A Life Cycle Assessment of Reusable and Single-Use Central Venous Catheter Insertion Kits : Anesthesia & Analgesia

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A Life Cycle Assessment of Reusable and Single-Use Central Venous Catheter Insertion Kits

McGain, Forbes MBBS, FANZCA, FCICM*; McAlister, Scott BSc, PGradDipSci, MWaterRM; McGavin, Andrew RN, PGrad Dip. Emerg Med, Pgrad. Dip. Bus.; Story, David MBBS, MD, FANZCA§,‖

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Anesthesia & Analgesia 114(5):p 1073-1080, May 2012. | DOI: 10.1213/ANE.0b013e31824e9b69

There are increasing concerns about health care's environmental costs (ref. 1 in Table 1).14 Approximately 8% of the total CO2 emissions from the United States arise from the health care sector.5 The manufacture, purchase, and acquisition of equipment and drugs contributes more to health care CO2 emissions than direct hospital energy consumption and transport to and from hospitals combined (ref. 2 in Table 1). Recycling of hospital waste has been reported in the medical literature,610 but less attention has been devoted to “reducing and reusing.” Simultaneously there has been an increasing adoption of single-use items in medicine.11,12

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Table 1:
Website Citations

Life cycle assessment is a “cradle-to-grave” approach for determining the financial and environmental costs of a product over its entire life.13,14 There are few published life cycle assessment studies of medical items (ref. 3 in Table 1).1521 Our group recently performed a life cycle assessment of anesthetic drug trays, finding that reusable trays were both environmentally and financially advantageous to single-use trays.19 Drug trays, however, do not require sterilization, an energy and water intensive process. Furthermore, in Melbourne, Australia, most electricity is sourced from brown coal, which is particularly CO2 emissions–intensive. Several hospitals in Melbourne and elsewhere have a much more efficient energy base: gas-fired, combined heat and power cogeneration.

We sought to examine common medical items that are sterilized because it was unclear whether there were financial and environmental benefits in using reusable instead of disposable versions. Both reusable and single-use central venous catheter kits are commonly used in anesthesia and other critical care areas. These kits are used to assist insertion of disposable central venous catheters. We did not examine the disposable catheter sets themselves, which included the catheters as well as various other plastic items. We asked the following questions: (1) What are the complete financial costs of the reusable and single-use kits when used in hospitals? (2) What are the environmental effects (CO2 emissions, water use, metal use, toxicity) of the life cycles of the reusable and single-use kits? And (3) what effect does the source of electricity have upon CO2 emissions?

METHODS

This study was performed at Western Health, a 650-bed, 17–operating room, university-affiliated group of 4 hospitals in Melbourne, Victoria, Australia, and at Athertons' Sterilizers Factory, also in Melbourne. Ethical approval was granted by the Western Health Ethics Committee (QA 2010.27). Using SimaPro life cycle assessment software (PRé Consultants, Amersfoort, The Netherlands), we modeled the financial and environmental life cycles of reusable and single-use central venous catheter kits that are used to aid insertion of disposable central venous catheters. SimaPro is one of the most commonly used life cycle assessment software packages for modeling peer reviewed, internationally standardized (ref. 4 in Table 1) life cycle assessments.

We analyzed the environmental effects of the central venous catheter kits including: CO2 emissions, water use, mineral use, aquatic and terrestrial ecotoxicity, and solid waste. A sensitivity analysis is an examination of the effects on the outputs (CO2 emissions) of altering the inputs (electricity source). We performed sensitivity analyses of altering the source of electricity for the reusable central venous catheter kits: brown coal, gas cogeneration, and the American (United States) and European standard electricity supply. We did not perform such sensitivity analyses for the single-use central venous catheter kits as cogeneration is an unusual source of electricity for plastic and metal manufacture, and the single-use plastic and metal items are almost exclusively sourced from China and Pakistan.

