Date of Award

Spring 2026

Document Type

Restricted Thesis

Terms of Use

© 2026 Jesus Saucedo, Bonji Onuma, and Miles Fleisher. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts

Department

Engineering Department

First Advisor

Maggie Delano

Abstract

Nasogastric (NG) tubes are essential in healthcare for delivering food, nutrients, and medication directly to the gut when oral intake is not feasible. NG tube placement must be confirmed to avoid placement in the lungs. Verification is usually done with X-ray imaging, leaving patients with high medical bills and potentially unnecessary radiation exposure. This design project used off-the-shelf components for capnography and bioimpedance monitoring to determine the placement of an NG tube without relying on X-ray imaging. The setup includes a SPRINTIR CO2 sensor [Appendix C, j], an SCD41 CO2 sensor [Appendix C, k], and an EVAL-AD5940BIOZ bioimpedance analyzer [Appendix C, a]. A testing setup was also designed and built to verify the accuracy of the device. Benefits of this device include lower cost, no radiation exposure, portability, and faster placement confirmation. The capnography device was able to correctly identify tube placement with an accuracy of 92.5%, a specificity of 85%, and a sensitivity of 100%, meeting our design requirement of successful identification a minimum of 65% of the time. The device met some of its other design requirements by providing an affordable alternative to X-rays and demonstrating a concept that could be made safe for internal use. However, the device did not meet all of its design requirements and constraints as it is not safe, biocompatible, single-use, or easy to sterilize. The device was also not able to pass applicable codes and standards, such as 21 CFR 876.5980. In total, the project cost $810, with specific costs varying between measurement approaches and hardware purchased versus already available.

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