- Question: Reusable versus disposable rigid laryngoscopes: which is least harmful to the environment and cheaper for an institution when considering the entire life cycle of each device?
- Findings: Life cycle assessment and life cycle costing methods reveal that reusable laryngoscopes produce far fewer environmental emissions, and are significantly cheaper at Yale-New Haven Hospital.
- Meaning: Administrators can use life cycle assessment and life cycle costing methods to evaluate environmental sustainability and economic criteria when making medical device management decisions.
Health care pollution is a growing concern,1,2 inspiring calls for greater transparency of environmental emissions throughout the medical product life cycle.3 Life cycle assessment (LCA) has been recommended for evaluating medical devices along environmental dimensions.3 LCA is an internationally standardized (ISO 14040)4 modeling tool used to quantify environmental and public health impacts of a product or process and is used to aid in materials selection and design (for producers) or to inform purchasing decisions (for consumers).5–7 LCA accounts for resource inputs and emissions that occur throughout the product’s entire life cycle (“cradle-to-grave”), including extraction of natural resources, materials production, device manufacturing, transport, use/reuse, and eventual waste treatment and disposal. In this way, LCA accounts for both direct emissions from product use and indirect impacts from upstream manufacturing and downstream disposal that are otherwise not considered when evaluating options.
LCA is frequently coupled with life cycle costing (LCC), which expands from a narrow focus on up-front purchasing costs to include considerations of device lifetime, cleaning and maintenance, and waste disposal to determine total cost of ownership. LCA and/or LCC methodology have been previously applied to medical devices, including reusable and disposable laryngeal mask airways,8 laparoscopic equipment,9 central line kits,10 and drug trays.11 They also have been applied to clinical services, including computed tomography scans,12 cataract treatment,13 hemodialysis,14 hysterectomy,15 and to entire health sectors at the national level.1,2
Reusable and disposable laryngoscopes are of current interest to anesthesiologists. To quickly meet or exceed conflicting infection prevention guidelines and oversight body recommendations,16–20 many institutions may be electively switching from reusable laryngoscope blades and handles to single-use disposable (SUD) alternatives or overcleaning reusable devices. SUD options may require less material and energy to produce individually than reusable equipment that must be more durable, but SUD options create considerably more solid waste as well. Alternatively, cleaning reusable laryngoscopes may be resource intensive—especially, when performing high-level disinfection (HLD) or sterilization (STZ) in central sterilization and supply (CSS) departments, as opposed to traditional low-level disinfection (LLD) performed in the operating room for the handles. Further, reusable models have higher up-front, attrition, and associated cleaning labor costs.
It is not immediately clear whether reusable or disposable laryngoscope handles and blades are preferable from either an environmental or economic standpoint when considering the entire device life cycle. The objective of this study was to compare reusable stainless steel laryngoscope handles and tongue blades to metal and plastic SUD alternatives, under a range of cleaning options, to aid in procurement and management protocol decision making.
We performed LCA and LCC analyses to directly compare 1 stainless steel reusable and 2 SUD rigid laryngoscope handle and blade alternatives representing 2 basic materials—steel and plastic (Table 1). As a quality improvement project, Human Investigations Committee review was not required, and Enhancing the QUAlity of Transparency Of health Research (EQUATOR) network Standards for QUality Improvement Reporting Excellence (SQUIRE), and Consolidated Health Economic Reporting Standards (CHEERS) guidelines21 applied.
The scope of this LCA was cradle to grave (Figure 1), including extraction of material and energy resources, manufacturing, packaging, transportation, cleaning scenarios, and final disposal. Analogously, the scope of this LCC included procurement, reprocessing, refurbishment, and waste disposal, reflecting facility total cost of ownership (Figure 1).
For the purpose of this investigation, device efficacy was presumed equivalent. The functional unit of comparison is 1 handle and 1 blade for a single patient encounter. Data for reusable components were scaled per use based on rated lifetimes of each component, plus 1 cleaning, and were then compared to SUD alternatives.