Both single-use and reusable central venous catheter kits contained a plastic kidney dish, 2 plastic galley pots, 3 surgical metal items (needle holder, scissors, and artery forceps), and plastic wraps (1 for the kit cover and 1 to provide a sterile field). For the reusable central venous catheter kit, the 2 plastic wraps were single use, while for the single-use central venous catheter kit, all items were single use. All items were weighed with an electronic balance accurate to ±0.5 g (Satrue KA-1000, Shang Chuen Co., Taichung City, Taiwan). Other items such as cotton gauze and antiseptic were not examined because they were common to insertion of all central venous catheters.

We followed the International Organization for Standardization—14,040 series standards to conducting life cycle assessments (ref. 4 in Table 1). We performed an attributional life cycle assessment based on currently available sources of electricity. Items such as washers and sterilizers that are already in place were not included in life cycle assessments (ref. 4 in Table 1). Data for life cycle assessments were either directly collected or obtained from life cycle inventories, i.e., local industry or internationally recognized databases (ref. 5 in Table 1). We obtained direct data for the washer and sterilizer electricity and water use, but most other inputs were acquired from databases. We examined inputs (e.g., the CO2 emissions for electricity) that contribute to a process (e.g., the CO2 emissions for stainless steel production). Processes included in the system boundary in this study were raw material extraction, manufacture, packaging, transport, washing, sterilization, and disposal (Fig. 1).

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Figure 1:
System boundary showing the processes included in the life cycle analyses.

The metal components were fabricated from stainless steel in both reusable and single-use central venous catheter kits.12 Details of the types of plastics used for the central venous catheter kits were provided by the manufacturer, which we confirmed with the “burn test,” i.e., the color and odor of the burnt plastic (ref. 6 in Table 1). The reusable central venous catheter kit's metal components were made in Germany and the plastic items in Australia. The single-use central venous catheter kit's metal components were made in Pakistan, and the plastics were fabricated in China. No life cycle inventory data are available from Pakistan, and there are only minimal Chinese data available. We therefore used local Australian inventory data for the manufacture of the reusable and single-use plastic items (ref. 7 in Table 1) and European data for the reusable and single-use metal components (ref. 5 in Table 1). Direct life cycle inventory data from China and Pakistan have not been collected in these countries.

All of the inputs in this life cycle assessment had associated uncertainty, which was conveyed as a probability distribution. A Pedigree Matrix22,23 was developed. This is a qualitative scoring system that allowed input uncertainty to be quantified on the basis of the data's temporal and geographical proximity to the study site, as well as reliability and completeness. For example, because we directly measured the sterilizers' electricity consumption on multiple occasions by several groups of investigators, the data's temporal and geographical proximity was high. Likewise the reliability and completeness was high, and thus the uncertainty was relatively low for these processes.

We used a Monte Carlo simulation to calculate the median and 95% confidence intervals (CIs).22,23 For example, the CO2 emissions emanating from just the manufacture of stainless steel (an output) requires many inputs, such as the production and transport of iron, chromium, and other metals, each with their own variations in CO2 emissions. A Monte Carlo assessment will randomly assign the data from each input on the basis of its individual distribution to create a probability distribution that describes the aggregate data and permits calculation of confidence intervals.

The Monte Carlo SimaPro software analysis involves at least 1000 “runs” of random sampling to reduce the likelihood of unusual results. These computer “runs” require many hours of computer time for random sampling of all (several thousand) inputs feeding into an output.

We obtained the purchase costs for the single-use and reusable central venous catheter kits for our hospitals (Table 2) and verified that these prices were similar to central venous catheter kits obtained by other local hospitals. For the single-use central venous catheter kit, costs were also determined for storage, logistics, and metal components disposal into sharps bins. We assumed that all other waste from both the reusable and single-use central venous catheter kits was placed into infectious/hazardous/clinical bins. For the reusable central venous catheter kits, we included electricity, water, gas for hot water, chemical and biological indicators, and maintenance costs for the washer and sterilizer, as well as washer detergents and packaging. For the sterilizer we also included “accessory loads” (warm ups and infection control cycles). Washing and sterilization was assumed to conform to the Australian and New Zealand Standards.24 On a conservative estimate the reusable metal components and plastic items were known to have a lifespan of 300 uses by Central Sterile Supply Department (“Central Supply”) staff, with the metal components requiring reprocessing (sharpening) every 100 uses. We did not assume loss of reusable items, but we did investigate the effects of loss of reusable central venous catheter kits at our hospitals.

