New portable radiofrequency position-sensitive sensory system to confirm correct nasogastric tube placement

Year Submitted: 2025
Published Date: 17 April 2025

Tags: Care Process ＆ Redesign, Value Based Care, Safe Care, Risk Management, International Patient Safety Goals, Quality Improvement, Workflow Redesign

About this Content

Aims

To develop a portable radiofrequency sensor system which is easy, safe, precise and intuitive that can be used at bedside by non-radiologists to ascertain the position of the NG tube to be in the stomach when pH testing of gastric contents is unable to provide the needed information.

Background

Confirmation of the position of NGT will not be achieved easily by conventional bedside methods at times and preforming chest X-ray to confirm its position can be inconvenient, resource intensive and laborious particularly for patients in community and nursing homes. Hence, a portable device system which is easy, precise and intuitive to use will be very helpful in reducing the need for X-rays to confirm the correct position of NGT prior to the feeding.

Methods

The sensor system has a small receiving coil that is placed at the tip of the Nasogastric tube (NGT) and a handheld transmitting coil outside the human body. Upon insertion of the NGT, the handheld transmitting coil is moved around the patient’s body over the area of the stomach until the tip of the NGT is located. The graphical user interface (GUI) consists of a signal strength display that helps to guide the medical professional in locating the tip of the NGT and an audio beep is emitted to indicate that the tip of the NGT has been found. This sensor system was tested in an anatomically accurate NGT mannequin with 3D printed stomach that was constructed to determine the positional error of the sensor system. A blind study was also conducted to determine the sensor system’s applicability in clinical practice.

Results

This sensor system was tested in an anatomically accurate NGT mannequin that was constructed to determine the positional error of the sensor system in-situ with a mean positional error of 0.8cm and standard deviation of 0.23cm. A blind study was also conducted to determine the sensor system’s applicability in clinical practice. Out of the 55 insertions conducted during the blind study, the sensor system achieved a specificity and sensitivity of 100% in localizing the tip of NGT in the stomach.

The sensor system designed is a portable device that is low-cost, precise, and intuitive to use at the bedside by non-radiologists. Compared to other RF/EM tracking products available in the market, the sensor system proposed does not require a custom NGT. The receiving coil with guidewire design fits into a standard NGT and operates in the kHz frequency range, posing no radiation safety concerns.

Conclusion

The sensor system designed is a portable device that is low-cost, precise, and intuitive to use at the bedside by non-radiologists. Compared to other RF/EM tracking products available in the market, the sensor system proposed does not require a custom NGT. The receiving coil with guidewire design fits into a standard NGT and operates in the kHz frequency range, posing no radiation safety concerns. The tracking system was found to successively function with sub-cm accuracy for distances of up to 16 cm between the transmitter and NG tube, and therefore has the potential to function as a tracking system for other similar catheter devices. However, further work is still required in engineering and biocompatibility of receiving coil with guidewire before the sensor system’s performance can be validated in a clinical trial.

Lessons Learnt

The multiple challenges faced are listed below:
1. Different Radiofrequencies were tested throughout this project. At some of the frequencies tested, we faced screening problems (which affected the accuracy of the sensor system) and posed potential reflection and attenuation effects on human body tissue (this affects the sensor system’s reliability across patients of different body sizes)
2. As the goal of the sensor system is that it must be portable and intuitive to use, the user interface and processing algorithms had to be redesigned multiple times throughout the project.
3. To improve localization of the sensor system to only detect the position of the tip of the NGT, a custom guidewire with a receiving coil had to be
constructed. As such, this custom guidewire’s biocompatibility must be evaluated before it can be used in a clinical trial setting.

Keywords

Product development, Proof of Concept, Proof of Value

Innovators' Details

Connect with this contributor!

Khin Khin Win - Khin_win_KHIN@ttsh.com.sg

Project Attachment