Article

Global Warming Potential of Inhaled Anesthetics: Application to Clinical Use

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Abstract

Inhaled anesthetics are recognized greenhouse gases. Calculating their relative impact during common clinical usage will allow comparison to each other and to carbon dioxide emissions in general. We determined infrared absorption cross-sections for sevoflurane and isoflurane. Twenty-year global warming potential (GWP(20)) values for desflurane, sevoflurane, and isoflurane were then calculated using the present and previously published infrared results, and best estimate atmospheric lifetimes were determined. The total quantity of each anesthetic used in 1 minimal alveolar concentration (MAC)-hour was then multiplied by the calculated GWP(20) for that anesthetic, and expressed as "carbon dioxide equivalent" (CDE(20)) in grams. Common fresh gas flows and carrier gases, both air/oxygen and nitrous oxide (N2O)/oxygen, were considered in the calculations to allow these examples to represent common clinical use of inhaled anesthetics. GWP(20) values for the inhaled anesthetics were: sevoflurane 349, isoflurane 1401, and desflurane 3714. CDE(20) values for 1 MAC-hour at 2 L fresh gas flow were: sevoflurane 6980 g, isoflurane 15,551 g, and desflurane 187,186 g. Comparison among these anesthetics produced a ratio of sevoflurane 1, isoflurane 2.2, and desflurane 26.8. When 60% N2O/40% oxygen replaced air/oxygen as a carrier gas combination, and inhaled anesthetic delivery was adjusted to deliver 1 MAC-hour of anesthetic, sevoflurane CDE(20) values were 5.9 times higher with N2O than when carried with air/O2, isoflurane values were 2.9 times higher, and desflurane values were 0.4 times lower. On a 100-year time horizon with 60% N2O, the sevoflurane CDE(100) values were 19 times higher than when carried in air/O2, isoflurane values were 9 times higher, and desflurane values were equal with and without N2O. Under comparable and common clinical conditions, desflurane has a greater potential impact on global warming than either isoflurane or sevoflurane. N2O alone produces a sizable greenhouse gas contribution relative to sevoflurane or isoflurane. Additionally, 60% N2O combined with potent inhaled anesthetics to deliver 1 MAC of anesthetic substantially increases the environmental impact of sevoflurane and isoflurane, and decreases that of desflurane. N2O is destructive to the ozone layer as well as possessing GWP; it continues to have impact over a longer timeframe, and may not be an environmentally sound tradeoff for desflurane. From our calculations, avoiding N2O and unnecessarily high fresh gas flow rates can reduce the environmental impact of inhaled anesthetics.

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... 10 The recent literature from the authors Sherman, Ryan, Andersen, Vollmer, and their respective teams, indicates the real global warming potential for all volatile anaesthetic agents in clinical use today. [11][12][13][14] Climate change has been described as the "defining issue of our time". The wide-ranging effects of climate change are well documented. ...
... Bromine-containing, and to a lesser degree chlorine-containing, substances are known to degrade ozone readily. 15 Studies to investigate the global warming potential of volatile agents were conducted by Andersen et al. 11 and Ryan et al. 14 According to Andersen et al., 11 halothane has a GWP 100 of 50, compared to 510, 2 540 and 130 for isoflurane, desflurane and sevoflurane, respectively. These results differ from results by a comparative study by Ryan et al. 14 Waste not, want not: the anaesthesiologist and the environment from another study that have been proven inaccurate by Calvert et al. 11,17 Although the exact values of the GWP of volatile agents differ in the literature, it is clear that all values calculated are very significant. ...
... 15 Studies to investigate the global warming potential of volatile agents were conducted by Andersen et al. 11 and Ryan et al. 14 According to Andersen et al., 11 halothane has a GWP 100 of 50, compared to 510, 2 540 and 130 for isoflurane, desflurane and sevoflurane, respectively. These results differ from results by a comparative study by Ryan et al. 14 Waste not, want not: the anaesthesiologist and the environment from another study that have been proven inaccurate by Calvert et al. 11,17 Although the exact values of the GWP of volatile agents differ in the literature, it is clear that all values calculated are very significant. ...
... As the climate emergency becomes ever more apparent, threatening to decimate complete ecosystems and triggering vast medical and societal emergencies [2], it is everyone's duty to minimize their personal ecological impact. Given the strong heat-trapping potency of volatile anaesthetics, anaesthetists have an important responsibility in this regard [3]. Remarkably simple choices made by the anaesthetist can reduce the climate impact by orders of magnitude without negatively impacting the quality of care. ...
... Resulting from the complexities of the atmospheric physics and chemistry, which is extensively described elsewhere, sevoflurane has a global heating effect which is 349 times worse than CO 2, while desflurane is even 3714 times worse [3]. Because volatile anaesthetics are widely and often continuously used in operating theatres, the total consumption of volatile anaesthetics in conventional low-flow settings may easily amount to 40 L of sevoflurane or 100 L of desflurane per anesthesia workstation per year. ...
... Because volatile anaesthetics are widely and often continuously used in operating theatres, the total consumption of volatile anaesthetics in conventional low-flow settings may easily amount to 40 L of sevoflurane or 100 L of desflurane per anesthesia workstation per year. This amounts to a financial cost of well in excess of 16,000€ per year of volatile anaesthetics, and a greenhouse gas equivalent of 21 metric tons of CO 2 for sevoflurane or 542 metric tons for desflurane [3,5]. As such, a reduction in volatile anaesthetic waste would lead to significant financial savings-easily covering the additional cost of modern equipment-and a huge reduction in atmospheric pollution. ...
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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.
... Several studies suggest that actual benefits of desflurane are small and can be readily replaced with other anaesthetic agents that are more environmentally friendly. [16][17][18] Chronic occupational exposure to unscavenged waste anaesthetic gases (WAGs) has also been reported to cause potential adverse effects. ...
... 27 The principle of this revolves around a lower FGF equating to higher fractions of gases recirculated within a system, leading to less wastage. Ryan and Nielsen 16 propose achieving ideal FGF rates at 2 L/ min with sevoflurane, and 0.5 L/min with desflurane. More recent studies have shown that using FGF <1 L/min with sevoflurane is safe, despite recommendations against this on product information sheets due to concern for compound A production. 28 Gordon 24 further emphasises the importance of low-flow anaesthesia as any FGF that exceeds the patient's needs and the system requirements will be delivered essentially unchanged into the atmosphere. ...
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Sustainability interventions were implemented at the Royal Brisbane and Women’s Hospital (RBWH) following identification of inhaled anaesthetic gases as a target for reducing medical carbon emissions. This quality improvement study assessed and evaluated the impact of sustainability interventions on the environmental and financial cost of inhaled anaesthetic gas use in order to guide future initiatives and research in reducing carbon emissions from healthcare practice. Ethical exemption was granted from the RBWH Research Ethics Committee (EX/2021/QRBW/76078). Usage (bottles) and expenditure for desflurane and sevoflurane from January 2016 to December 2021 were obtained. Global warming potential and carbon dioxide equivalent (CO 2 e) were used to report environmental impact of volatile agents. Methods to estimate this were performed in Excel based on Campbell and Pierce methodology. An Environmental Protection Agency greenhouse gas equivalency calculator was used to convert CO 2 e to equivalent petrol carbon emissions and kilometres travelled by a typical passenger vehicle. The total number of bottles of sevoflurane and desflurane purchased between January 2016 and December 2021 decreased by 34.76% from 1991 to 1299. The number of desflurane bottles purchased decreased by 95.63% from 800 to 35 bottles. The number of sevoflurane bottles purchased increased by 6.13% from 1191 bottles to 1264 bottles. This was achieved by implementing quality improvement interventions such as staff education of desflurane-sparing practices, distribution of posters and progressive removal of desflurane from operating theatres. Total carbon emission from volatile anaesthetics equalled 2326 tonnes CO 2 e. Combined desflurane and sevoflurane emissions decreased by 87.88%. In 2016, desflurane made up 92.39% of the annual CO 2 e, which steadily decreased to 33.36% in 2021. Combined sevoflurane and desflurane usage costs decreased by 58.33%. Substantial reductions in carbon emissions from volatile anaesthetics demonstrate the significant degree to which environmentally sustainable practices have been implemented. Applying desflurane-sparing practice can heavily limit anaesthetic drug expenditure and contribution to environmental waste. This is important given the global health sector’s challenge to optimise patient outcomes in the face of global climate change crisis.
