New 3D-Printed Model Trains Caregivers How to Tube Feed Kittens

Tube feeding is a specialized skill required when caring for kittens under 4 weeks old, but caregivers often learn it on an ad hoc basis when a newborn is most in need. A professor of veterinary medicine and a team of development engineers aim to improve and increase access to the training of this technique with a 3D-printed kitten model they created at the University of California, Davis.

The idea started with Karen Vernau, a clinical professor at UC Davis School of Veterinary Medicine and a faculty advisor for The Orphan Kitten Project, or OKP. The OKP is a student-run non-profit organization within the School of Veterinary Medicine that rescues neonatal kittens, or those 4 weeks old and younger. 

"I spend a lot of time with the students in the Orphan Kitten Project every year to teach them how to assess and tube feed kittens," Vernau said.  

Training students how to safely tube feed is a time-consuming process, and it is not feasible to train everyone with a live kitten. At a shelter like OKP, where the kittens are so young and in need of care, tube feeding needs to happen right away.   

While video tutorials can be useful, hands-on teaching of the method is essential, because if someone does it improperly, it can lead to injury or, in some extreme cases, death for the kitten. This puts a lot of pressure on Vernau and senior mentors at OKP to be available to instruct volunteers and community members who are willing to foster these young kittens.  

Working through solutions to this challenge, she landed on the idea of a model of a kitten for students to safely practice tube feeding on but needed someone to design and fabricate it. On the recommendation of a colleague, she reached out to the Translating Engineering Advances to Medicine, or TEAM, Lab with her idea. 

The idea, while new, was not necessarily out of the ordinary for the TEAM Lab, which processes about 500 projects per year. As part of the Department of Biomedical Engineering, the lab provides prototype development support to faculty across the UCs and universities like Stanford, as well as private companies and individuals, with each new project requiring an open-minded, collaborative approach. That mindset was key for this project, which required careful handling and consideration. 

"The most important thing from our perspective, especially in our initial consultations, is ensuring that we ask the right questions and that we truly understand what the challenge is from our client's perspective," said Steven Lucero, the lab's director and principal development engineer. "We wanted to make sure that we understood the tube feeding process so that when designing, we incorporated features into the final model so that it was functional, from a user's perspective." 

Beyond a few specific requests, such as them building the model to the scale of a CT scan of a neonatal kitten, Vernau let Lucero and his fellow development engineer Valerie Quiroz free to experiment with the design. 

After several benchtop prototypes, they landed on a to-scale model made of silicone, a soft plastic material that's like rubber, as it lends a more life-like feeling. The silicone model also features a trachea and esophagus, which was very important to Vernau, who wanted the design to feature immediate feedback to the user that they had gone down the wrong path. Lucero and Quiroz's solution was to design a specific Y-shaped fork to the hole, so if a user puts the tube down the trachea, or windpipe, it pops out of the 3D-printed model's chest to alert them to try again. 

The kitten model's other important feature is the inclusion of a 3D-printed rib cage. One of the more technical components of tube feeding is knowing if the tube is too far in or too far out, and the kitten's ribs help with this. 

"The ribcage is in there because [caregivers] use the last rib as a landmark," Quiroz said. "Having it embedded in the model and having the students be able to palpate that is amazing. They use that to measure the feeding tube from the last rib to the mouth, and that length is really important for making sure that they're not putting it too far or far enough."

One of the more experimental aspects of this project was Quiroz's idea to flock the models, inspired by the toys she had as a kid growing up. Flocking is a decorative process where tiny fibers are added to the surface of a material to provide a soft, velvety touch. The technique also allows the TEAM Lab to produce kitten models in various colors to look like certain breeds, such as an orange tabby or a black Bombay. However, they were hesitant to pitch the idea to Vernau, as the TEAM Lab had never done something like this before — blending art with engineering, as Lucero put it.

"It looks good," Vernau said, who was immediately in favor of the idea. "You know, when we're teaching the students on a model, we want them to think about it like it's a real kitten, that what they're doing matters. And having them be flocked and be different colors just makes them look and feel more real." 

With the model's design complete, Vernau is excited to debut them at the 2024 Feline Symposium on Nov. 2 at UC Davis. Vernau will host a hands-on demonstration of how to use the models so attendees can learn how to successfully and safely tube feed neonatal kittens. 

This demonstration is a significant event, as tube feeding, despite clinics and shelters using the technique nationwide, is controversial within veterinary medicine due to its inherent danger. Neonatal kitten care in general is an underdeveloped area in veterinary medicine.  

"Underage and neonatal kittens have really not been a huge part of veterinary medicine," Vernau said. "They're the ones who are euthanized because they need such specialized, around-the-clock care. I think the care of underage kittens is becoming more and more important with our shelter and rescue groups and with our students interested in shelter and rescue as well." 

More than being a tool that Vernau and the OKP team can use to increase access to and improve the training of tube feeding, the TEAM Lab's kitten model might also signal a change in how the technique is viewed by experts in the field.