Anesthesia Point-of-Care Nitrous Oxide Cylinder Leakage and a Proposed Engineering Control Solution

Anesthesia Point-of-Care Nitrous Oxide Cylinder Leakage and a Proposed Engineering Control Solution | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Short Report Anesthesia Point-of-Care Nitrous Oxide Cylinder Leakage and a Proposed Engineering Control Solution David Wax, Muoi Trinh This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6865840/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract Nitrous oxide is a potent greenhouse gas and there are ongoing efforts to reduce the environmental impact of its use in healthcare. Substantial leakage of nitrous oxide from centralized supplies has led some centers to convert to storage in point-of-care cylinders. However, these tanks may also leak if not manually closed between uses, and compliance with such closure by staff may be poor. We endeavored to quantify the leakage from these cylinders connected to an anesthesia machine, and test an engineering control to automatically reduce such leakage. We observed that an E-cylinder of nitrous oxide left open leaks at a rate of 10 mL/min, leading to pollution without clinical utility as well as wasted resources. We developed a system consisting of a valve actuator and countdown timer that was shown to be capable of automatically opening and closing the cylinder as needed to reduce waste, obviating the need for staff to do so manually. Nitrous oxide anesthesia sustainability healthcare waste green healthcare Figures Figure 1 Figure 2 BACKGROUND Nitrous oxide (N 2 O) is a potent greenhouse gas with significant environmental impact and is commonly used in the healthcare sector. It has a global warming potential (GWP100) of 273 and lasts over a century with an atmospheric lifetime of 117 years. 1 , 2 It continues to be used in clinical anesthesia practice and so has been the subject of investigations into ways to reduce its environmental impact in this setting. Efforts have been made to reduce clinical usage by promoting low-flow anesthesia practices or discouraging its use altogether. However, these efforts have a minimal impact on reducing nitrous oxide from healthcare when compared to the amount lost from the central piping system. Previous work has identified the pipeline systems carrying nitrous oxide gas from centralized cryogenic tanks or compressed gas supplied through manifolds as prone to leakage, resulting in substantial waste and pollution without any clinical benefit. 3 , 4 , 5 This has led to efforts to deactivate centralized supplies of nitrous oxide and instead utilize point-of-care nitrous oxide cylinders connected directly to anesthesia workstations. In one study, this change eliminated nearly all waste attributable to gas leakage. 6 (Of note, we clarified by personal communication with the author of that investigation that their study protocol included closing the tanks between clinical use and at the end of each day, with excellent compliance.) In our institution, we have similarly deactivated our centralized nitrous supply and switched to use of point-of-care E-cylinders. However, our rate of cylinder depletion far exceeded that of clinical use. It was our assumption that, once opened at the cylinder valve, the cylinders leak continuously at some rate. In fact, one source indicates that a leak of up to 15 mL/min is acceptable for a new anesthesia machine cylinder yoke. 7 Based on this, we encouraged clinicians to manually close the tank valves after use and instructed our technicians to do the same at the end of each shift. However, compliance with this request outside of a study protocol was very poor. Therefore, we sought to confirm and quantify the cylinder leak when left open, as well as test an engineering control to address the problem of gas leak and poor compliance with closing unused tanks. METHODS To test our theory regarding cylinder leakage, we weighed two new nitrous oxide E-cylinders and then attached them to two anesthesia machines (GE Aisys CS2) with the cylinder yokes. On one machine, the tank was left closed. On the other machine, the valve was opened completely. The cylinders were left in place and the machines were left powered off for a period of 2 weeks. After week 1 and 2, the open valve was closed and both cylinders were removed and weighed and then reconnected as before. As a potential engineering control solution, we utilized an AC-powered valve actuator with fail-safe spring return (BELIMO Aircontrols TF24-SR) and fashioned a fitting using 3D printing to couple the actuator with the cylinder valve stem. The apparatus was affixed to the cylinder by means of malleable aluminum rods. The power supply was connected in series with a spring-wound electrical timer. In this configuration (Fig. 1 ), activating the timer would cause the actuator to open the valve one-quarter turn. When the timer runs out, the actuator loses power and the fail-safe spring closes the valve. Thus, clinicians could use the timer to open the N 2 O supply for up to one hour, and then the valve would automatically be closed. This time could be manually extended as needed during patient care by refreshing the timer. RESULTS Both cylinders weighed 6.2 kg prior to the test period. Over the course of 2 