... An estimated 51% of emissions associated with ORs is attributed to inhaled anesthetic gases ( 45 ). Despite being released in small amounts, inhaled anesthetics have significantly higher global warming potential than carbon dioxide and are recognized today as GHGs ( 46 ). The currently available inhaled anestheticssevoflurane, desflurane, and isoflurane-undergo very little in vivo metabolism with over 95% exhaled ( 46 ). ...
... Despite being released in small amounts, inhaled anesthetics have significantly higher global warming potential than carbon dioxide and are recognized today as GHGs ( 46 ). The currently available inhaled anestheticssevoflurane, desflurane, and isoflurane-undergo very little in vivo metabolism with over 95% exhaled ( 46 ). Upon exhalation, the gases are vented out of the building as medical waste gases that directly enter the atmosphere. ...
... The knowledge about the influence of anaesthetic gases is evolving and deepening from year to year, which was propagated by many authors 3,7,14,33,34 . In 2011 Ishizawa et al. 35 said that "All volatile anaesthetics that are currently used are halogenated compounds destructive to the ozone layer". ...
... The possibility of replacing nitrous oxide in the anaesthetic gas mixture was also considered to reduce the harmful effects on global warming. However, after replacing the carrier gas with an air/oxygen mixture, this effect turned out to be even greater 3,7 . ...
Article
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Isoflurane is an anaesthetic gas widely used in both human and veterinary medicine. All currently used volatile anaesthetics are ozone-depleting halogenated compounds. The use of total intravenous anaesthesia (TIVA) allows to induce the effect of general anaesthesia by administering drugs only intravenously without the use of anaesthetic gases. This allows you to create a protocol that is safe not only for the patient, but also for doctors and the environment. However, so far, no anaesthetic protocol based on induction of anaesthesia with tiletamine-zolazepam without the need to maintain anaesthesia with anaesthetic gas has been developed. Our study showed that the use of this combination of drugs for induction does not require the use of additional isoflurane to maintain anaesthesia. Thanks to Dixon's up-and-down method we proved that with the induction of anaesthesia with tiletamine-zolazepam at a dose of 5 mg/kg the use of isoflurane is not needed to maintain anaesthesia in minimally invasive surgical procedures. Until now, this dose has been recommended by the producer for more diagnostic than surgical procedures or for induction of general anaesthesia. The maintenance was required with anaesthetic gas or administration of another dose of the tiletamine-zolazepam. The results obtained in this study will allow for a significant reduction in the consumption of isoflurane, a gas co-responsible for the deepening of the greenhouse effect, having a negative impact on patients and surgeons. These results are certainly the first step to achieving a well-balanced and safe TIVA-based anaesthetic protocol using tiletamine-zolazepam, the obvious goal of which will be to maximize both the safety of the patient, people involved in surgical procedures, and the environment itself. Being aware of the problem of the greenhouse effect, we are committed to reducing the consumption of anaesthetic gases by replacing them with infusion agents.
... A previous study demonstrated that desflurane is associated with faster emergence, a shorter time to eye-opening, and an earlier response to verbal commands than sevoflurane [4]. In contrast, sevoflurane has been reported to offer the advantages of low airway irritation, cardioprotection, and minor impact on global warming [5,6]. A previous meta-analysis showed no significant difference in the incidence of PONV between sevoflurane-and desflurane-based general anesthesia [7]. ...
... A previous study demonstrated that the carbon dioxide equivalent (CDE 20 ) of sevoflurane and desflurane under 1 minimal alveolar concentration (MAC)hr at 2 L fresh gas flow was 6980 g and 187,186 g, respectively. The twenty-year global warming potential (GWP 20 ) value for the latter was higher than that for the former [6]. Hence, sevoflurane seemed preferable over desflurane because of the lower incidence of late POV and PON and its environmental friendliness. ...
Article
Study objective This systematic review and meta-analysis aimed at assessing the effects of two commonly used anesthetics in general anesthesia (GA), sevoflurane and desflurane, on early postoperative vomiting (POV) in hospitalized adults. Design Systematic review and meta-analysis of randomized controlled trials (RCTs). Setting Early postoperative vomiting after GA. Patients A total of 266 adult patients receiving inpatient surgeries under GA maintained with sevoflurane or desflurane. Interventions We searched PubMed, Medline, Cochrane Central Register of Controlled Trials, ScienceDirect, and Embase for eligible RCTs comparing postoperative outcomes following sevoflurane- or desflurane-maintained anesthesia. Measurements The primary outcome was early POV. Secondary outcomes included late POV, early and late postoperative nausea (PON), time to extubation, and emergence time. Main results Eight trials were included. There was no significant difference in the risk of early POV (risk ratio [RR] 1.03, 95% confidence interval [CI] 0.64–1.64, p = 0.91). No significant difference in early PON was observed (RR 1.09; 95% CI, 0.77–1.56; p = 0.62). Nevertheless, the incidence of late POV and late PON were significantly lower in the sevoflurane group than that in the desflurane group (RR 0.47, 95% CI 0.23–0.94, p = 0.03; RR 0.45, 95% CI 0.24–0.84, p = 0.01, respectively). The extubation time was longer in the sevoflurane group than in the desflurane group (standardized mean difference [SMD] 0.56, 95% CI 0.14–0.97, p = 0.009). The emergence time of patients in the sevoflurane group was longer than that in those receiving desflurane (SMD 0.76, 95% CI 0.1–1.42, p = 0.02). Conclusions Desflurane had the same effects on early POV and early PON as sevoflurane. However, the association between late POV and late PON with desflurane was stronger than that with sevoflurane if the effects of opioids were not considered. The desflurane group had shorter time to extubation and emergence time than the sevoflurane group. PROSPERO registration number: CRD42020218988.
... Twenty-year global warming potential (GWP20) values for the inhaled anesthetics are 3,714 for desflurane, 1,401 for isoflurane, and 349 for sevoflurane. 21 To illustrate the impact of these gases in more familiar terms, the use of an anesthetic machine for 1 hour of desflurane anesthesia is equivalent to driving 370 km in a car, compared with 50 km for 1 hour of sevoflurane use. ...
Article
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Health care accounted for 4.6% of global greenhouse gas (GHG) emissions in 2017. If global health care services were a country, they would represent the fifth-largest source of GHG emissions. Health care emissions stem directly from the operations of health care facilities (defined as scope 1 emissions) as well as indirectly from purchased sources of energy (scope 2) and the supply chain of health care services and goods (scope 3). In this article, the authors briefly review sources of GHG emissions in health care and explore opportunities for mitigation that can help to move toward an environmentally sustainable, net-zero health care system. The authors focus on mechanisms to reduce scope 1 and scope 2 emissions along with scope 3 emissions that can be significantly influenced by health care systems. They categorize interventions across five categories: buildings, transport, food, pharmaceuticals, and waste. As a sixth category, they detail the role that physicians can play in mitigating emissions from health care and society in general. The authors also describe co-benefits of these interventions along with potential barriers to adoption. Operationalizing these changes will require actions at individual, institutional, and regional/federal levels, employing a sustainability lens in each decision that impacts the delivery of health care. The world has already warmed by at least 1.1°C compared with preindustrial levels, resulting in worsening planetary and human health, and is moving closer to the agreed limit of maintaining temperatures "well below 2°C."1 Climate change has resulted in increased frequency of heat waves,
... Finally, the opportunity to use low doses of anesthetic drugs represents a challenge not only for animal health but also for the environment. The influence of anaesthetic gases on global warming is being investigated, as some authors claim that volatile anaesthetics are halogenated compounds destructive to the ozone layer, so any protocol leading to a reduction of these drugs in addition to safeguarding animal welfare may also improve environmental pollution [37][38][39][40]. ...
Article
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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.
