In Vitro and In Vivo Vein Assessment of a Novel Vein Visualizing Device to Improve First-Time Peripheral Venous Access

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Liddelow, Phuoc Hao Ho, Cara A. Boyce, Matthew D. Redknap, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4652430/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Inserting needles into veins is fundamental to medical care with up to 90% of inpatients requiring a peripheral intravenous catheter/cannula (PIVC) during their stay. Yet 40%-50% of PIVC insertions fail on the first attempt. Here, we present an easy-to-use novel vein visualizing ultrasound prototype device and data from in vitro and in vivo performance. Our prototype’s locational accuracy in simulated forearm veins is 0.16mm ±1.63mm (s.d.) (97.8% agreement to the ground truth, p<.001), across variations of vein diameter (3-5mm), depth (10-20mm), and velocity (10-100mm/s). Usability trials conducted with nine clinicians found that 100% of users were able to handle the prototype in a sterile manner with minimal assistance. In 80 forearm scans of 40 volunteers, sensitivity was excellent to both find veins (94%). In comparison, sensitivity of vein finding using landmark technique with torniquet (visible 46% and palpable 74%) were far inferior. The prototype is a novel ultrasound device which empowers clinicians to detect and visualize well-perfused veins at depth in the coronal view of vein pathways whilst enabling, ultra portability, accessibility and ease of use. Physical sciences/Engineering/Biomedical engineering Health sciences/Medical research/Pre clinical studies Physical sciences/Physics/Applied physics/Acoustics Physical sciences/Physics/Techniques and instrumentation/Imaging techniques Ultrasound Device Usability Sensitivity Visibility Cannulation Figures Figure 1 Figure 2 1 Introduction 1.1 Background Cannulation is one of the fundamental procedures underpinning modern medical care, with estimates of 60–90% of inpatients requiring a cannula [ 2 ]. The average first pass cannulation failure rate is 40%; this can be as high as 70% in difficult intravenous access (DIVA) patients [ 3 , 4 ], leading to patient dissatisfaction, clinical inefficiencies and wasted healthcare cost, as each failed cannula requires around $ 15 USD to replace [ 5 – 11 ]. This high failure rate is due to manual vein-finding using landmark technique (naked-eye visualization and palpation) being the most commonly used method [ 12 ]. This means that veins which are not visible and/or palpable are difficult to cannulate, and the lack of visual or palpable veins being 2 determining variables of the 5-variable Adult Difficult Intravenous Access (A-DIVA) scale [ 13 ]. Current alternate solutions to landmark vein-finding include infrared-based devices, cart-based ultrasound, and portable/handheld ultrasound. Infrared-based devices use light frequencies in the near-infrared spectrum to create a map of vein locations on the skin. While this technique is portable and less expensive than some competitors (e.g., portable ultrasound), first-pass cannulation success rates are similar to unassisted cannulation [ 14 , 15 ]. Additionally, the true visualization depth is approximately 6mm [ 16 ], which is insufficient for DIVA patients who do not have superficial veins available for cannulation. Traditional ultrasound-guided cannulation uses large, cart-based ultrasound machines. These are proven to reduce first pass cannulation fail rates from the standard 40% to 10–20% [ 17 ]. However, high costs, extensive training, bulky machines, and limited availability in hospitals pose significant barriers to adopt as a standard cannulation procedure [ 18 ]. Portable ultrasound devices are increasing in availability and affordability by pairing wireless probes to smart devices for image display. However, their purchase is restricted to licensed medical professionals and the images only view cross-sectional areas of the forearm – they are unable zto display a coronal view of the vein pathway. The training requirements and complex workflow blunt adoption into cannulation practice [ 1 ]. There is an unmet clinical need for a solution that is as accurate as ultrasound, whilst being ultraportable, easy to use and providing crucial vein pathway information. We have developed a prototype that is ultraportable, easy to use and ultrasound-based, that addresses this need. The prototype detects well-perfused veins at depth and provides the coronal view of vein pathways, allowing for visualization of vessel direction and diameter along the vein. This paper presents preliminary verification and validation performed throughout development of the prototype to date. In vitro accuracy was investigated, with the aim of evaluating the ability of the prototype to accurately locate a simulated vessel, with varying diameters, depths and velocities, created by perfusing blood-mimicking fluid through a tissue-mimicking material. Next, this paper outlines the usability of the prototype design through studies performed in hospitals and clinics to demonstrate success in using the proposed sterile workflow and ease of interpretation of the coronal view image. Finally, an initial in vivo trial was completed on human subjects with the aim of determining the feasibility of the prototype to successfully operate on a range of human arms and measuring the sensitivity of the prototype in a variety of demographic characteristics. 2 Results 2.1 In vitro Accuracy Assessment The prototype vessel location display was compared to the ground truth of a known vessel location inside in-house developed gelatin tissue-mimicking phantoms with flowing blood-mimicking liquid [BRS185-DOPPLER, CAE Healthcare, Montreal, Canada]. Testing was completed on a range of vessel characteristics with varying diameters (3–5 mm), depths (10–20 mm) and velocities (10–100 mm/s) for a total of 18 phantoms. The overall location accuracy determined by the average r value of the correlation plots, was 0.978 ± 0.006 (s.e.m.) (p < .0001), and the mean residual difference was − 0.160mm ± 1.627mm (s.d.), as illustrated in Fig. 1 . Through the locational accuracy testing, the prototype was able to detect peak signals in all vessel diameters measured (3, 4, 5mm) at 10mm depth and velocity > 10mm/s. It was able to detect flow above 50mm/s in vessels of 20mm depth in all vessel diameters measured. As seen in Fig. 1 (g), the residual difference did not vary significantly between the vessel characteristics, however, there appears to be a trend of decreasing residuals as velocity increases. 2.2 Usability Study A qualitative usability study was conducted with nine cannulating clinicians (3 x Intensive Care Unit (ICU) consultants, 3 x ICU registrars and 3 x Oncology/Cancer nurses) at Royal Perth Hospital and Chemo@Home to evaluate the proposed sterile workflow of the imaging and sheath prototype. The sheath prototype was a plastic cover designed to provide a complete sterile barrier between the imaging device and external environment. All clinicians were successfully able to unpackage and deploy the sheath, complete the mock cannulation procedure, and dispose of the sheath while maintaining sterility, all with minimal training assistance (67% completed without assistance). This usability study did not identify any proposed workflow steps that would cause a failure in the normal canulation workflow, however changes to the provided training were identified to enhance the success of maintaining a sterile field (label instructions, training videos, etc.). Additionally, learnings from the usability evaluation were used to optimize the prototype for in vivo data collection. 2.3 In vivo Sensitivity Analysis Having demonstrated the prototype’s performance in benchtop experiments and optimized its form and function through usability evaluations, we collected preliminary data in the forearm of human subjects, as shown in Fig. 2 , demonstrating the feasibility of identifying veins in a real-world environment. We recruited 40 volunteers, the average age was 38.18 ± 16.85 (s.d.) years (ranging 21–83), and 53% were female and 47% were male, 10% had a known history of cardiovascular complications, 10% took blood pressure affecting medication, and 23% had a previous history of difficult intravenous access. Prototype sensitivity was then measured by finding vein location and direction which was compared to the ground truth established through conventional ultrasound (Clarius L15 HD3 High Frequency Linear Ultrasound Scanner, Vancouver, Canada) visualization and characterization (compressibility and flow direction). The ground truth was established before prototype sensitivity was measured, as described in Fig. 2 . The prototype had an overall sensitivity to correctly detect the location of venous flow of 94% (n = 240) averaged over the three sensors used in the prototype, with the distal sensor (cannulating side) having a sensitivity of 98% (n = 80). Results are summarized in Table 1 , including further analysis to describe the effects of vein characteristics (visibility, palpability, depth, flow, diameter). Backwards variable elimination procedure was used to identify which variables are significantly (.05 level) and independently associated with prototype detection. All demographic variables were eliminated (p > .05), besides age which had a curved relationship (p = .0065). All vessel characteristic variables were eliminated (p > .05), besides palpable vessels with torniquet application (p = .0042) and diameter (p = .0342). The sensitivity was poorer in younger and older participants, and in non-palpable and smaller diameter veins. Table 1 In vivo sensitivity analysis study data. All 40 participants were volunteer, with written informed consent. The average age of participants was 38.18 ± 16.85 (s.d.) in years (ranging 21–83). 