Abstract
This life cycle assessment compares the environmental footprint of reusable surgical head covers with single-use disposable surgical head covers.
Health care delivery is estimated to be responsible for 4% to 10% of global greenhouse gas emissions,1,2 in large part originating from the supply chain and waste of surgical equipment and surgical attire.3 The latter is progressive, since an increasing amount of surgical equipment has transitioned from reusable to single-use disposable versions. This study compares the environmental footprint of reusable surgical head covers with single-use disposable surgical head covers.
Methods
We performed a life cycle assessment (LCA), the standard method to quantify the environmental impact of a product within all stages of the life cycle in accordance with ISO 14040:2006 and ISO 14044:2006 guidelines for sustainability research. We investigated 3 types of surgical head covers composed of single-use disposable nonwoven viscose (Model Kosak; Mölnlycke), single-use disposable nonwoven polypropylene (PP) (Model Annie Green; Mölnlycke), and washable reusable polyester (Model Selma; CleanLease B.V.). The functional unit was defined as the annual supply of head covers. The study was performed at Amsterdam University Medical Centres (AUMC), a tertiary hospital with 25 operating rooms (ORs) using 100 000 disposable head covers annually. The reusable headcovers were certified by the manufacturer for 100 reuses before disposal. Life cycle assessment methods are detailed in the eMethods, system boundaries are depicted in eFigures 1 and 2, and product inputs are listed in eTables 1 and 2 in Supplement 1.
The primary outcome was the carbon equivalent footprint (CO2-eq). We included 17 secondary environmental impact categories, including ozone depletion, fine particulate matter, and water ecotoxicity. A sensitivity analysis was performed to test assumptions in key input parameters. Statistics were obtained using 10 000 Monte Carlo simulations of the LCA model. For all methods, SimaPro software, version 9.1.0.7 (PRé Sustainability BV), was used. Significance was set at 2-sided P < .05.
Results
The mean carbon footprint in metric tons CO2-eq for an annual supply of head covers was 1.9 (95% CI, 1.7-2.2) for disposable viscose, 1.7 (95% CI, 1.6-1.8) for PP, and 0.7 (95% CI, 0.6-0.9) for reusable head covers (P < .001) (Figure, A). Comparative analysis showed that reusable head covers have a 56% to 61% lower carbon footprint than disposable head covers. For 16 of 17 secondary outcomes, reusable head covers had a lower environmental impact (Table).
Figure. Distribution of the Carbon Footprint and Head Cover Use.
CO2-eq indicates carbon equivalent footprint. Error bars indicate 95% CIs.
Table. Environmental Impact Assessment.
| Impact category (unit) | Surgical head cover type, value, mean (95% CI) | ||
|---|---|---|---|
| Disposable viscose | Disposable polypropylene | Reusable | |
| Primary outcome | |||
| Carbon footprint (kg CO2 eq) | 1910 (1720 to 2150) | 1670 (1580 to 1780) | 737 (639 to 860) |
| Secondary outcomes | |||
| Fine particulate matter formation (kg PM2.5 eq) | 4.5 (4.0 to 5.1) | 2.7 (2.5 to 2.9) | 0.7 (0.6 to 0.8) |
| Fossil resource scarcity (kg oil eq) | 461 (418 to 508) | 801 (759 to 844) | 583 (504 to 680) |
| Freshwater | |||
| Ecotoxicity (kg 1 DCB) | 178 (95 to 396) | 155 (72 to 379) | 110 (84 to 144) |
| Eutrophication (kg P eq) | 0.6 (0.3 to 1.3) | 0.4 (0.2 to 0.8) | 0.4 (0.2 to 0.7) |
| Human toxicity | |||
| Carcinogenic (kg 1,4-DCB) | 72 (35 to 211) | 57 (28 to 158) | 29 (13 to 83) |
| Noncarcinogenic (kg 1,4-DCB) | 3750 (1720 to 11500) | 2770 (949 to 1000) | 1690 (1190 to 2530) |
| Ionizing radiation (kBq Co-60 eq) | 87 (14 to 381) | 72 (11 to 314) | 51 (7 to 236) |
| Land use (m2a crop eq) | 418 (301 to 580) | 90 (65 to 126) | 17 (13 to 22) |
