemisorption between Pt-MoS2 and desflurane with the chemical bonds between them. The results of IGMH, ELF, and DOS also confirm it. The sensing characterization results show that the recovery time of Pt-MoS2 ranges between 85.27 and 0.027 s, and the sensitivity ranges from 99.26 to 25.69%, all of which can meet the requirements of the sensor. Considering the adsorption effect and sensing characteristics, Pt-MoS2 can be used as a gas-sensitive material for detecting the concentration of desflurane.

Anaesthetic gases and the environment: Is it time for a rethink?

BACKGROUND

General anaesthesia is in common use for patients undergoing surgical procedures, with the option of both inhalational and intravenous anaesthetic techniques. Anaesthetic gases are often excluded from discussions on sustainable healthcare delivery, despite being a significant contributor to the overall environmental impact of healthcare services.

METHODS

A literature review was carried out on previously published papers on the impact anaesthetic gases have on our environment and at ways to reduce their impact in current anaesthetic practice. The aim was to write a narrative review detailing the areas of concern as well as the current clinical situation in the European setting.

SUMMARY/CONCLUSIONS

The two classes of inhaled anaesthetic agent most frequently used are nitrous oxide and volatile agents (most commonly sevoflurane, isoflurane and desflurane). Both are recognised greenhouse gases that contribute to climate change. Minor modifications in the use of anaesthetic gases can have a significant environmental impact. These modifications include avoiding nitrous oxide whenever possible, avoiding desflurane (and using sevoflurane instead), using low flow anaesthesia during maintenance, swapping volatile-based anaesthesia for a TIVA technique when clinically appropriate and considering the use of central neuraxial or regional anaesthesia in place of general anaesthesia when possible.

Effect of a non-reactive absorbent with or without environmentally oriented electronic feedback on anesthesia provider's fresh gas flow rates: A greening initiative

STUDY OBJECTIVE

To examine the effects of a non-reactive carbon dioxide absorbent (AMSORB® Plus) versus a traditional carbon dioxide absorbent (Medisorb™) on the FGF used by anesthesia providers and an electronic educational feedback intervention using Carestation™ Insights (GE HealthCare) on provider-specific change in FGF.

DESIGN

Prospective, single-center cohort study set in a greening initiative.

SETTING

Operating room.

PARTICIPANTS

157 anesthesia providers (i.e., anesthesiology trainees, certified registered nurse anesthetists, and solo anesthesiologists).

INTERVENTIONS

Intervention #1 was the introduction of AMSORB® Plus into 8 Aisys CS2, Carestation™ Insights-enabled anesthesia machines (GE HealthCare) at the study site. At the end of week 6, anesthesia providers were educated and given an environmentally oriented electronic feedback strategy for the next 12 weeks of the study (Intervention #2) using Carestation™ Insights data.

MEASUREMENTS

The dual primary outcomes were the difference in average daily FGF during maintenance anesthesia between machines assigned to AMSORB® Plus versus Medisorb™ and the provider-specific change in average fresh gas flows after 12 weeks of feedback and education compared to the historical data.

MAIN RESULTS

Over the 18-week period, there were 1577 inhaled anesthetics performed in the 8 operating rooms (528 for intervention 1, 1049 for intervention 2). There were 1001 provider days using Aisys CS2 machines and 7452 provider days of historical data from the preceding year. Overall, AMSORB® Plus was not associated with significantly less FGF (mean - 80 ml/min, 97.5% confidence interval - 206 to 46, P = .15). The environmentally oriented electronic feedback intervention was not associated with a significant decrease in provider-specific mean FGF (-112 ml/min, 97.5% confidence interval - 244 to 21, P = .059).

CONCLUSIONS

This study showed that introducing a non-reactive absorbent did not significantly alter FGF. Using environmentally oriented electronic feedback relying on data analytics did not result in significantly reduced provider-specific FGF.

Carbon footprint in trauma surgery, is there a way to reduce it?

BACKGROUND

Inhaled anaesthetic agents like sevoflurane contribute for approximately 5% to healthcare's carbon footprint. Previous studies suggested that the use of these agents should be minimized. Although multiple trauma surgeries can be performed under regional anaesthesia, most are performed under general anaesthesia. This study aims to evaluate the environmental benefits of using regional anaesthesia over general anaesthesia and to compare the associated complication rates.

METHODS

This retrospective study included all trauma patients (≥ 18 years) who underwent surgical intervention for hand, wrist, hip, or ankle fractures from 2017 to 2021. The hypothetical environmental gain was calculated based on the assumption that all surgeries were performed under regional anaesthesia. Complication rates were compared between regional and general anaesthesia.

RESULTS

Of the 2,714 surgeries, 15% were hand, 26% wrist, 36% hip, and 23% ankle fractures. General anaesthesia was used in 95%, regional in 5%. Switching this 95% to regional anaesthesia would reduce the sevoflurane use by 92 k, comparable to driving 406,553 km by car. The complication rate was higher with general anaesthesia compared to regional (7.7% vs 6.9%, p = 0.75).

CONCLUSION

The potential gain of the reduction of sevoflurane in trauma surgeries which can be performed under regional anaesthesia can be significant.

Efficiency of passive activated carbon anaesthetic gas capturing systems during simulated ventilation

BACKGROUND

Interest in passive flow filter systems to remove sevoflurane from anaesthetic machine exhaust have increased recently to mitigate the environmental impact of volatile anaesthetics. These filter systems consist of chemically activated carbon, with limited evidence on their performance characteristics. We hypothesised that their efficiency depends on filter material.

METHODS

Binding capacity was tested for three carbon filter materials (CONTRAfluran®, FlurAbsorb®, and Anaesthetic Agent Filter AAF633). Adsorption efficiency and resistive pressure were determined during simulated ventilation at different stages of filter saturation and fresh gas flow. In addition, sevoflurane concentration in filtered gas was measured at randomly selected anaesthesia workstations.

RESULTS

Sevoflurane concentration in filtered gas exceeded 10 ppm when saturated with 184 ml sevoflurane each for CONTRAfluran and FlurAbsorb and 276 ml for AAF633. During simulated ventilation, sevoflurane concentration >10 ppm passed through CONTRAfluran and AAF633 at fresh gas flow 10 L min-1 only at maximum saturation, but through FlurAbsorb at all stages of saturation. The resistance pressure of all filters was negligible during simulated ventilation, but increased up to 5.2 (0.2) cm H2O during simulated coughing. At two of seven anaesthesia workstations, sevoflurane concentration in filtered exhaust gas was >10 ppm.

CONCLUSIONS

Depending on the filter material and saturation, the likelihood of sevoflurane passing through passive flow carbon filters depends on the filter material and fresh gas flow. Combining the filter systems with anaesthetic gas scavenging systems could protect from pollution of ambient air with sevoflurane.

Precision in practice: An audit study on low-flow anesthesia techniques with desflurane and sevoflurane for cost-effective and sustainable care

Introduction

In the backdrop of escalating healthcare costs and an increasing focus on resource optimization, this audit study delves into the realm of anesthesia management, specifically exploring the application of low-flow anesthesia (LFA). The primary objective was to assess adherence to hospital standards and evaluate the economic implications of LFA (<1 L/min).