53% were female and 47% were male. Prototype sensitivity refers to the percentage of trials in which a vein was definitively detected, which is defined as a cycle of 2 consecutive signal peaks in each of the three sensors. Continuous variables were split into tertile categories. Mean depth 4.24mm (ranging 1.45–9.26mm), velocity 19.02mm/s (ranging 6.20–104.00 mm/s), and diameter 3.80mm (ranging 1.24–7.27 mm) of vessels were measured. Sensitivity was compared between different variable groups; comparison was deemed significant at p < .05 with *. Variable Sensitivity Comparison p-value Landmark Technique Detection/Vessel (%) Visual detection of vein Without torniquet 32/80 (40%) N/A With torniquet 37/80 (46%) Palpable detection of vein Without torniquet 37/80 (46%) N/A With torniquet 59/80 (74%) Novel Ultrasound Prototype Detection/Sensor (%) Overall 225/240 (94%) Visual appearance of vein with torniquet Yes 107/111 (96%) 0.3972 No 118/129 (91%) Palpable appearance of vein with torniquet Yes 173/177 (98%) 0.0042* No 52/63 (83%) Depth of vein 4.64mm 75/81(93%) Velocity of blood flow 39.8mm/s 77/81 (95%) Diameter of vein 4.07mm 81/81 (100%) History of difficult intravenous access Yes 47/54 (87%) 0.8486 No 175/183 (96%) Skin tone Tanned/ Dark 91/96 (95%) 0.5271 Fair 134/144 (93%) Values are represented as numbers (proportions). Participants are compared regarding the primary outcome with the Wald Chi-Squared test. * P < .05 3 Discussion Here we present a novel, ultraportable and easy to use ultrasound-based vein visualization prototype developed to detect well-perfused veins at depth that provides a coronal view of vein pathways in the forearm. The device aims to meet the clinical need to reduce first-pass cannulation failure rates present with landmark and infrared-based techniques, while providing an affordable and usable technique improving upon cart-based ultrasound assisted techniques. The prototype aims to utilize the precision and reliability of ultrasound visualization, while presenting the information in an unambiguous and clear light-weight method to improve the ability for clinicians to visualize veins prior to cannulation. The prototype was able to accurately locate a variety of simulated veins in vitro . The tested variables encompass the range typically cannulated or seen within human forearms [ 19 – 21 ] and therefore our prototype is likely to be capable of accurately detecting most human adult veins that are suitable for PIVC insertion. This forms the detection limits of this prototype which signal and coupling optimization will improve in future prototypes. The ease of maintaining a sterile workflow is critical in preventing cross contamination between the imaging device and patient during cannulation. To facilitate the use of the imaging prototype in a sterile manner, a consumable sheath compatible with the ultrasound prototype was developed to easily integrate into the current sterile cannulation workflow. The usability and ease-of-use of the prototype sheath and workflow was demonstrated in an early usability study, which confirmed that all users were able to maintain a sterile environment with minimal assistance. Prior to implementation and testing in educational programs our findings suggest that improvements are required for the provided training, which will include the introduction of a task analysis and incorporating labels into the sheath design to further improve the success of maintaining a sterile field. The results show that future sheath iterations can plausibly be integrated into current sterile cannulation workflow and that the intended sterile workflow would not be a detriment to maintaining sterility. Additional to the sterile workflow, a proposed “clean” workflow has also been developed following the World Health Organization (WHO) “Guidelines for the prevention of bloodstream infections and other infections associated with the use of intravascular catheters” [ 22 ]. This guideline suggests that insertion of PIVCs should be completed as a clean procedure using an aseptic “no-touch” technique (ANTT), where there is a focus on non-contacting areas that could cause infection (ie insertion site, catheter tip). The prototype sheath and “clean” workflow would adhere to a clean environment, where there is a less burdensome approach for deploying and using the sheath in comparison to a sterile environment. Within the in vivo trial, the prototype performed well in deep veins (93%; >4.64mm), detecting the deepest vein identified at 9.26mm, moderately deep vessels (3-15mm) have been shown to be a more successful cannulation site [ 23 ]. This highlights the ability for our novel device to outperform infrared based cannulation assisting devices, as they were unable to accurately measure below a depth of 6mm [ 16 ]. The prototype also performed well in veins that had flow faster than 39.8mm/s (95%), higher flow rates have been indicated to provide better perfusion for cannulation [ 24 ]. There is a reduction in performance in in smaller veins < 3.27mm (88%), which can be a characteristic for difficult intravenous access patients such as children, however future optimizations can address this need for pediatric application [ 13 ]. There is a limitation with the current prototype as the sensor transducer element pitch is 1.2mm, therefore resolution and detection of smaller veins can be improved by decreasing the pitch. The prototype sensitivity data highlights a high sensitivity rate for veins that were difficult to visualise with the naked eye (91%), veins with no palpable appearance (83%), veins of self-identified DIVA patients (87%), and veins in participants with a tanned-to-dark skin tone (95%). Over a third of patients (16), have veins with these characteristics and the ability of the prototype to detect 94% of them, indicates high potential for reducing first pass insertion failure (1,2). Whilst there was a decrease in the device sensitivity to non-palpable veins, the device outperformed landmark technique visualisation and palpation by 104% and 25%, respectively. Despite the many strengths of the prototype and study, there are more limitations worth noting. Within the in vivo study, the procedure was on healthy participants who were assumed to have minimal differences in vessel characteristics compared to typical in-patients requiring cannulation. These continuous variables measured, including age, depth, velocity, and diameter, had limited range, and age was particularly skewed, as seen in Appendix A. We intend on repeating the study on a wider variety of participants. Other limitations included sensitivity being recorded after finding a suitable vein with standard ultrasound [Clarius L15 HD3 High Frequency Linear Ultrasound Scanner, Vancouver, Canada], introducing bias. The ultrasound operator was a product engineer, not an officially trained clinician. Lastly, The device is an early prototype with planned software and hardware optimization, including the transducer optimization, that will enhance the applicability to a more diverse range of venous anatomy and patient groups (e.g. children). The study presented a novel ultrasound-based vein visualization prototype device which detects well-perfused veins at depth and provides the coronal view of vein pathways. The results illustrate promising accuracy of the early-stage prototype, working in both phantoms and key anatomical insertion sites of healthy patients, thus providing a strong foundation for future pilot human studies. The continued usability trials inform prototype development to improve form factor and workflow integration, increasing the prototype ability to accurately identify and display vein location whilst maintaining sterility. The goal of this study was to measure the performance of the prototype without software enhancement or optimisation, anticipating that as our device continues to be developed the performance will continue to improve, making it an extremely useful tool for clinicians to use and lowering their risk of peripheral cannula insertion failure. 4 Methods 4.1 In-vitro Accuracy Assessment A series of in vitro phantom experiments were performed to determine the locational accuracy of the prototype using artificial veins with known diameter, depth and velocity. Tissue-mimicking gelatin-based phantoms were created and continuously perfused with blood-mimicking liquid to simulate typical characteristics of forearm veins. Phantoms were constructed based on eight guiding principles for a robust test rig [ 25 ], including tissue-like properties and tunability of the gelatin stiffness, stability of the properties over time, architectural flexibility to be adjusted to suit the desired vein characteristics, reproducibility of the gelatin fabrication, simple maintenance, nontoxic, and having ingredients that are readily available. Phantoms were created using a mixture of gelatin powder, water, vinegar, and Metamucil, as outlined in Appendix B. The gelatin hydrogel provides a tissue-mimicking bulk material with similar mechanical behaviour to native human tissue [ 26 – 28 ]. Metamucil increases echogenicity of the gelatin phantom to show acoustic similarity to human tissue under ultrasound [ 27 , 29 , 30 ]. White vinegar was added to preserve the longevity of the gelatin phantoms [ 31 ]. The gelatin mixture was poured into 3D printed rectangular molds and refrigerated to allow the gelatin to set. The molds were used to pre-define target depths and diameters for the simulated veins, along with an inlet and outlet to be connected to the flow loop. Once set, the phantom was removed from the mold and connected to the flow loop and the vessel depth and diameter was verified using a commercial ultrasound scanner, as illustrated in Appendix C. A flow loop consisting of a small pump connected to a valve system was developed to deliver a specific flow rate and target velocities for testing. To ensure the correct velocity was delivered, the commercial ultrasound scanner [Clarius L15 HD3 High Frequency Linear Ultrasound Scanner, Vancouver, Canada] was used to validate the target flow through the phantom. The fluid properties of blood were mimicked by CAE Blue Phantoms doppler fluid [BRS185-DOPPLER, CAE Healthcare, Montreal, Canada]. As illustrated in Fig. 1 .a, a phone camera and translation stage was used to collect video footage of the prototype output. The prototype was turned on and the prototype middle indicator line was aligned with the centre of the ‘vein’ so that the prototype was centered on the phantom. A Creality CR-10 Smart 3-D printer [Creality, Shenzhen, China] was customized to provide a controlled translation stage with a ± 0.1mm X-Y translation precision. The translation stage with a custom prototype holder moved the prototype 17.5 mm to the left of the vein centre. The prototype was then moved in 2.5mm increments to the right for a total of 35 mm, to ensure full coverage of the prototype field