Reusable Devices Research Articles

Environmental impact of pediatric ENT surgery: A STROBE analysis

IntroductionIncreasing emissions of greenhouse gases contribute to climate change. The healthcare sector, and particularly the operating room, is a significant emitter of greenhouse gases. In head-and-neck surgery, pediatric procedures are very common, but few studies have assessed their ecological impact. Our objective was to quantify the carbon footprint of common pediatric head-and-neck surgeries (tonsillectomy, adenoidectomy, and transtympanic tube placement). MethodsAn eco-epidemiological study was conducted in December 2022 in a tertiary hospital center. The carbon footprint of 10 pediatric head-and-neck surgeries (tonsillectomies, adenoidectomies, transtympanic tube placements) was calculated, as the sum of carbon dioxide (CO2eq) emissions generated by patient and medical staff transport, waste production, energy consumption in operating rooms, manufacturing and transport of disposable and reusable medical devices (MDs), medication production, and sterilization of reusable MDs. ResultsThe carbon footprint of 1 pediatric head-and-neck surgery was 57.86kgCO2eq. Disposable MDs were the most polluting item with 30.82kgCO2eq (53.3%). Patient transport accounted for 27.4%, medication for 12.6% and reusable MDs for 2.9%. ConclusionsPediatric head-and-neck surgeries generate a significant quantity of CO2, mostly due to the production and delivery of disposable MDs. These observations could serve as a starting point for ecological actions consistent with an environmentally sustainable and climate-resilient health system.

Potential impacts to human health from climate change: A comparative life-cycle assessment of single-use versus reusable devices flexible ureteroscopes

Climate change poses a significant global health challenge, with medical procedures contributing substantially to CO2 emissions. Urology, as part of the broader healthcare sector, has begun integrating Planetary Health concepts to address this issue. While earlier studies have focused on Life Cycle Assessments (LCA) of urological procedures, these evaluations remain data-dependent, and insights into intra-hospital emissions are limited. This study introduces a methodical approach for analyzing intra-institutional processes of LCA for single-use and reusable flexible ureterorenoscopes (fURS). The LCA method was applied to assess the greenhouse gas emissions (CO2 equivalents, CO2-eq) generated across the life cycle of fURS, including production, use-phase, reprocessing, maintenance, and disposal. The study approximated the Global Warming Potential (GWP) per one-hour use and evaluated associated health impacts using the ReCiPe2016(H) method, which measures Disability-Adjusted Life Years (DALYs). Results showed that for reusable fURS, assuming 133 usages per device and maintenance after every 11th use, each application generated 1.24 kg CO2-eq, equivalent to 1.15E-06 DALYs. In contrast, single-use fURS generated 4.93 kg CO2-eq and 4.57E-06 DALYs per application. The production and reprocessing stages were identified as having the greatest environmental and health impacts. For reusable fURS, electricity required during refurbishment and use phases was a key contributor, whereas the production phase accounted for most of the impact in single-use devices. Overall, singleuse fURS had a substantially higher potential environmental and health impact than their reusable counterparts. This study underscores the environmental and health impacts of ureterorenoscopy and highlights the importance of incorporating Planetary Health principles into healthcare practices. It provides a foundation for further analyses and research, aiming to drive transformative action in the healthcare sector toward sustainability.

Rigid–flexible coupling dynamics of a threaded reusable low-shock spacecraft separation device

Rigid–flexible coupling dynamics of a threaded reusable low-shock spacecraft separation device

Uncovering the Evidence for Sustainability in Urology: A Scoping Review.