Material composition of all components under investigation was determined through a combination of manufacturer specifications, deconstruction, and density testing (Table 2). The mass of each material was measured using a microgram scale. Data collection specific to Yale-New Haven Hospital (YNHH) included device transportation distance, and washer- and autoclave-associated energy, water, and chemical requirements for reprocessing. Alternate cleaning and waste management scenarios were considered, and sensitivity analyses were performed around device attrition and labor requirements so that results are applicable to a range of operational situations.
Life Cycle Assessment
According to the ISO 14040 standard,4 LCA includes 4 phases: (1) goal and scope definition; (2) life cycle inventory, which is an accounting of all resource inputs and emissions over the product life cycle and includes site-specific (“foreground”) data that are directly measured, combined with regional or national (“background”) data taken from existing databases; (3) life cycle impact assessment, where emissions are linked to their eventual environmental or health impacts using physical science–based models; and (4) interpretation of results. LCA modeling was performed here using the commercial software package, SimaPro 8.1 (Amersfoort, the Netherlands). Laryngoscope materials (Table 2) and energy and process inputs were matched with background life cycle inventory data from the ecoinvent v2.2 database adjusted for the US energy system (US-EI database, Earthshift, Huntington, VT). Impact assessment was performed using the US Environmental Protection Agency's Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI) method.22 Each of these software packages, databases, and models is widely used by LCA practitioners in the United States and internationally, supported by international standards and guidance.5–7
The primary environmental impact category of interest was global warming caused by greenhouse gas (GHG) emissions, expressed in carbon dioxide equivalents (CO2-eq). In addition to global warming, 9 other standard environmental and human health impact categories were considered (measured in equivalents of respective reference compound): stratospheric ozone depletion (trichlorofluromethane equivalents); PM2.5 (particulate matter [<2.5 micron aerodynamic diameter] equivalents) and ground-level ozone (ozone equivalents), which contribute to respiratory disease; cancer and noncancer disease through chemical exposure (comparative toxicity unit-human equivalents); degradation of water quality and ecosystem health by acidification (sulfur dioxide equivalents) and eutrophication (nitrogen equivalents); aquatic ecotoxicity (comparative toxicity unit-ecotoxicity equivalents); and use of nonrenewable fossil resources (megajoule surplus of energy). Having results for multiple categories of environmental and human health impacts allows for consideration of potential trade-offs when comparing device alternatives.
Modeling Parameters and Assumptions
The reusable stainless steel laryngoscope handle considered here is rated for 4000 uses, whereas the SUD alternatives are rated for 1 use (Table 1). To compare devices, 1/4000th of the manufacturing, transportation, and disposal impacts of a reusable handle plus 1 reprocessing cycle are therefore compared to the manufacturing, transportation, and disposal impacts of 1 SUD alternative. Reusable handle light bulbs and hinge pins become worn over time, especially as the level of disinfection is increased, and are periodically replaced. We conservatively estimated refurbishment once every 40 uses. The reusable tongue blade considered here is comprised of a stainless steel blade and a removable fiber-optic light conduit pipe. The steel blade has no rated limit; however, we assumed 4000 uses per lifetime. The removable fiber-optic light pipe is rated for 500 uses (Table 1). Total results for these components are similarly scaled to a single use and reprocessing cycle to compare to 1 SUD alternative.
Transportation and Packaging.
Transportation distances of devices to YNHH were determined through distributing company information on final manufacturing locations. Overseas transportation was assumed by cargo ship from the country of origin. North American transportation was assumed by truck to distribution centers and then to New Haven, CT. Bulk shipment considered 20 units per cardboard box, evenly attributed. All new handles and blades are separately packaged by the manufacturer in plastic film and paper. CSS-reprocessed reusable devices are repackaged at YNHH in peel-packs equivalent in materials, size, and weight to the original individual packaging. Thus, packaging is attributed to each SUD blade and SUD handle and to each use of the reusable tongue blade and reusable handle if treated by either HLD or STZ. LLD of the handle is historically performed in the operating room and without repackaging.
The rigid reusable stainless steel handle is powered by 2 alkaline C-batteries. These batteries are used until the laryngoscope light source appears weak or spent. Battery inputs are allocated proportionally to reflect conservative replacement every 40 uses. Similar use/reuse of 2 alkaline C-batteries is assumed for the SUD metal handle. The SUD plastic laryngoscope handle is powered by 3 embedded button-sized lithium ion batteries, discarded within the handle after a single use.