of view. Code was written in Python [V3.8.2, DE, USA] to extract three stable screenshots of the prototype screen and surrounding phantom at each location, from which the peak location coordinates for each sensor were manually extracted, as shown in Fig. 1 .d. The peak in signal represents flow at that direction. Peak height was ignored but transverse location measured values were compared to the known centre coordinates of the vessel. Using this approach, 18 types of tests were performed on phantoms with differing vessel diameters (3mm, 4mm, 5mm), depths (10mm, 20mm), and velocities (10mm/s, 50mm/s, 100mm/s) to analyse the difference between the vein location identified by the prototype and the known vessel location, for a total of 703 position measurements, as seen in Fig. 1 . Characteristics were chosen based on peripheral venous cannulation guidelines, which state that clinicians should ideally cannulate veins with diameters greater than 4mm, shallower than 16mm and flow rates ranging from 15.1–250mm/s [ 19 – 21 ]. Data extraction involved the analysis of signal peaks to extract vein locations for comparison with the ground truth. Correlation coefficients were calculated using Spearman's Rho and results were deemed significant at p < .05. Residual analysis was also performed to analyze absolute differences between known and measured positions. Outliers were removed using the interquartile range (IQR) method where data points outside three times the IQR are removed from analysis. Finally, the relationship between diameter, depth and velocity and accuracy was investigated. 4.2 Usability Study The aim of the usability study was to evaluate the effectiveness and ease of the proposed sterile workflow of the system, and thus identify use related errors which lead to a breach of sterile technique. To evaluate the proposed workflow, nine cannulating clinicians at Royal Perth Hospital and Chemo@Home (Ethics approval: RGS0000005480) completed a mock cannulation procedure that was observed for completion of key tasks (seen in Appendix D). The study was conducted in accordance to the institutional regulations and guidelines, and informed consent was obtained from all subjects. Clinicians were supplied with a cannula pack, a cannula, sterile gloves, a 3D printed mock imaging prototype and a prototype sheath. Before starting the procedure, clinicians were trained on how to use the sheath workflow before applying it for the mock cannulation. Clinicians were tasked with completing three main tasks: deploying the sheath, performing a mock cannulation with the imaging system and removing the sheath, whilst maintaining sterility. Clinicians’ interactions were recorded with a camera and analysis was completed by investigators (HH, EH, CB) to evaluate task completion success (using sterile technique). 4.3 In vivo Sensitivity Analysis We recruited 40 adult volunteers for an in vivo sensitivity analysis. The study was conducted at VeinTech’ Laboratory (Perth, Australia) in accordance with institutional regulations and guidelines, where written informed consent was collected from all participants. Demographic data (age, sex, skin tone, history of cardiovascular complications, regular cardiovascular medication, and previous history of difficult intravenous access) was collected. Measurements were recorded on the left and right ventral forearm of each participant and were conducted as illustrated in Fig. 2 . Participants were not asked to perform any exercises or change hydration habits prior to testing, and heat was not applied to the forearm. Certain exercises, heat and oral hydration have been shown to have an effect on vessel characteristics [ 32 , 33 ]. The subject was seated, with dorsal surface of the forearm resting on a table. The ventral forearm location is recommended by clinical care standards as it provides the most stable site for cannulation [ 34 ]. For each location, a suitable vein was selected through a commercial ultrasound scanner ( Clarius L15 HD3 High Frequency Linear Ultrasound Scanner , Vancouver, Canada), where the compressibility and flow direction of an identified vessel was used to characterise the vessel as a vein. The images were used to measure the depth, diameter and flow velocity of each vein using the in-built measuring feature of the Clarius Mobile Health Corp program [V9568a9d, Vancouver, Canada]. The palpability and visibility of the veins as determined by the investigator were recorded, and the location of the vein was marked on the skin. The proposed prototype was then used to scan the marked region and the sensitivity of the prototype was assessed as the ability to measure 2 consecutive signal peaks on the mark vein. Data analysis was performed in an open-source statistical package, SAS Studio [V3.81, NC, USA]. For each measure, the mean and standard deviation were reported as split by the demographic variables (age, sex, skin tone, history of cardiovascular complications, regular cardiovascular medication, and previous history of difficult intravenous access) and vein characteristic variables (visibility, palpability, depth, flow, diameter). Backwards variable elimination procedure with single hierarchy was used to identify which variables are significantly (.05 level) and independently associated with prototype detection in a logistic regression model. At each step of the procedure, individual parameters are examined using the Wald Chi-Square test. Multicollinear variables were removed from the procedure, such as palpation prior to torniquet application, ensuring correct statistical significance calculations. Squares of quantitative variables and interactions were only investigated where the component main effects were present (hierarchy principle). Declarations Competing Interests The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: N.B., K.A., N.M.B. are named inventors on a patent describing the ultrasound technology (WO2022221913A1). The study was funded by VeinTech Pty Ltd of which M.D.L., P.H.H., C.A.B., M.D.R., E.L.H., N.M.B., K.A. and N.B. are employees and in which N.M.B., K.A. and N.B. hold equity. M.D.L., P.H.H. and M.D.R. hold Employee Share Options and P.J.C. and B.J.D. are members of the scientific advisory board of VeinTech and are also compensated by Employee Share Options. Author Contribution M.D.L. was involved in planning study protocols, determining the study design and protocols, contributed to collection, lead the analysis and discussion of the in vitro and in vivo studies, and wrote the majority of the manuscript, leading subsequent reviews and submission. P.H.H. was involved in planning the in vivo study, determining study design and protocols, analysis methods and lead the usability study. C.A.B. was the primary lead in collecting and contributed to the analysis of the in vitro data. M.D.R. was the primary lead in collecting all in vivo data. E.L.H. was the primary lead in collecting and analysing usability data. N.M.B. was responsible for the overall execution of the usability study. K.A. assisted with the conception of the study. P.J.C. and B.J.D. contributed to the analysis and discussion of the data. N.B. contributed to the study conception, study design, analysis and discussion of data, writing the manuscript and overall supervision of the work. All authors read and approved the manuscript for submission. Acknowledgement This activity is/has been supported by the Western Australian Future Health Research and Innovation Fund, Grant ID InnovSeedFund2022 and IF2022, which is an initiative of the WA State Government. We would like to acknowledge the volunteers who participated in the in vivo sensitivity study and our clinical partners, Royal Perth Hospital and Chemo@Home, for providing clinicians to complete the usability study. Data Availability The datasets generated as part of this study are available from the corresponding author on reasonable request. References Stolz, L. A. et al. Prospective Evaluation of the Learning Curve for Ultrasound-guided Peripheral Intravenous Catheter Placement. J. Vasc. Access 17, 366–370 (2016). Platt, V. & Osenkarski, S. Improving Vascular Access Outcomes and Enhancing Practice. J. Infus. Nurs. 41, 375–382 (2018). Keogh, S. & Mathew, S. Peripheral intravenous catheters: A review of guidelines and research . (2019). Kleidon, T. M., Cattanach, P., Mihala, G. & Ullman, A. J. Implementation of a paediatric peripheral intravenous catheter care bundle: A quality improvement initiative. J Paediatr Child Health 55, 1214–1223 (2019). Mermel, L. A. 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Criteria for the design of tissue-mimicking phantoms for the standardization of biophotonic instrumentation. Nat. Biomed. Eng. 6, 541–558 (2022). Chen, A. I. et al. Multilayered tissue mimicking skin and vessel phantoms with tunable mechanical, optical, and acoustic properties. Med. Phys. 43, 3117–3131 (2016). Jafary, R. et al. Fabrication and Characterization of Tissue-Mimicking Phantoms for Ultrasound-Guided Cannulation Training. ASAIO J. Am. Soc. Artif. Intern. Organs 1992 68, 940–948 (2022). Madsen, E. L., Hobson, M. A., Shi, H., Varghese, T. & Frank, G. R. Stability of heterogeneous elastography phantoms made from oil dispersions in aqueous gels. Ultrasound Med. Biol. 32, 261–270 (2006). Bude, R. O. & Adler, R. S. An easily made, low-cost, tissue-like ultrasound phantom material. J. Clin. Ultrasound JCU 23, 271–273 (1995). Chao, S.-L., Chen, K.-C., Lin, L.-W., Wang, T.-L. & Chong, C.-F. Ultrasound Phantoms Made of Gelatin Covered with Hydrocolloid Skin Dressing. J. Emerg. Med. 45, 240–243 (2013). Said, M. S. M. & Seman, N. Preservation of gelatin-based phantom material using vinegar and its life-span study for application in microwave imaging. IEEE Trans. Dielectr. Electr. Insul. 24, 528–534 (2017). Eren, H., Calıskan, N. & Durmus Iskender, M. Effect of Fist Clenching on Vein Visibility and Palpability: An Observational Descriptive Study. J. Infus. Nurs. 45, 252–257 (2022). Sharp, R., Childs, J., Bulmer, A. C. & Esterman, A. The effect of oral hydration and localised heat on peripheral vein diameter and depth: A randomised controlled trial. Appl. Nurs. Res. 42, 83–88 (2018). Wallis, M. et al. Risk factors for peripheral intravenous catheter failure: a multivariate analysis of data from a randomized controlled trial. Infect. Control Hosp. Epidemiol. 