weeks, the control cylinder weight was unchanged while the two subsequent test cylinder weights were 6.0 and 5.8 kg. Using a conversion factor of 506 L of N 2 O gas per kg N 2 O liquid, the loss of 0.4 kg N 2 O translates to approximately 200 L or 10 mL/min N 2 O leak. 8 The valve actuator worked as expected, opening the valve when the timer was activated resulting in pressurization of the supply line, and shutting the valve when the set time expired resulting in loss of pressure in the supply line (Fig. 2 ). DISCUSSION We have confirmed that a nitrous oxide E-cylinder connected to an anesthesia machine with the cylinder valve left open will leak, resulting in greenhouse gas emissions without any clinical utility. Therefore, a reliable system (i.e., not dependent on human compliance) for closing the cylinders between uses could mitigate this waste and environmental impact. It is unknown if any of this leakage is captured by the scavenging system or vents directly into the operating room since we do not know exactly where in the system the leak occurs. Regardless, it ultimately ends up released into the atmosphere where it acts as a greenhouse gas and depletes the ozone layer. Additionally, this leakage has economic impact: aside from the direct cost of the wasted N 2 O, a steady leak from an open cylinder will deplete it prematurely requiring more frequent change of cylinders by staff. This added maintenance effort could be a deterrent to moving from centralized to point-of-care gas supplies. Our results are for a single nitrous oxide cylinder and a specific anesthesia machine, so our quantitative results may not be representative of other equipment. We also did not test whether a fully open valve vs. partially open valve leak at different rates. However, our qualitative results indicate that leakage occurs at some rate resulting in occult pollution. This engineering control could decrease pollution, supply costs, and frequency of cylinder swaps. Further research is needed to test the system for efficacy in reducing waste and cost in actual clinical practice, as well as for acceptance by clinicians. If effective, such a solution could be implemented as an add-on to existing anesthesia workstations or perhaps integrated into future anesthesia workstation designs. Declarations The authors have no relevant financial or non-financial interests to disclose. All authors made substantial contributions to the conception/design of the work; the acquisition/interpretation of data; drafted/revised the work; approved the final version; and agree to be accountable for all aspects of the work in ensuring that questions related to its accuracy or integrity are appropriately investigated and resolved. No human subjects were involved in the research. FUNDING No external funding was utilized for this investigation. Author Contribution DW designed and built the prototype system described herein.DW and MT designed the study, collected the data, and prepared & reviewed the manuscript. References https://www.epa.gov/ghgemissions/understanding-global-warming-potentials#:~:text=Nitrous%20Oxide%20(N2O,Sinks%20uses%20a%20different%20value (Last accessed 6/10/2025) Prather M, Hsu J, DeLuca N. Measuring and modeling the lifetime of nitrous oxide including its variablility. JGR Atmospheres. 2015: 5693–5705. Chakera A, Fennel-Wells A, Allen C. Piped Nitrous Waste Reduction Strategy. Jan 15, 2021. https://anaesthetists.org/Portals/0/PDFs/Environment/Nitrous%20waste%20methodology.pdf?ver=2021-04-26-115439-240 (Last accessed 6/10/2025) Lui Y, Lee-Archer P, Sheridan NM. Nitrous oxide use in Australian health care: strategies to reduce the climate impact. Anesth Analg. 2023: 819–829. Seglenieks R, Wong F, Pearson F, McGain F. Discrepancy between procurement and clinical use of nitrous oxide: waste not, want not. Br J Anaesth. 2022: e32-34. Chesebro BB, Gandhi S. Mitigating the systemic loss of nitrous oxide: a narrative review and data-driven practice analysis. Br J Anaesth. 2024:1413–1418. Diba A. The anaesthetic workstation. Anesthesia Key: https://aneskey.com/the-anaesthetic-workstation/ (Last accessed 6/10/2025) https://www.aqua-calc.com/calculate/weight-to-volume/substance/nitrous-blank-oxide (Last accessed 6/10/2025) Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 03 Aug, 2025 Reviews received at journal 03 Aug, 2025 Reviewers agreed at journal 08 Jul, 2025 Reviews received at journal 06 Jul, 2025 Reviewers agreed at journal 23 Jun, 2025 Reviewers invited by journal 16 Jun, 2025 Editor assigned by journal 16 Jun, 2025 Submission checks completed at journal 15 Jun, 2025 First submitted to journal 10 Jun, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6865840","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Short Report","associatedPublications":[],"authors":[{"id":472335346,"identity":"deb6c427-30b5-46db-9b68-b3c446c4e2a3","order_by":0,"name":"David Wax","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAy0lEQVRIiWNgGAWjYDCCA0DEA2KwNyBEiNTCcwAhQlALA1iLRAKRWviOnzE88IbhsLzBzdfJH3/mMMjx3UjAr0XyTI7BwTkMhw1nzs7dJs27jcFYkpAWgwNpCYd5GG4z9kvnbmNm3MaQuIGglvPPwFrs2yTPbv74cxtDPWEtN5IPgLQk9kvwbpAAOizBgKBfbjw+cHCOwf/kmT1gv0gYzjzzAL8WvvOJzR/eVKTZbjgOdpiNPN9xArZAnQdnSRCjfBSMglEwCkYBIQAAdxdODCNEigMAAAAASUVORK5CYII=","orcid":"","institution":"Mount