... These ratings could be explained by the widely shared concept of antibiotic stewardship, if taking into account the impact of antibiotics on the environment (Richards et al., 2004), and the evolving evidence showing that avoidance of inhalation anaesthetics significantly reduce the carbon footprint of theatres. The effect of a single inhalation general anaesthesia is estimated to be equivalent to releasing approximately 22 kg of CO 2 into the environment (MacNeill et al., 2017;Ryan and Nielsen, 2010) and using alternative techniques such as WALANT, or similarly blocks, regional or intravenous anaesthesia would have a significantly lesser impact on the environment. Similarly, although virtual clinics would reduce the carbon footprint by cutting down the need for patients to travel to hospital, the survey showed that these would only be considered by 40% of respondents. ...
... Previous studies have addressed the environmental impacts of GHGs caused by the healthcare sector, primarily contributed to the large energy consumption of treatment to procedures. To illustrate, Gilliam et al. (Gilliam, Davidson, & Guest, 2008) estimated direct CO 2 emissions from laparoscopic surgeries, while Ryan and Nielsen (Ryan & Nielsen, 2010) determined the 20-year global warming potentials of three common anesthetic gases, including sevoflurane, isoflurane, and desflurane, through clinical scenarios to estimate the impacts on the environment. The consumption and generation of energy are associated with significant damages to the climate, environment, and, consequently, economy. ...
Article
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With the increasing demand for hospital services amidst the COVID-19 pandemic, allocation of limited public resources and management of healthcare services are of paramount importance. In the field of patient flow scheduling, previous research primarily focused on classical-based objective functions, while ignoring environmental-based objective functions. This study presents a flexible job shop scheduling problem to optimize patient flow and, thereby, minimize the total carbon footprint, as the sustainability-based objective function. Since flexible job shop scheduling is an NP-hard problem, a metaheuristic optimization algorithm, called Chaotic Salp Swarm Algorithm Enhanced with Opposition-Based Learning and Sine Cosine (CSSAOS), was developed. The proposed algorithm integrates the Salp Swarm Algorithm (SSA) with chaotic maps to update the position of followers, the sine cosine algorithm to update the leader position, and opposition-based learning for a better exploration of the search space. generating more accurate solutions. The proposed method was successfully applied in a real-world case study and demonstrated better performance than other well-known metaheuristic algorithms, including differential evolution, genetic algorithm, grasshopper optimization algorithm, SSA based on opposition-based learning, quantum evolutionary SSA, and whale optimization algorithm. In addition, it was found that the proposed method is scalable to different sizes and complexities.
... Among all the volatile anesthetics currently used, desflurane has the lowest blood solubility, suggesting the fastest induction and awakening [4]. Despite the advantage of faster recovery, even compared to sevoflurane, undesirable effects, including airway stimulation, tachycardia, and greenhouse effect, can limit the use of desflurane [16][17][18][19]. In such cases, sevoflurane can be mostly chosen for anesthesia induction and maintenance due to its little airway stimulation effect. ...
Article
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While sevoflurane and desflurane have been regarded as inhalation agents providing rapid induction and emergence, previous studies demonstrated the superiority of desflurane-anesthesia compared to sevoflurane-anesthesia in the postoperative recovery in obese and geriatric patients. We investigated whether a short-term switch of sevoflurane to desflurane at the end of sevoflurane-anesthesia enhances patient postoperative recovery profile in non-obese patients. We randomly divide patients undergoing elective surgery (n = 60) into two groups: sevoflurane-anesthesia group (Group-S, n=30) and sevoflurane-desflurane group (Group-SD, n=30). In Group-S, patients received only sevoflurane-anesthesia until the end of surgery (for >2 hours). In Group-SD, sevoflurane was stopped and switched to desflurane-anesthesia before the completion of sevoflurane-anesthesia (for approximately 30 minutes). We assessed the intergroup differences in the times to get eye-opening, extubation, and a bispectral index of 80 (BIS-80). Group-SD showed significantly shorter times to get eye-opening (438±101 vs. 295±45 s; mean difference, 143 s; 95% confidence interval [CI], 101–183; p<0.001), extubation (476±108 vs. 312±42 s; mean difference, 164 s; 95% CI, 116–220; p<0.001), and BIS-80 (378±124 vs. 265±49 minutes; mean difference, 113 s; 95% CI, 58–168 p<0.001) compared to Group-S. There was no between-group difference in postoperative nausea, vomiting, and hypoxia incidences. Our results suggested that the short-term (approximately 30 minutes) switch of sevoflurane to desflurane at the end of sevoflurane-anesthesia can facilitate the speed of postoperative patient recovery.
... Heat stress negatively affects the ability of an animal to become pregnant through many mechanisms affecting fertilization, follicular development, and early embryonic development. When the rectal temperature of the animals increased from 38.5 to 40°C at 72 h after insemination, pregnancy rate decreased up to 50% [7] . A significant reduction in the pregnancy rate in beef cattle during summer (62%) when the THI was equal to or above 72.9 ...
Article
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Heat stress during the summer disturbs reproductive processes in farm animals as it affects the physiology of reproductive tract by several means like hormonal imbalance, decreased oocyte and semen quality, and decreased embryo development and survival. Heat causes decreased secretion of the luteinizing hormone and oestradiol which causes reduced length and intensity of estrus expression, increased incidence of anoestrus and silent heat in farm animals. Oocytes exposed to thermal stress lose its competence for fertilization and development into the blastocyst stage, which results in decreased fertility because of the production of poor-quality oocytes and embryos. Furthermore, low progesterone secretion limits the endometrial functions, and subsequently embryo development. In addition, the increased secretion of endometrial prostaglandin F2 alpha during heat stress threatens the maintenance of pregnancy. The effects of heat stress on livestock can be minimized via adapting suitable scientific strategies comprising physical modifications of the environment, nutritional management and genetic development of breeds that are less sensitive to heat stress. In addition, the summer infertility may be countered through advanced reproductive technologies involving hormonal treatments, timed artificial insemination, and embryo transfer, which may enhance the chances for establishing pregnancy in farm animals. Introduction Climate affects the performance, health, and well-being of livestock. Among the environmental variables affecting livestock, heat stress seems to be one of the most intriguing factors hampering animal production in many regions of the world. Heat stress due to high ambient temperatures, high direct and indirect solar radiation and humidity are environmental stressing factors leads to strain on animals. Even though new knowledge on the animal responses to the environment continually arises, managing livestock to reduce the impact of climate remains a challenge. Considerable efforts are, therefore, needed from livestock researchers to counter the impact of environmental stresses on livestock production. Besides ensuring the livelihood security to our poor and marginal farmers, stress mitigation can also improve the economy of livestock industry. Hence, it is crucial to understand the impact of environmental stress on livestock production and reproduction. These efforts may help in identifying the appropriate targets for developing suitable mitigation strategies [1]. Thermal stress effects on livestock are of multifactorial nature. It directly alters and impairs the cellular functions in various tissues of the body and the redistribution of blood flow, as well as the reduction in food intake, which ultimately results in reduced production performance. Reproductive functions of livestock are particularly vulnerable to climate change; it has been established that large ruminants are more prone to heat stress compared with small ruminants. Heat stress is the major cause for infertility and reproductive inefficiency in livestock, resulting in profound economic losses. Heat stress reduces the libido, fertility, and embryonic survival in livestock and favours the occurrence of diseases in neonates with reduced immunity. Heat stress affects the fertility and reproductive performance of livestock species through compromising the functions of the reproductive tract, disrupting the hormonal balance, decreasing the oocyte quality, and thereby decreasing embryo development and survival [2]. The threshold level of temperature humidity index (THI) for the high performance in terms of milk yield and reproduction is around THI 72 in tropical and subtropical climates. However, recent studies on THI in temperate climate emphasized that the THI lower than 68 is suitable for cattle performance and welfare [3] .
... To calculate the amount of each type of non-gaseous anesthetics used for each patient, the amounts of each type of anesthetic across all time periods were summed into a single value. For gaseous anesthetics, the volume of anesthetic was calculated using this equation: Gas (L) = Time * Free gas flow (L/min) * End-tidal gas concentration (%) [2] . This was performed at every 15minute time interval in the anesthesia flowsheet, and then summed to provide a total volume for each type of anesthetic. ...