35, 63–68 (2014). Additional Declarations Competing interest reported. The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: N.B., K.A., N.M.B. are named inventors on a patent describing the ultrasound technology (WO2022221913A1). The study was funded by VeinTech Pty Ltd of which M.D.L., P.H.H., C.A.B., M.D.R., E.L.H., N.M.B., K.A. and N.B. are employees and in which N.M.B., K.A. and N.B. hold equity. M.D.L., P.H.H. and M.D.R. hold Employee Share Options and P.J.C. and B.J.D. are members of the scientific advisory board of VeinTech and are also compensated by Employee Share Options. Supplementary Files MLiddelowSupplementaryMaterialInVitroandInVivoVeinAssessmentofanovelVeinVisualizingDevicetoImproveFirstTimePeripheralVenousAccess.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4652430","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":332498748,"identity":"f349421e-20c5-468c-9598-bfecce8cfdf9","order_by":0,"name":"Michael D. Liddelow","email":"","orcid":"","institution":"VeinTech Pty Ltd","correspondingAuthor":false,"prefix":"","firstName":"Michael","middleName":"D.","lastName":"Liddelow","suffix":""},{"id":332498749,"identity":"18b22b76-39b5-4ad9-ba7a-688207252865","order_by":1,"name":"Phuoc Hao Ho","email":"","orcid":"","institution":"VeinTech Pty Ltd","correspondingAuthor":false,"prefix":"","firstName":"Phuoc","middleName":"Hao","lastName":"Ho","suffix":""},{"id":332498750,"identity":"f9ff5fd5-3dcf-4591-bd2e-4dad5e0c1bd1","order_by":2,"name":"Cara A. Boyce","email":"","orcid":"","institution":"VeinTech Pty Ltd","correspondingAuthor":false,"prefix":"","firstName":"Cara","middleName":"A.","lastName":"Boyce","suffix":""},{"id":332498751,"identity":"edc59128-abc7-4db3-8acf-0d649b046dd4","order_by":3,"name":"Matthew D. Redknap","email":"","orcid":"","institution":"VeinTech Pty Ltd","correspondingAuthor":false,"prefix":"","firstName":"Matthew","middleName":"D.","lastName":"Redknap","suffix":""},{"id":332498752,"identity":"d00f5560-7f29-4c5a-81bb-b9a2ffd36dd7","order_by":4,"name":"Ellaby L. Hansen","email":"","orcid":"","institution":"VeinTech Pty Ltd","correspondingAuthor":false,"prefix":"","firstName":"Ellaby","middleName":"L.","lastName":"Hansen","suffix":""},{"id":332498753,"identity":"cd87d906-e625-421e-b091-76f35f0ec607","order_by":5,"name":"Nicholas M. Buckley","email":"","orcid":"","institution":"VeinTech Pty Ltd","correspondingAuthor":false,"prefix":"","firstName":"Nicholas","middleName":"M.","lastName":"Buckley","suffix":""},{"id":332498754,"identity":"15961ee5-47b4-4af0-a0c7-35f453a6633c","order_by":6,"name":"Katherine Arenson","email":"","orcid":"","institution":"VeinTech Pty Ltd","correspondingAuthor":false,"prefix":"","firstName":"Katherine","middleName":"","lastName":"Arenson","suffix":""},{"id":332498755,"identity":"5f4e74d0-798b-4c56-9240-38c300e90fa6","order_by":7,"name":"Peter J. Carr","email":"","orcid":"","institution":"University of Galway","correspondingAuthor":false,"prefix":"","firstName":"Peter","middleName":"J.","lastName":"Carr","suffix":""},{"id":332498756,"identity":"11af1a3a-8dc4-4593-b3a0-acf2a05b7ffc","order_by":8,"name":"Barry J. Doyle","email":"","orcid":"","institution":"The University of Western Australia","correspondingAuthor":false,"prefix":"","firstName":"Barry","middleName":"J.","lastName":"Doyle","suffix":""},{"id":332498757,"identity":"494ad2bc-4647-4ccb-9872-a225ad255f01","order_by":9,"name":"Nikhilesh Bappoo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6ElEQVRIiWNgGAWjYDACCQglx8DA2ABiJBCtxRis5QApWhLBVhClxVy6+dnjggqb9A3Hm9sef6iwy2NgP3x0A0PNYZxaLOccMzeecSYtd8OZg+0GB84kFzPwpKXdYDiGW4vBjQQzad62w7kzZyS2SRxsO5DYIMFjdoOBDZ+W9G8gLemS8x8CtfyDafmHT0sO2JYEfglGoJYGqBbGNjxa7pwpB/nFsJ8H6LAzx5IT20B+SexLx63ldvs2UIjJs7EffyZRUWOX2M9++NiND9+scWoBAjZmVC6ISMCnAUPLKBgFo2AUjAJ0AADp8VlX9MvBvgAAAABJRU5ErkJggg==","orcid":"","institution":"VeinTech Pty Ltd","correspondingAuthor":true,"prefix":"","firstName":"Nikhilesh","middleName":"","lastName":"Bappoo","suffix":""}],"badges":[],"createdAt":"2024-06-28 06:16:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4652430/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4652430/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":62157461,"identity":"73ca1d69-7347-4b5a-a45b-681f03206f7b","added_by":"auto","created_at":"2024-08-09 21:18:36","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":4370650,"visible":true,"origin":"","legend":"\u003cp\u003eIn vitro validation results of the prototype location measurement, showing measured and known vessel positions. (a) Isometric view of the experimental prototype accuracy testing rig. Blood-mimicking fluid is stirred and pumped through tubing within a gelatin-based tissue-mimicking phantom. The prototype is being recorded and the translation stage moved the prototype incrementally across the phantom. Magnified section illustrates the prototype position and the resultant array peaks in relation to the simulated vein. (b) Image and illustration of vessel visualization prototype. Image of the prototype displaying the vein pathway on a human subject with informed consent. Illustration shows an isometric view depicting the prototype display of the vessel, vessel target, vein, and battery indication, as well as, an external box including a modality “A” and “B” buttons, a power button, and a charging port. (c) Phantom vessel characteristics, highlighting vessel variables. (d) Example peak location identified through manual selection. (e) Comparison of absolute measured distance from datum vs actual distance to the centre of the vessel. (f) Residual plot across all vessel characteristics. (g) Separated residual plots over varying vessel characteristics with average absolute difference ± standard deviation displayed.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-4652430/v1/520e926513b7dbb4834de903.png"},{"id":62157462,"identity":"7b72a686-6d5a-4ace-afc1-1790aa8c6393","added_by":"auto","created_at":"2024-08-09 21:18:36","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":5988952,"visible":true,"origin":"","legend":"\u003cp\u003eIn vivo sensitivity analysis procedure. a) A B-mode ultrasound is placed onto the forearm and a vein is identified through compressibility and flow direction using colour doppler. b) The target vein is marked with a surgical marker. c) The prototype is placed on the arm in the same location as the marked vein, where peaks in the displayed signal correlate to detection of flow. Sensitivity was assessed as peaks displayed in the same location for two cycles.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-4652430/v1/b719611ad7a8e26d0113f707.png"},{"id":67735594,"identity":"08f9b5b5-d9ef-4088-9fab-761558702276","added_by":"auto","created_at":"2024-10-29 07:54:22","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":16633508,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4652430/v1/305914f9-e7c4-42f7-a042-75f2828bc9b2.pdf"},{"id":62157463,"identity":"b32986e3-0957-47d8-8f16-8455698868e0","added_by":"auto","created_at":"2024-08-09 21:18:36","extension":"docx","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":1881480,"visible":true,"origin":"","legend":"","description":"","filename":"MLiddelowSupplementaryMaterialInVitroandInVivoVeinAssessmentofanovelVeinVisualizingDevicetoImproveFirstTimePeripheralVenousAccess.docx","url":"https://assets-eu.researchsquare.com/files/rs-4652430/v1/7951561443aaf39a883feab4.docx"}],"financialInterests":"Competing interest reported. The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: N.B., K.A., N.M.B. are named inventors on a patent describing the ultrasound technology (WO2022221913A1). The study was funded by VeinTech Pty Ltd of which M.D.L., P.H.H., C.A.B., M.D.R., E.L.H., N.M.B., K.A. and N.B. are employees and in which N.M.B., K.A. and N.B. hold equity. M.D.L., P.H.H. and M.D.R. hold Employee Share Options and P.J.C. and B.J.D. are members of the scientific advisory board of VeinTech and are also compensated by Employee Share Options.","formattedTitle":"In Vitro and In Vivo Vein Assessment of a Novel Vein Visualizing Device to Improve First-Time Peripheral Venous Access","fulltext":[{"header":"1\tIntroduction","content":"\n\u003ch3\u003e1.1 Background\u003c/h3\u003e\n\u003cp\u003eCannulation is one of the fundamental procedures underpinning modern medical care, with estimates of 60\u0026ndash;90% of inpatients requiring a cannula [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The average first pass cannulation failure rate is 40%; this can be as high as 70% in difficult intravenous access (DIVA) patients [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], leading to patient dissatisfaction, clinical inefficiencies and wasted healthcare cost, as each failed cannula requires around \u003cspan\u003e$\u003c/span\u003e15 USD to replace [\u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9 CR10\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. This high failure rate is due to manual vein-finding using landmark technique (naked-eye visualization and palpation) being the most commonly used method [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. This means that veins which are not visible and/or palpable are difficult to cannulate, and the lack of visual or palpable veins being 2 determining variables of the 5-variable Adult Difficult Intravenous Access (A-DIVA) scale [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCurrent alternate solutions to landmark vein-finding include infrared-based devices, cart-based ultrasound, and portable/handheld ultrasound. Infrared-based devices use light frequencies in the near-infrared spectrum to create a map of vein locations on the skin. While this technique is portable and less expensive than some competitors (e.g., portable ultrasound), first-pass cannulation success rates are similar to unassisted cannulation [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Additionally, the true visualization depth is approximately 6mm [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], which is insufficient for DIVA patients who do not have superficial veins available for cannulation. Traditional ultrasound-guided cannulation uses large, cart-based ultrasound machines. These are proven to reduce first pass cannulation fail rates from the standard 40% to 10\u0026ndash;20% [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. However, high costs, extensive training, bulky machines, and limited availability in hospitals pose significant barriers to adopt as a standard cannulation procedure [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Portable ultrasound devices are increasing in availability and affordability by pairing wireless probes to smart devices for image display. However, their purchase is restricted to licensed medical professionals and the images only view cross-sectional areas of the forearm \u0026ndash; they are unable zto display a coronal view of the vein pathway. The training requirements and complex workflow blunt adoption into cannulation practice [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. There is an unmet clinical need for a solution that is as accurate as ultrasound, whilst being ultraportable, easy to use and providing crucial vein pathway information.