This article focuses on the environmental impact of urology devices and procedures in hospitals and identifies practices that can reduce greenhouse gas emissions associated with urology services. A scoping review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted using MEDLINE, EMBASE, and Google Scholar to find studies on the carbon footprint of urologic procedures and sustainable practices. We identified 14 studies, 6 of which used life cycle assessments to compare the environmental impact of single-use and reusable urology devices. Three studies favored single-use devices, 2 favored reusable ones, and 1 found no significant difference, with the sterilization of reusable devices being a major carbon contributor. To enhance sustainability in urology, 8 articles suggested measures including day-case procedures, minimizing low-value care, drapeless cystoscopy, fluid management systems, using quick response (QR) codes in documentation, telehealth initiatives, and low-emission anesthetics. Promoting sustainability in healthcare requires more than just using reusable equipment; it necessitates a comprehensive approach from manufacturing to disposal, including the carbon footprint of sterilization. Encouraging low-emission anesthetics, QR codes, and telemedicine can significantly reduce emissions in urology.

A-357 Evaluation of a home kit for lay user collection, centrifugation, and refrigeration of capillary blood specimens

Abstract Background While solutions enabling at-home self-collection of capillary blood samples are maturing, many analytes require blood separation and controlled shipping temperatures for stable analysis in centralized laboratories. Here we present results of a pilot lay user study evaluating usability and specimen quality of at-home blood collection with centrifugation and refrigerated shipping of capillary serum specimens. Methods N=45 consented subjects were mailed kits including supplies for a capillary blood self-collection using a Tasso+™ device, a Labcorp TrueTherm™ reusable shipper containing a temperature tracker, a Labcorp TrueSpin™ battery-powered centrifuge, written instructions, and a usability survey. Subjects independently followed the instructions for blood collection, separation, and thermal protection and returned the kits to Labcorp via overnight shipping. Received kits were evaluated for correct return, volume of blood collected, volume of serum, visual hemolysis, and temperature throughout shipment. Results Of the n=45 consented subjects, 39 subjects returned the kits, one subject unsuccessfully attempted to collect blood two times, and the remaining five subjects did not return the kits. Primary analysis parameters are outlined in Table 1. Conclusions Untrained subjects were able to collect their own capillary blood samples, process them, and ship them using the investigational home collection kits. While kit return can be a challenge with home collection, the vast majority of subjects were able to return a testable sample. Combining blood separation prior to shipment using the Labcorp TrueSpin centrifuge and temperature control with the reusable Labcorp TrueTherm device successfully protected samples from hemolysis. These results indicate that such kits are a promising at-home blood collection method and may increase test accuracy and menu availability for sensitive analytes.

A new quantitative method for determining patient risk for reusable medical device categorization based on using and interpreting Kremer's cleaning classification system

The cleaning of reusable medical devices involves inherent challenges that can impact on the effectiveness of the cleaning process; consequently, the subsequent safety of patients. Fluid dynamics play a critical role in determining the flow and distribution of cleaning agents where the design of the device can either facilitate or hinder this important process. Complex geometries, narrow channels, or irregular surfaces can impede effective flushing of contaminants leading to incomplete cleaning that creates a greater likelihood for patient contamination risks. Device features (n =23) were exposed to the most challenging cleaning conditions to find the point of failure in both fluid dynamics and soil retention. Experimental results obtained from the aforementioned along with associated compound risks were used to assign a risk value. Using the "hardest to clean" device feature approach as the base risk value, the total quantitative risk score was calculated for different reusable medical devices from numerical values obtained from addressing 14 questions focusing on variability in geometry, material use, types of cleaning, and intended patient use. Patient risk values for devices with different features were calculated from using Kremer's cleaning categories based on position within value ranges. Occurrences less than 18 correspond to minimal risk devices while a total risk score between the values of 18-39 are moderate and equal to or above 40 scores corresponds to the maximal category. Application of this quantitative assessment approach will facilitate appropriate mitigation of risk for cleaning reusable medical devices by informing use of targeted effective interventions. Future use of this Kremer cleaning classification will complement and augment disinfection and sterilization modalities.

