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The American Academy of Pediatrics Neonatal Resuscitation Program (NRP) is required training for thousands of physicians and medical staff who attend the delivery of newborns. Placement of an intravenous catheter in the umbilical vein of the cord stump in a distressed newborn is one way to provide life saving medication and is a skill that is essential to the NRP course. Hands-on training in the placement of an umbilical venous catheter has received increased attention and emphasis since the 2005 update of the NRP course. Currently, two models for hands-on training are available. Some companies make newborn models for CPR that also have artificial umbilical cords (ex Laerdol). These models appear to inadequately mimic placement in a real cord and are very expensive. Alternatively, the American Academy of Pediatrics recommends using sections of an umbilical cord obtained after delivery. The cord section is placed in a glass baby bottle with part of the nipple cut off so the cord extends about 1/2 an inch from the top of the nipple. While this model has the advantage of using a real cord, the cord is secured poorly and thus does not adequately mimic placement in a newborn. My design idea is to make a support for real umbilical cords that would more closely mimic the umbilical stump of a newborn. The model could be made out of a material that might mimic the abdominal wall, such as ballistic grade gel, and might perhaps have two halves that clamp around a section of real cord. The model could mimic the curves of the umbilical vein after it enters the body, making placement more realistic. Ultimately, this model, which would best be quite inexpensive and disposable, could be marketed to the over 25,000 individuals in the US who teach NRP and would likely represent a vast improvement over the "baby bottle" model.
From Left to Right: Padraic Casserly, Kelvin Ng, Tim Balgemann, Ann Sagstetter and Angwei Law
We have met with our client and conferenced on her ideas and expectations of this project.
Our client organized a day for us to come in and practice inserting umbilical catheters into real umbilical cords. This helped us get a feel for what the current model was like and how we could improve on it.
Kelvin, Ann and Padraic are all scrubbed up and ready to practice some catheterization.
Kelvin and Ann take turns manipulating the cords, taking note on the rubbery amniotic epithelium covering the cord and gooey Whartonís jelly supporting the vessels.
A cross-sectional view of the umbilical cord reveals one umbilical vein and two umbilical arteries
The currently accepted model is composed of a baby bottle filled with red liquid and the umbilical cord inserted into a hole cut out of the nipple.
The difficulty in using this model became evident from the very beginning. The cord is not stabilized by the nipple of the baby bottle, and slips in and out as the catheter is inserted. The extra cord present in the bottle isnít anatomically correct either. In a real infant, the umbilical vein stops twisting and splits off from the arteries.
As can be seen in this picture, the nipple does a poor job securing the cord . The cord is allowed to rotate and be pulled free. Both of these motions are not realistic to what occurs in the actual procedure.
If the incision of the nipple is made smaller, then it often constricts the cord. This causes the vein to be pinched and doesnít allow the catheter to pass through smoothly. In this photo, the constriction caused the catheter to be forced through the Whartonís jelly and amniotic epithelium.
We are currently brainstorming design ideas and developing a design matrix.
Finishing up the mid-semester report and presentation
This picture shows the set up for a set of experiments testing for optimal gel concentration for cord stabilization.
Preliminary catheterization testing of the Cord-in-Gel and Cuff models. The scope of the project has been narrowed down to focusing on the stabilization of the cord; the clients main request.
The gelís ability to hold the cord was tested using a spring scale. Similar tests were done with the cuff model to optimize sandpaper placement. Both models performed far better than the baby bottle model (see attached report).
After weeks of testing the gel model began to reach its final form. This photo shows the gel model being used for a catheterization test. The model base being used is a disposable stand-in.
Final cord-in-gel prototype with and without foam model base.
Final cuff prototype with and without model base
|Week||Reporting Period Beginning||Activities|
|1||September 7||Submitted a proposal for the Umbilical Vein Catheterization project and were awarded it.|
|2||September 14||Began preliminary research dealing with umbilical cords, current procedures and current products.|
|3||September 21||Met with our client and she discussed her expectations with the project and what she wanted us to accomplish over the upcoming semester.|
|4||September 28||Worked in the neonatology laboratory with umbilical cords. We were able to practice inserting catheters into the umbilical cords, using the current baby bottle model|
|5||October 5||Started to brainstorm and finished any outstanding research|
|6||October 12||Finished brainstorming and developed a design matrix. We then presented our design ideas to our clients.|
|7||October 19||Finishing up the final touches on our midsemester report and presentation|
|8||October 26||Tested gel and inflatable cuff cord stabilization methods and are awaiting results from our client.|
|9||November 2||Preliminary testing done on the cuff model to see if it is a feasible idea. Gel concentration testing done to asses changes in gel-cord interaction depending on the concentration of gel powder to water.|
|10||November 9||Experiments were carried out to determine how much force was required to pull the cord from the gel and also how using a plastic liner worked in preparing the cord-in-gel model.|
|11||November 16||Carried out testing to determine what concentration of gel held the cord better under tensile testing. Testing was also done to see how the storage of the cord affected the ability to successfully catheterize. Attempted to create a better inflatable bladder out of softer rubber, these attempts were unsuccessful and better suited materials must be found.|
|12||November 23||Finalizing the poster and finished building the final testing and presentation prototypes. Dr. Kessel is very pleased with both designs|
|13||November 30||The team presented our design prototypes at the Biomedical Engineering Expo. There were many vistors who were very interested with our project and how we addressed the problem|
|Mid-Semester Presentation (Oct 19 2007, 10067 kb)|
|Mid-Semester Report and PDS (Oct 24 2007, 374 kb)|
|Final Presentation Poster (Dec 8 2007, 9815 kb)|
|Prototype and Baby Bottle Model Demonstration Video (Dec 11 2007, 3390 kb)|
|Final Semester Report (Dec 12 2007, 5429 kb)|
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