\u003c/p\u003e \u003cp\u003eWe have developed a prototype that is ultraportable, easy to use and ultrasound-based, that addresses this need. The prototype detects well-perfused veins at depth and provides the coronal view of vein pathways, allowing for visualization of vessel direction and diameter along the vein. This paper presents preliminary verification and validation performed throughout development of the prototype to date. \u003cem\u003eIn vitro\u003c/em\u003e accuracy was investigated, with the aim of evaluating the ability of the prototype to accurately locate a simulated vessel, with varying diameters, depths and velocities, created by perfusing blood-mimicking fluid through a tissue-mimicking material. Next, this paper outlines the usability of the prototype design through studies performed in hospitals and clinics to demonstrate success in using the proposed sterile workflow and ease of interpretation of the coronal view image. Finally, an initial \u003cem\u003ein vivo\u003c/em\u003e trial was completed on human subjects with the aim of determining the feasibility of the prototype to successfully operate on a range of human arms and measuring the sensitivity of the prototype in a variety of demographic characteristics.\u003c/p\u003e"},{"header":"2 Results","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 \u003cem\u003eIn vitro\u003c/em\u003e Accuracy Assessment\u003c/h2\u003e \u003cp\u003eThe prototype vessel location display was compared to the ground truth of a known vessel location inside in-house developed gelatin tissue-mimicking phantoms with flowing blood-mimicking liquid [BRS185-DOPPLER, CAE Healthcare, Montreal, Canada]. Testing was completed on a range of vessel characteristics with varying diameters (3\u0026ndash;5 mm), depths (10\u0026ndash;20 mm) and velocities (10\u0026ndash;100 mm/s) for a total of 18 phantoms. The overall location accuracy determined by the average r value of the correlation plots, was 0.978\u0026thinsp;\u0026plusmn;\u0026thinsp;0.006 (s.e.m.) (p\u0026thinsp;\u0026lt;\u0026thinsp;.0001), and the mean residual difference was \u0026minus;\u0026thinsp;0.160mm\u0026thinsp;\u0026plusmn;\u0026thinsp;1.627mm (s.d.), as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThrough the locational accuracy testing, the prototype was able to detect peak signals in all vessel diameters measured (3, 4, 5mm) at 10mm depth and velocity\u0026thinsp;\u0026gt;\u0026thinsp;10mm/s. It was able to detect flow above 50mm/s in vessels of 20mm depth in all vessel diameters measured. As seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e (g), the residual difference did not vary significantly between the vessel characteristics, however, there appears to be a trend of decreasing residuals as velocity increases.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Usability Study\u003c/h2\u003e \u003cp\u003eA qualitative usability study was conducted with nine cannulating clinicians (3 x Intensive Care Unit (ICU) consultants, 3 x ICU registrars and 3 x Oncology/Cancer nurses) at Royal Perth Hospital and Chemo@Home to evaluate the proposed sterile workflow of the imaging and sheath prototype. The sheath prototype was a plastic cover designed to provide a complete sterile barrier between the imaging device and external environment. All clinicians were successfully able to unpackage and deploy the sheath, complete the mock cannulation procedure, and dispose of the sheath while maintaining sterility, all with minimal training assistance (67% completed without assistance). This usability study did not identify any proposed workflow steps that would cause a failure in the normal canulation workflow, however changes to the provided training were identified to enhance the success of maintaining a sterile field (label instructions, training videos, etc.). Additionally, learnings from the usability evaluation were used to optimize the prototype for \u003cem\u003ein vivo\u003c/em\u003e data collection.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 \u003cem\u003eIn vivo\u003c/em\u003e Sensitivity Analysis\u003c/h2\u003e \u003cp\u003eHaving demonstrated the prototype\u0026rsquo;s performance in benchtop experiments and optimized its form and function through usability evaluations, we collected preliminary data in the forearm of human subjects, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e2\u003c/span\u003e, demonstrating the feasibility of identifying veins in a real-world environment. We recruited 40 volunteers, the average age was 38.18\u0026thinsp;\u0026plusmn;\u0026thinsp;16.85 (s.d.) years (ranging 21\u0026ndash;83), and 53% were female and 47% were male, 10% had a known history of cardiovascular complications, 10% took blood pressure affecting medication, and 23% had a previous history of difficult intravenous access. Prototype sensitivity was then measured by finding vein location and direction which was compared to the ground truth established through conventional ultrasound (Clarius L15 HD3 High Frequency Linear Ultrasound Scanner, Vancouver, Canada) visualization and characterization (compressibility and flow direction). The ground truth was established before prototype sensitivity was measured, as described in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe prototype had an overall sensitivity to correctly detect the location of venous flow of 94% (n\u0026thinsp;=\u0026thinsp;240) averaged over the three sensors used in the prototype, with the distal sensor (cannulating side) having a sensitivity of 98% (n\u0026thinsp;=\u0026thinsp;80). Results are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, including further analysis to describe the effects of vein characteristics (visibility, palpability, depth, flow, diameter). Backwards variable elimination procedure was used to identify which variables are significantly (.05 level) and independently associated with prototype detection. All demographic variables were eliminated (p\u0026thinsp;\u0026gt;\u0026thinsp;.05), besides age which had a curved relationship (p\u0026thinsp;=\u0026thinsp;.0065). All vessel characteristic variables were eliminated (p\u0026thinsp;\u0026gt;\u0026thinsp;.05), besides palpable vessels with torniquet application (p\u0026thinsp;=\u0026thinsp;.0042) and diameter (p\u0026thinsp;=\u0026thinsp;.0342). The sensitivity was poorer in younger and older participants, and in non-palpable and smaller diameter veins.\u003c/p\u003e \u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cb\u003eIn vivo\u003c/b\u003e\u003cb\u003esensitivity analysis study data.\u003c/b\u003e All 40 participants were volunteer, with written informed consent. The average age of participants was 38.18\u0026thinsp;\u0026plusmn;\u0026thinsp;16.85 (s.d.) in years (ranging 21\u0026ndash;83). 53% were female and 47% were male. Prototype sensitivity refers to the percentage of trials in which a vein was definitively detected, which is defined as a cycle of 2 consecutive signal peaks in each of the three sensors. Continuous variables were split into tertile categories. Mean depth 4.24mm (ranging 1.45\u0026ndash;9.26mm), velocity 19.02mm/s (ranging 6.20\u0026ndash;104.00 mm/s), and diameter 3.80mm (ranging 1.24\u0026ndash;7.27 mm) of vessels were measured. Sensitivity was compared between different variable groups; comparison was deemed significant at p\u0026thinsp;\u0026lt;\u0026thinsp;.05 with *.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSensitivity\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eComparison p-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLandmark Technique\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDetection/Vessel (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVisual detection of vein\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWithout torniquet\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e32/80 (40%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWith torniquet\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e37/80 (46%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePalpable detection of vein\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWithout torniquet\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e37/80 (46%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eN/A\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWith torniquet\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e59/80 (74%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eNovel Ultrasound Prototype\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eDetection/Sensor (%)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOverall\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e225/240 (94%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVisual appearance of vein with torniquet\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e107/111 (96%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e0.3972\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e118/129 (91%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePalpable appearance of vein with torniquet\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e173/177 (98%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e0.0042*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e52/63 (83%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDepth of vein\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;3.15mm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e76/81(94%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e0.9964\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3.15\u0026ndash;4.64mm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e74/78 (95%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;4.64mm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e75/81(93%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVelocity of blood flow\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;23.2mm/s\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e73/81 (90%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e0.2911\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e23.2\u0026ndash;39.8mm/s\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e75/78 (96%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;39.8mm/s\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e77/81 (95%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDiameter of vein\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;3.27mm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e71/81 (88%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e0.0342*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3.27\u0026ndash;4.07mm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e73/78 (94%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;4.07mm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e81/81 (100%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHistory of difficult intravenous access\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e47/54 (87%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e0.8486\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e175/183 (96%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSkin tone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTanned/ Dark\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e91/96 (95%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e0.5271\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFair\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e134/144 (93%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eValues are represented as numbers (proportions). Participants are compared regarding the primary outcome with the Wald Chi-Squared test.\u003c/p\u003e\u003cp\u003e* P\u0026thinsp;\u0026lt;\u0026thinsp;.05\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e \u003c/div\u003e"},{"header":"3 Discussion","content":"\u003cp\u003eHere we present a novel, ultraportable and easy to use ultrasound-based vein visualization prototype developed to detect well-perfused veins at depth that provides a coronal view of vein pathways in the forearm. The device aims to meet the clinical need to reduce first-pass cannulation failure rates present with landmark and infrared-based techniques, while providing an affordable and usable technique improving upon cart-based ultrasound assisted techniques. The prototype aims to utilize the precision and reliability of ultrasound visualization, while presenting the information in an unambiguous and clear light-weight method to improve the ability for clinicians to visualize veins prior to cannulation.\u003c/p\u003e \u003cp\u003eThe prototype was able to accurately locate a variety of simulated veins \u003cem\u003ein vitro\u003c/em\u003e. The tested variables encompass the range typically cannulated or seen within human forearms [\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] and therefore our prototype is likely to be capable of accurately detecting most human adult veins that are suitable for PIVC insertion. This forms the detection limits of this prototype which signal and coupling optimization will improve in future prototypes.\u003c/p\u003e \u003cp\u003eThe ease of maintaining a sterile workflow is critical in preventing cross contamination between the imaging device and patient during cannulation. To facilitate the use of the imaging prototype in a sterile manner, a consumable sheath compatible with the ultrasound prototype was developed to easily integrate into the current sterile cannulation workflow. The usability and ease-of-use of the prototype sheath and workflow was demonstrated in an early usability study, which confirmed that all users were able to maintain a sterile environment with minimal assistance. Prior to implementation and testing in educational programs our findings suggest that improvements are required for the provided training, which will include the introduction of a task analysis and incorporating labels into the sheath design to further improve the success of maintaining a sterile field. The results show that future sheath iterations can plausibly be integrated into current sterile cannulation workflow and that the intended sterile workflow would not be a detriment to maintaining sterility.\u003c/p\u003e \u003cp\u003eAdditional to the sterile workflow, a proposed \u0026ldquo;clean\u0026rdquo; workflow has also been developed following the World Health Organization (WHO) \u0026ldquo;Guidelines for the prevention of bloodstream infections and other infections associated with the use of intravascular catheters\u0026rdquo; [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. This guideline suggests that insertion of PIVCs should be completed as a clean procedure using an aseptic \u0026ldquo;no-touch\u0026rdquo; technique (ANTT), where there is a focus on non-contacting areas that could cause infection (ie insertion site, catheter tip). The prototype sheath and \u0026ldquo;clean\u0026rdquo; workflow would adhere to a clean environment, where there is a less burdensome approach for deploying and using the sheath in comparison to a sterile environment.\u003c/p\u003e \u003cp\u003eWithin the \u003cem\u003ein vivo\u003c/em\u003e trial, the prototype performed well in deep veins (93%; \u0026gt;4.64mm), detecting the deepest vein identified at 9.26mm, moderately deep vessels (3-15mm) have been shown to be a more successful cannulation site [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. This highlights the ability for our novel device to outperform infrared based cannulation assisting devices, as they were unable to accurately measure below a depth of 6mm [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The prototype also performed well in veins that had flow faster than 39.8mm/s (95%), higher flow rates have been indicated to provide better perfusion for cannulation [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. There is a reduction in performance in in smaller veins\u0026thinsp;\u0026lt;\u0026thinsp;3.27mm (88%), which can be a characteristic for difficult intravenous access patients such as children, however future optimizations can address this need for pediatric application [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. There is a limitation with the current prototype as the sensor transducer element pitch is 1.2mm, therefore resolution and detection of smaller veins can be improved by decreasing the pitch.\u003c/p\u003e \u003cp\u003eThe prototype sensitivity data highlights a high sensitivity rate for veins that were difficult to visualise with the naked eye (91%), veins with no palpable appearance (83%), veins of self-identified DIVA patients (87%), and veins in participants with a tanned-to-dark skin tone (95%). Over a third of patients (16), have veins with these characteristics and the ability of the prototype to detect 94% of them, indicates high potential for reducing first pass insertion failure (1,2). Whilst there was a decrease in the device sensitivity to non-palpable veins, the device outperformed landmark technique visualisation and palpation by 104% and 25%, respectively.\u003c/p\u003e \u003cp\u003eDespite the many strengths of the prototype and study, there are more limitations worth noting. Within the \u003cem\u003ein vivo\u003c/em\u003e study, the procedure was on healthy participants who were assumed to have minimal differences in vessel characteristics compared to typical in-patients requiring cannulation. These continuous variables measured, including age, depth, velocity, and diameter, had limited range, and age was particularly skewed, as seen in Appendix A. We intend on repeating the study on a wider variety of participants. Other limitations included sensitivity being recorded after finding a suitable vein with standard ultrasound [Clarius L15 HD3 High Frequency Linear Ultrasound Scanner, Vancouver, Canada], introducing bias. The ultrasound operator was a product engineer, not an officially trained clinician. Lastly, The device is an early prototype with planned software and hardware optimization, including the transducer optimization, that will enhance the applicability to a more diverse range of venous anatomy and patient groups (e.g. children).\u003c/p\u003e \u003cp\u003eThe study presented a novel ultrasound-based vein visualization prototype device which detects well-perfused veins at depth and provides the coronal view of vein pathways. The results illustrate promising accuracy of the early-stage prototype, working in both phantoms and key anatomical insertion sites of healthy patients, thus providing a strong foundation for future pilot human studies. The continued usability trials inform prototype development to improve form factor and workflow integration, increasing the prototype ability to accurately identify and display vein location whilst maintaining sterility. The goal of this study was to measure the performance of the prototype without software enhancement or optimisation, anticipating that as our device continues to be developed the performance will continue to improve, making it an extremely useful tool for clinicians to use and lowering their risk of peripheral cannula insertion failure.