Impact of COVID-19 pandemic on reusable device precleaning training for front-line staff

High-level disinfection and sterilization are complex processes, requiring initial and ongoing training of frontline staff.1 A key component of appropriate disinfection and sterilization is point-of-use pre-cleaning performed by front-line staff. Our facility implemented an annual hospital-wide education and competency program for staff that perform pre-cleaning of reusable medical devices.

HYGIENE DES DISPOSITIFS MEDICAUX REUTILISABLES DANS LA GESTION DES VOIES AERIENNES EN ANESTHESIE AU CHUD/ BORGOU-ALIBORI

Introduction :Nosocomial infection is a priority concern for hospitals. The aim of this study was to investigate the hygiene of reusable medical devices (DMR) used in anesthesia at CHUD-B/A. Methods :The study was observational, cross-sectional, descriptive and analytical. It surveyed nursing staff in the anesthesia department of CHUD Borgou/Alibori. Sampling was non-random, with a census of all staff. Data analysis was performed using IBM SPSS Statistics 21 software. Observations in the study were presented in proportions for qualitative variables and quantitative data using central tendency parameters such as mean with standard deviation, median as appropriate, mode and extremums. Results :A total of 14 caregivers were surveyed. Intermediate risks were related to semi-critical materials, according to 64.3% of subjects. Knowledge of DMR processing steps was affirmed by 92.2% of staff. Decontamination followed by cleaning and rinsing was confirmed by 84.6% of respondents. It was observed that equipment was immersed in a small jar containing a small volume of non-renewed decontamination solution, that there was no decontamination protocol, that hand hygiene was observed in 25 cases, and that gloves were worn in 30 cases. Conclusion:The absence of a DMR management protocol is apparent. Device hygiene needs to be improved. The development of a protocol for DMR treatment and the promotion of single-use equipment are necessary.

PMCA to demonstrate the efficacy of prion inactivation methods on reusable medical devices: a relevant alternative to animal bioassays

Validation of prion inactivation processes for medical devices relies on in vivo experimental protocols. However, bioassays are costly, long (one to two years) and ethically disputable. Additionally, results obtained with one prion strain, for example 263K (hamster-adapted strain originating from sheep scrapie), cannot be easily extrapolated to relevant human prion strains, further questioning the utility of bioassays. Over the past two decades, cell-free prion amplification assays have emerged as potential alternatives to bioassays. Rather than measuring prion infectivity, they quantify prion seeding activity, i.e. the capacity to convert the normal prion protein into the disease-associated isoform. The results obtained by an optimized cell-free assay termed miniaturized-bead protein misfolding cyclic amplification (mb-PMCA), with four processes using three different prion strains, 263K and two human prions derived from variant and sporadic Creutzfeldt-Jakob diseases, were compared to published bioassays using the same three strains and processes, when available. Tests performed on reference processes (steam, sodium hydroxide, sodium hypochlorite) and low temperature H2O2 sterilization process (STERRAD NXTM Advanced cycle), showed perfect alignment between mb-PMCA and available bioassays. STERRAD NXTM Advanced cycle was efficacious on all three prion strains. These data confirm that PMCA and in particular mb-PMCA is a relevant alternative to animal bioassays for assessment of prion inactivation processes and the interest of some low temperature H2O2 sterilization cycles.

Cascade Fluorescence Modulation in Photochromic Microcapsules.

Certain derivatives of terarylene are able to undergo a highly efficient oxidative cycloreversion cascade effect, a ring opening reaction with quantum yields above unity, resulting in a colored-to-colorless transition in solution. In the presence of chloroform, high-energy UV and X-rays can trigger this phenomenon, potentially acting as a visual detection system for ionizing radiation. However, chloroform is sensitive to different irradiation wavelengths without distinction, making it difficult to adapt to a reusable device. Chlorobenzene was chosen as an alternative halogenated solvent, as it offers wavelength selectivity between photocyclization and cascade effect cycloreversion. Nile Red was also incorporated into the system with the aim of improving the sensitivity of the visual detection via fluorescence photoswitching. Finally, microencapsulation of both terarylene and Nile Red was targeted to obtain both the cascade effect and photoswitching in a single system. In microcapsules made from a Pickering emulsion, this terarylene-Nile Red system showed high fatigue resistance to repeated photocyclization and cycloreversion irradiation, giving access to repeated ON/OFF fluorescence photoswitching. The cascade effect was also successfully demonstrated along with fluorescence recovery, showing the versatility of the two phenomena in different media.