Sinai Health System","correspondingAuthor":true,"prefix":"","firstName":"David","middleName":"","lastName":"Wax","suffix":""},{"id":472335347,"identity":"1c85df01-4b53-4d08-bc9a-a5c38a0d9bf3","order_by":1,"name":"Muoi Trinh","email":"","orcid":"","institution":"Mount Sinai Health System","correspondingAuthor":false,"prefix":"","firstName":"Muoi","middleName":"","lastName":"Trinh","suffix":""}],"badges":[],"createdAt":"2025-06-10 19:23:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6865840/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6865840/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":84887967,"identity":"c49319a7-d691-4c77-9fe2-a9ceeb76ab0d","added_by":"auto","created_at":"2025-06-18 12:07:43","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":742976,"visible":true,"origin":"","legend":"\u003cp\u003eSystem for opening an anesthesia machine nitrous oxide cylinder and automatically closing it after a set period of time, using a motorized valve actuator with spring return controlled by a spring-wound electrical timer.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6865840/v1/ccaa7fa8ea8bebc85be48d54.jpeg"},{"id":84887555,"identity":"018e851c-1403-4167-9f3f-cb6be8b70383","added_by":"auto","created_at":"2025-06-18 11:59:43","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":686492,"visible":true,"origin":"","legend":"\u003cp\u003eAnesthesia machine gas monitor showing nitrous oxide supply pressures with use of a system for opening and automatically closing the cylinder using a timer connected to a valve actuator – (a) before timer activation, (b) during N\u003csub\u003e2\u003c/sub\u003eO use, and (c) after timer expiration.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6865840/v1/794f511baa61474f203ef48a.jpeg"},{"id":84887968,"identity":"b6cd4586-78f8-4b80-aca0-ad6fa0a4dc5e","added_by":"auto","created_at":"2025-06-18 12:07:47","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1655538,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6865840/v1/4604e11b-916b-4588-a285-4f5c825f2264.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Anesthesia Point-of-Care Nitrous Oxide Cylinder Leakage and a Proposed Engineering Control Solution","fulltext":[{"header":"BACKGROUND","content":"\u003cp\u003eNitrous oxide (N\u003csub\u003e2\u003c/sub\u003eO) is a potent greenhouse gas with significant environmental impact and is commonly used in the healthcare sector. It has a global warming potential (GWP100) of 273 and lasts over a century with an atmospheric lifetime of 117 years.\u003csup\u003e1\u003c/sup\u003e\u003csup\u003e,\u003c/sup\u003e\u003csup\u003e2\u003c/sup\u003e It continues to be used in clinical anesthesia practice and so has been the subject of investigations into ways to reduce its environmental impact in this setting. Efforts have been made to reduce clinical usage by promoting low-flow anesthesia practices or discouraging its use altogether. However, these efforts have a minimal impact on reducing nitrous oxide from healthcare when compared to the amount lost from the central piping system. Previous work has identified the pipeline systems carrying nitrous oxide gas from centralized cryogenic tanks or compressed gas supplied through manifolds as prone to leakage, resulting in substantial waste and pollution without any clinical benefit.\u003csup\u003e3\u003c/sup\u003e\u003csup\u003e,\u003c/sup\u003e\u003csup\u003e4\u003c/sup\u003e\u003csup\u003e,\u003c/sup\u003e\u003csup\u003e5\u003c/sup\u003e This has led to efforts to deactivate centralized supplies of nitrous oxide and instead utilize point-of-care nitrous oxide cylinders connected directly to anesthesia workstations. In one study, this change eliminated nearly all waste attributable to gas leakage.\u003csup\u003e6\u003c/sup\u003e (Of note, we clarified by personal communication with the author of that investigation that their study protocol included closing the tanks between clinical use and at the end of each day, with excellent compliance.)\u003c/p\u003e \u003cp\u003eIn our institution, we have similarly deactivated our centralized nitrous supply and switched to use of point-of-care E-cylinders. However, our rate of cylinder depletion far exceeded that of clinical use. It was our assumption that, once opened at the cylinder valve, the cylinders leak continuously at some rate. In fact, one source indicates that a leak of up to 15 mL/min is acceptable for a new anesthesia machine cylinder yoke.\u003csup\u003e7\u003c/sup\u003e Based on this, we encouraged clinicians to manually close the tank valves after use and instructed our technicians to do the same at the end of each shift. However, compliance with this request outside of a study protocol was very poor. Therefore, we sought to confirm and quantify the cylinder leak when left open, as well as test an engineering control to address the problem of gas leak and poor compliance with closing unused tanks.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003eTo test our theory regarding cylinder leakage, we weighed two new nitrous oxide E-cylinders and then attached them to two anesthesia machines (GE Aisys CS2) with the cylinder yokes. On one machine, the tank was left closed. On the other machine, the valve was opened completely. The cylinders were left in place and the machines were left powered off for a period of 2 weeks. After week 1 and 2, the open valve was closed and both cylinders were removed and weighed and then reconnected as before.