\u003c/p\u003e"},{"header":"4 Methods","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e4.1 In-vitro Accuracy Assessment\u003c/h2\u003e \u003cp\u003eA series of \u003cem\u003ein vitro\u003c/em\u003e phantom experiments were performed to determine the locational accuracy of the prototype using artificial veins with known diameter, depth and velocity. Tissue-mimicking gelatin-based phantoms were created and continuously perfused with blood-mimicking liquid to simulate typical characteristics of forearm veins. Phantoms were constructed based on eight guiding principles for a robust test rig [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], including tissue-like properties and tunability of the gelatin stiffness, stability of the properties over time, architectural flexibility to be adjusted to suit the desired vein characteristics, reproducibility of the gelatin fabrication, simple maintenance, nontoxic, and having ingredients that are readily available. Phantoms were created using a mixture of gelatin powder, water, vinegar, and Metamucil, as outlined in Appendix B. The gelatin hydrogel provides a tissue-mimicking bulk material with similar mechanical behaviour to native human tissue [\u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Metamucil increases echogenicity of the gelatin phantom to show acoustic similarity to human tissue under ultrasound [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. White vinegar was added to preserve the longevity of the gelatin phantoms [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The gelatin mixture was poured into 3D printed rectangular molds and refrigerated to allow the gelatin to set. The molds were used to pre-define target depths and diameters for the simulated veins, along with an inlet and outlet to be connected to the flow loop. Once set, the phantom was removed from the mold and connected to the flow loop and the vessel depth and diameter was verified using a commercial ultrasound scanner, as illustrated in Appendix C.\u003c/p\u003e \u003cp\u003eA flow loop consisting of a small pump connected to a valve system was developed to deliver a specific flow rate and target velocities for testing. To ensure the correct velocity was delivered, the commercial ultrasound scanner [Clarius L15 HD3 High Frequency Linear Ultrasound Scanner, Vancouver, Canada] was used to validate the target flow through the phantom. The fluid properties of blood were mimicked by CAE Blue Phantoms doppler fluid [BRS185-DOPPLER, CAE Healthcare, Montreal, Canada].\u003c/p\u003e \u003cp\u003eAs illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e.a, a phone camera and translation stage was used to collect video footage of the prototype output. The prototype was turned on and the prototype middle indicator line was aligned with the centre of the \u0026lsquo;vein\u0026rsquo; so that the prototype was centered on the phantom. A \u003cem\u003eCreality CR-10 Smart\u003c/em\u003e 3-D printer [Creality, Shenzhen, China] was customized to provide a controlled translation stage with a\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1mm X-Y translation precision. The translation stage with a custom prototype holder moved the prototype 17.5 mm to the left of the vein centre. The prototype was then moved in 2.5mm increments to the right for a total of 35 mm, to ensure full coverage of the prototype field of view. Code was written in Python [V3.8.2, DE, USA] to extract three stable screenshots of the prototype screen and surrounding phantom at each location, from which the peak location coordinates for each sensor were manually extracted, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e.d. The peak in signal represents flow at that direction. Peak height was ignored but transverse location measured values were compared to the known centre coordinates of the vessel.\u003c/p\u003e \u003cp\u003eUsing this approach, 18 types of tests were performed on phantoms with differing vessel diameters (3mm, 4mm, 5mm), depths (10mm, 20mm), and velocities (10mm/s, 50mm/s, 100mm/s) to analyse the difference between the vein location identified by the prototype and the known vessel location, for a total of 703 position measurements, as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Characteristics were chosen based on peripheral venous cannulation guidelines, which state that clinicians should ideally cannulate veins with diameters greater than 4mm, shallower than 16mm and flow rates ranging from 15.1\u0026ndash;250mm/s [\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eData extraction involved the analysis of signal peaks to extract vein locations for comparison with the ground truth. Correlation coefficients were calculated using Spearman's Rho and results were deemed significant at p\u0026thinsp;\u0026lt;\u0026thinsp;.05. Residual analysis was also performed to analyze absolute differences between known and measured positions. Outliers were removed using the interquartile range (IQR) method where data points outside three times the IQR are removed from analysis. Finally, the relationship between diameter, depth and velocity and accuracy was investigated.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e4.2 Usability Study\u003c/h2\u003e \u003cp\u003eThe aim of the usability study was to evaluate the effectiveness and ease of the proposed sterile workflow of the system, and thus identify use related errors which lead to a breach of sterile technique. To evaluate the proposed workflow, nine cannulating clinicians at Royal Perth Hospital and Chemo@Home (Ethics approval: RGS0000005480) completed a mock cannulation procedure that was observed for completion of key tasks (seen in Appendix D). The study was conducted in accordance to the institutional regulations and guidelines, and informed consent was obtained from all subjects. Clinicians were supplied with a cannula pack, a cannula, sterile gloves, a 3D printed mock imaging prototype and a prototype sheath. Before starting the procedure, clinicians were trained on how to use the sheath workflow before applying it for the mock cannulation. Clinicians were tasked with completing three main tasks: deploying the sheath, performing a mock cannulation with the imaging system and removing the sheath, whilst maintaining sterility. Clinicians\u0026rsquo; interactions were recorded with a camera and analysis was completed by investigators (HH, EH, CB) to evaluate task completion success (using sterile technique).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e4.3 \u003cem\u003eIn vivo\u003c/em\u003e Sensitivity Analysis\u003c/h2\u003e \u003cp\u003eWe recruited 40 adult volunteers for an \u003cem\u003ein vivo\u003c/em\u003e sensitivity analysis. The study was conducted at VeinTech\u0026rsquo; Laboratory (Perth, Australia) in accordance with institutional regulations and guidelines, where written informed consent was collected from all participants. Demographic data (age, sex, skin tone, history of cardiovascular complications, regular cardiovascular medication, and previous history of difficult intravenous access) was collected. Measurements were recorded on the left and right ventral forearm of each participant and were conducted as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Participants were not asked to perform any exercises or change hydration habits prior to testing, and heat was not applied to the forearm. Certain exercises, heat and oral hydration have been shown to have an effect on vessel characteristics [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. The subject was seated, with dorsal surface of the forearm resting on a table. The ventral forearm location is recommended by clinical care standards as it provides the most stable site for cannulation [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. For each location, a suitable vein was selected through a commercial ultrasound scanner (\u003cem\u003eClarius L15 HD3 High Frequency Linear Ultrasound Scanner\u003c/em\u003e, Vancouver, Canada), where the compressibility and flow direction of an identified vessel was used to characterise the vessel as a vein. The images were used to measure the depth, diameter and flow velocity of each vein using the in-built measuring feature of the Clarius Mobile Health Corp program [V9568a9d, Vancouver, Canada]. The palpability and visibility of the veins as determined by the investigator were recorded, and the location of the vein was marked on the skin.\u003c/p\u003e \u003cp\u003eThe proposed prototype was then used to scan the marked region and the sensitivity of the prototype was assessed as the ability to measure 2 consecutive signal peaks on the mark vein.\u003c/p\u003e \u003cp\u003eData analysis was performed in an open-source statistical package, \u003cem\u003eSAS Studio\u003c/em\u003e [V3.81, NC, USA]. For each measure, the mean and standard deviation were reported as split by the demographic variables (age, sex, skin tone, history of cardiovascular complications, regular cardiovascular medication, and previous history of difficult intravenous access) and vein characteristic variables (visibility, palpability, depth, flow, diameter). Backwards variable elimination procedure with single hierarchy was used to identify which variables are significantly (.05 level) and independently associated with prototype detection in a logistic regression model. At each step of the procedure, individual parameters are examined using the Wald Chi-Square test. Multicollinear variables were removed from the procedure, such as palpation prior to torniquet application, ensuring correct statistical significance calculations. Squares of quantitative variables and interactions were only investigated where the component main effects were present (hierarchy principle).\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eCompeting Interests\u003c/h2\u003e\u003cp\u003eThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: N.B., K.A., N.M.B. are named inventors on a patent describing the ultrasound technology (WO2022221913A1). The study was funded by VeinTech Pty Ltd of which M.D.L., P.H.H., C.A.B., M.D.R., E.L.H., N.M.B., K.A. and N.B. are employees and in which N.M.B., K.A. and N.B. hold equity. M.D.L., P.H.H. and M.D.R. hold Employee Share Options and P.J.C. and B.J.D. are members of the scientific advisory board of VeinTech and are also compensated by Employee Share Options.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eM.D.L. was involved in planning study protocols, determining the study design and protocols, contributed to collection, lead the analysis and discussion of the in vitro and in vivo studies, and wrote the majority of the manuscript, leading subsequent reviews and submission. P.H.H. was involved in planning the in vivo study, determining study design and protocols, analysis methods and lead the usability study. C.A.B. was the primary lead in collecting and contributed to the analysis of the in vitro data. M.D.R. was the primary lead in collecting all in vivo data. E.L.H. was the primary lead in collecting and analysing usability data. N.M.B. was responsible for the overall execution of the usability study. K.A. assisted with the conception of the study. P.J.C. and B.J.D. contributed to the analysis and discussion of the data. N.B. contributed to the study conception, study design, analysis and discussion of data, writing the manuscript and overall supervision of the work. All authors read and approved the manuscript for submission.