The Centers for Disease Control (CDC) requires that noncritical devices (those contacting intact skin) undergo a minimum of LLD, whereas semicritical devices (those contacting mucous membranes or broken skin) undergo a minimum of HLD. Laryngoscope tongue blades are uniformly classified as semicritical.16–20 For laryngoscope handles, there is inconsistent classification by professional bodies as either noncritical17,19 or semicritical,18 and the CDC defers to manufacturer instructions for use (IFUs).16,17 Thus, reusable tongue blades and handles were both evaluated under HLD and STZ cleaning scenarios, and the reusable handle was also evaluated under the LLD scenario. CSS energy, chemical, and water requirements were determined through washer (Getinge 8666; Getinge Group, Englewood, CO) and autoclave (Getinge 833HC, Englewood, CO) specifications and were apportioned to each device assuming a full load (180 and 240 devices per tray, respectively). One quarter of a chemical wipe was allocated per handle LLD, as we observed a single cloth was used to clean additional surfaces (Supplemental Digital Content, Materials, https://links.lww.com/AA/C146). SUD handles and blades were assumed treated with HLD as part of the manufacturing process per original package labeling.
Disposal/End of Life.
After reaching the end of their useful lives, both SUD and reusable laryngoscope handles and blades, including packaging, entered waste management. Waste management modeling was performed using US average rates of recycling plastics (6%) and metals (30%–70%), while remaining solid waste is either landfilled (80%) or incinerated (20%).23 An alternative recycling scenario (100%) was also modeled to examine the sensitivity of the results to end-of-life assumptions.
Life Cycle Costing
The scope of the cost analysis included procurement, reprocessing, refurbishment, and waste removal costs at YNHH (Figure 1). Capital equipment acquisition (eg, autoclaves) and indirect fees were excluded.
Purchase costs were assessed through YNHH accounting records and thus included bulk discounts. The SUD metal handle and tongue blade (Table 1), which are included in the environmental analysis, were not under contract and thus excluded from this cost analysis as their nondiscounted purchase prices were incomparable.
Central reprocessing of reusable components was broken down into separate treatment steps for each cleaning scenario, and per-unit total cleaning time was determined through observation by CSS staff (Supplemental Digital Content, Table S1, https://links.lww.com/AA/C146). Average midlevel staff salary including benefits was assumed at $50,000 per annum, and per-component labor costs were subsequently determined. Restocking times were presumed similar for both reusable and SUD components and were therefore excluded. Energy, water, and chemical costs for washing machine (HLD) and autoclave (STZ) cycles were allocated to each device assuming trays were fully loaded based on manufacturer specifications. One quarter of the cost of a chemical wipe was allocated per handle for LLD, as noted above.
Replacement light bulbs and hinge pin costs were based on YNHH accounting records. Labor cost is based on an estimated 5 minutes per refurbishment. As noted above, batteries are assumed replaced every 40 uses.
Disposal/End of Life.
Waste hauling costs were attributed by weight for each waste stream. At YNHH, discarded devices and packaging enter the municipal solid waste stream, while cardboard shipping materials and removable batteries are recycled. Alkaline battery vendor hauling is a free service for YNHH, and weight was excluded. Labor for laryngoscope waste removal (within the hospital) was deemed negligible and was excluded from this analysis.
Uncertainty and Sensitivity Analysis
In this study, we assume that values for device component weights and component contract costs apply to the entire population of devices (reflecting expected consistency in manufacturing). Therefore, neither sample-based statistical tests nor statistical analysis of model parameter uncertainty were appropriate. To test uncertainty in the results due to modeling assumptions, we undertook a sensitivity analysis through applying an alternate 100% recycling scenario to reflect health care facilities or communities that have aggressive recycling programs,1 and allowing the model to vary reprocessing parameters of time and device attrition to calculate break-even scenarios between reusable and SUD options.2
Life Cycle Assessment
LCA results for reusable and SUD rigid laryngoscope handle and blade alternatives, representing different cleaning scenarios, are presented in relative terms in Table 3 and in absolute terms in Figure 2. The life cycle emissions from reusables are largely due to reprocessing and thus depend on the level of cleaning utilized. Overall, the majority of life cycle emissions that SUD components generate are created during initial material manufacturing and device assembly.