Materials and Methods

This retrospective audit focused on 700 adult patients undergoing elective surgeries with general anesthesia. Data sources included anesthesia records, electronic recording systems, and audits by a dedicated team. Fresh gas flow rates (FGFRs), minimum alveolar concentration (MAC), and volatile anesthetic consumption were analyzed. Cost comparisons between low-flow and high-flow anesthesia were conducted, employing specific cost per milliliter metrics.

Results

The average FGFR during the maintenance phase was found to be 0.45 ± 0.88 L/min. Adherence to hospital standards was notably high, with 94.29% of patients being maintained on low-flow gas rates. The differences in anesthetic consumption between low-flow and high-flow FGFR were statistically significant for both desflurane (12.17 ± 10.84 ml/MAC hour versus 43.12 ± 27.25 ml/MAC hour) and sevoflurane (3.48 ± 7.22 ml/MAC hour versus 5.20 ± 5.20 ml/MAC hour, P < 0.001). The calculated savings per patient with low-flow desflurane and sevoflurane anesthesia compared to high flow were found to be 109.25 AED and 6.74 AED, respectively.

Conclusion

This audit advocates for the widespread adoption of LFA as a standard practice. Beyond aligning with hospital standards, the study highlights the multi-faceted benefits of LFA, encompassing economic savings, environmental safety, and enhanced patient care.

Green Hospital as a new Standard in Japan: How far can Neurosurgery go in Japan?

BACKGROUND

Climate change is a significant challenge that the medical community must address. Hospitals are large facilities with high water and energy consumption, as well as high levels of waste generation, which makes it important to pursue green hospital initiatives. Neurosurgery requires substantial energy for surgeries and tests.

METHODS

Based on the keywords "Climate change," "green hospital," "neurosurgery," "energy consumption," "environmental impact" listed in this paper, we extracted representative manuscripts, and the practices employed in the authors' hospital were assessed.

RESULTS

The "Guidelines for Environmental Consideration in Hospitals" and "Guidelines for the Sustainability of Hospital Environments" have been developed; however, they are not implemented in most hospitals in Japan. Inhalational anesthetics were found to contribute significantly to greenhouse gas emissions. Educating patients and staff and employing the "8 Rs" (rethink, refuse, reduce, reuse, recycle, research, renovation, and revolution) showed promise in achieving green hospital standards.

CONCLUSIONS

The advent of 'green hospitals' in Japan is imminent. The active participation of neurosurgeons can play a crucial role in diminishing the environmental footprint of health care while simultaneously enhancing medical standards. Given the pressing challenges posed by climate change, there is a critical need for an overhaul of medical practices. It is imperative for neurosurgeons to pioneer the adoption of new, sustainable medical methodologies.

What Is the Carbon Footprint of Adult Spinal Deformity Surgery?

Background/Objectives: While the economic cost of adult spinal deformity (ASD) surgery has been studied extensively, its environmental impact is unknown. The aim of this study is to determine the carbon footprint (CF) associated with ASD surgery. Methods: ASD patients who underwent > four levels of corrective surgery between 2017 and 2021 were included. The open group included a posterior-only, single-stage technique, while the minimally invasive surgery (MIS) group was defined as the use of lateral interbody fusion and percutaneous posterior screw fixation. The two groups were propensity-score matched to adjust for baseline demographic, surgical, and radiographic characteristics. Data on all disposables and reusable instruments, anesthetic gas, and non-gas medications used during surgery were collected from medical records. The CF of transporting, using, and disposing of each product and the footprint of energy use in operating rooms were calculated. The CF produced was evaluated using the carbon dioxide equivalent (CO2e), which is relative to the amount of CO2 with an equivalent global warming potential. Results: Of the 175 eligible patients, 15 pairs (65 ± 9 years, 47% female) were properly matched and analyzed for all variables. The average CF generated per case was 147.7 ± 37.3 kg-CO2e, of which 54% was attributable to energy used to sterilize reusable instruments, followed by anesthetic gas released into the environment (17%) and operating room air conditioning (15%). Conclusions: The CF generated during ASD surgery should be reduced using a multidisciplinary approach, taking into account that different surgical procedures have different impacts on carbon emission sources.

Ecogastroenterology: cultivating sustainable clinical excellence in an environmentally conscious landscape

Gastrointestinal practices, especially endoscopy, have a substantial environmental impact, marked by notable greenhouse gas emissions and waste generation. As the world struggles with climate change, there emerges a pressing need to re-evaluate and reform the environmental footprint within gastrointestinal medicine. The challenge lies in finding a harmonious balance between ensuring clinical effectiveness and upholding environmental responsibility. This task involves recognising that the most significant reduction in the carbon footprint of endoscopy is achieved by avoiding unnecessary procedures; addressing the use of single-use endoscopes and accessories; and extending beyond the procedural suites to include clinics, virtual care, and conferences, among other aspects of gastrointestinal practice. The emerging digital realm in health care is crucial, given the potential environmental advantages of virtual gastroenterological care. Through an in-depth analysis, this review presents a path towards sustainable gastrointestinal practices, emphasising integrated strategies that prioritise both patient care and environmental stewardship.

Electricity consumption of anesthesia workstations and potential emission savings by avoiding standby

BACKGROUND

Anesthesiology has a relevant carbon footprint, mainly due to volatile anesthetics (scope 1 emissions). Additionally, energy used in the operating theater (scope 2 emissions) contributes to anesthesia-related greenhouse gas (GHG) emissions.

OBJECTIVES

Optimizing the electricity use of medical devices might reduce both GHG emissions and costs might hold potential to reduce anaesthesia-related GHG-emissions and costs. We analyzed the electricity consumption of six different anesthesia workstations, calculated their GHG emissions and electricity costs and investigated the potential to reduce emissions and cost by using the devices in a more efficient way.

METHODS

Power consumption (active power in watt , W) was measured with the devices off, in standby mode, or fully on with the measuring instrument SecuLife ST. Devices studied were: Dräger Primus, Löwenstein Medical LeonPlus, Getinge Flow C, Getinge Flow E, GE Carestation 750 and GE Aisys. Calculations of GHG emissions were made with different emission factors, ranging from very low (0.09 kg CO2-equivalent/kWh) to very high (0.660 kg CO2-equivalent/kWh). Calculations of electricity cost were made assuming a price of 0.25 € per kWh.

RESULTS

Power consumption during operation varied from 58 W (GE CareStation 750) to 136 W (Dräger Primus). In standby, the devices consumed between 88% and 93% of the electricity needed during use. The annual electricity consumption to run 96 devices in a large clinical department ranges between 45 and 105 Megawatt-hours (MWh) when the devices are left in standby during off hours. If 80% of the devices are switched off during off hours, between 20 and 46 MWh can be saved per year in a single institution. At the average emission factor of our hospital, this electricity saving corresponds to a reduction of GHG emissions between 8.5 and 19.8 tons CO2-equivalent. At the assumed prices, a cost reduction between 5000 € and 11,600 € could be achieved by this intervention.