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The datasets presented here quantify and compare the relative carbon footprints emitted by general versus spinal anesthesia in patients undergoing single-level transforaminal lumbar interbody fusions (TLIFs). Data were retrospectively collected from electronic medical records of 100 consecutive patients who underwent a single-level TLIF from a single neurosurgeon at a U.S. academic center. 50 patients were under general anesthesia, and another 50 patients were under spinal anesthesia. Clinic and operative notes were used to extract demographic and surgical information, whereas anesthesia records were used to extract anesthetic information. Using the anesthetic information, carbon dioxide equivalents (CO2e) were calculated for each type of anesthetic and summed together to compute the total carbon footprint for each patient. Our article entitled “Assessing the environmental carbon footprint of spinal versus general anesthesia in single-level transforaminal lumbar interbody fusions” is based on this data [1]. Raw datasets of the primary data collection as well as cleaned and analyzed datasets are presented. These datasets highlight the first known environmental impact calculation from medical records of a spine procedure, serving as a model for other interested investigators to explore and emulate. This data brief may help to pave the way towards future environmental research and practice changes within neurosurgical and orthopedic literature, an issue critical to the sustainability of our modern society.
... 4 Direct comparators equating the environmental impact of these gases suggest that using desflurane for 1 hour has a similar effect to driving 235 to 470 miles in a mid-sized family car. 25 The impact of halogenated gases is well characterised where they contribute to the broader issue of chemical waste and the "greenhouse gas effect". 26,27 Nitrous oxide is also widely used in clinical procedures and has a marked environmental impact with an atmospheric lifetime of 150 years and incurs a global warming potential greater than 300 times that of CO 2 per equivalent volume. ...
... Anesthesia providers can minimize their footprint by agent selection and FGF reduction. Multiple studies suggest both desflurane and nitrous oxide should only be used when they reduce morbidity and mortality compared to other drugs [5,25,29,30], because their environmental impact is much higher than that of sevoflurane [5,27,29,31]. Sevoflurane is, however, not ideal either, and decisions concerning agent use should always involve a cost-benefit analysis [1]. ...
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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 (FETsevo) 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 FETsevo 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 FETsevo 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 FETsevo 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.
... Heat stress negatively affects the ability of an animal to become pregnant through many mechanisms affecting fertilization, follicular development, and early embryonic development. When the rectal temperature of the animals increased from 38.5 to 40°C at 72 h after insemination, pregnancy rate decreased up to 50% [7] . A significant reduction in the pregnancy rate in beef cattle during summer (62%) when the THI was equal to or above 72.9 ...
Article
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Heat stress during the summer disturbs reproductive processes in farm animals as it affects the physiology of reproductive tract by several means like hormonal imbalance, decreased oocyte and semen quality, and decreased embryo development and survival. Heat causes decreased secretion of the luteinizing hormone and oestradiol which causes reduced length and intensity of estrus expression, increased incidence of anoestrus and silent heat in farm animals. Oocytes exposed to thermal stress lose its competence for fertilization and development into the blastocyst stage, which results in decreased fertility because of the production of poor-quality oocytes and embryos. Furthermore, low progesterone secretion limits the endometrial functions, and subsequently embryo development. In addition, the increased secretion of endometrial prostaglandin F2 alpha during heat stress threatens the maintenance of pregnancy. The effects of heat stress on livestock can be minimized via adapting suitable scientific strategies comprising physical modifications of the environment, nutritional management and genetic development of breeds that are less sensitive to heat stress. In addition, the summer infertility may be countered through advanced reproductive technologies involving hormonal treatments, timed artificial insemination, and embryo transfer, which may enhance the chances for establishing pregnancy in farm animals. Introduction Climate affects the performance, health, and well-being of livestock. Among the environmental variables affecting livestock, heat stress seems to be one of the most intriguing factors hampering animal production in many regions of the world. Heat stress due to high ambient temperatures, high direct and indirect solar radiation and humidity are environmental stressing factors leads to strain on animals. Even though new knowledge on the animal responses to the environment continually arises, managing livestock to reduce the impact of climate remains a challenge. Considerable efforts are, therefore, needed from livestock researchers to counter the impact of environmental stresses on livestock production. Besides ensuring the livelihood security to our poor and marginal farmers, stress mitigation can also improve the economy of livestock industry. Hence, it is crucial to understand the impact of environmental stress on livestock production and reproduction. These efforts may help in identifying the appropriate targets for developing suitable mitigation strategies [1]. Thermal stress effects on livestock are of multifactorial nature. It directly alters and impairs the cellular functions in various tissues of the body and the redistribution of blood flow, as well as the reduction in food intake, which ultimately results in reduced production performance. Reproductive functions of livestock are particularly vulnerable to climate change; it has been established that large ruminants are more prone to heat stress compared with small ruminants. Heat stress is the major cause for infertility and reproductive inefficiency in livestock, resulting in profound economic losses. Heat stress reduces the libido, fertility, and embryonic survival in livestock and favours the occurrence of diseases in neonates with reduced immunity. Heat stress affects the fertility and reproductive performance of livestock species through compromising the functions of the reproductive tract, disrupting the hormonal balance, decreasing the oocyte quality, and thereby decreasing embryo development and survival [2]. The threshold level of temperature humidity index (THI) for the high performance in terms of milk yield and reproduction is around THI 72 in tropical and subtropical climates. However, recent studies on THI in temperate climate emphasized that the THI lower than 68 is suitable for cattle performance and welfare [3] .
... However, it is possible to use propofol for both the induction and maintenance phases, in a process known as total intravenous anaesthesia (TIVA). There is a growing body of evidence of the advantages of TIVA over the more conventional volatile-based anaesthesia, including: reduced short-term side-effects [3], reduced cognitive effects [4][5][6], the potential for improved long-term survival rates for cancer patients [7,8], and a significantly reduced environmental impact [9][10][11]. ...
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This paper presents a review of established and emerging methods for detecting and quantifying the intravenous anaesthetic propofol in solution. There is growing evidence of numerous advantages of total intravenous anaesthesia using propofol compared to conventional volatile-based anaesthesia, both in terms of patient outcomes and environmental impact. However, volatile-based anaesthesia still accounts for the vast majority of administered general anaesthetics, largely due to a lack of techniques for real-time monitoring of patient blood propofol concentration. Herein, propofol detection techniques that have been developed to date are reviewed alongside a discussion of remaining challenges.
Article
Despite the growing evidence of the benefits of total-intravenous anaesthesia using propofol compared to conventional volatile-based anaesthesia, both in terms of environmental impact and patient outcomes, the majority of administered general anaesthetics use volatile agents. A significant reason for this is the lack of suitable methods for continuous, real-time propofol monitoring. Here we present a cytochrome P450 2B6/carbon nanotube/graphene oxide/metal oxide nanocomposite sensor for propofol monitoring. The enzyme prevents electrode fouling by converting the propofol into a quinone/quinol redox pair and the nanocomposite enables rapid and sensitive detection. The nanocomposite was synthesised via a simple ‘green synthesis’-based approach using an extract of common bay laurel. It was found that composites containing iron oxide nanoparticles resulted in the best performance, with a limit of detection of 7.0 ± 0.7 ng/ml and a sensitivity of 29.9 ± 6.4 nA/μg/ml/mm². The sensor demonstrated good specificity with respect to several common perioperative drugs, propofol detection was demonstrated in a ‘serum-like’ solution and produced a linear response across the therapeutic range of propofol (1–10 μg/ml).
Article
The climate crisis is omnipresent and one of the most pressing challenges of the 21st century. In the position paper “Ecological sustainability in anaesthesiology and intensive care medicine”, the Professional Association of German Anesthesiologists (BDA) and the German Society for Anesthesiology and Intensive Care Medicine (DGAI) made specific recommendations which contribute to a consistent and sustainable reduction in CO2 emissions. This article highlights the aspects of the position paper which the authors believe can be easily implemented in clinical practice and have a major effect on reducing CO2 emissions. The recommendations focus on the topics of medication, medical products, waste management, mobility, energy management, research and teaching with practical examples and results from the Green Team (Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn) and from the toolkit of the DGAI/BDA. Ways are shown to limit inhalation anesthetic-caused CO2-emissions, to reduce drug waste, to change single-use for reusable materials and to develop sustainable waste concepts.