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Table 2:
Itemized Financial Costs for One Single-Use and Reusable Central Venous Catheter (CVC) Kit

We examined the entire financial costs of making the reusable central venous catheter kits “patient ready” again. With Central Supply staff we developed a “time-in-motion” study that compartmentalized labor costs. We included the following time periods: carriage of the reusable central venous catheter kits from the intensive care unit to Central Supply, decontamination, loading and unloading the washer, inspection, barcoding and scanning, second checking, loading and unloading the sterilizer, and packaging. Staff used stop clocks to time the duration of each segment of the processing of the reusable central venous catheter kits and entered these times onto sheets. Staff entered their estimate of how full (as a percentage) the washer and sterilizer were with each load. For the time-in-motion study to be representative, all staff were encouraged to complete the study, but no more than twice per staff member.

The hospital washer used was a Steris Reliance synergy disinfector (Steris Corporation, Mentor, OH), and the sterilizer was an Athertons Gorilla (Athertons, Melbourne, Australia). We measured the volumes of hot (gas heated) and cold water used by both devices and the kilowatt hours of electricity. The sterilizer has 3 sources of water use for (1) steam generation, (2) the vessel jacket to keep the sterilizer warm, and (3) the liquid ring vacuum pump to “pull a vacuum” for efficient sterilization. Sterilizers can either have an internal electric element to heat water to steam or rely upon an external steam source such as a gas boiler. Because gas boiler–dependent steam heating within hospitals in Australia is becoming less common, we examined the electric sterilizer.

We measured the electricity consumption of the washer and sterilizer with a “power clamp”: a Hioki 3197 Power Quality Analyzer, accurate to ±3% (Hioki Corporation, Nagano, Japan). We verified our calculations of electricity consumption both with external consultant engineers (Aquaklar, Melbourne, Australia) and by measurements at the Athertons sterilizer manufacturing facility in Melbourne. On each of these 3 occasions we measured the sterilizer's electricity consumption over a 48-hour period, including routine and “accessory” cycles (warm ups and infection control cycles). Sterilizer water consumption was measured by direct flow meters at the Athertons' factory. Water consumption of the hospital washer was measured with flow meters with an error rate of ±5% (S-100 and V-100 water meters, Elster, Essen, Germany).

We obtained details of the sterilization with ethylene oxide (by Steritech, Melbourne, Australia) of the single-use central venous catheter kit. Sharps bins waste and infectious waste were treated with sodium hypochlorite or incinerated. Despite requests to the infectious waste company contracted to our hospitals, we were not able to examine directly the environmental effects of such waste disposal processes, instead relying upon industry data (ref. 5 in Table 1).

RESULTS

The cost of the reusable central venous catheter kit to the hospital was $6.35 Australian ($A) (95% CI, $A5.89 to $A6.86), while the single-use central venous catheter kit cost $A8.65 (Table 2). There was minimal variation in the cost of the single-use central venous catheter kits in other hospitals in Melbourne, Australia. Water usage and CO2 emissions are given in Table 3. Energy and water use based on brown coal electricity generation were 3 and 10 times greater, respectively, for the reusable kits in comparison with the single-use kits. Sterilization was approximately 70% of the total CO2 emissions for the reusable central venous catheter kit, whereas for the single-use central venous catheter kit, manufacture of plastics contributed 70% and stainless steel metal components 25% (Table 4). The reusable kit weighed 627 g, including approximately 50 g of single-use wrap, and the single-use kit weighed 171 g including wrap (Table 4). Other environmental effects were either similar or of minor importance for the 2 approaches including aquatic and terrestrial ecotoxicity, carcinogens, solid waste, and mineral use.