CONCLUSION

The power consumption varies considerably between the different types of anesthesia workstations. All devices exhibit a high electricity consumption in standby mode. Avoiding standby mode during off hours can save energy and thus GHG emissions and cost. The reductions in GHG emissions and electricity cost that can be achieved with this intervention in a large anesthesiology department are modest. Compared with GHG emissions generated by volatile anesthetics, particularly desflurane, optimization of electricity consumption of anesthesia workstations holds a much smaller potential to reduce the carbon footprint of anesthesia; however, as switching off anesthesia workstations overnight is relatively effortless, this behavioral change should be encouraged from both an ecological and economical point of view.

What is the environmental impact of a blood transfusion? A life cycle assessment of transfusion services across England

BACKGROUND

Healthcare activities significantly contribute to greenhouse gas (GHG) emissions. Blood transfusions require complex, interlinked processes to collect, manufacture, and supply. Their contribution to healthcare emissions and avenues for mitigation is unknown.

STUDY DESIGN AND METHODS

We performed a life cycle assessment (LCA) for red blood cell (RBC) transfusions across England where 1.36 million units are transfused annually. We defined the process flow with seven categories: donation, transportation, manufacturing, testing, stockholding, hospital transfusion, and disposal. We used direct measurements, manufacturer data, bioengineering databases, and surveys to assess electrical power usage, embodied carbon in disposable materials and reagents, and direct emissions through transportation, refrigerant leakage, and disposal.

RESULTS

The central estimate of carbon footprint per unit of RBC transfused was 7.56 kg CO2 equivalent (CO2eq). The largest contribution was from transportation (2.8 kg CO2eq, 36% of total). The second largest was from hospital transfusion processes (1.9 kg CO2eq, 26%), driven mostly by refrigeration. The third largest was donation (1.3 kg CO2eq, 17%) due to the plastic blood packs. Total emissions from RBC transfusion are ~10.3 million kg CO2eq/year.

DISCUSSION

This is the first study to estimate GHG emissions attributable to RBC transfusion, quantifying the contributions of each stage of the process. Primary areas for mitigation may include electric vehicles for the blood service fleet, improving the energy efficiency of refrigeration, using renewable sources of electricity, changing the plastic of blood packs, and using methods of disposal other than incineration.

A web tool for exploring the usage of medicines in hospitals in England

Datasets on the amounts of different medicines used over time and location are a valuable resource, with the power to reveal insights into healthcare trends, cost efficiencies, and geographic disparities. In England, primary care prescription data has been openly accessible for analysis for some time through a web tool, providing significant benefits. Since 2020, the National Health Service in England has also released data on secondary care medicine usage, processed from stock control databases, which provides detailed information on medicine usage within hospitals. This is an important dataset, but until now has been available only in a raw form that requires considerable technical skills to be used for even the analysis of basic trends. I have built a web application that enables anyone to easily analyse trends in this data, which is available at hospitalmedicines.genomium.org.

A randomised controlled trial comparing quality of recovery between desflurane and isoflurane inhalation anaesthesia in patients undergoing ophthalmological surgery at a tertiary hospital in South Africa (DIQoR trial)

Background

The patient's experience of their postoperative recovery is an important perioperative outcome, with the 15-item quality of recovery scale (QoR-15) recommended as a standardised outcomes measure. Desflurane has a faster emergence from anaesthesia compared with other volatile anaesthetics, but it is uncertain whether this translates to better subjective quality of recovery. The hypothesis for this study is that patients receiving desflurane for maintenance of anaesthesia would have better postoperative quality of recovery than patients receiving isoflurane.

Methods

Male and female adult patients undergoing ophthalmological surgery under general anaesthesia were randomly allocated to receive desflurane or isoflurane for maintenance of anaesthesia. The primary outcome was to compare postoperative QoR-15 scores. Secondary outcomes included comparing preoperative QoR-15 scores, volatile agent consumption, and time spent in the recovery room.

Results

Data from 164 patients were analysed (80 desflurane, 84 isoflurane). Median (Q1, Q3) postoperative QoR-15 scores were not significantly different (desflurane: 145 [141, 148], isoflurane: 144 [139, 147], 95% confidence interval 0-3, P=0.176, minimal clinically important difference=8). Median (Q1, Q3) volatile agent consumption was 15.4 (12.5, 19.3) ml hr-1 in the desflurane group, and 7.4 (5.9, 9.7) ml hr-1 in the isoflurane group. Median (Q1, Q3) time spent in the recovery room was significantly shorter in the desflurane group (desflurane: 18 [13, 23]; isoflurane: 25 [19, 32], 95% confidence interval -10 to 5, P<0.001).

Conclusions

This study found no difference in quality of recovery between patients who received desflurane or isoflurane for maintenance of general anaesthesia during ophthalmological surgery. A shorter time in the recovery room was not associated with improved QoR-15 scores.

Clinical trial registration

NCT04188314.

Addressing Climate Health: A Practical Guide to Quantifying and Reducing Health Care-Associated Emissions

OBJECTIVE

The objective was to quantify annual greenhouse gas emissions from a surgical specialty hospital and identify high-yield areas to reduce emissions associated with patient care.

STUDY DESIGN

Pre-post study, greenhouse gas inventory.

SETTING

Specialty hospital.

METHODS

A scope 1 and scope 2 greenhouse gas inventory of the Massachusetts Eye and Ear main campus for calendar years (CY) 2020, 2021, and 2022 was performed by assessing emissions attributable to on-site sources (scope 1) and purchased electricity and steam (scope 2). The associated carbon dioxide equivalent was then calculated using known global warming potentials and emission factors.

RESULTS

The major contributors to scope 1 and scope 2 emissions at our institution for CY 2020 to 2022 were waste anesthetic gases and purchased steam. These results were reviewed with hospital leadership and a plan was developed to reduce these emissions. Emission monitoring is ongoing to assess the efficacy of these interventions.

CONCLUSION

Measuring scope 1 and scope 2 emissions at the facility level allows health care facilities to develop institution-specific interventions and compare data across health care organizations. Surgeons can lead on health care system sustainability by collaborating with clinical and nonclinical staff to measure emissions, developing targeted emissions-reduction interventions, and tracking progress with yearly assessments.

Environmental Impact of Adult Tonsillectomy: Life Cycle Assessment and Cost Comparison of Techniques

OBJECTIVES

To quantify and compare the cost and environmental impact of different techniques for adult tonsillectomy surgery, and to identify target areas for impact reduction.

METHODS

Fifteen consecutive adult tonsillectomy surgeries were prospectively randomized to one of three tonsillectomy techniques: cold, monopolar electrocautery, or low-temperature radiofrequency ablation (Coblation). Life cycle assessment was used to comprehensively evaluate the environmental impact of study surgeries. Outcomes assessed included multiple measures of environmental impact, including greenhouse gas (GHG) emissions, and cost. Environmental impact measures were analyzed to identify highest-yield areas for improvement, and outcomes were compared between surgical techniques using statistical analysis.