\u003c/p\u003e \u003cp\u003eAs a potential engineering control solution, we utilized an AC-powered valve actuator with fail-safe spring return (BELIMO Aircontrols TF24-SR) and fashioned a fitting using 3D printing to couple the actuator with the cylinder valve stem. The apparatus was affixed to the cylinder by means of malleable aluminum rods. The power supply was connected in series with a spring-wound electrical timer. In this configuration (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), activating the timer would cause the actuator to open the valve one-quarter turn. When the timer runs out, the actuator loses power and the fail-safe spring closes the valve. Thus, clinicians could use the timer to open the N\u003csub\u003e2\u003c/sub\u003eO supply for up to one hour, and then the valve would automatically be closed. This time could be manually extended as needed during patient care by refreshing the timer.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eBoth cylinders weighed 6.2 kg prior to the test period. Over the course of 2 weeks, the control cylinder weight was unchanged while the two subsequent test cylinder weights were 6.0 and 5.8 kg. Using a conversion factor of 506 L of N\u003csub\u003e2\u003c/sub\u003eO gas per kg N\u003csub\u003e2\u003c/sub\u003eO liquid, the loss of 0.4 kg N\u003csub\u003e2\u003c/sub\u003eO translates to approximately 200 L or 10 mL/min N\u003csub\u003e2\u003c/sub\u003eO leak.\u003csup\u003e8\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe valve actuator worked as expected, opening the valve when the timer was activated resulting in pressurization of the supply line, and shutting the valve when the set time expired resulting in loss of pressure in the supply line (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eWe have confirmed that a nitrous oxide E-cylinder connected to an anesthesia machine with the cylinder valve left open will leak, resulting in greenhouse gas emissions without any clinical utility. Therefore, a reliable system (i.e., not dependent on human compliance) for closing the cylinders between uses could mitigate this waste and environmental impact.\u003c/p\u003e \u003cp\u003eIt is unknown if any of this leakage is captured by the scavenging system or vents directly into the operating room since we do not know exactly where in the system the leak occurs. Regardless, it ultimately ends up released into the atmosphere where it acts as a greenhouse gas and depletes the ozone layer. Additionally, this leakage has economic impact: aside from the direct cost of the wasted N\u003csub\u003e2\u003c/sub\u003eO, a steady leak from an open cylinder will deplete it prematurely requiring more frequent change of cylinders by staff. This added maintenance effort could be a deterrent to moving from centralized to point-of-care gas supplies.\u003c/p\u003e \u003cp\u003eOur results are for a single nitrous oxide cylinder and a specific anesthesia machine, so our quantitative results may not be representative of other equipment. We also did not test whether a fully open valve vs. partially open valve leak at different rates. However, our qualitative results indicate that leakage occurs at some rate resulting in occult pollution.\u003c/p\u003e \u003cp\u003eThis engineering control could decrease pollution, supply costs, and frequency of cylinder swaps. Further research is needed to test the system for efficacy in reducing waste and cost in actual clinical practice, as well as for acceptance by clinicians. If effective, such a solution could be implemented as an add-on to existing anesthesia workstations or perhaps integrated into future anesthesia workstation designs.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003eAll authors made substantial contributions to the conception/design of the work; the acquisition/interpretation of data; drafted/revised the work; approved the final version; and agree to be accountable for all aspects of the work in ensuring that questions related to its accuracy or integrity are appropriately investigated and resolved.\u003c/p\u003e\n\u003cp\u003eNo human subjects were involved in the research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFUNDING\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo external funding was utilized for this investigation.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eDW designed and built the prototype system described herein.DW and MT designed the study, collected the data, and prepared \u0026amp; reviewed the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003e \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.epa.gov/ghgemissions/understanding-global-warming-potentials#:~:text=Nitrous%20Oxide%20(N2O,Sinks%20uses%20a%20different%20value\u003c/span\u003e\u003cspan address=\"https://www.epa.gov/ghgemissions/understanding-global-warming-potentials#:~:text=Nitrous%20Oxide%20(N2O,Sinks%20uses%20a%20different%20value\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (Last accessed 6/10/2025)\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e Prather M, Hsu J, DeLuca N. Measuring and modeling the lifetime of nitrous oxide including its variablility. JGR Atmospheres. 