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThis activity is/has been supported by the Western Australian Future Health Research and Innovation Fund, Grant ID InnovSeedFund2022 and IF2022, which is an initiative of the WA State Government. We would like to acknowledge the volunteers who participated in the in vivo sensitivity study and our clinical partners, Royal Perth Hospital and Chemo@Home, for providing clinicians to complete the usability study.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets generated as part of this study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eStolz, L. A. \u003cem\u003eet al.\u003c/em\u003e Prospective Evaluation of the Learning Curve for Ultrasound-guided Peripheral Intravenous Catheter Placement. J. Vasc. Access 17, 366\u0026ndash;370 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePlatt, V. \u0026amp; Osenkarski, S. Improving Vascular Access Outcomes and Enhancing Practice. J. Infus. Nurs. 41, 375\u0026ndash;382 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKeogh, S. \u0026amp; Mathew, S. \u003cem\u003ePeripheral intravenous catheters: A review of guidelines and research\u003c/em\u003e. (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKleidon, T. M., Cattanach, P., Mihala, G. \u0026amp; Ullman, A. J. Implementation of a paediatric peripheral intravenous catheter care bundle: A quality improvement initiative. J Paediatr Child Health 55, 1214\u0026ndash;1223 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMermel, L. A. Short-term Peripheral Venous Catheter\u0026ndash;Related Bloodstream Infections: A Systematic Review. Clin. Infect. Dis. 65, 1757\u0026ndash;1762 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTuffaha, H. W. \u003cem\u003eet al.\u003c/em\u003e Cost-effectiveness analysis of clinically indicated versus routine replacement of peripheral intravenous catheters. 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J. \u003cem\u003eet al.\u003c/em\u003e The Modified A-DIVA Scale as a Predictive Tool for Prospective Identification of Adult Patients at Risk of a Difficult Intravenous Access: A Multicenter Validation Study. J Clin Med 8, (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePerry, A. M., Caviness, A. C. \u0026amp; Hsu, D. C. Efficacy of a near-infrared light device in pediatric intravenous cannulation: a randomized controlled trial. Pediatr. Emerg. Care 27, 5\u0026ndash;10 (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAulagnier, J. \u003cem\u003eet al.\u003c/em\u003e Efficacy of AccuVein to facilitate peripheral intravenous placement in adults presenting to an emergency department: a randomized clinical trial. Acad Emerg Med 21, 858\u0026ndash;63 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCuper, N. J. \u003cem\u003eet al.\u003c/em\u003e The use of near-infrared light for safe and effective visualization of subsurface blood vessels to facilitate blood withdrawal in children. Med. Eng. Phys. 35, 433\u0026ndash;440 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003evan Loon, F. H. J., Buise, M. P., Claassen, J. J. F., Dierick-van Daele, A. T. M. \u0026amp; Bouwman, A. R. A. Comparison of ultrasound guidance with palpation and direct visualisation for peripheral vein cannulation in adult patients: a systematic review and meta-analysis. Br J Anaesth 121, 358\u0026ndash;366 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoore, C. L. Ultrasound first, second, and last for vascular access. J. Ultrasound Med. 33, 1135\u0026ndash;1142 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBlanco, P. Ultrasound-guided peripheral venous cannulation in critically ill patients: a practical guideline. Ultrasound J. 11, 1\u0026ndash;7 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTakahashi, T. \u003cem\u003eet al.\u003c/em\u003e Ultrasonographic measurement of blood flow of peripheral vein in the upper limb of healthy participants: a pilot study. J. Jpn. Soc. Wound Ostomy Cont. Manag. 25, 576\u0026ndash;584 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlbayrak, R. \u003cem\u003eet al.\u003c/em\u003e Hemodynamic changes in the cephalic vein of patients with hemodialysis arteriovenous fistula. J. Clin. Ultrasound 35, 133\u0026ndash;137 (2007).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWorld Health Organization. \u003cem\u003eGuidelines for the prevention of bloodstream infections and other infections associated with the use of intravascular catheters: part I: peripheral catheters\u003c/em\u003e. (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWitting, M. D., Schenkel, S. M., Lawner, B. J. \u0026amp; Euerle, B. D. Effects of Vein Width and Depth on Ultrasound-Guided Peripheral Intravenous Success Rates. J. Emerg. Med. 39, 70\u0026ndash;75 (2010).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDoyle, B., Kelsey, L., Carr, P. J., Bulmer, A. \u0026amp; Keogh, S. Determining an Appropriate To-Keep-Vein-Open (TKVO) Infusion Rate for Peripheral Intravenous Catheter Usage. J. Assoc. Vasc. Access 26, 13\u0026ndash;20 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHacker, L. \u003cem\u003eet al.\u003c/em\u003e Criteria for the design of tissue-mimicking phantoms for the standardization of biophotonic instrumentation. Nat. Biomed. Eng. 6, 541\u0026ndash;558 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen, A. I. \u003cem\u003eet al.\u003c/em\u003e Multilayered tissue mimicking skin and vessel phantoms with tunable mechanical, optical, and acoustic properties. Med. Phys. 43, 3117\u0026ndash;3131 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJafary, R. \u003cem\u003eet al.\u003c/em\u003e Fabrication and Characterization of Tissue-Mimicking Phantoms for Ultrasound-Guided Cannulation Training. ASAIO J. Am. Soc. Artif. Intern. Organs 1992 68, 940\u0026ndash;948 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMadsen, E. L., Hobson, M. A., Shi, H., Varghese, T. \u0026amp; Frank, G. R. Stability of heterogeneous elastography phantoms made from oil dispersions in aqueous gels. Ultrasound Med. Biol. 32, 261\u0026ndash;270 (2006).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBude, R. O. \u0026amp; Adler, R. S. An easily made, low-cost, tissue-like ultrasound phantom material. J. Clin. Ultrasound JCU 23, 271\u0026ndash;273 (1995).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChao, S.-L., Chen, K.-C., Lin, L.-W., Wang, T.-L. \u0026amp; Chong, C.-F. Ultrasound Phantoms Made of Gelatin Covered with Hydrocolloid Skin Dressing. J. Emerg. Med. 45, 240\u0026ndash;243 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSaid, M. S. M. \u0026amp; Seman, N. Preservation of gelatin-based phantom material using vinegar and its life-span study for application in microwave imaging. IEEE Trans. Dielectr. Electr. Insul. 24, 528\u0026ndash;534 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEren, H., Calıskan, N. \u0026amp; Durmus Iskender, M. Effect of Fist Clenching on Vein Visibility and Palpability: An Observational Descriptive Study. J. Infus. Nurs. 45, 252\u0026ndash;257 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSharp, R., Childs, J., Bulmer, A. C. \u0026amp; Esterman, A. The effect of oral hydration and localised heat on peripheral vein diameter and depth: A randomised controlled trial. Appl. Nurs. Res. 42, 83\u0026ndash;88 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWallis, M. \u003cem\u003eet al.\u003c/em\u003e Risk factors for peripheral intravenous catheter failure: a multivariate analysis of data from a randomized controlled trial. Infect. Control Hosp. Epidemiol. 35, 63\u0026ndash;68 (2014).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Ultrasound, Device, Usability, Sensitivity, Visibility, Cannulation","lastPublishedDoi":"10.21203/rs.3.rs-4652430/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4652430/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eInserting needles into veins is fundamental to medical care with up to 90% of inpatients requiring a peripheral intravenous catheter/cannula (PIVC) during their stay. Yet 40%-50% of PIVC insertions fail on the first attempt. Here, we present an easy-to-use novel vein visualizing ultrasound prototype device and data from \u003cem\u003ein vitro\u003c/em\u003e and \u003cem\u003ein vivo \u003c/em\u003eperformance. Our prototype’s locational accuracy in simulated forearm veins is 0.16mm ±1.63mm (s.d.) (97.8% agreement to the ground truth, p\u0026lt;.001), across variations of vein diameter (3-5mm), depth (10-20mm), and velocity (10-100mm/s). Usability trials conducted with nine clinicians found that 100% of users were able to handle the prototype in a sterile manner with minimal assistance. In 80 forearm scans of 40 volunteers, sensitivity was excellent to both find veins (94%). In comparison, sensitivity of vein finding using landmark technique with torniquet (visible 46% and palpable 74%) were far inferior. The prototype is a novel ultrasound device which empowers clinicians to detect and visualize well-perfused veins at depth in the coronal view of vein pathways whilst enabling, ultra portability, accessibility and ease of use.\u003c/p\u003e","manuscriptTitle":"In Vitro and In Vivo Vein Assessment of a Novel Vein Visualizing Device to Improve First-Time Peripheral Venous Access","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-09 21:18:31","doi":"10.21203/rs.3.rs-4652430/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e7cb442d-12dd-4f8f-ba62-57d0a4e2a16a","owner":[],"postedDate":"August 9th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":35207530,"name":"Physical sciences/Engineering/Biomedical engineering"},{"id":35207531,"name":"Health sciences/Medical research/Pre clinical studies"},{"id":35207532,"name":"Physical sciences/Physics/Applied physics/Acoustics"},{"id":35207533,"name":"Physical sciences/Physics/Techniques and instrumentation/Imaging techniques"}],"tags":[],"updatedAt":"2024-10-29T07:53:17+00:00","versionOfRecord":[],"versionCreatedAt":"2024-08-09 21:18:31","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4652430","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4652430","identity":"rs-4652430","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}