RESULTS

GHG emissions for cold, monopolar electrocautery, and Coblation techniques were 157.6, 184.5, and 204.7 kilograms of carbon dioxide equivalents (kgCO2 -eq) per surgery, respectively, with costs totaling $472.51, $619.10, and $715.53 per surgery, respectively. Regardless of surgery technique, anesthesia medications and disposable equipment contributed most to environmental harm. Cold technique demonstrated reduced environmental impact related to disposable surgical equipment in the categories of greenhouse gas emissions, acidification of soil and water, eutrophication of air, ozone depletion, release of carcinogenic, and non-carcinogenic toxic substances, and respiratory pollutant production (p < 0.05 for all comparisons with other techniques).

CONCLUSION

Within the boundaries of operating room processes, cold technique minimizes cost and environmental impact of adult tonsillectomy surgery, with statistical significance noted in the impact of disposable surgical equipment. Areas of highest potential for improvement identified include reducing use of disposable equipment and collaboration with the Anesthesiology care team to streamline medication use.

LEVEL OF EVIDENCE

2, randomized trial Laryngoscope, 134:622-628, 2024.

Investigating theoretical and experimental cross sections for elastic electron scattering from isoflurane

We present a comprehensive analysis of elastic electron scattering from isoflurane in the intermediate energy range of 50-300 eV. This research is motivated by the significant impact of this molecule on global warming effects. We conducted this investigation through experimental measurements using a crossed-beam apparatus and covering a wide angular range from 25 to 125 degrees. Relative differential cross sections (DCSs) were obtained and subsequently normalized on an absolute scale by using the relative flow technique, with argon as the reference gas. These DCS values were then extrapolated and integrated to determine the experimental integral cross sections (ICSs). Additionally, we employed the independent atom model and the screening corrected additivity rule with incorporated Interference effects (IAM-SCAR+I) to calculate the theoretical differential and integral cross-sections. Remarkably, the calculated cross sections align closely with the experimental measurements across the entire energy and angular range. Furthermore, this study involved a comparison of the DCSs for isoflurane with previously published DCS values for two other volatile anesthetics, sevoflurane and halothane.

Paving the way to environment-friendly greener anesthesia

Health-care settings have an important responsibility toward environmental health and safety. The operating room is a major source of environmental pollution within a hospital. Inhalational agents and nitrous oxide are the commonly used gases during general anesthesia for surgeries, especially in the developing world. These greenhouse gases contribute adversely to the environmental health both inside the operating room and in the outside atmosphere. Impact of these anesthetic agents depends on the total consumption, characteristics of individual agents, and gas flows, with higher levels increasing the environmental adverse effects. The inimical impact of nitrous oxide is higher due to its longer atmospheric half-life and potential for destruction of the ozone layer. Anesthesiologist of today has a choice in the selection of anesthetic agents. Prudent decisions will help in mitigating environmental pollution and contributing positively to a greener planet. Therefore, a shift from inhalational to intravenous-based technique will reduce the carbon footprint of anesthetic agents and their impact on global climate. Propofol forms the mainstay of intravenous anesthesia technique and is a proven drug for anesthetic induction and maintenance. Anesthesiologists should appreciate growing concerns about the role of inhalational anesthetics on the environment and join the cause of environmental responsibility. In this narrative review, we revisit the pharmacological and pharmacokinetic considerations, clinical uses, and discuss the merits of propofol-based intravenous anesthesia over inhalational anesthesia in terms of environmental effects. Increased awareness about the environmental impact and adoption of newer, versatile, and user-friendly modalities of intravenous anesthesia administration will pave the way for greener anesthesia practice.

Estimating the carbon emissions from a resource-limited surgical suite in Papua New Guinea: The climate change potential

Introduction

The upscale of surgical service delivery in low to middle income countries will increase health sector greenhouse gas emissions globally. Understanding surgical greenhouse gas emissions from surgical suite activities can direct decarbonization strategies and achieve local, and global climate change objectives.

Material and methods

A prospective surgical suite carbon foot print study was conducted at the Alotau Provincial Hospital from the 28th March 2022 to the 28th of May 2022.

Results

The total carbon emission for the surgical suite in APH over the study period was 2,665.8 kgCO2e. The average carbon emission per surgical case within the boundary of the surgical suite was 8.4 kgCO2e. Scope one emissions (anaesthetic gases) accounted for 44.7% (1171.3 kgCO2e) of all carbon emissions.

Conclusion

If no action is taken, carbon emissions in the western pacific region will continue to increase from surgical suites. Therefore, proactive efforts to reduce greenhouse gas emissions must be prioritized.

Minimal fixed flow anesthesia for off-pump coronary artery bypass surgery: A parallel randomized trail

Objectives

The aim of the present study was to test a safety of a fixed minimal (0.5 l/min) fresh gas flow (FGF) anesthesia as a method ensuring adequate oxygenation during off-pump coronary artery bypass grafting operations.

Design

A randomized, prospective study.

Setting

Single-center clinical hospital affiliated with a university.

Participants

208 patients underwent off-pump coronary artery bypass surgery.

Interventions

All patients received endotracheal inhalational anesthesia with fixed minimal FGF. Half of them were anesthetized by sevoflurane and another half by isoflurane. The fresh (carrier) gas was pure oxygen in the control groups and a mixture of medical air and oxygen (FiO2 0.8) in the trial groups.

Measurements and main results

In the control groups inhaled oxygen concentration changed minimally during the operation. In the trial groups in 28.8 % of cases inhaled oxygen concentration dropped below preliminary margin (0.4). Body surface area (BSA) (B = 38.7; p = 0.002) and patient's age (B = -0.47; p = 0.004) were retained into final logistic regression model as independent predictors. We divided BSA into subcategories and analyzed data by survival cox regression with Forward LR method. Patients with BSA>2.3 (Exp.B = 183) and BSA [2.2-2.3] (Exp.B = 59) had high chance to get less than 0.4 of inhaled oxygen concentration compared to the patients with BSA <2.0 (p < 0.001).Exp(B) or OR for the patients' age as independent predictor tested in multiple logistic regression was 0.628 In other words, for every year less the patient had 1/0.628 = 1.6 times more chance to reach the preliminary low margin (0.4) of oxygenation.

Conclusions

Fixed minimal FGF 0.5 l/min with FiO2 0.8 may not be sufficient for the younger patients with BSA >2.0 to maintain inhaled oxygen concentration above 0.4. Using pure oxygen as a carrier gas during fixed minimal flow long term anesthesia is much safer and more reliable.

UK health researchers' considerations of the environmental impacts of their data-intensive practices and its relevance to health inequities

BACKGROUND

The health sector aims to improve health outcomes and access to healthcare. At the same time, the sector relies on unsustainable environmental practices that are increasingly recognised to be catastrophic threats to human health and health inequities. As such, a moral imperative exists for the sector to address these practices. While strides are currently underway to mitigate the environmental impacts of healthcare, less is known about how health researchers are addressing these issues, if at all.

