Development and Clinical Verification of a Small Intestine Motility Measurement System Using an Ileus Tube

Shinji Hosokawa, Akihiro Naganawa, Takeshi Seki, Kiyoshi Oka, Noriaki Manabe, Ken Haruma, Junji Yoshino
Vol. 11 (2022) p. 228-236

Intestinal obstruction is generally treated with an ileus tube. Success of treating functional ileus due to abnormal intestinal motility is judged through auscultation and medical interviews. Therefore, functional tests to visually evaluate the motility of the small intestine are important to elucidate the pathophysiology and observe the recovery process. An internal pressure measurement method that directly measures small intestine motility has been explored as a type of functional test. However, because the catheter is not in contact with the inner intestine wall, it is possible to measure the peristalsis movement, which is a large motility, but not the automatic rhythmic movement, which is a small motility. Therefore, we have developed a small intestine motility measurement system using an ileus tube. Small intestine motility is measured using the pressure applied to a balloon attached to an ileus tube. Peristaltic and automatic movement can be measured as the balloon contacts the inner intestinal wall, allowing more detailed evaluation of small intestinal motility. This study aimed at determining whether this measurement system can be applied clinically to accurately measure the small intestine motility. Hence, we first applied pressure to the balloon of the ileus tube using a pressurizing device to evaluate the basic performance ex vivo. We then conducted preliminary tests on a healthy volunteer. Analysis of the pressure test results showed that although the time delay of the balloon pressure measurement with respect to pressurization status was 4–6%, the cycles of the balloon pressure and displacement were consistent. Thus, it was concluded that the time delay had no effect on the proposed small intestine motility measurement system. In the preliminary test in a healthy volunteer, the pressure waveforms obtained during testing revealed a mixture of large and small pressure values of ~2 kPa at ~1–2 cycles/min and ~0.5 kPa at ~6–11 cycles/min, respectively. We confirmed that the larger pressure was similar to a peristalsis motility pattern, whereas the smaller pressure was similar to an automatic motility pattern. These results demonstrate that our measurement system is able to measure the small intestine motility and thus can be applied to comprehensive and visual measurement of small intestine motility.