The most favorable scenario from an environmental perspective is the reusable stainless steel handle treated to HLD standards. LLD of the reusable handle produces 40% more GHG emissions (0.08 kg CO2-eq per use) and STZ nearly 400% more (0.23 kg CO2-eq) than HLD (0.06 kg CO2-eq). The SUD generates approximately 25 times more GHG emissions (1.41 kg CO2-eq and 1.60 kg CO2-eq for the plastic and metal SUD handles, respectively) than the reusable handle treated with HLD (Figure 2). Considering other types of environmental impacts, the SUD handles were the overall worst option from an environmental standpoint under all scenarios, and metal was worse than plastic, whereas HLD of the reusable handle produced the fewest emissions in all impact categories except fossil fuel depletion (Table 3).
The most favorable scenario from an environmental perspective across all emissions categories is the reusable steel tongue blade treated to the minimum HLD standards (Table 3). Similar to the results for handles, sterilizing reusable blades increases GHG emissions by nearly 400% (0.22 kg CO2-eq) compared to HLD (0.06 kg CO2-eq per use). SUD options for blades generate 6–8 times as much GHG emissions per use as the reusable HLD option depending on whether the SUD blade is made of plastic (0.38 kg CO2-eq) or metal (0.44 kg CO2-eq). Even if treated with STZ, the reusable device generates 40%–50% fewer GHG emissions than the SUD alternatives (Figure 2). The SUD tongue blades were the overall worst option from an environmental standpoint under all scenarios, and metal was worse than plastic.
Life Cycle Costing
LCC results for reusable and SUD rigid laryngoscope handle and blade alternatives are presented in Figure 3. For reusable components, reprocessing labor dominated per-use costs. For SUDs, procurement costs dominated per-use costs.
Life cycle costs were lowest for the reusable handle treated with LLD ($0.58 per use). Treating the reusable handle to HLD ($0.98 per use) increased costs by 68%, and treating with STZ ($2.39 per use) increased costs by 300% over LLD. In all cleaning cases, the reusable handle was significantly cheaper than the SUD alternative. The SUD handle ($10.66 per use) increased costs by more than 18 times over LLD of the reusable handle and by 5–18 times over the semicritical cleaning options. When extrapolated over 1 year at YNHH (60,000 intubations), using SUD handles increased overall costs by an estimated $495,000–$604,000 depending on the cleaning scenario.
Treating the reusable tongue blade with STZ ($2.10 per use) more than doubled the costs incurred through the minimum required HLD ($0.69 per use) alone. The reusable tongue blade was significantly more favorable than the SUD alternative. The SUD blade ($5.11 per use) increased costs by 2–7 times over the reusable tongue blades depending on the cleaning scenario. When extrapolated over 1 year at YNHH, disposable blade use increased costs by an estimated $180,000–$265,000 (Figure 3).
Uncertainty and Sensitivity Analysis
Labor Reprocessing Time.
Human effort is the largest contributor to costs for reusable options. Based on observed reprocessing times of 0.5 minutes for LLD of the handle, 1.5 minutes for HLD, or 2 minutes for STZ of either the handle or tongue blade, SUD options are considerably more expensive. Holding all other costs constant (device purchase price, reprocessing material and energy costs, labor technician salary, and waste disposal fees), SUD options only become more cost-effective under HLD if reusable handles required 26 minutes and blades required 13 minutes of CSS reprocessing time, respectively, both of which are unreasonably high and far in excess of what was observed. LLD of the reusable handle would also require 26 minutes of cleaning to break even with a SUD, whereas STZ would require 23 and 10 minutes of labor for the reusable handle and blade, respectively.
Premature discard, before the rated lifetime of a device, is a critical factor in determining the relative benefits of multiuse devices. In terms of total costs, reusable handles treated as noncritical (LLD) are more cost-effective on a per-use basis than single-use devices as long as its lifetime does not fall below 4 uses. If a reusable handle is treated as semicritical (HLD or STZ), attrition rates would have to fall below 4–5 lifetime uses for a single-use device to become more cost-effective. For a reusable tongue blade treated as semicritical, component lifetime would have to fall below 5 lifetime uses under HLD or 7 lifetime uses under STZ for an SUD to become economically preferably.