METHODS

This paper uses an interview methodology to explore the attitudes of UK health researchers using data-intensive methodologies about the adverse environmental impacts of their practices, and how they view the importance of these considerations within wider health goals.

RESULTS

Interviews with 26 researchers showed that participants wanted to address the environmental and related health harms associated with their research and they reflected on how they could do so in alignment with their own research goals. However, when tensions emerged, their own research was prioritised. This was related to their own desires as researchers and driven by the broader socio-political context of their research endeavours.

CONCLUSION

To help mitigate the environmental and health harms associated with data-intensive health research, the socio-political context of research culture must be addressed.

Noncovalent chemistry of xenon opens the door for anesthetic xenon recovery using Bio-MOFs

Designing an inexpensive and highly efficient recovery process for xenon (Xe) is gaining importance in the development of sustainable applications. Using metal organic frameworks (MOFs) for separating Xe from anesthetic gas mixtures has been a recent topic studied rarely and superficially in the literature. We theoretically investigated Xe recovery performances of 43 biological MOFs (Bio-MOFs) formed by biocompatible metal cations and biological endogenous linkers. Xe uptakes and Xe permeabilities in its binary mixtures with CO2, O2, and N2 were investigated by applying Grand Canonical Monte Carlo and Molecular Dynamics simulations. Materials with metalloporphyrin, hexacarboxylate, triazine, or pyrazole ligands, dimetallic paddlewheel units, relatively large pore sizes (PLD > 5 Å and LCD > 10 Å), large void fractions (≈0.8), and large surface areas (>2900 m2 g-1) have been determined as top performing Bio-MOFs for Xe recovery. By applying Density Functional Theory simulations and generating electron density difference maps, we determined that Xe-host interactions in the top performing Bio-MOFs are maximized mainly due to noncovalent interactions of Xe, such as charge-induced dipole and aerogen-π interactions. Polarized Xe atoms in the vicinity of cations/anions as well as π systems are fingerprints of enhanced guest-host interactions. Our results show examples of rarely studied aerogen interactions that play a critical role in selective adsorption of Xe in nanoporous materials.

Guidelines for reducing the environmental impact of general anaesthesia

OBJECTIVE

To provide guidelines for reducing the environmental impact of general anaesthesia.

DESIGN

A committee of ten experts from SFAR and SF2H and SFPC learned societies was set up. A policy of declaration of competing interests was applied and observed throughout the guideline-writing process. Likewise, it did not benefit from any funding from a company marketing a health product (drug or medical device). The committee followed the GRADE® method (Grading of Recommendations Assessment, Development and Evaluation) to assess the quality of the evidence on which the recommendations were based.

METHODS

We aimed to formulate recommendations according to the GRADE® methodology for three different fields: anaesthesia vapours and gases; intravenous drugs; medical devices and the working environment. Each question was formulated according to the PICO format (Population, Intervention, Comparator, Outcome). The literature review and recommendations were formulated according to the GRADE® methodology.

RESULTS

The experts' work on the synthesis and application of the GRADE® method led to the formulation of 17 recommendations. Since the GRADE® method could not be entirely applied to all of the questions, some of the recommendations were formulated as expert opinions.

CONCLUSION

Based on strong agreement between experts, we produced 17 recommendations designed to guide reducing the environmental impact of general anaesthesia.

Recovery Benefit With Total Intravenous Anesthesia in Patients Receiving Rhinoplasty

OBJECTIVE

The aim was to evaluate the difference in recovery when comparing total intravenous anesthesia (TIVA) to inhalational gas anesthesia in patients receiving rhinoplasty.

STUDY DESIGN

Retrospective review.

SETTING

Postoperative anesthesia care unit (PACU).

METHODS

Patients who received a functional or cosmetic rhinoplasty at a single academic institution between April 2017 and November 2020 were included. Inhalational gas anesthesia was in the form of sevoflurane. Phase I recovery time, which was defined as the time it took a patient to reach ≥9/10 on the Aldrete scoring system was recorded, as well as the usage of pain medication in the PACU. The postoperative course and incidence of postoperative nausea and vomiting (PONV) were also collected.

RESULTS

Two hundred and two patients were identified with 149 (73.76%) who received TIVA and 53 (26.24%) who received sevoflurane. For the patients who received TIVA, the average recovery time was 101.44 minutes (standard deviation [SD]: 34.64) compared to an average recovery time of 121.09 minutes (SD: 50.19) for patients who received sevoflurane leading to a difference of 19.65 minutes (p = 0.002). Patients who received TIVA experienced less PONV (p = 0.001). There were no differences in the postoperative course including surgical or anesthesia complications, postoperative complications, hospital or Emergency Department admissions, or administration of pain medication (p > 0.05 for all).

CONCLUSION

When utilizing TIVA over inhalational anesthesia, patients undergoing rhinoplasty had significantly increased benefits in terms of reduced phase I recovery times and decreased incidence of PONV. TIVA was demonstrated to be a safe and efficacious method of anesthesia for this patient population.

Assessing the potential climate impact of anaesthetic gases

There is increasing concern within the health-care community about the role care delivery plays in environmental degradation, sparking research into how to reduce pollution from clinical practice. Inhaled anaesthetics is a particular research area of interest for two reasons. First, several gases are potent greenhouse gases, and waste gas is mostly emitted directly to the environment. Second, there are options to reduce gas waste and substitute medications and procedures with fewer embodied emissions while delivering high-quality care. Performance improvements are contingent on a proper understanding of the emission estimates and climate metrics used to ensure consistent application in guiding mitigation strategies and accounting at various scales. We review the current literature on the environmental impact and the estimation of the potential climate forcing of common inhaled anaesthetic drugs: desflurane, sevoflurane, isoflurane, methoxyflurane, and nitrous oxide.

Environmental effects of surgical procedures and strategies for sustainable surgery

There is a bidirectional relationship between climate change and health care. Climate change threatens public health, and health care contributes to climate change. For example, surgery is the most energy-intensive practice in the health-care sector, and gastrointestinal conditions are responsible for a substantial environmental burden. However, environmental costs associated with health care are often overlooked. This issue has been examined more closely in current times. Emerging data are mainly focused on surgery, as the most resource-intensive practice. However, there is still a lack of global awareness and guidance on sustainable surgical practices. This Perspective aims to reassess the evidence on health care and surgery carbon footprints, focusing on gastrointestinal conditions, identify issues that need to be addressed to achieve a more sustainable practice and develop perspectives for future surgical procedures. The proposed framework to mitigate the environmental effects of surgery could be translated to other health-care sectors.

Innovations towards achieving environmentally sustainable operating theatres: A systematic review

INTRODUCTION

The NHS accounts for 5.4% of the UK's total carbon footprint, with the perioperative environment being the most resource hungry aspect of the hospital. The aim of this systematic review was to assimilate the published studies concerning the sustainability of the perioperative environment, focussing on the impact of implemented interventions.

METHODS

A systematic review was performed using Pubmed, OVID, Embase, Cochrane database of systematic reviews and Medline. Original manuscripts describing interventions aimed at improving operating theatre environmental sustainability were included.