A Clean You Can Trust: Using an Evidence-Based Bundle to Transform Point-of-Use Treatment for Reusable Medical Devices at a Military Treatment Facility

ABSTRACT Introduction Throughout surgical and invasive procedures, reusable instruments and flexible endoscopes become soiled with organic and inorganic materials. When these substances are permitted to dry, a matrix of microbial cells, called biofilm, forms on the surface of devices, irreversibly binding and subsequently impeding the disinfection and sterilization process. To prevent biofilm formation from occurring, devices must be continuously flushed and wiped with water throughout the procedure and at the end of the case. This process, known as point-of-use treatment (POUT), is the critical first step in the decontamination of medical devices. Poor compliance with POUT can increase patient morbidity and mortality and result in failing hospital accreditation. Materials and Methods An interdisciplinary team used the Plan-Do-Study-Act (PDSA) to develop and implement an audit assessing 29 evidence-based criteria for POUT treatment. Each PDSA cycle supported evidence-based opportunities addressing feedback, workflow analysis, policy development, competency assessment creation, training module development, and infection prevention grand rounds. Four audits were performed over ten months to achieve improved organizational POUT compliance. Results Implementing recurrent PDSA cycles that included audits with feedback led to an evidence-based bundle of policies, competencies, and training for 34 different clinical areas. These interventions resulted in a 26% compliance increase (66% to 92%). Program-specific improvements included flexible endoscopes (+4%) and reusable instruments (+20%). Conclusions Multimodal evidence-based initiatives to improve compliance with workflow processes is a translatable POUT evidence-based practice project for similar Defense Health Agengy facilities. Workflow processes can be vetted and distributed using interdisciplinary teams to ensure viability, sustainability, and conformity with organizational requirements, resulting in a more ready force.

Active diagnostic ingredients (ADIs) for PCR: A mini-bioreactor producing dNTPs with silica immobilized R5-kinases.

Low availability of routine nucleic acid amplification testing (NAAT) during infection outbreaks, especially in less resourced environments, was highlighted by the Covid pandemic. One of the barriers lies with the supply chain and cost of the active diagnostic ingredients (ADIs) that are the reagents for NAATs. This work explores a novel synthesis method to produce a key NAAT reagent, namely the 2'-deoxynucleoside 5'-triphosphate (dNTPs), via a reusable enzyme bioreactor, that can be integrated into a NAAT workflow. A self-immobilizing R5-silaffin kinase fusion enzyme was designed for immobilization on silica, converting dNMPs to their respective dNTP ADIs for PCR in a R5-kinase mini-bioreactor, designed to be implemented in a reusable device, stable over 2 months, when stored at 4°C. The performance is demonstrated for PCR reactions of the lambda genome and showed successful amplification up to 7.5 kb. In comparison with commercial dNTPs, in Plasmodium malariae NAATs, a high linear correlation was shown between the Ct value and the log(Copy Number), with lower incidence of false positives than with the commercial dNTPs. Overall a pathway to generate deoxynucleotides from monophosphate precursors was demonstrated, and an immobilized enzyme mini-bioreactor investigated as a proof-of-principle for work-flow integration with NAAT in low-resource research and diagnostics labs.