Similar results for environmental impacts can be derived from Table 3. Single-use handles become environmentally preferable if reusable device lifetime falls below 5 and 4 uses for plastic and metal SUDs, respectively. Single-use plastic blades become environmentally preferable if multiuse device lifetime falls below 5 uses, and for SUD metal blades its 3 uses of the reusable.
How discarded materials are treated at end of life can influence LCA results. To test the sensitivity of the influence of the standard US waste mix assumption (US Durable Goods Waste Scenario), an alternate 100% recycling scenario was modeled. The total recycling scenario demonstrated marginal reductions in GHG emissions over the standard waste disposal scenario for SUDs and had no significant impact on reusable device emissions (Figure 3). Total recycling of laryngoscope materials had no significant impact on costs at YNHH.
Our results strongly suggest that reusable rigid laryngoscopy handles and blades result in significantly lower environmental impacts when compared to SUD alternatives. This is primarily due to the materials and energy required to manufacture multiple SUDs versus 1 reusable device. Due primarily to the energy intensity of metal mining and refining (including iron, chromium, and nickel), SUD stainless steel handles and blades produce significantly more GHG emissions compared to SUD plastic (polyvinyl chloride or polycarbonate) alternatives. For reusable laryngoscope cleaning options, emissions were lowest for HLD and highest for STZ. Because the STZ process includes an HLD step (preceding autoclaving), this result is expected. What is perhaps unexpected is that LLD was not the most favorable scenario. LLD resulted in higher GHG emissions than HLD, rivaled STZ in several other pollutant categories, and dramatically exceeded STZ in ozone-depleting emissions. These emissions occur upstream in the production of chemicals used in the LLD wipes. These results suggest the importance of avoiding overcleaning with STZ and of not wasting disinfectant wipes when performing LLD. Because the majority of pollution impacts stemmed from upstream manufacturing in the case of disposable supplies and from energy for reusable reprocessing, environmental results are expected to be similar for other US institutions. However, results may vary in other countries and regions with different energy systems.24
Perioperative managers and vendors may refer to recycling offsets as justification for relying on SUD laryngoscopes. Recycling of some laryngoscope components is possible, provided recycling vendors agree to accommodate spent devices and hospital infrastructure for collection is established. Some recycling venders may require CSS decontamination before accepting laryngoscope components. Furthermore, recycling is not energy- or emissions-free. Recycling requires energy to transport, shred, separate, clean, and remelt material, which then must undergo extrusion, shaping, forming, and finishing into a new handle or blade. In the case of stainless steel, it is rarely recycled back into stainless steel. Instead, it is typically “downcycled” by combining it with other ferrous scrap to make carbon steel.25 Therefore, recycled components will not simply substitute for new ones. Our results indicate that, even assuming 100% recycling, only marginal reductions in GHG emissions would be achieved over the standard waste management scenario (Figure 2). This discussion is not meant to discourage recycling; there are still energy and environmental advantages for the materials considered here. Also importantly, recycling is highly visible and can increase awareness and inspire other resource-conservation behaviors.26
In this study, we have assumed equivalent performance between reusable and SUD options. However, inferior SUD blade performance has been reported in the literature owing to the higher deformability of the blade/joint, especially those comprised of plastic materials, making vocal cord visualization more difficult.27–35 For this reason, institutions electing to use SUDs may opt for “disposable” steel; however, this material is concerning from an environmental perspective, as our results and others36 indicate. Some users anecdotally report preference for SUD handles owing to the brightness of the newer LED-type light. It should be noted that LED technology also exists in reusable handles and thus should not serve as justification for procurement of disposable handles.