RESULTS

675 abstracts were screened with 34 manuscripts included. Studies were divided into broad themes; recycling and waste management, waste reduction, reuse, reprocessing or life cycle analysis, energy and resource reduction and anaesthetic gases. This review summarises the interventions identified and their resulting effects on theatre sustainability.

DISCUSSION

This systematic review has identified simple, yet highly effective interventions across a variety of themes that can lead to improved environmental sustainability of surgical operating theatres. Combining these interventions will likely result in a synergistic improvement to the environmental impact of surgery.

The processes behind drug loading and release in porous drug delivery systems

Porous materials are ubiquitous and exhibit properties suitable for depositing therapeutic compounds. Drug loading in porous materials can protect the drug, control its release rate, and improve its solubility. However, to achieve such outcomes from porous delivery systems, effective incorporation of the drug in the internal porosity of the carrier must be guaranteed. Mechanistic knowledge of the factors influencing drug loading and release from porous carriers allows rational design of formulations by selecting a suitable carrier for each application. Much of this knowledge exists in research areas other than drug delivery. Thus, a comprehensive overview of this topic from the drug delivery aspect is warranted. This review aims to identify the loading processes and carrier characteristics influencing the drug delivery outcome with porous materials. Additionally, the kinetics of drug release from porous materials are elucidated, and the common approaches to mathematical modeling of these processes are outlined.

Optimizing Pediatric Mask Induction Fresh Gas Flow

INTRODUCTION

The environmental impact of inhaled anesthetics is a subject of increasing research. However, little attention has been paid to optimizing high-concentration volatile anesthetics during the inhalational (mask) inductions that begin most pediatric anesthetics.

METHODS

The performance of the GE Datex Ohmeda TEC 7 sevoflurane vaporizer was analyzed at different fresh gas flow (FGF) rates and two clinically relevant ambient temperatures. We found that an FGF rate of 5 liters per minute (LPM) is likely optimal for inhalational inductions, rapidly achieving dialed sevoflurane concentrations at the elbow of an unprimed pediatric breathing circuit while minimizing waste associated with higher FGF rates. We began educating our department regarding these findings, first with QR code labels on anesthetic workstations, then with targeted e-mails to pediatric anesthesia teams. We analyzed peak induction FGF in 100 consecutive mask inductions at our ambulatory surgery center at three different periods - baseline, post-labels, and post-emails - to assess the efficacy of these educational interventions. We also analyzed the time from induction to the start of myringotomy tube placement in a subset of these cases to determine if reducing mask induction FGF was associated with any change in the speed of induction.

RESULTS

Our institution's median peak FGF during inhalational inductions decreased from 9.2 LPM at baseline to 8.0 LPM after labels were placed on anesthetic workstations to 4.9 LPM after targeted e-mails. There was no associated decrease in the speed of induction.

CONCLUSION

Total fresh gas flow can be limited to 5 LPM during pediatric inhalational inductions, decreasing anesthetic waste and environmental impact without slowing the speed of induction. Educational labels on anesthetic workstations and direct e-mails to clinicians were effectively used in our department to enact change in this practice.

A call for immediate climate action in anesthesiology: routine use of minimal or metabolic fresh gas flow reduces our ecological footprint

PURPOSE

Climate change is a global threat, and inhalational anesthetics contribute to global warming by altering the photophysical properties of the atmosphere. On a global perspective, there is a fundamental need to reduce perioperative morbidity and mortality and to provide safe anesthesia. Thus, inhalational anesthetics will remain a significant source of emissions in the foreseeable future. It is, therefore, necessary to develop and implement strategies to minimize the consumption of inhalational anesthetics to reduce the ecological footprint of inhalational anesthesia.

SOURCE

We have integrated recent findings concerning climate change, characteristics of established inhalational anesthetics, complex simulative calculations, and clinical expertise to propose a practical and safe strategy to practice ecologically responsible anesthesia using inhalational anesthetics.

PRINCIPAL FINDINGS

Comparing the global warming potential of inhalational anesthetics, desflurane is about 20 times more potent than sevoflurane and five times more potent than isoflurane. Balanced anesthesia using low or minimal fresh gas flow (≤ 1 L·min-1) during the wash-in period and metabolic fresh gas flow (0.35 L·min-1) during steady-state maintenance reduces CO2 emissions and costs by approximately 50%. Total intravenous anesthesia and locoregional anesthesia represent further options for lowering greenhouse gas emissions.

CONCLUSION

Responsible anesthetic management choices should prioritize patient safety and consider all available options. If inhalational anesthesia is chosen, the use of minimal or metabolic fresh gas flow reduces the consumption of inhalational anesthetics significantly. Nitrous oxide should be avoided entirely as it contributes to depletion of the ozone layer, and desflurane should only be used in justified exceptional cases.

Reducing Volatile Anesthetic Waste Using a Commercial Electronic Health Record Clinical Decision Support Tool to Lower Fresh Gas Flows

BACKGROUND

Volatile anesthetic consumption can be reduced by minimizing excessive fresh gas flows (FGFs). Currently, it is unknown whether decision support tools embedded within commercial electronic health record systems can be successfully adopted to achieve long-term reductions in FGF rates. The authors describe the implementation of an electronic health record-based clinical decision support tool aimed at reducing FGF and evaluate the effectiveness of this intervention in achieving sustained reductions in FGF rates and volatile anesthetic consumption.

METHODS

On August 29, 2018, we implemented a decision support tool within the Epic Anesthesia Information Management System (AIMS) to alert providers of high FGF (>0.7 L/min for desflurane and >1 L/min for sevoflurane) during maintenance of anesthesia. July 22, 2015, to July 10, 2018, served as our baseline period before the intervention. The intervention period spanned from August 29, 2018, to December 31, 2019. Our primary outcomes were mean FGF (L/min) and volatile agent consumption (mL/MAC-h). Because a simple comparison of 2 time periods may result in false conclusions due to underlying trends independent of the intervention, we performed segmented regression of the interrupted time series to assess the change in level at the start of the intervention and the differences in slopes before and after the intervention. The analysis was also adjusted for potential confounding variables. Data included 44,899 cases using sevoflurane preintervention with 26,911 cases postintervention, and 17,472 cases using desflurane with 1185 cases postintervention.

RESULTS

Segmented regression of the interrupted times series demonstrated a decrease in mean FGF by 0.6 L/min (95% CI, 0.6-0.6 L/min; P < .0001) for sevoflurane and 0.2 L/min (95% CI, 0.2-0.3 L/min; P < .0001) for desflurane immediately after implementation of the intervention. For sevoflurane, mL/MAC-h decreased by 3.8 mL/MAC-h (95% CI, 3.6-4.1 mL/MAC-h; P < .0001) after implementation of the intervention and decreased by 4.1 mL/MAC-h (95% CI, 2.6-5.6 mL/MAC-h; P < .0001) for desflurane. Slopes for both FGF and mL/MAC-h in the postintervention period were statistically less negative than the preintervention slopes (P < .0001 for sevoflurane and P < .01 for desflurane).