Article
Health care systems contribute a significant amount of global greenhouse gas (GHG) emissions, and operating rooms are among the most resource intensive and waste producing locations in hospitals. Surgery's high environmental impact is due to many factors including: widespread use of anesthetic and medical gases; pharmaceutical production and waste; substantial non-recycled waste from disposable single-use devices; and energy consumption for equipment use and reprocessing, in addition to the significant energy needed for heating, cooling and ventilation of ORs. As the urgency of addressing global climate change increases, health care providers must do all they can to minimize the environmental impacts of health care in a sustainable, yet safe manner. Thoughtful management techniques by anesthesiologists, surgeons, and operating room staff before, during, and after procedures can minimize the environmental impact of surgery while maintaining cost-efficient, excellent patient care.
Article
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Opportunities offered by precision medicine have long been promised in the medical and health literature. However, precision medicine – and the methodologies and approaches it relies on – also has adverse environmental impacts. As research into precision medicine continues to expand, there is a compelling need to consider these environmental impacts and develop means to mitigate them. In this article, we review the adverse environmental impacts associated with precision medicine, with a particular focus on those associated with its underlying need for data-intensive approaches. We illustrate the importance of considering the environmental impacts of precision medicine and describe the adverse health outcomes that are associated with climate change. We follow this with a description of how these environmental impacts are being addressed in both the health and data-driven technology sector. We then describe the (scant) literature on environmental impacts associated with data-driven precision medicine specifically. We finish by highlighting various environmental considerations that precision medicine researchers, and the field more broadly, should take into account.
Article
Sustainability means reducing waste, principally through ‘reduce-reuse-recycle’. Lean pathways for orthopaedics surgery are an example of sustainable healthcare by reducing waste. Streamlining care and processes at every stage improves patient outcomes, minimizes costs and reduces carbon emissions. Perioperative care, from the moment an operation is contemplated until full recovery, has variability in practice. Preoperative assessment should be linked to optimization. Interventions such as exercise reduce complications by between 30% and 80%. Successful interventions include: ‘surgery schools’; early detection of anaemia; pre-emptive discharge planning; preoperative introduction of walking aids; planning of intraoperative equipment; techniques that allow early mobilization/discharge and reduced use of anaesthetic vapours. New streamlined pathways should be developed with the whole multidisciplinary team (MDT) focusing on practicalities. A ‘trans-disciplinary team’ approach, sharing skills, works better than silos. A standardized pathway allows care to be individualized where needed. In trauma care, lean pathways mean common issues can be pre-empted. For example, good patient information given by the emergency department, shared decision-making in fracture clinic and planning for day-case trauma lists. Change management is difficult. Tips include: learning from other sites; creating good information for patients; analysing unit data comparative to other sites; and discussing improvements as a whole team.
Article
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.
Article
Background Climate change is a significant public health threat. Health care comprises 10% of greenhouse gas emissions in the United States, where surgery is especially resource intensive. We did a systematic review to assess and summarize the published evidence of the environmental impact of surgery. Methods We searched Medline, Embase, Web of Science, and GreenFILE databases for publications that report any environmental impact measure by all surgical subspecialties, including anesthesia. Inclusion criteria were published in English, original research, and passed peer review. Because data were heterogeneous and the aim was broad, we conducted a qualitative summary of data. Where possible, we compare impact measures. Results In the study, 167 articles were identified by our search strategy and reviewed, of which 55 studies met criteria. Eight were about anesthesia, 27 about operating room waste, and 6 were life cycle assessments. Other topics include carbon footprint and greenhouse gas emissions. Nine papers fell into 2 or more categories. Overall, the operating room is a significant source of emissions and waste. Using anesthetic gases with low global warming potential reduces operating room emissions without compromising patient safety. Operating room waste is often disposed of improperly, often due to convenience or knowledge gaps. There are environmental benefits to replacing disposable materials with reusable equivalents, and to proper recycling. Surgeons can help implement these changes at their institution. Conclusion Although there is a clear need to lower the carbon footprint of surgery, the quality of research with which to inform protocol changes is deficient overall. Our attempt to quantify surgery’s carbon footprint yielded heterogeneous data and few standardized, actionable recommendations. However, this data serves as a starting point for important future initiatives to decrease the environmental impact of surgery.
Article
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.
Article
Ab initio quantum chemistry calculations were performed to investigate the degradation reaction mechanism of sevoflurane radical in the presence of NO. The geometries of all the species were optimized using B3LYP/6-311++G(d, p) method. Single point energies were further calculated using QCISD(T)/6-311G(d, p). Three pathways P(1), P(2) and P(3) were found and six reaction steps were analyzed with the Gibbs barriers of 3.16, 39.45, 53.64, 49.64, 156.16 and 78.47 kJ/mol, respectively. The corresponding rate constants were also calculated. The results show that Reaction (3) is a rate-determining step of (CF3)2CHOC(O)F formation using QCISD(T)//B3LYP methods. However, this rate-determining step is probably affected by methodology errors. Reaction 6 is a rate-determining one resulting in the formation of (CF3)2CO and HCOF. These findings are helpful for understanding the atmospheric chemistry of sevoflurane radical degradation process.
Article
Obstetric general anaesthesia technique usually involves intravenous induction and maintenance with volatile agents. Total intravenous anaesthesia has gained in popularity in non-obstetric practice because of environmental concerns associated with volatile inhalational anaesthetics and evidence of a superior recovery profile. Publications on the use of total intravenous anaesthesia for caesarean delivery are sparse. The limited evidence suggests that total intravenous anaesthesia may confer benefits for caesarean delivery, including reducing the risk of haemorrhage. However, there are practical barriers to utilising total intravenous anaesthesia in obstetric anaesthesia. We discuss the evidence and potential role of total intravenous anaesthesia for caesarean delivery.
Article
Background The U.S. healthcare sector produces ∼10% of national greenhouse gas emissions, paradoxically harming human health. Neurosurgery is a resource-intensive specialty that likely contributes significantly, yet literature assessing this impact is absent. We investigate the difference in carbon emissions between spinal versus general anesthesia in lumbar spine surgery. Methods 100 patients underwent a single-level transforaminal lumbar interbody fusion (TLIF) from a single surgeon, 50 receiving spinal anesthesia and 50 receiving general anesthesia. Data was extracted from patient records. Amounts of anesthetics were calculated from intraoperative records and converted to carbon dioxide equivalents (CO2e). Results The median CO2e for general anesthesia was 4,725 grams vs. 70 grams for spinal anesthesia (p=7.07e-18). Mean CO2e for general anesthesia was 22,707 grams vs. 63 grams for spinal anesthesia. Desflurane use led to outsized carbon emissions. Carbon footprint comparisons are made to familiar units such as miles driven by a car, and are provided for a single TLIF, 50 TLIFs (single surgeon’s cases in a year), and 488,000 TLIFs (annual spinal fusions in the U.S.). Conclusion This is one of the first known comparative carbon footprint study performed in neurosurgical literature. We highlight the dramatic carbon footprint reduction associated with using spinal anesthesia and reflect a single neurosurgeon’s change in practice from using only general anesthesia to incorporating the use of spinal anesthesia. Within general anesthesia patients, desflurane use was particularly harmful to the environment. We hope that our study will pave the way towards future research aimed at uncovering and reducing neurosurgery’s environmental impact.