Total Cost of Ownership
The most favorable cost management system at YNHH is with reusable laryngoscope handles and blades. Costs for cleaning reusable laryngoscopes and device attrition are major concerns for managers and are often used to justify reliance on SUDs. However, as presented in the Results section, SUDs would only become more cost-effective at YNHH if reusable handles required unreasonable amounts of cleaning time or were thrown out far before their rated lifetimes. Demands on cleaning infrastructure are another common concern and motivation for switching to SUDs. With 60,000 annual intubations per year at YNHH, an average of 164 dirty reusable laryngoscope blades and handles each are produced each day. Given that YNHH currently reprocesses 12,000 individual medical instruments daily in CSS, reprocessing all laryngoscope components would only amount to a 2.7% increase in daily reprocessing volume. Even if more laborers were hired to reprocess laryngoscopes, these results indicate that it would still be more favorable than the expense of SUDs. These results suggest that careful management of reusable devices to ensure reasonable cleaning times and avoid premature disposal is essential for multiuse components to retain their financial advantage.
Proper cleaning of medical equipment and selective use of SUDs are essential to prevent health care–acquired infections.37 Reducing risk of transmissible infection to zero is a laudable goal; however, infection etiology is multifactorial.38 Overtreating laryngoscopes beyond evidence-based standards or routine reliance on SUD equipment may be well intentioned, but they cannot make up for deficiencies in other core infection prevention areas, such as bolstering host defenses or health care worker hand-washing compliance.39 Infection risk reduction through overcleaning or through reliance on SUDs may be real; however, the significance may be exaggerated and indirect pollution harm to society can no longer be neglected.40
Device Risk Classification
Laryngoscope tongue blades are uniformly categorized by regulatory, oversight, and professional guidelines as semicritical in the United States.16–20 Historically, the handle has been considered as noncritical and treated with LLD in the operating room. However, currently there is lack of consensus on the handle classification. American Association of Nurse Anesthetists20 and Association of periOperative Registered Nurses19 guidelines classify the handle as noncritical. The American Society of Anesthesiologists18 describes the laryngoscope as semicritical and recommends a minimum of HLD; however, it does not distinguish between the handle and blade. The CDC16 and The Joint Commission17 make no clear determination on the handle as either noncritical or semicritical and instead refer to manufacturer’s IFU. Manufacturers are tasked with providing instructions for how to use a device, including various CDC-approved cleaning methods from which the user can choose. However, entrusting manufacturers with determining risk classification invites their arbitrary designation of higher risk class due to the financial incentive to sell more devices. If a facility traditionally performing LLD discovers that its handle IFU is now classified as semicritical, its managers will be faced with the choice of switching to either central reprocessing to a minimum of HLD or to SUD handles. A national consensus could serve to influence the CDC to make clearer determination and remove manufacturer conflict of interest, thus potentially reducing pollution and costs.40
These results demonstrate a clear benefit of reusable laryngoscope handles and blades over SUD alternatives from an environmental perspective, with HLD the least polluting reprocessing method. In select cases where SUDs may be indicated, plastic is a more desirable material than metal from an environmental perspective; however, routine SUD use should not be encouraged. Results may vary in other countries and regions with different energy systems. From a cost perspective, reusable devices were considerably cheaper compared to SUDs, and LLD was the least costly method of cleaning at YNHH. Costs may differ at other institutions, and our results demonstrate the importance of time-motion labor analysis and knowledge of institution-specific implementation barriers. Managers must weigh environmental emissions along with the total cost of ownership, in addition to traditional procurement criteria. Ultimately, the practice of anesthesia should be centered on maximizing patient safety—including public health—as well as the value of care. Life cycle assessment and costing methods can aid in this expanded view of procurement decision making.
The authors acknowledge the contributions of Walter Hall, Director of Central Sterilization and Supply at Yale-New Haven Hospital, and Denise Hersey, Librarian for the Department of Anesthesiology, New Haven, CT; and Emily Anderson and E. Brent Dowd, both BS students in the Department of Civil & Environmental Engineering, Northeastern University, Boston, MA.
Name: Jodi D. Sherman, MD.
Contribution: This author helped design the research; analyze, interpret, and prepare the manuscript.
Name: Lewis A. Raibley IV, BS, MBA.
Contribution: This author helped design the research; analyze, interpret, and prepare the manuscript.
Name: Matthew J. Eckelman, PhD.
Contribution: This author helped design the research; analyze, interpret, and prepare the manuscript.
This manuscript was handled by: Avery Tung, MD, FCCM.
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