B
N
CVC Placement
Solutions
Design Innovation for Central Circulatory Medicine
Central Venus Catheter [CVC] placement is a common medical procedure with high-risks, and a low-margin for error. Partnering with the VCUHS Medical Campus, our team worked with Dr. Michael Vitto to redesign, and engineer a safer CVC placement process and toolkit.
Among our team-members were two engineers, a fashion designer, and myself with a recent background in advertising serving as desgn lead. Having no background in med-tech or prior knowledge of CVC placement, this became one of the most uniquely challenging and rewarding projects I've undertaken. (Note: All graphics & animations on this page are original)
My Role: Team Lead, Design Strategy, 2D & 3D graphic design, Animation, CLIENT PRESENTATION
Background
Central Venus Catheter [CVC] placement is a medical procedure commonly performed for patients who are unable to receive medication topically, orally, or intravenously. By placing a catheter into a major artery, doctors can more directly deliver medications to their patients circulatory system. This is especially useful for patients facing long-term care needs such as coma treatment, chemotherapy, and dialysis. During the process of administering a CVC; however, doctors face the risk losing an integral medical component - known as the CVC guidewire - within the central venous system. Loosing this piece of equipment can cause catastrophic damage to a patient as it becomes circulated around the body, and leaves doctors with very limited options to locate or retrieve it.
Because the process of administering a Central Venous Catheter isn't the easiest to explain - even to many in the medical field who don't commonly preform the procedure - I created a series of videos and graphics below to help demonstrate the mechanics of the process and the problems faced by the medical community.
problem
The loss of CVC guidewires has posed a long-standing risk for patients and doctors. Due to the design of current CVC placement kits, one in 3,000 CVC placement procedures result in complications due to guidewire loss, and 20% of these losses result in death. These losses not only compromise patient safety, but also pose procedural risks for doctors and increase hospital costs. While multiple attempts have been made to design a safer guidewire placement kit since the procedure was introduced in 1929, most have proved both unsuccessful, and excessively arduous for doctors conducting the procedure.
Current Toolkit
Much like explaining the procedure itself, the equipment used in the current CVC placement process has unique design features that are easier to explain visually than verbally. With this in mind, I created a short info-graphic and animation to show the design features for each of the primary tools.
The syringe is used to make the initial entry into a target vessel. After taking a blood sample to identify the correct vessel has been located, the doctor removes "barrel and plunger" - or the body - of the syringe, while leaving the head of the needle in place so the guidewire may be inserted through it. After the guidewire is inserted, the head of the needle is removed, and a dilator is slid over the guidewire to increase the size of the intrusion.
The guidewire is a thin, flexible wire that is temporarily inserted into the body to guide the placement of additional components. The guidewires used for CVC placement range from 40-50 cm in length, and feature a nitinol core that forms a "J" hook in its natural state. This prevents the accidental puncture of the veins when inserted into the body. When pressure is applied to the wires outer coils; however, the wire lays flat for passage in and out of the body.
The catheter is a soft tube that is placed into the patients vein in the final step of CVC placement. This allows the doctor to administer intravenous medicine and other fluids directly into the patients circulatory system. In addition, these may also provide the doctor the ability to draw and monitor blood over the course of long term therapy and home treatments. This may help prevent damage to veins that can come from frequent needle pricks.
initial ask
Coming into the problem space with no prior knowledge of the CVC placement process or the dangers this poses, the first task for us was to simply understand the problem. From there, we were tasked with redesigning the CVC placement process and toolkit to reduce the risk of guidewire loss. To begin working on the project, we started by meeting with Dr. Michael Vitto, Associate Medical Director for the Center for Human Simulation and Patient Safety at the VCU Department of Emergency Medicine, to begin learning more. Through our initial meetings, we found Dr. Vitto's primary focus in the placement process to be steps 7 and 8 (outlined above). Through four months of continued research; however, we identified multiple additional areas of risk in the process for doctors placing catheters under differing circumstances. Through competitive research, agile development and trail and error, we refined our initial assumptions and set the the following design parameters.