Article
Objectives: To compare cost and time spent in surgical and postoperative courses in patients with obstructive sleep apnea (OSA) undergoing surgery with either total intravenous anesthesia (TIVA) or inhalational anesthesia. Study design: Retrospective chart review. Methods: Retrospective review on patients undergoing surgery for OSA under general anesthesia from January 2019 to October 2020. Cost per service was acquired for the day of surgery. Results: A total of 230 patients were included: 95 received TIVA; 135 received inhalation anesthesia. Total cost was significantly higher in the TIVA nasal surgery group by $286 (P = .035). TIVA produced significantly higher pharmacy and operating room costs across all surgeries and OSA severities. These increased costs were offset by significantly lower supply costs in upper airway stimulator (UAS, -$419.50; P = .007) and uvulopalatopharyngoplasty (UPPP, -$115.16; P = .015) patients receiving TIVA. In the TIVA cohort, there was a trend toward lower recovery room costs after UAS (-$111.09; P = .063) and nasal surgery (-$64.45; P = .096) and anesthesia costs after nasal surgery (-$36.67; P = .054). Total recovery time was reduced by 18 minutes (P = .004) for nasal surgery, 25 minutes (P = .043) for UAS, and 27 minutes (P = .147) for UPPP patients receiving TIVA. Conclusion: When used in an outpatient setting for patients with OSA, TIVA adds to pharmacy and operating room costs, but this is usually offset by lower supply, anesthesia, and recovery room costs. We found decreased recovery times in the TIVA cohort. TIVA has proven benefits in patient outcomes and can be cost-effective in OSA surgery. Level of evidence: 3 Laryngoscope, 2022.
Poster
Carcinoid tumours are a subtype of neuroendocrine tumour, which typically begin in the digestive tract with the capability of producing bioactive substances such as serotonin, histamine and kinins. Perioperative anaesthetic management is required due to the possibility of carcinoid crisis (diarrhoea, flushing and hypotension). We present the case of a 64-year-old male patient with acute abdomen, who was indicated for colonoscopy and laparoscopy for a biopsy after a mass was seen on computed tomography, which confirmed carcinoid tumour in the small intestine. The patient was scheduled for an emergency laparotomy and was anaesthetised with propofol, rocuronium and fentanyl under rapid sequence induction, with his blood pressure significantly dropping shortly after. The patient received bolus high doses of phenylephrine and was put on infusion; however, his blood pressure could not be maintained. We administered bolus octreotide and a vasopressin infusion intra-operatively, and a good response was observed. Following the surgery, the patient was extubated uneventfully and transferred to the post-anaesthetic care unit to wean off from the phenylephrine and octreotide infusion. Carcinoid tumours can be a challenge for anaesthetists due to their clinical unpredictability. The goal of perioperative management is to prevent carcinoid crises and, additionally, these patients typically have a delayed emergence from anaesthesia as a result of high serotonin levels, hence requiring postoperative monitoring. This case highlights the need to use phenylephrine and vasopressin with octreotide in patients undergoing anaesthesia with carcinoid tumours, as there is a need to forgo many vasopressors and ionotropic drugs (adrenaline, noradrenaline, ephedrine, etc.), as well as other drugs used during anaesthesia such as succinylcholine and thiopental, to prevent carcinoid crises.
Poster
Ludwig’s angina (LA) is a rare severe diffuse cellulitis of the submandibular, submental and sublingual spaces of the neck, which can potentially be lethal. It commonly arises from an untreated dental infection, and it is characterised by its rapid ability to spread to surrounding tissues. Complications can result in acute airway obstruction, which is why pre-operative assessment is key in determining the presence of a difficult airway. We present a 42-year-old woman, who arrived in the emergency department with acute airway obstruction. She reported that she was afraid to visit the doctor to look at her dental abscess due to her fear of contracting COVID-19. After 1 week, it had become a very extensive neck abscess, with computed tomography showing invasion of deep-neck structures with significant distortion of the tracheal wall. The treatment required was to secure the airway and drain the abscess. There were two options to secure the airway: awake fibreoptic intubation or tracheostomy under local or inhalational anaesthesia. After discussion with the surgeon, we chose to go ahead with awake fibreoptic intubation, with the surgeon scrubbed and ready to secure the airway surgically. The airway was anaesthetised with a 4% lidocaine nebuliser and the patient was given oxygen along with intravenous dexmedetomidine and glycopyrrolate. Upon starting the awake intubation, there were too many secretions to visualise the vocal cords or airway, and after 20 min of struggle, we decided to switch to inhalational anaesthesia with sevoflurane. The patient started to desaturate and the airway was further obstructed. A tracheostomy was performed by the surgeon and the airway successfully secured. Afterward, the abscess was successfully drained and the patient was brought to the intensive care unit. After 3 days the tracheostomy was removed and the patient was discharged to the surgical floor and sent home a few days later uneventfully. Airway management is the first step in managing LA, as airway obstruction is the primary reason for death. A thorough pre-operative clinical assessment is important as it can identify features that could pose a risk for a difficult airway and allow for a quick decision on airway management. The anaesthetist must choose the safest option available given the clinical picture, the urgency to secure the airway, while preparations for an emergency surgical airway should be made available.
Article
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.
Chapter
Pharmaceuticals and personal care products (PPCPs) constitute an integral part of modern healthcare systems which enter the environment through various routes. Because of their inherent biological activity, their presence in soil and the aquatic environment poses several eco-toxicological problems. Antibiotic contamination of soil and water bodies is leading to the development of microbial resistance to antibiotics and this has been recognized by several global bodies like WHO and EPA. Effective steps need to be taken in this regard including increased awareness, reduced pharmaceutical discharges in environment, green and sustainable pharmaceutical practice by pharmaceutical industry and healthcare professionals and improved remediation/bioremediation methods. This chapter outlines the various anticipated routes of exposure of pharmaceuticals to the environment along with their detrimental effects, fate and degradation in aquatic and terrestrial environments. The chapter also dwells upon the role of various regulatory bodies and plausible measures that may be adopted to alleviate the problem.
Chapter
Sevoflurane has been widely used for decades as an inhalational anesthetic agent with an excellent benefit-risk profile. Recently, reports on the use of sevoflurane as an off-label topical drug are emerging. Applied on painful wounds, sevoflurane reliably produced an analgesic effect that typically appeared rapidly in a few minutes, was intense enough to allow for many debridements to be performed, and lasted for several hours, regardless of whether the pain was somatic or neuropathic in nature. Mild and transient itching at wound edges was the most frequent local adverse effect, whereas no systemic unwanted effects have been reported so far. Irrigation lacks technical difficulties, which allowed for at-home treatments. Consequently, patient quality of life was greatly improved. In addition, some clinical experiences suggest a probable antimicrobial effect on infected wounds and a possible prohealing effect on hard-to-heal wounds. Further research on repurposing sevoflurane as a topical agent for difficult-to-manage wounds is warranted.
Article
Because of its energy intensive requirements and multi-disciplinary interdependencies, perioperative care, including surgery, anesthesia, and pathology, is one of the greatest contributors to the direct greenhouse gas emissions of healthcare systems. By reducing this contribution, the paradox of harming human health through the delivery of healthcare services can be addressed. Energy use and waste generation are the main underlying factors contributing to these downstream health harms of providing surgical care. On-site energy is consumed primarily by heating ventilation and air conditioning systems, lighting, and equipment. A variety of different types of waste are also generated on-site, including regulated medical waste, healthcare plastic and packaging waste, single-use devices, anesthetic gases, medication, chemicals, and water. In this review, we discuss practical ways to reduce direct energy use and decrease and avoid waste generation during the surgical experience. Following these environmental best practices supports triple bottom line performance, which delivers significant financial, environmental, and social benefits.
Technical Report
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This report examines at a high level health care waste using data from district health boards (DHB) in Aotearoa New Zealand. The report uses data from waste weights, audits and a survey from sustainability managers to understand the barriers and opportunities to create a more circular economy of health care waste in Aotearoa New Zealand.
Article
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The field of pediatric intensive care has come a long way, especially with the recognition that adequate sedation and analgesia form an imperative cornerstone of patient management. With various drugs available for the same, the debate continues as to which is the better: total intravenous anesthesia (TIVA) or inhalational agents. While each have their own advantages and disadvantages, in the present era of balance toward the IV agents, we should not forget the edge our volatile agents (VAs) might have in special scenarios. And ultimately as anesthesiologists, let us not forget that be it knob and dial, or syringe and plunger, our aim is to put pain to sleep and awaken a new faith to breathe.