Multistable twist metastructures with enhanced collapsibility and multidimensional programmability

Multistable metastructures with compression-twist coupling offer promising applications in reusable protective devices, deployable structures and reconfigurable robotics. However, existing designs based on either Kresling origami or truss-based mechanisms, suffer from limited deformability, due to the accumulation of bending deformation in creases or trusses. Herein, we propose a novel multistable twist metastructure by integrating hinged beams with Kresling-inspired trusses. A two-step procedure, combining 3D printing and interlocking assembling, is utilized to fabricate the multistable twist samples. This multistable twist mechanism leverages the elastic instability and shape reconfiguration of hinged beams, enabling transitions between stable configurations with minimal bending in the trusses. This approach achieves exceptional collapsibility with a reusable maximum allowable compression up to 80 % of the structural height. Additionally, the compression-twist coupling of trusses protects hinged beams from severe tensile damage. Furthermore, our strategy offers multidimensional programmability. Geometric design tailors configuration stability (i.e., multi/bistability, monostability, monotonicity), while arraying method controls deformation modes. This culminates in the realization of customized functions of impact resistance and vibration mitigation. Specially, by incorporating trusses, negative stiffness with loop hysteresis can be programmed to enhance energy dissipation, which facilitates to damping the impact and vibration. Experimental tests confirm the compatibility of excellent collapsibility, programmability and multifunctionality. This finding underscores the potential of such multistable metastructure with compression-twist coupling for designing next-generation reusable multifunctional devices.

Efficacy of gaseous ozone and UVC radiation against Candida auris biofilms on polystyrene surfaces

The growth and attachment of highly resistant biofilms on/to polymer-based surfaces, including reusable medical devices is a significant health concern in infection control. The increasing prevalence of the multidrug-resistant yeast, Candida auris, has recently garnered immense interest as a contributor to healthcare-associated infections. In this study, we investigate the potential of disinfection processes (ozone, UVC, and ozone + UVC) to inactivate C. auris biofilms (NCPF 8971), grown on polystyrene surfaces. A bespoke decontamination chamber is used to expose the substrate for 20–60 mins, corresponding to ozone doses between 1000 and 3000 ppm.min and UVC doses between 2864 and 11,592 mJ/cm2, respectively. The performance of these 3 treatment methods against the biofilms and vegetative/planktonic cells of the organism is comparatively evaluated. While complete inactivation (> 8 log10 reduction, CFU/mL) of the vegetative cells is observed within 40 mins by all methods, the biofilms proved considerably difficult to inactivate. Only 3.3 log10 reduction was achieved using ozone for 40 min, whereas 7.2 log10 reduction was obtained using UVC for 40 min. A hybrid application of ozone and UVC improved the decontamination efficacy compared to their independent applications (i.e., ozone only and UVC only). Scanning electron microscopy results yielded new insights into the inactivation mechanisms; thus providing the needed foundation for newer developments in oxidation-based processes for biofilm mitigation and control.

How green is my reusable bronchoscope?

IntroductionSingle-use bronchoscopes have replaced reusable ones in many institutions. This study aimed to evaluate the environmental and financial impacts of both strategies: reusable and single-use bronchoscopes. Material and methodsWe conducted a pragmatic study in a 21-bed polyvalent ICU, in Saint-Brieuc, Bretagne, France. The eco-audit consisted of estimating greenhouse gas (GHG) emissions, considering the life cycle of each strategy. Greenhouse gas (GHG) emissions related to construction, packaging, transport and waste elimination were compared between 2 devices: the reusable bronchoscope, a Pentax® FI-16RBS that was disinfected twice daily; and the single-use bronchoscope, the bronchoflex agile® from TSC. ResultsFor the reusable bronchoscope, GHG emissions were marginally impacted by the number of bronchoscopies performed (from 185 kg eq.CO2 per year to 192 kg eq.CO2 for 10 or 110 bronchoscopies per year). For the reusable device, GHG emissions directly depended on the number of bronchoscopies performed with 3.82 kg eq.CO2 emitted per bronchoscopy. The breakeven point for the reusable bronchoscope was estimated at 50 bronchoscopies in terms of GHG emissions and 96 bronchoscopies for financial considerations. ConclusionConsidering current practice in our ICU, reusable bronchoscopes have lower GHG emissions when used more than 50 times a year and a lower cost when used more than 96 times a year as compared with single-use bronchoscopes.