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Table 3:
CO2 Emissions and Water Use for the Single-Use and Reusable Central Venous Catheter (CVC) Kits Accounting for Different Energy Sources
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Table 4:
Effects by Life Cycle Stage for the Reusable and Single-Use Central Venous Catheter (CVC) Kits

There were 33 Central Supply staff at the Western Hospital, Melbourne, Australia. The time-in-motion study was completed on 29 occasions with no staff member completing the study more than thrice. The mean labor time to make 1 reusable central venous catheter kit patient ready again was rounded up to 9 minutes (range of 5-12 minutes, 80% between 6 and 10 minutes). The mean hourly pay rate for Central Supply staff in November 2011 was $A31.22 (including all on-costs such as sick leave and superannuation). Other financial costs (washer detergents and maintenance of the washer and sterilizer) were relatively minor (Table 2). The washer and sterilizer at full capacity were measured to take 32 and 48 reusable central venous catheter kits, respectively. The Central Supply staff estimated that on average the washer and sterilizer were 90% full for the 29 occasions (Table 2).

The water and electricity use of the washer was determined on 19 occasions over a 48-hour period. The mean washer electricity usage was 4.1 kWh/load, gas-fired hot water (65°C) use was 79 L/load and cold water use was 126 L/load. The washer was assumed to be 85% efficient and thus use 25.2 MJ of gas to heat the 79 L of water from 15°C to 65°C. The sterilizer electricity and water usages were measured for 2 separate periods at the hospital (a total of 23 routine and 8 accessory cycles) and at the Athertons' factory. The Athertons' factory sterilizer performed 6 routine and 5 accessory loads, using an average of 22.3 kWh per routine load, 30.3 L of steam, 72.3 L of jacket water, and 433.6 L of vacuum pump water. Because an average operating day consists of several accessory sterilizer loads, these were also included in the energy and water calculations, i.e., 4 accessory loads per 10 routine loads per 24-hour period. The final sterilizer electrical consumption per load was thus 27.3 kWh. Because of difficulties in obtaining accurate sterilizer jacket water use at the hospital and because the electricity usage at the factory was by direct measurement, we used these factory data in our final analysis. The electricity usage per cycle for the sterilizer when measured at the factory when compared with the hospital was up to 10% greater.

For the single-use central venous catheter kit, only 5% of the total environmental effects were due to processes other than manufacture of the plastic and metal components (Table 4). Such processes as shipping transport from countries distant from Australia, ethylene oxide sterilization, infectious waste treatment, and discard to landfill were relatively insignificant from an environmental and toxicological perspective.

Hospital procurement documents of central venous catheter kits showed that loss of items was very rare in the operating rooms, but that loss of scissors or needle holders occurred on average once per 5 uses in the critical care unit. Loss of a single $A10 reusable scissors for every 5 kit uses would increase the overall cost of the central venous catheter kits to 5× $A6.35 + $A10 = $A41.75 for 5 uses, approximately the same ($A8.35) as 5 single-use kits at $A8.65 each. Adding new instruments to central venous catheter kits before sterilization has little effect on water use and CO2 emissions.

DISCUSSION

We modeled the financial and environmental costs of reusable and single-use central venous catheter kits in the operating room using life cycle assessment. The reusable kit was less expensive, but had greater environmental effects except for solid waste and mineral use. At our hospitals in Melbourne, Australia, to make the reusable central venous catheter kit patient-ready again required 3 times the CO2 emissions and 10 times the water use of the single-use central venous catheter kit. Sterilization contributed to the majority of the environmental effects for the reusable kit, whereas for the single-use kit, plastic and metal ware manufacture were the most prominent. A reusable central venous catheter kit made patient-ready in a hospital on gas cogeneration instead of brown coal would produce similar CO2 emissions as a single-use kit, although water use would be greater for the reusable central venous catheter kit.

