Engineering a Needle Elevates Emergency Care

The term intraosseous (IO) needle may seem like a convoluted name for an innocuous instrument, but this life saving device provides a vital pathway into the circulatory systems of pediatric patients. In critical care situations when vasculature is collapsed, hidden, or impossible to find, failed intravascular (IV) access can spell the end to human life. The IO needle avoids impediments associated with IV placement by drilling into the bone below the knee (proximal tibia) and inserting the needle directly into bone marrow to deliver life-sustaining fluids. However, complications associated with improper IO needle placement abound.

To prevent dangerous fluid leakage and improper depth placement during pediatric emergencies, University of Minnesota graduate Dilshan Rajan and his team members, including Anuk Dias and Shaliny Jadhav, engineered a patent-pending redesign of the standard intraosseous (IO) needle. The project originated in the Bakken Medical Devices Center (BMDC) Medical Device Innovation Experience for Undergraduates course, where advisor Dr. Gwen Fischer, Director, Division of Pediatric Critical Care Medicine, University of Minnesota Medical School challenged the team to address critical issues with current IO needles, including dislodgement and fluid leakage. Through extensive anatomical research and functional prototyping, the team created a standardized device featuring a built-in depth-control shoulder that physically prevents over-insertion across all patient age groups.

“This is exactly what we hope happens when clinicians and engineers work together: you start with a real problem at the bedside, ask whether there is a better way to solve it, and then follow the evidence wherever it leads. Dilshan, Anuk and Shaliny rethought the problem entirely and developed a solution with the potential to make emergency care safer for children and adults. As an ICU physician, I can’t wait until this is available for patient use, because I believe it will make this procedure both safer and faster.” - Gwen Fischer

What clinical challenge initially led to this project, and why are current intraosseous (IO) needles prone to failure?

Dilshan: IO needles are used in pediatric and adult emergencies when rapid IV access can't be established within 30 to 90 seconds, especially during trauma or cardiac arrest when veins collapse.

Current needles rely on drilling through the bone and setting depth relative to the patient's skin and soft tissue. Because soft tissue thickness varies wildly from patient to patient, clinicians frequently drill too deep (passing through the back wall of the bone) or too shallow. Going too deep causes caustic medications and fluids to leak into surrounding tissue rather than entering the bloodstream, leading to severe tissue damage and preventing critical drug delivery. Additionally, high fluid delivery pressures and patient movement during transport often cause standard needles to dislodge over time. Customer discovery showed first-time failure rates as high as 20–40%.

Representative CT and MRI scan of the proximal tibia.

What key discovery or research insight shifted the approach toward a complete needle redesign?

Dilshan: The original problem given to us was to design an electrical sensor system to detect fluid leakage after it occurs. However, we realized it was far more effective to redesign the needle to prevent improper placement and leakage altogether.

To understand the anatomical parameters, our team conducted a retrospective study evaluating over 680 pediatric CT and MRI scans (measuring soft tissue thickness, bone thickness, and medullary canal diameter across age groups). We published a paper on our findings, which revealed two key insights:

1. Bone thickness in the proximal tibia remains relatively consistent across different ages, while soft tissue thickness accounts for most of the variation.
2. Existing sizing guidelines force clinicians to choose between limited needle lengths, leading to a high rate of incorrect depth placements.

How does the new needle design function, and what was the development process from concept to testing?

Dilshan: Instead of referencing depth from the surface of the skin, our redesigned needle features a mechanical "shoulder" at the end of the threaded drill section. This shoulder stops against the outer surface of the bone itself. Combined with a low-torque drill, the increased physical resistance makes it virtually impossible to drill past the intended depth. This mechanical stop allows a single needle size to work safely across all patient sizes regardless of soft tissue variations.

It also features self tapping threads, which allow it to easily drill into the bone and anchor in place, reducing or eliminating the dislodgement that can occur with the current needles. Our progress through design, validation, and testing included:

• Proof-of-Concept & Prototyping: We moved from early CAD models to physical prototypes, securing funding through the BMDC and a $3,000 MVP Challenge grant for second-generation prototypes.
• Competitions & Recognition: We publicly shared the design for the first time at the 2024 Design of Medical Devices Conference Student Design Showcase, placed second in the 2025 Design of Medical Devices Conference 5-minute Pitch Competition, named as an honorable mention in the 2025 NIH DEBUT Challenge and most recently were finalists in the 2026 Collegiate Inventors Competition.
• Commercialization & Discovery: We completed an NIH commercialization program (C3i) focused on customer discovery, interviewing physicians across regional and national hospitals to confirm market need.
• Pre-Clinical Validation: We partnered with The Visible Heart® Laboratories to conduct animal studies (in vivo swine models), utilizing fluoroscopy, contrast injection, and micro-CT scans to verify that the needle works as intended in a large animal model, and high fluid flow rates are delivered  into central circulation without causing fluid leakage or bone structural damage. We are also conducting mechanical force testing in collaboration with the BMDC.

Fluoroscope image of the Flow-IO needle inserted into the porcine tibia, with contrast flowing through the needle and into the intraosseous vasculature.

What’s next for Dilshan and the project?

• Academic Expansion: Having completed his bachelor's degree at the University of Minnesota (Bachelor of Science in Human Physiology and Psychology, Minors in Management of Technology, and Biomedical Engineering) Dilshan is heading to the University of Oxford for a Master’s in Biomedical Engineering. His long-term ambition is to return to the University of Minnesota’s Medical School and become a physician-scientist, combining engineering and medicine to pioneer new therapies and devices.
• Continued Development at UMN: The project will remain anchored at the University of Minnesota. Dilshan will continue directing research remotely while local team members handle physical testing and coordinate potential new additions to the team.
• Publication & Pre-Clinical Progress: The team is preparing to publish the findings from The Visible Heart® Laboratories translational animal study to provide robust preclinical evidence of the device's efficacy.
• Licensing & Commercialization Pathways: With patent-pending status secured through the UMN Technology Commercialization, the primary commercial goal is to navigate regulatory strategy and ultimately license the technology to an established medical device manufacturer to bring it into clinical production.

Hear from Anuk Dias:

Mr. Dias completed his Bachelors of Science from the University of Minnesota in Psychology and Computer Science in 2026 and is currently pursuing his DPhil in Clinical Neurosciences at the University of Oxford. 

“The IO needle project has been one of the most fulfilling and exciting parts of my time at the U, and I’ve learned a lot by working on it. I believe that our idea is sound, and I hope we will be able to get our improved IO needles used to improve emergency care. Regardless, the learning opportunity provided me by this experience has been immensely rewarding and I will be using the skills and lessons I’ve learned moving forward in my clinical research career.”

Dilshan Rajan, Anuk Dias, Shaliny Jadhav