CONCLUSIONS

A commercial AIMS-based decision support tool can be adopted to change provider FGF management patterns and reduce volatile anesthetic consumption in a sustainable fashion.

Increasing the reflection efficiency of the Sedaconda ACD-S by heating and cooling the anaesthetic reflector: a bench study using a test lung

BACKGROUND

As volatile anaesthetic gases contribute to global warming, improving the efficiency of their delivery can reduce their environmental impact. This can be achieved by rebreathing from a circle system, but also by anaesthetic reflection with an open intensive care ventilator. We investigated whether the efficiency of such a reflection system could be increased by warming the reflector during inspiration and cooling it during expiration (thermocycling).

METHODS

The Sedaconda-ACD-S (Sedana Medical, Danderyd, Sweden) was connected between an intensive care ventilator and a test lung. Liquid isoflurane was infused into the device at 0.5, 1.0, 2.0 and 5.0 mL/h; ventilator settings were 500 mL tidal volume, 12 bpm, 21% oxygen. Isoflurane concentrations were measured inside the test lung after equilibration. Thermocycling was achieved by heating the breathing gas in the inspiratory hose to 37 °C via a heated humidifier without water. Breathing gas expired from the test lung was cooled to 14 °C before reaching the ACD-S. In the test lung, body temperature pressure saturated conditions prevailed. Isoflurane concentrations and reflective efficiency were compared between thermocycling and control conditions.

RESULTS

With thermocycling higher isoflurane concentrations in the test lung were measured for all infusion rates studied. Interpolation of data showed that for achieving 0.4 (0.6) Vol% isoflurane, the infusion rate can be reduced from 1.2 to 0.7 (2.0 to 1.2) mL/h or else to 56% (58%) of control.

CONCLUSION

Thermocycling of the anaesthetic gas considerably increases the efficiency of the anaesthetic reflector and reduces anaesthetic consumption by almost half in a test lung model. Given that cooling can be miniaturized, this method carries a potential for further saving anaesthetics in clinical practice in the operating theatre as well as for inhaled sedation in the ICU.

[Zero Emissions. A shared responsibility. Gas capture and recycling project at the Cruces University Hospital (Spain).]

OBJECTIVE

The use of volatile anesthetics plays an important role in the production of greenhouse gases and other environmental pollutants that negatively affect global health. Programs to reduce anesthesia contaminants have been shown to be effective and reduce costs. For this reason, we conducted a study to implementing a Zero Emissions Program for zero carbon dioxide emissions derived from anesthetic gases used in the operating room, as recommended by the Green Deal of the European Union by 2030 and be climate neutral in 2050, maintaining satisfaction and current clinical results.

METHODS

A Zero Emissions Program was implemented within the Zero safety programs of the Cruces University Hospital in order to produce zero emissions of carbon dioxide derived from the anesthetic gases used in the operating rooms. The contribution of anesthetic gases to carbon dioxide production before and after implementation of program was determined. Data analysis was conducted descriptively to analyze program effectiveness.

RESULTS

The implementation of a Zero Emissions Program allowed us to achieve a reduction in emissions to zero.

CONCLUSIONS

Anesthesiologists must understand that minimizing our harmful impact on environmental health sustainability is not only desirable, but ethically necessary. A way to contribute to this ethical responsibility is Zero Emissions Programs which are effective in reducing emissions to zero, probably improving our impact on planet health.

Association Between Anesthesia Provider Education and Carbon Footprint Related to the Use of Inhaled Halogenated Anesthetics

BACKGROUND

Inhaled halogenated anesthetics are responsible for half of operating room total greenhouse gas emissions. Sustainable anesthesia groups were set up in 4 Lyon, France, university hospitals (Hospices Civils de Lyon) in January 2018 and have supported a specific information campaign about the carbon footprint related to the use of inhaled halogenated anesthetics in June 2019. We aimed to assess whether implementing such information campaigns was associated with a decrease in the carbon footprint related to inhaled halogenated anesthetics.

METHODS

This retrospective cohort study was conducted from January 1, 2015, to February 29, 2020, in 4 hospitals of the Hospices Civils de Lyon in France. Information meetings on sustainable anesthesia practices were organized by sustainable anesthesia groups that were set up in January 2018. In addition, a specific information campaign about the carbon footprint related to inhaled halogenated anesthetics was conducted in June 2019; it was followed by a questionnaire to be completed online. The monthly purchase of sevoflurane, desflurane, and propofol was recorded, and the estimated monthly carbon footprint from desflurane- and sevoflurane-related perioperative emissions was calculated. The interrupted time-series data from January 2015 to February 2020 were analyzed by segmented regression, considering both interventions (setting up of the sustainable anesthesia groups and specific information campaign) in the analysis and adjusting for 2 confounding factors (seasonality of the data and number of general anesthesia uses).

RESULTS

Among the 641 anesthesia providers from the study hospitals, 121 (19%) attended the information meetings about the carbon footprint of inhaled halogenated anesthetics, and 180 (28%) completed the questionnaire. The anesthetic activity from all 641 providers was considered in the analysis. After the sustainable anesthesia groups were set up, the carbon footprint of sevoflurane and desflurane started decreasing: the slope significantly changed ( P < .01) and became significantly negative, from -0.27 (95% confidence interval [CI], -1.08 to 0.54) tons.month -1 to -14.16 (95% CI, -16.67 to -11.65) tons.month -1 . After the specific information campaign, the carbon footprint kept decreasing, with a slope of -7.58 (95% CI, -13.74 to -1.41) tons.month -1 ( P = .02), which was not significantly different from the previous period ( P = .07).

CONCLUSIONS

The setup of the sustainable anesthesia groups was associated with a dramatic reduction in the carbon footprint related to halogenated anesthetics. These results should encourage health care institutions to undertake information campaigns toward anesthesia providers so that they also take into account the environmental impact in the choice of anesthetic drugs, in addition to the benefits for the patient and economic concerns.

The Environmental Impact of Open Versus Endoscopic Carpal Tunnel Release

PURPOSE

The environmental impact of common ambulatory hand surgeries has been an area of growing interest in recent years. There were 2 objectives of this study: (1) to quantify the carbon footprint of carpal tunnel surgery and its principal driving components; and (2) to compare the carbon footprints of open carpal tunnel release (oCTR) and endoscopic carpal tunnel release (eCTR).

METHODS

We performed a life cycle assessment to quantify the environmental impacts of 2 surgical procedures: oCTR and eCTR. Patients were retrospectively identified by querying the Mass General Brigham institutional billing database. Fourteen oCTR procedures and 14 eCTR procedures in 28 patients were included in the life cycle assessment. The boundaries of the life cycle assessment were the start and end times of the procedures. The environmental impacts were estimated using the carbon footprint, expressed in the equivalent mass of carbon dioxide released into the atmosphere (kgCO₂-eq). The facility-related, processing-related, solid waste-related, and total kgCO₂-eq were calculated.