2015: 5693\u0026ndash;5705.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e Chakera A, Fennel-Wells A, Allen C. Piped Nitrous Waste Reduction Strategy. Jan 15, 2021. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://anaesthetists.org/Portals/0/PDFs/Environment/Nitrous%20waste%20methodology.pdf?ver=2021-04-26-115439-240\u003c/span\u003e\u003cspan address=\"https://anaesthetists.org/Portals/0/PDFs/Environment/Nitrous%20waste%20methodology.pdf?ver=2021-04-26-115439-240\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (Last accessed 6/10/2025)\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e Lui Y, Lee-Archer P, Sheridan NM. Nitrous oxide use in Australian health care: strategies to reduce the climate impact. Anesth Analg. 2023: 819\u0026ndash;829.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e Seglenieks R, Wong F, Pearson F, McGain F. Discrepancy between procurement and clinical use of nitrous oxide: waste not, want not. Br J Anaesth. 2022: e32-34.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e Chesebro BB, Gandhi S. Mitigating the systemic loss of nitrous oxide: a narrative review and data-driven practice analysis. Br J Anaesth. 2024:1413\u0026ndash;1418.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e Diba A. The anaesthetic workstation. Anesthesia Key: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://aneskey.com/the-anaesthetic-workstation/\u003c/span\u003e\u003cspan address=\"https://aneskey.com/the-anaesthetic-workstation/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (Last accessed 6/10/2025)\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.aqua-calc.com/calculate/weight-to-volume/substance/nitrous-blank-oxide\u003c/span\u003e\u003cspan address=\"https://www.aqua-calc.com/calculate/weight-to-volume/substance/nitrous-blank-oxide\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (Last accessed 6/10/2025)\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-medical-systems","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Journal of Medical Systems](https://www.springer.com/journal/10916)","snPcode":"10916","submissionUrl":"https://submission.nature.com/new-submission/10916/3","title":"Journal of Medical Systems","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Nitrous oxide, anesthesia, sustainability, healthcare waste, green healthcare","lastPublishedDoi":"10.21203/rs.3.rs-6865840/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6865840/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eNitrous oxide is a potent greenhouse gas and there are ongoing efforts to reduce the environmental impact of its use in healthcare. Substantial leakage of nitrous oxide from centralized supplies has led some centers to convert to storage in point-of-care cylinders. However, these tanks may also leak if not manually closed between uses, and compliance with such closure by staff may be poor. We endeavored to quantify the leakage from these cylinders connected to an anesthesia machine, and test an engineering control to automatically reduce such leakage. We observed that an E-cylinder of nitrous oxide left open leaks at a rate of 10 mL/min, leading to pollution without clinical utility as well as wasted resources. We developed a system consisting of a valve actuator and countdown timer that was shown to be capable of automatically opening and closing the cylinder as needed to reduce waste, obviating the need for staff to do so manually.\u003c/p\u003e","manuscriptTitle":"Anesthesia Point-of-Care Nitrous Oxide Cylinder Leakage and a Proposed Engineering Control Solution","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-18 11:59:36","doi":"10.21203/rs.3.rs-6865840/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-08-04T03:16:31+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-04T02:36:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"66307124103087917077381753645730214931","date":"2025-07-08T20:10:15+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-07T03:39:25+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"63128168562088854054507805770364609190","date":"2025-06-23T19:18:43+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-17T02:23:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-16T11:11:19+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-06-16T03:06:26+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Medical Systems","date":"2025-06-10T19:15:27+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-medical-systems","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Journal of Medical Systems](https://www.springer.com/journal/10916)","snPcode":"10916","submissionUrl":"https://submission.nature.com/new-submission/10916/3","title":"Journal of Medical Systems","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"4a302e43-2ce0-4443-a92a-f5b2b5f6938c","owner":[],"postedDate":"June 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-08-25T03:38:38+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-18 11:59:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6865840","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6865840","identity":"rs-6865840","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}