| Marine | |||
| Ecotoxicity (kg 1,4-DCB) | 237 (127 to 530) | 201 (93 to 499) | 145 (111 to 190) |
| Eutrophication (g N eq) | 90 (80 to 100) | 78 (68 to 90) | 54 (47 to 64) |
| Mineral resource scarcity (kg Cu eq) | 12 (10 to 14) | 4.0 (2.8 to 6.2) | 5.4 (4.5 to 6.4) |
| Ozone formation | |||
| Human health (kg NOx eq) | 5.0 (4.4 to 5.7) | 6.1 (5.1 to 7.4) | 1.4 (1.2 to 1.8) |
| Terrestrial ecosystems (kg NOx eq) | 5.1 (4.5 to 5.7) | 6.3 (5.3 to 7.6) | 1.5 (1.3 to 1.9) |
| Stratospheric ozone depletion (g CFC11 eq) | 1.4 (1.1 to 1.6) | 0.9 (0.6 to 1.8) | 0.5 (0.4-0.6) |
| Terrestrial | |||
| Acidification (kg SO2 eq) | 10 (9 to 11) | 6.8 (6.2 to 7.4) | 1.8 (1.6 to 2.1) |
| Ecotoxicity (kg 1,4-DCB) | 11600 (9470 to 15700) | 4010 (2760 to 6830) | 2640 (1930 to 4420) |
| Water consumption (m3) | 32 (−675 to 609) | 13 (−447 to 391) | 6 (−143 to 134) |
Abbreviations: CFC11, chlorofluorocarbon-11; Cu, copper; DCB, dichlorobenzene; eq, equivalent; kBq Co-60, kilobecquerel Cobalt-60; m2a, area time; NOx, nitrogen oxide; P, phosphorus; PM2.5, particulate matter with an aerodynamic diameter up to 2.5 μm; SO2, sulfur dioxide.
Varying the number of lifetime-uses showed that the reduction in carbon footprint with reusable head covers increased with the number of uses (Figure, B). The break even (number of uses after which the reusable head cover has a lower carbon footprint than the equivalent number of the disposable head cover) between the reusable head cover and the viscose and PP head cover was between 16 and 19 uses.
Discussion
This LCA found that reusable head covers have a significantly lower environmental impact than disposable head covers. Detailed LCAs of products, such as our LCA, use local data derived directly from suppliers and are therefore specific to their situation, which can be a limitation. When comparing our results with LCAs of reusable and disposable surgical products, we found a similar decrease in carbon footprint in favor of the reusable variants.4
Based on procurement data from AUMC in the Netherlands, reusable head covers could be implemented as having neutral cost. This is in line with the growing body of evidence that reusable products are cost-neutral or have a cost advantage (17%-94% lower costs).4
Seemingly small changes in a single hospital can have a substantial environmental benefit if applied in a wide range. On a global scale, replacing 1 billion disposable with 10 million reusable surgical head covers would reduce global greenhouse gas emissions by 10 000 metric tons, equivalent to taking more than 2000 passenger vehicles off the roads for 1 year. Facilitating the transition from disposable to reusable surgical attire and instruments will positively contribute to climate change mitigation and the reduction of its adverse health effects.
eMethods. Data and Modeling Information
eReference
eFigure 1: System Boundary and Product Flow of Disposable Viscose and Polypropylene Head Covers
eFigure 2: System Boundary and Product Flow of Reusable Head Covers
eTable 1. Product Information Disposable Head Cover
eTable 2. Product Information for Reusable Headcover, ‘Laundry Head Cover’ Reusable Head Cover, and LCA Reusable Head Cover
Data Sharing Statement
References
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Associated Data
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Supplementary Materials
eMethods. Data and Modeling Information
eReference
eFigure 1: System Boundary and Product Flow of Disposable Viscose and Polypropylene Head Covers
eFigure 2: System Boundary and Product Flow of Reusable Head Covers
eTable 1. Product Information Disposable Head Cover
eTable 2. Product Information for Reusable Headcover, ‘Laundry Head Cover’ Reusable Head Cover, and LCA Reusable Head Cover
Data Sharing Statement