RESULTS

The average carbon footprint of carpal tunnel release was 83.1 kgCO₂-eq and was dominated by processing-related and facilities-related factors. The average carbon footprint of eCTR (106.5 kgCO₂-eq) was significantly greater than that of oCTR (59.6 kgCO₂-eq).

CONCLUSIONS

Endoscopic carpal tunnel release leaves a greater carbon footprint than oCTR, and its environmental impact is dominated by facility-related and central processing-related factors.

TYPE OF STUDY/LEVEL OF EVIDENCE

Economic and Decision Analyses IV.

Prospective validation of gas man simulations of sevoflurane in O2/air over a wide fresh gas flow range

The use of inhaled anesthetics has come under increased scrutiny because of their environmental effects. This has led to a shift where sevoflurane in O₂/air has become the predominant gas mixture to maintain anesthesia. To further reduce environmental impact, lower fresh gas flows (FGF) should be used. An accurate model of sevoflurane consumption allows us to assess and quantify the impact of the effects of lowering FGFs. This study therefore tested the accuracy of the Gas Man® model by determining its ability to predict end-expired sevoflurane concentrations (F_ETsevo) in patients using a protocol spanning a wide range of FGF and vaporizer settings. After IRB approval, 28 ASA I-II patients undergoing a gynecologic or urologic procedure under general endotracheal anesthesia were enrolled. Anesthesia was maintained with sevoflurane in O₂/air, delivered via a Zeus or FLOW-i workstation (14 patients each). Every fifteen min, FGF was changed to randomly selected values ranging from 0.2 to 6 L/min while the sevoflurane vaporizer setting was left at the discretion of the anesthesiologist. The F_ETsevo was collected every min for 1 h. For each patient, a Gas Man® simulation was run using patient weight and the same FGF, vaporizer and minute ventilation settings used during the procedure. For cardiac output, the Gas Man default setting was used (= Brody formula). Gas Man®'s performance was assessed by comparing measured with Gas Man® predicted F_ETsevo using linear regression and Varvel's criteria [median performance error (MDPE), median absolute performance error (MDAPE), and divergence]. Additional analysis included separating performance for the wash-in (0-15 min) and maintenance phase (15-60 min). For the FLOW-i, MDPE, MDAPE and divergence were 1% [- 6, 8], 7% [3, 15] and - 0.96%/h [- 1.14, - 0.88], respectively. During the first 15 min, MDPE and MDAPE were 18% [1, 51] and 21% [8, 51], respectively, and during the last 45 min 0% [- 7, 5] and 6% [2, 10], respectively. For the Zeus, MDPE, MDAPE and divergence were 0% [- 5, 8], 6% [3, 12] and - 0.57%/h [- 0.85, - 0.16], respectively. During the first 15 min, MDPE and MDAPE were 7% [- 6, 28] and 13% [6, 32], respectively, and during the last 45 min - 1% [- 5, 5] and 5% [2, 9], respectively. In conclusion, Gas Man® predicts F_ETsevo in O₂/air in adults over a wide range of FGF and vaporizer settings using different workstations with both MDPE and MDAPE < 10% during the first hour of anesthesia, with better relative performance for simulating maintenance than wash-in. In the authors' opinion, this degree of performance suffices for Gas Man® to be used to quantify the environmental impact of FGF reduction in real life practice of the wash-in and maintenance period combined.

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

Both ecological and economic considerations dictate minimising wastage of volatile anaesthetics. To reconcile apparent opposing stakes between ecological/economical concerns and stability of anaesthetic delivery, new workstations feature automated software that continually optimizes the FGF to reliably obtain the requested gas mixture with minimal volatile anaesthetic waste. The aim of this study is to analyse the kinetics and consumption pattern of different approaches of sevoflurane delivery with the same 2% end-tidal goal in all patients. The consumption patterns of sevoflurane of a Flow-i were retrospectively studied in cases with a target end-tidal sevoflurane concentration (Etsevo) of 2%. For each setting, 25 cases were included in the analysis. In Automatic Gas Control (AGC) regulation with software version V4.04, a speed setting 6 was observed; in AGC software version V4.07, speed settings 2, 4, 6 and 8 were observed, as well as a group where a minimal FGF was manually pursued and a group with a fixed 2 L/min FGF. In 45 min, an average of 14.5 mL was consumed in the 2L-FGF group, 5.0 mL in the minimal-manual group, 7.1 mL in the AGC4.04 group and 6.3 mL in the AGC4.07 group. Faster speed AGC-settings resulted in higher consumption, from 6.0 mL in speed 2 to 7.3 mL in speed 8. The Etsevo target was acquired fastest in the 2L-FGF group and the Etsevo was more stable in the AGC groups and the 2L-FGF groups. In all AGC groups, the consumption in the first 8 min was significantly higher than in the minimal flow group, but then decreased to a comparable rate. The more recent AGC4.07 algorithm was more efficient than the older AGC4.04 algorithm. This study indicates that the AGC technology permits very significant economic and ecological benefits, combined with excellent stability and convenience, over conventional FGF settings and should be favoured. While manually regulated minimal flow is still slightly more economical compared to the automated algorithm, this comes with a cost of lower precision of the Etsevo. Further optimization of the AGC algorithms, particularly in the early wash-in period seems feasible. In AGC mode, lower speed settings result in significantly lower consumption of sevoflurane. Routine clinical practice using what historically is called "low flow anaesthesia" (e.g. 2 L/min FGF) should be abandoned, and all anaesthesia machines should be upgraded as soon as possible with automatic delivery technology to minimize atmospheric pollution with volatile anaesthetics.

Effects of Cisatracurium in Sevoflurane and Propofol Requirements in Dog-Undergoing-Mastectomy Surgery

The purpose of the present study was to test whether the addition of cisatracurium in combination with propofol and sevoflurane would result in a change in doses of used anesthetic drugs. Ten dogs (Group A) undergoing elective unilateral mastectomy surgery were included in the study. To induce and maintain anesthesia, subjects received propofol and sevoflurane at varying doses; analgesia was performed with remifentanil. After three months, the same subjects (Group B) underwent contralateral mastectomy and received the same anesthetic protocol with the addition of cisatracurium at a dosage of 0.2 mg/kg−1. The following parameters were monitored during anesthesia: heart rate, systolic blood pressure, end-tidal CO2, oxygen saturation, halogenate requirement, and rectal temperature at baseline (T0), induction (T1), 5 (T5), 10 (T10), 15 (T15), 20 (T20), 25 (T25), 30 (T30), and 35 (T35) time points. In Group A, halogenate requirement was reduced at all the time points other than T1 (p < 0.001); in Group B, the percentage of halogenate requirement was already reduced at T1 and remained constant during the experimental period, showing no significant intragroup differences. The dose requirements of sevoflurane and propofol varied significantly between the two groups, with significantly lower dosages in the Group B (the cisatracurium-treated group). Moreover, patients treated with cisatracurium showed a stable anesthetic plan. The nondepolarizing-muscle-relaxant cisatracurium besylate could be considered a useful adjunct to anesthetic protocols.