Design Parameters
Among the key design considerations we identified were:
1. Making modifications exclusively to parts of the CVC kit that do not enter the body in order to reduce regulatory restrictions
2. Reducing, rather than increasing the steps required to preform the CVC placement procedure
3. Ensuring all elements function equally well in dry and wet conditions (such as in trauma cases where blood is present)
AGILE Refinement
After composing our initial designs, we conducted operating room observations and follow-up interviews with additional doctors in the field, and discovered multiple unmet needs that were not previously identified. Continuing our survey of medical professionals in various fields, we composed an analysis of the strengths and weakness of each of our initial designs, and set out to begin our final design with the insights we gained.
Utilizing a clamp on the external end of guidewire when a doctor is not holding it would prevent loss; however, this would require the doctor perform an extra step in the procedure. If the doctors forgets to clip the end of the wire between every step, the clip loses its purpose.
Increasing the length of the guidewire would reduce the likelihood of loss; however, a significantly longer wire may lead to sanitary issues. Having more wire outside the body would result in a higher probability of contamination during the procedure.
The expansion cap utilizes a stent hidden under a sliding cap on the external end of the guidewire that physicians can open or close when needed. When the cap is open, a stint will deploy and act as a barrier to prevent the wire from sliding through.
This zip-tie design adds ridges to the catheter and guidewire. Once the catheter goes over the ridges its unable to go back. This means both will always move in opposite directions preventing the guidewire from advancing into the patient; however, it can only work once.
This design allows the user to activate barbs surrounding the external end of the wire; opposite of the ‘J’ hook. They are activated by twisting the wire in the same motion as a retractable pen. This would create a barrier to prevent the guidewire from slipping.
This design incorporates a hook on both ends of the guidewire. The external hook will be less ductile than the “J” so that it will not collapse and slide into the patient. The ease of passing the catheter and dilator over the external end is one of the main challenges for this design.
A great deal of additional designs were considered with features such as an inflatable balloon, expansive nitinol coils, and even the concept of developing a guidewire that is biodegradable within the bloodstream; however, all appeared to pose secondary risks that outweighed their benefit.
Final Design
Questioning defeat after four months of medical research, prototypes, and revisions, we were near ready to throw our hands in the air when the missing puzzle piece came at exactly the right time. In the final week before the project was set to end, I shifted our focus from making adjustments to the guidewire and catheter as assigned to us, and began focusing more heavily on other parts of the kit. It was at that time the our most full-proof solution came out of the blue: if we used a longer syringe, we could place the dilator over it and eliminate an entire series of steps where the guidewire would be unsecured in the process. With this insight, we could make only minor adjustments to the guidewire and catheter - changing the process instead - and could all but ensure there are no points of risk at any step in placement process.
Needle Dilator
Extending the length of the needle to 6.5 inches allows the dilator to be placed over the needle head and inserted during the initial process of taking a blood sample to identify the correct vessel. This allows the doctor to consolidate the initial steps of CVC placement into one, and eliminates multiple points in time where the guidewire is inserted into the body and doctors hands are not consistently secured to it.
Nitinol
Wings
Adding nitinol wings to the exterior end of the guidewire that deploy only when pressure is not intentionally applied by the doctor allows them to work safely and hands free in the middle stages of CVC placement. In addition, placing a plastic cap over the wings will automate the process of deploying the wings during the step of removing the needle. Modifying only the exterior end of the guidewire will also lead to faster FDA clearance.
Revised
ZIP-TIE
Implementing a small ridge on both the interior of the catheter and the exterior of the guidewire will enable the two to function in a manner similar to a zip-tie. This means that once the catheter has been placed over the guidewire, there is no way for the guidewire to advance beyond the end of the catheter. This ensures the guidewire does not get lost in the final step of catheter placement when the doctor is unable to keep their hands on it at all times.
FINAL STEPS
Original Artwork for Book - Nick Brown
Publication and
development
After completing the final design, we created a 50 page publication on our research and suggested design modifications to present to a board of medical administrators at VCUHS. Receiving excellent feedback, we were awarded a provisional patent on the design and were invited to present at the VCUHS Global Medical Innovation Expo. Presenting as the only student speaker without a background in the field of medicine was truly a once-in-a-lifetime experience.
Following this, I began our 3D engineering and renders using OnShape & Blender. With these designs, our hope is to conduct an FDA clearance assessment and move into product development. Both the left-field - last-minute successes - and the opportunity to work with such a phenomenal team of peers and medical professionals made this project a true highlight of my experience in product design & product management. Huge thanks to everyone who worked on this together!
OUR TEAM
Our Special Thanks to