Background Operating rooms (ORs) contribute up to 30% of a hospital's waste, are very resource-intensive, and thus provide an opportunity for improvement. Methods A narrative review was conducted, searching MEDLINE, EMBASE, and ProQuest databases. The study included 78 of the 108 published articles. Results The researchers identified and categorized articles according to the following major themes: Committee and Leadership; Waste Reduction; Segregating OR waste; Minimizing unnecessary devices and packaging; Reducing energy consumption; Choosing anesthetic gases; Education; Reducing water consumption; Different surgical venues; Donating medical supplies. Formation of an OR committee or a hospital Green Team dedicated to environmentally sustainable initiatives can significantly improve health care's impact on the environment while saving money. Changes in supply chain with preferences for reusable devices, effective recycling, repurposing instruments, and donating items can all be effective means of diverting waste away from landfills. Reducing unnecessary packaging and instruments would eliminate excess in the waste stream. Curtailing energy and water usage results in cost and environmental savings. Surgical venue (inpatient vs. outpatient surgical center) can also contribute to waste. Transitioning away from certain inhaled anesthetics can minimize greenhouse gas impact. Education to all levels in the health care system is important to drive change and maintain change. Conclusion Optimizing efficiency and decreasing waste generation can have a positive impact on the environment and can be accompanied by cost reduction. Because the field of sustainability in health care is young but burgeoning, increased research is needed to support evidence-based approaches.
Chapter
We live in unprecedented times - the Anthropocene - defined by far-reaching human impacts on the natural systems that underpin civilisation. Planetary Health explores the many environmental changes that threaten to undermine progress in human health, and explains how these changes affect health outcomes, from pandemics to infectious diseases to mental health, from chronic diseases to injuries. It shows how people can adapt to those changes that are now unavoidable, through actions that both improve health and safeguard the environment. But humanity must do more than just adapt: we need transformative changes across many sectors - energy, housing, transport, food, and health care. The book discusses specific policies, technologies, and interventions to achieve the change required, and explains how these can be implemented. It presents the evidence, builds hope in our common future, and aims to motivate action by everyone, from the general public to policymakers to health practitioners.
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We measure infrared absorption spectra of 18 hydrochlorofluorocarbons and hydrofluorocarbons, seven of which do not yet appear in the literature. The spectra are used in a narrowband model of the terrestrial infrared radiation to calculate radiative forcing and global warming potentials. We investigate the sensitivity of the radiative forcing to the absorption spectrum temperature dependence, halocarbon vertical profile, stratospheric adjustment, cloudiness, spectral overlap, and latitude, and we make some recommendations for the reporting of radiative forcings that would help to resolve discrepancies between assessments. We investigate simple methods of estimating instantaneous radiative forcing directly from a molecule's absorption spectrum and we present a new method that agrees to within 0.3% with our narrowband model results.
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Climate change can be driven by changes in the atmospheric concentrations of a number of radiatively active gases and aerosols. We have clear evidence that human activities have affected concentrations, distributions and life cycles of these gases. These matters, discussed in this chapter, were assessed at greater length in IPCC WGI report ""Radiative Forcing of Climate Change"" (IPCC 1994). The following summary contains some material more fully discussed in IPCC (1994): bullets containing significant new information are marked ""***""; those containing information which has been updated since IPCC (1994)are marked ""**""; and those which contain information which is essentially unchanged since IPCC (1994)are marked. Pages: 69-131
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Unwelcome Dominance Stratospheric ozone is depleted by many different chemicals; most prominently, chlorofluorocarbons (CFCs) responsible for causing the Antarctic ozone hole. Nitrous oxide is also an ozone-depleting substance that has natural sources in addition to anthropogenic ones. Moreover, unlike CFCs, its use and emission are not regulated by the Montreal Protocol, which has helped to reverse the rate of growth of the ozone hole. Surprisingly, Ravishankara et al. (p. 123 , published online 27 August; see the Perspective by Wuebbles ) now show that nitrous oxide is the single greatest ozone-depleting substance that, if its emissions are not controlled, is expected to remain the dominant ozone-depleting substance throughout the 21st century. Reducing nitrous oxide emissions would thus enhance the rate of recovery of the ozone hole and reduce the anthropogenic forcing of climate.
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To compare the volatile anesthetic sevoflurane with halothane, enflurane, and isoflurane on the uptake and biotransformation in humans. Prospective pharmacokinetic study of sevoflurane administration in human subjects. Inpatient surgery clinic at a university medical center. Thirty-two Japanese patients, free of systemic diseases, undergoing minor elective surgery with endotracheal general anesthesia. The patients were assigned randomly to one of four groups: halothane, enflurane, isoflurane, or sevoflurane. One of the four volatile anesthetics being investigated [equivalent to 1.1 minimum alveolar concentration (MAC): halothane, 0.85%; enflurane, 1.85%; isoflurane, 1.27%; and sevoflurane, 1.88%; in inspired concentrations throughout the first hour of anesthesia] was administered for 60 minutes. In all patients, serum and urinary fluoride concentrations were measured. The concentrations of all gases were measured separately with a mass spectrometer. The cumulative uptake of each anesthetic agent during a certain period was calculated as an integration of the uptake rate per minute. The results for one-hour inhalation of sevoflurane (1.1 MAC) showed an uptake (corrected for body surface area and MAC) of 490 ml/m2/MAC and estimated degradation rate of 3.3%. For purposes of comparison, similar studies of halothane (uptake, 653 ml/m2/MAC; degradation rate 15.7%), enflurane (1150 ml/m2/MAC; 1.3%), and isoflurane (439 ml/m2/MAC; 0.6%) were also conducted. Sevoflurane had a peak serum inorganic fluoride concentration of 19.3 mumol/L, and no abnormality in hepatic or renal functions was observed in any of the subjects during the two weeks postoperatively. Accurate determinations of uptake and degradation rate for sevoflurane and three other volatile anesthetics in Japanese patients were obtained. These findings have established that, despite its relatively large MAC (1.71%), sevoflurane has a small uptake due to its low solubility. However, the degradation rate was shown to be as high as 3.3%, resulting in a higher serum fluoride concentration than seen after administration of isoflurane, halothane, and (possibly) enflurane.
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Concern has been expressed over the use of the halogenated anaesthetics halothane (CF3CClBrH), enflurane (CF2HOCF2CFClH) and isoflurane (CF2HOCHClCF3) because of their potential for stratospheric ozone destruction. Halogenated species also contribute to global warming. The significance of the anaesthetics in stratospheric ozone loss or in 'greenhouse' heating depends on their atmospheric lifetimes. Because reaction with hydroxyl (OH) radicals is likely to be the main homogeneous sink for these species in the troposphere, we have measured absolute rates of reaction with OH. Comparison with a one-dimensional model indicates that the lifetimes of halothane, enflurane and isoflurane with respect to this reaction are 2, 6 and 5 years, respectively. Thus the small production of the anaesthetics is not offset by anomalously long atmospheric lifetimes to give a large atmospheric burden of the compounds. The anaesthetics will contribute at most a fraction of approximately 5 x 10(-4) to the total atmospheric content of chlorine-containing species.
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Several characteristics of sevoflurane biotransformation are apparent from the preceding investigations. Metabolism is rapid, with fluoride and HFIP appearing in plasma within minutes after the start of sevoflurane administration (38-40,51). Peak plasma fluoride concentrations generally occur within approximately 1 h after the termination of sevoflurane administration in most patients, regardless of the dose or duration of exposure (ranging from 0.35-9.5 MAC-h) (39,48). Peak plasma inorganic fluoride concentrations are proportional to sevoflurane dose, measured in MAC-h (42-44). Inorganic fluoride concentrations decline rapidly after termination of sevoflurane administration, with concentrations well below peak levels by the first postoperative day. HFIP is rapidly conjugated, with more than 85% circulating in plasma as the glucuronide. Plasma HFIP concentrations peak later than fluoride concentrations, but both metabolites are eliminated at similar rates (52). Metabolism of sevoflurane does not contribute to the termination of clinical drug effect (52), unlike more extensively metabolized drugs such as halothane (55). Sevoflurane is metabolized by P-450 2E1, so pathophysiologic factors and drug interactions altering P-450 2E1 activity will also influence sevoflurane metabolism (52). The extent of metabolism of sevoflurane, 2% to 5%, is less than that of all other volatile anesthetics except isoflurane and desflurane. It has been proposed that the ideal anesthetic should resist biotransformation because anesthetic toxicity is related to anesthetic metabolism (67,68). Experience to date suggests that biotransformation of sevoflurane has not been causally related to either hepatic or renal toxicity. Sevoflurane does not result in formation of fluoroacetylated liver neoantigens or other reactive metabolites. Although both sevoflurane and methoxyflurane may produce plasma fluoride concentrations in excess of 50 microM, they have not produced the same nephrotoxic effects. Clearly, anesthetic metabolism and anesthetic toxicity can no longer be considered synonymous. The introduction of sevoflurane into clinical practice will hopefully stimulate new investigations into biochemical mechanisms of anesthetic toxicity and continued clinical investigations regarding the relationship between anesthetic metabolism and organ toxicity.