Material compatibility of epoxies exposed to repeated low temperature vaporized hydrogen peroxide sterilization

ABSTRACT Through technological advancements, medical devices have evolved in their designs and have become more complex in both their design and materials of construction. Medical grade biocompatible epoxies are widely used in reusable medical devices. Choosing an epoxy that maintains its performance characteristics when subjected to repeated sterilization throughout the reusable medical device’s lifespan is a known challenge for medical device manufacturers. This study evaluated the material compatibility of seven cured 2-part and 1-part epoxies used in medical devices following exposure to 100 cycles in a low temperature vaporized hydrogen peroxide sterilizer. Six of the seven epoxies tested were found to be compatible with vaporized hydrogen peroxide sterilization based on qualitative, hardness and weight measurements conducted post exposure to 100 VHP cycles. The epoxies deemed to be compatible displayed no visual signs of physical defects, minimal reduction in hardness (≤2%) and total weight gain (≤2.9%). One of the epoxy samples did not maintain its texture and exhibited 17% loss in hardness post exposure to 100 VHP sterilization cycles and was found to be incompatible with the low temperature vaporized hydrogen peroxide process. This study verifies the need for material compatibility evaluations of epoxies prior to designing and developing a medical device while keeping in mind the application, lifecycle and intended use of medical devices.

Inventory of the Sterilization Units at a Tertiary-Level South Tunisian University Hospital

Sterilization of reusable medical devices (RMD) is considered as one of the major components of healthcare associated infection (HAI) prevention that should be strictly maintained. Microorganisms responsible for HAI can be transmitted from a common inanimate vehicle such as medical RMD to patients. Sterilization is a complete process with a set of successive steps to finally achieve a sterile RMD. In addition to these steps, which must be carefully controlled, the whole environment of this process should also conform to quality and security standards and criteria in order to ensure a robust sterilization process and a secure RMD. Therefore, a complete and exhaustive evaluation of this process is highly recommended. This evaluation aimed firstly to examine the inventory of sterilization process, architecture, and environment as well as to present recommendations to be adopted to adjust the practices and failures recorded accordingly.

Research on reversible bonding of microfluidic chips based on stretch release adhesive strips

AbstractThe reversible bonding of microfluidic chips has been developing rapidly with the requirement of reusable microfluidic devices or the need to obtain the samples inside the chip. Traditional bonding methods for polymer‐based microfluidics, e.g., thermal bonding, permanently attach the substrate and cover plate. Sometimes, once the chip flow channel is blocked, it is difficult to clean and affect the reusability of the chip. This study proposes a new reversible bonding method for poly (methyl methacrylate) (PMMA) microfluidic chips with the help of stretch release adhesive strips. The designed microchannels were fabricated on the surface of PMMA plates using CO2 laser irradiation. Then, stretch release adhesive strips were used as an intermediate layer between the substrate (with microchannels) and another flat PMMA/PS/PC plate to seal the microchannel. The assembled chip sets were bonded at room temperature with bonding strength comparable with other permanent bonding methods. Experimental results show that simply pulling the adhesive layer by applying a shear force can easily detach the intermediate adhesive layer from both the substrate and cover plate to separate the bonded chipset. The proposed reversible bonding method is simple, rapid and has low residue and high bonding strength. Bacterial culture experiments were also conducted to verify the biocompatibility of the proposed bonding method. The proposed reversible bonding technique can be used for polymer‐based microfluidic devices that require sample recovery or chip reuse.Highlights The stretch release adhesive strip can provide high bond strength. It allows easy peeling for reversible bonding. It bonds at room temperature with simple operation. It has good transparency for easy observation of experiments. It has good biocompatibility.