In comparison with using brown coal, using electricity from the current American and European mix would have resulted in approximately 33% and 50% less CO2 emissions to process the reusable central venous catheter kit. Some hospitals have on-site gas boilers for steam generation, which would have <50% of the CO2 emissions than brown coal-sourced electrical sterilization. Water use was greater for reusable central venous catheter kits with electricity sourced from the American and European mix due primarily to the large amount of water required for nuclear energy.

There are limitations to this study. As for most life cycle assessments, the majority of data was not directly measured, but sourced from reputable databases (ref. 5 in Table 1). It is likely that we have underestimated the CO2 emissions in particular for the single-use central venous catheter kit, because we used European data for metal components production, because direct data from China and Pakistan have not been performed in these countries. We did obtain source data for ethylene oxide sterilization of the single-use kit, but infectious waste processing data were incomplete. Despite imprecise data, many processes such as the manufacture of stainless steel and different plastics do not vary considerably between locations, and the environmental effects of such processes are in the public domain. Furthermore, because many processes were common to both central venous catheter kits (e.g., stainless steel and plastic manufacturing), not having source data available is unlikely to lead to significant variations. It is more important for life cycle assessment to have as much direct data for processes that are different between 2 alternative products, in this case washing and sterilizing the reusable central venous catheter kits.

We did not account for a loss of reusable items, even though this contributes to the drive towards single-use items.12 We found that loss of reusable items is infrequent in the operating room because of double counting and checking to prevent loss (or retention within patients) of items. Loss of metal items in the critical care unit was more frequent because of the lack of double checking and the presence of single-use metal items creating confusion and increasing discard of reusable items into the sharps bins. We recognize that there will be a large variation in the loss of reusable items both within and between hospitals, and these losses can quickly negate any potential financial savings. The reusable kits (627 g) weighed almost 4 times as much as the single-use kits (171 g), but unless large numbers of reusable kits were being lost, the subsequent environmental effects due to this weight difference would be relatively insignificant in comparison with the CO2 and water costs of sterilization and washing. Recycling of infectious or sharps waste does not occur in Australia unless there is prior decontamination, which is often prohibitively expensive.

It was beyond the scope of this study to examine central venous catheter kit reformulation. Considerable environmental and financial improvements could be made by reformulating these (and other) kits to routinely include or exclude cotton gauze, sutures, and antiseptic. The reusable central venous catheter kits included a single-use polypropylene wrap (“blue wrap” in many hospitals). We examined whether this plastic wrap could be replaced by reusable steel cases, but found that a sterile field would still necessitate the use of either a single-use plastic or a reusable linen wrap.

On multiple occasions we directly measured the electricity and water use of the washer and sterilizer used to make the reusable central venous catheter kit patient-ready again. This life cycle assessment was modeled upon the routine sterilizer without alterations. Our findings that the reusable item had worse environmental effects for most variables than did the single-use item is at odds with the few other medical life cycle assessments of sterilized items. An Australian study of sterile gowns (ref. 3 in Table 1) and 3 German studies of laparotomy pads,15 surgical drapes16 and laparoscopic instruments17 found that the reusable items had lower CO2 emissions and water use than did single-use variants. In the Australian study, gas-fired boilers were used as the steam energy source with resultant lower CO2 emissions. The 3 German studies1517 had reusable devices reliant to some degree upon nuclear-powered electricity with significantly lower CO2 emissions than brown coal. The small size and relatively unsubstantial central venous catheter kits compared with large surgical trays1517 and heavy linen packs (ref. 3 in Table 1) are also greatly contributory to our findings. Although it is possible to load 48 reusable central venous catheter kits into the sterilizer examined, this represents 5 kg of metal components, similar to just 1 major orthopedic tray. It may be possible to alter the design of the sterilizer racks to accommodate more central venous catheter kits while conforming to local sterilization standards.