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Human biotransformation of the newer anesthetics, desflurane and sevoflurane, has been characterized in vitro and in vivo. Major metabolites of desflurane are inorganic fluoride and trifluoroacyl chloride, which may bind to tissue proteins or form trifluoroacetic acid, which is excreted in urine. Major metabolites of sevoflurane are fluoride and hexafluoroisopropanolol (HFIP), which is rapidly glucuronidated and excreted as HFIP-glucuronide in urine. The rate of sevoflurane metabolism is approximately one-third that of methoxyflurane, and 1.5-2 times that of enflurane, while that of desflurane is minimal. The extent of metabolism of sevoflurane and desflurane is 2-5% and 0.02-0.2% of the dose taken up, respectively. Peak serum fluoride concentrations occur within one hour after sevoflurane anesthesia, are usually in the range of 20-40 microM, and decline rapidly. Fluoride concentrations have exceeded 50 microM in approximately 7% of sevoflurane patients. For sevoflurane, the plasma fluoride concentration-time profile most closely resembles that of enflurane. For desflurane, elevations of plasma metabolite concentrations can only be detected after prolonged anesthesia. Investigations to date suggest that the biotransformation of sevoflurane does not appear to result in clinically significant hepatotoxicity or nephrotoxicity. Only a single case of immune-mediated desflurane hepatotoxicity has been reported.
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Potent inhaled anesthetics degrade in the presence of the strong bases (sodium hydroxide or potassium hydroxide) in carbon dioxide (CO2) absorbents. A new absorbent, Amsorb (Armstrong Medical Ltd., Coleraine, Northern Ireland), does not employ these strong bases. This study compared the scavenging efficacy and compound A production of two commercially available absorbents (soda lime and barium hydroxide lime) with Amsorb in humans undergoing general anesthesia. Four healthy volunteers were anesthetized on different days with desflurane, sevoflurane, enflurane, and isoflurane. End-tidal carbon dioxide (ETCO2) and anesthetic concentrations were measured with infrared spectroscopy; blood pressure and arterial blood gases were obtained from a radial artery catheter. Each anesthetic exposure lasted 3 h, during which the three fresh (normally hydrated) CO2 absorbents were used for a period of 1 h each. Anesthesia was administered with a fresh gas flow rate of 2 l/min of air:oxygen (50:50). Tidal volume was 10 ml/kg; respiratory rate was 8 breaths/min. Arterial blood gases were obtained at baseline and after each hour. Inspired concentrations of compound A were measured after 15, 30, and 60 min of anesthetic administration for each CO2 absorbent. Arterial blood gases and ETCO2 were not different among three CO2 absorbents. During sevoflurane, compound A formed with barium hydroxide lime and soda lime, but not with Amsorb. This new CO2 absorbent effectively scavenged CO2 and was not associated with compound A production.
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The inhaled anaesthetic sevoflurane is metabolised into two products that have the potential to produce renal injury. Fluoride ions are produced by oxidative defluorination of sevoflurane by the cytochrome P450 system in the liver. Until recently, inorganic fluoride has been thought to be the aetiological agent responsible for fluorinated anaesthetic nephrotoxicity, with a toxic concentration threshold of 50 μmol/L in serum. However, studies of sevoflurane administration in animals and humans have not shown evidence of fluoride-induced nephrotoxicity, despite serum fluoride concentrations in this range. Compound A (fluoromethyl-2,2-difluoro-l-[trifluoromethyl] vinyl ether) is a breakdown product of sevoflurane produced by its interaction with carbon dioxide absorbents in the anaesthesia machine. The patient then inhales compound A. Compound A produces evidence of transient renal injury in rats. The mechanism of compound A renal toxicity is controversial, with the debate focused on the role of the renal cysteine conjugate β-lyase pathway in the biotransformation of compound A. The significance of this debate centres on the fact that the β-lyase pathway is 10- to 30-fold less active in humans than in rats. Therefore, if biotransformation by this pathway is responsible for the production of nephrotoxic metabolites of compound A, humans may be less susceptible to compound A renal toxicity than are rats. In three studies in human volunteers and one in surgical patients, prolonged (8-hour) sevoflurane exposures and low fresh gas flow rates resulted in significant exposures to compound A. Transient abnormalities were found in biochemical markers of renal injury measured in urine. These studies suggested that sevoflurane can result in renal toxicity, mediated by compound A, under specific circumstances. However, other studies using prolonged sevoflurane administration at low flow rates did not find evidence of renal injury. Finally, there are substantial data to document the safety of sevoflurane administered for shorter durations or at higher fresh gas flow rates. Therefore, the United States Food and Drug Administration recommends the use of sevoflurane with fresh gas flow rates at least 1 L/min for exposures up to 1 hour and at least 2 L/min for exposures greater than 1 hour. We believe this is a rational, cautious approach based on available data. However, it is important to note that other countries have not recommended such limitations on the clinical use of sevoflurane and problems have not been noted.
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The properties of two new-generation CO(2) absorbents, Amsorb Plus (Armstrong Medical, Coleraine, UK) and Drägersorb Free (Drager, Lubeck, Germany), were compared with those of Amsorb (Armstrong Medical) and Sodasorb II (W.R. Grace, Lexington, MA, USA). The concentration of compound A produced by each absorbent was determined in a low-flow circuit containing sevoflurane, and the CO(2) absorption capacity of the absorbent was measured. The circuit contained 1000 g of each absorbent and had a fresh gas (O(2)) flow rate of 1 l.min(-1) containing 2% sevoflurane. CO(2) was delivered to the circuit at a flow rate of 200 ml.min(-1). The maximum concentrations of compound A were 2.2 +/- 0.0, 2.3 +/- 0.3, 2.2 +/- 0.2, and 23.5 +/- 1.5 ppm (mean +/- SD) for Amsorb Plus, Drägersorb Free, Amsorb, and Sodasorb II, respectively. The maximum concentration of compound A for Sodasorb II was significantly higher than those for the other absorbents (P < 0.01). The CO(2) absorption capacities (time taken to reach an inspiratory CO(2) level of 2 mmHg) were 1023 +/- 48, 1074 +/- 36, 767 +/- 41, and 1084 +/- 54 min, respectively, and the capacity of Amsorb was significantly lower than that of the other absorbents (P < 0.01). The new-generation carbon dioxide absorbents, Amsorb Plus and Drägersorb Free, produce a low concentration of compound A in the circuit while showing sufficient CO(2) absorption capacity.
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The infrared and ultraviolet-visible absorption cross sections, effective quantum yield of photolysis, and OH, Cl, and NO3 reaction rate coefficients of CHF2CHO are reported. Relative rate measurements at 298 +/- 2 K and 1013 +/- 10 hPa gave kOH = (1.8 +/- 0.4) x 10(-12) cm3 molecule(-1) s(-1) (propane as reference compound), kCl = (1.24 +/- 0.13) x 10(-11) cm3 molecule(-1) s(-1) (ethane as reference compound), and kNO3 = (5.9 +/- 1.7) x 10(-17) cm3 molecule(-1) s(-1) (trans-dichloroethene as reference compound). The photolysis of CHF2CHO has been investigated under pseudonatural tropospheric conditions in the European simulation chamber, Valencia, Spain (EUPHORE), and an effective quantum yield of photolysis equal to 0.30 +/- 0.05 over the wavelength range 290-500 nm has been extracted. The tropospheric lifetime of CHF2CHO is estimated to be around 1 day and is determined by photolysis. The observed photolysis rates of CH3CHO, CHF2CHO, and CF3CHO are discussed on the basis of results from quantum chemical calculations.