WITHDRAWN: Cadaveric Testing of a Novel Intraoperative Load Sensor for Soft-tissue balancing during Total Knee Replacements

AimThe aim of this research was to prove the functionality of a smart tibial sensor for use during total knee replacements to increase the clinical accuracy of a balanced knee. The accuracy of such device provides surgeons with an objective tool for load balancing in the knee, where currently the joint is balanced based on the surgeon’s ‘feel’ of a balanced knee. BackgroundLiterature surrounding the kinematics and tibiofemoral joint forces through the flexion arc coupled with qualitative feedback from an orthopaedic surgeon provided a basis for proving the functionality of the smart-sensor. MethodologyTwo full body cadavers underwent a cruciate-retaining total knee replacement using Zimmer’s Persona Knee System. Varying thicknesses adjusted the height of the tibial smart-sensor between 10mm-13mm in increments of 1mm. The contact points and loads were observed through the flexion arc (0°,45°, and 90°). ResultsThe results were between the literature surrounding both the compartmental forces and contact points throughout the range of motion. Moreover, qualitative feedback determined that the smart-sensor was robust and durable throughout its use in both cadavers demonstrating its potential as a reusable device. Minor adjustments to the graphical user interface would improve the ease of use for the surgical team. ConclusionThis sensor demonstrated the functionality of the smart-sensor through cadaveric testing in predicating both the load and location throughout a range of motion. Continued development of this sensor would provide surgeons with an accurate and robust tool for intraoperative joint balancing which could extend to all joints in the body for a more evidence based surgical procedure.

Harm perceptions across vaping product features: An on-line cross-sectional survey of adults who smoke and/or vape in the United Kingdom.

Vaping products are diverse with a wide variety of features, and popular products change rapidly. This study examined the features and types of vaping products that people who smoke and/or vape perceive contribute to the health harms of vaping. This was a cross-sectional survey co-designed with adults who smoked/vaped and pre-registered. An on-line survey (November 2022) was used of a convenience sample of adults in the United Kingdom who smoked and/or vaped (n = 494). As primary outcomes, respondents were asked to select any of 15 vaping product features they perceived might have any effect on the health harms of vaping (for each: selected, not selected). Independent variables were smoking/vaping status (smoke and vape; vape, formerly smoked; vape, never regularly smoked; smoke, do not currently vape); relative vaping harm perceptions [less harmful than smoking (accurate), equally/more harmful than smoking or do not know/refused (other)]. Binary logistic regressions were used to compare outcomes by current vaping/smoking status and relative harm perceptions, adjusting for age and sex. Most people (54.7%) selected between one and three features. The most frequently selected were nicotine concentration (62.2%) and amount of e-liquid consumed (59.1%), followed by nicotine type (e.g. salt or freebase; 33.0%), source/purchase location (25.3%), flavours (24.7%), temperature to heat e-liquid (21.1%), heat produced by device (20.9%), e-liquid brand (20.9%), amount of emissions (18.6%), device type (e.g. disposable, pod, tank; 17.2%), material of tank (17.0%), power/wattage (13.0%), device brand (8.1%), device size (4.1%) and device weight (2.4%). Higher nicotine concentrations, more e-liquid and salt (versus freebase) nicotine were perceived to confer greater harms. Disposables were perceived as slightly more harmful than reusable devices. There were few differences by current vaping/smoking status and between those with accurate (versus other) harm perceptions of vaping relative to smoking (P > 0.05 for most contrasts, adjusting for age and sex). Certain features and types of vaping products [higher nicotine concentrations, more e-liquid consumed and salt (versus freebase) nicotine]were perceived to confer greater health harms among a sample of UK adults who smoked and/or vaped. Findings are consistent with pervasive misperceptions that nicotine is a major cause of harm, although e-liquid volume is likely to contribute to harms.