In this study we found that the reusable central venous catheter insertion kits had considerably greater environmental effects, but were less expensive than the single-use kits. These findings are primarily explained by our hospitals' brown coal–based electricity and sterilizer energy and water inefficiencies. For hospitals such as ours, which use about 500 central venous catheter insertion kits yearly, use of reusable central venous catheter kits would save $1000, but produce 400 kg more CO2 and use 12,500 more liters of water than with the single-use variant. For Australian hospitals using electricity from gas-fired cogeneration, use of reusable central venous catheter kits in comparison with single-use kits would result in similar CO2 emissions, $1000 financial savings, but 12,500 L increased water consumption. Although the environmental effects of the central venous catheter kits could be extrapolated to any hospital according to the energy source, financial costs would be region specific.

The large amounts of water use for the reusable central venous catheter kits is a concern: water used for sterilization may preclude its use for other activities, which is particularly pertinent in the many areas of the world under water stress, and water increasingly has an energy (monetary and CO2) content, because it is sourced from desalination. Investigation of more water-efficient washers and sterilizers and opportunities for water reuse/recycling are warranted.

The solid waste for the single-use central venous catheter kits was greater than for the reusable variants. Most of the wastes were plastics or metals that are minimally toxic in landfill and have low environmental flows. As a result, these solid wastes are of minor importance despite the large numbers of central venous catheter kits used at our hospitals. Financial costs to dispose of infectious and sharps waste will vary greatly among countries. Furthermore, although discard of single-use stainless steel metal components appears wasteful, because the metals used are relatively abundant (iron, chromium) and inexpensive for small instruments, mineral use for the single-use central venous catheter kits was minor. Other ecological effects such as carcinogens and aquatic/terrestrial toxicity for the 2 different kits, including the effects of ethylene oxide sterilization, were either not statistically significant or of minimal difference. The environmental effects of the mode of waste disposal (incineration, steam autoclaving, or chemical treatment) are likely to vary and require further research. The overall environmental effects of shipping from distant countries were minor.

Discarding a single-use central venous catheter kit intuitively appears wasteful. However, we conclude that for hospitals using coal-fired electricity, the environmental effects are greater if one uses reusable kits instead of the single-use variants. Efforts to reduce the environmental effects of reusable items should be directed towards the inefficiencies and energy sources of steam sterilizers. Further investigations of different-sized medical devices with different sources of electricity are required to clarify uncertainty surrounding the environmental and financial effects of most operating room purchases.

DISCLOSURES

Name: Forbes McGain, MBBS, FANZCA, FCICM.

Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

Attestation: Forbes McGain has seen the original study data, reviewed the analysis of the data, approved the final manuscript, and is the author responsible for archiving the study files.

Name: Scott McAlister, BSc, PGradDipSci, MWaterRM.

Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

Attestation: Scott McAlister has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Andrew McGavin, RN, PGrad Dip. Emerg Med, Pgrad. Dip. Bus.

Contribution: This author helped conduct the study, analyze the data, and write the manuscript.

Attestation: Andrew McGavin has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: David Story, MBBS, MD, FANZCA.

Contribution: This author helped conduct the study, analyze the data, and write the manuscript.

Attestation: David Story has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

This manuscript was handled by: Steven L. Shafer, MD.

ACKNOWLEDGMENTS

We thank Karen Tricker, Rowena Willmette, Carlos Pacioccoa et al. from the Sterile Supply Department of Western Health, Melbourne, Aquaklar (Melbourne), engineering consultants, and Sean Boston et al. from Athertons, Melbourne, for their time and expertise in access to sterilizers.

REFERENCES

1. Sneyd JR, Montgomery H, Pencheon D. The anaesthetist and the environment. Anaesthesia 2010;65:435–7
2. Sherman JD, Ryan S. Ecological responsibility in anesthesia practice. Int Anesthesiol Clin 2010;48:139–51
3. Griffiths J, Hill A, Spilby J, Stott R. Ten practical steps for doctors to fight climate change. BMJ 2008;336:1507
4. Pencheon D. Health services and climate change: what can be done? J Health Serv Res Policy 2009;14:2–4
5. Chung JW, Meltzer DO. Estimate of the carbon footprint of the US health care sector. JAMA 2009;302:1970–2
6. Tieszen M, Gruenberg J. A quantitative, qualitative, and critical assessment of surgical waste. Surgeons venture through the trash can. JAMA 1992;267:2765–8
7. Lee BK, Ellenbecker MJ, Moure-Eraso R. Analyses of the recycling potential of medical plastic wastes. Waste Management 2002;22:461–70
8. Hutchins DCJ, White SM. Coming round to recycling. BMJ 2009;338:609
9. Tudor TL, Marsh CL, Butler S, Van Horn JA, Jenkin LE. Realising resource efficiency in the management of healthcare waste from the Cornwall National Health Service (NHS) in the UK. Waste Manag 2008;28:1209–18
10. McGain F, Clark M, Williams T, Wardlaw T. Recycling plastics from the operating suite. Anaesth Intensive Care 2008;36:913–4
11. Kwakye G, Pronovost P, Makary M. Commentary: a call to go green in health care by reprocessing medical equipment. Academic Med 2010;85:398–400
12. McGain F, Sussex G, O'Toole J, Story D. What makes metalware single use? Anaesth Intens Care 2011;39:972–3
13. Rebitzer G, Hunkeler D. Life cycle costing in LCM: ambitions, opportunities and limitations. Int J Life Cycle Assess 2003;8: 253–6
14. Klöpffer W. Role of SETAC in the development of life cycle assessment. Int J Life Cycle Assessment 2006;11:116–22
15. Kummerer K, Dettenkofer M, Scherrer M. Comparison of reusable and disposable laparotomy pads. Int J Life Cycle Assess 1996;1:67–73
16. Dettenkofer M, Griesshammer R, Scherrer M, Daschner F. Life-cycle assessment of single-use versus reusable surgical drapes (cellulose/polyethylene-mixed cotton system). Chirurg 1999;70:485–91
17. Adler S, Scherrer M, Ruckauer KD, Daschner FD. Comparison of economic and environmental impacts between disposable and reusable instruments used for laparoscopic cholecystectomy. Surg Endosc 2005;19:268–72
18. Ison E, Miller A. The use of life cycle assessment to introduce life-cycle thinking into decision making for the purchase of medical devices in the NHS. J Environ Assess, Policy Manage 2000;2:453–76
19. McGain F, McAlister S, McGavin A, Story D. The financial and environmental costs of reusable and single-use plastic anaesthetic drug trays. Anaes Intens Care 2010;38:538–44
20. Connor A, Lillywhite R, Cooke MW. The carbon footprints of home and in-center maintenance hemodialysis in the United Kingdom. Hemodial Int 2011 . doi: 10.1111/j.1542-4758.2010.00523.x [Epub ahead of print]
21. Subaiya S, Hogg E, Roberts I. Reducing the environmental impact of trials: a comparison of the carbon footprint of the CRASH-1 and CRASH-2 clinical trials. Trials 2011;12:31
22. Frischknecht R, Jungbluth N, Althaus H-J, Doka G, Dones R, Heck T, Hellweg S, Hischier R, Nemecek T, Rebitzer G, Spielmann M, Wernet G. The econinvent database: overview and methodological framework. Int J Life Cycle Assess 2005;10:259–65
23. Weidema B. Multi-user test of the data quality matrix for product life cycle inventory data. Int J Life Cycle Assess 1998;3:259–65
24. Standards Australia. Cleaning, disinfecting and sterilizing reusable medical and surgical instruments and equipment, and maintenance of associated environments in health care facilities. AS/NZS 4187 2003;NA:14–24
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