Assessing ischemic injury in human intestine ex vivo with electrical impedance spectroscopy

Abstract

Electrical impedance spectroscopy is a well-established tool for monitoring changes in the electrical properties of tissue. Most tissue and organ types have been investigated in various studies. As for the small intestine, there are several published studies conducted on pig and rat models. This study investigates the changes in passive electrical properties of the complete wall of the human intestine non-invasively during ischemia. We aim to use the passive electrical properties to assess intestinal viability. The bioimpedance measurements were performed using a two-electrode set-up with a Solartron 1260 Impedance/gain-phase analyser. The small intestinal samples were resected from patients who underwent pancreaticoduodenectomy. Impedance measurements were conducted following resection by placing the electrodes on the surface of the intestine. A voltage was applied across the intestinal sample and the measured electrical impedance was obtained in the ZPlot software. Impedance data were further fitted into a Cole model to obtain the Cole parameters. The Py value was calculated from the extracted Cole parameters and used to assess the cell membrane integrity, thus evaluate the intestinal viability. Eight small intestinal segments from different patients were used in this study and impedance measurements were performed once an hour for a ten-hour period. One hour after resection, the impedance decreased, then increased the next two hours, before decreasing until the end of the experiment. For all the intestinal segments, the Py values first increased and reached a plateau which lasted for 1 - 2 hours, before it decreased irreversibly. The time interval where Py value reached the maximum is consistent with reported viable/non-viable limits from histological analysis.

Real-Time Monitoring Using Multiplexed Multi-Electrode Bioelectrical Impedance Spectroscopy for the Stratification of Vascularized Composite Allografts: A Perspective on Predictive Analytics

“…The Cole Model consists of low-frequency resistance ( R 0 ), high-frequency resistance ( R ∞ ), a shape parameter (α) associated with dielectric dispersion, and a time constant ( τ ) [ 30 , 31 ].…”

“…They found that bioimpedance could provide a quantitative organ assessment that would allow for more accurate pre-transplant clinical decisions. In the recent work of Hou et al [ 30 ], they studied the temporal bioimpedance of resected segments of the highly layered human small intestine. They found that the normalized resistance ((R 0 − R i )/R 0 ) × 100 = P y ) initially decreased and subsequently increased before decreasing over a 10 h period of monitoring.…”

The determining the photoluminescence intensity for assessing of the small bowel viability in the experiment

“…Various ways have been proposed for the viability assessment [6][7][8][9][10][11][12][13][14][15]. Most of these ways determine the state of blood circulation in the vessels of bowel walls.…”

“…Therefore, the ways that do not use injections and evaluate the condition of all bowel tissues, and not only the bowel vessels, are more effective [14,16,17]. However, the well-known ways are not widely used.…”

Assessment of Intestinal Ischemia–Reperfusion Injury Using Diffuse Reflectance VIS-NIR Spectroscopy and Histology

“…Recently, Strand-Amundsen et al [ 15 ] used bioimpedance measurements together with machine learning algorithms (LSTM-RNN) to more accurately assess intestinal viability in a pig model. Some years later, Hou et al [ 16 ] used bioimpedance measurements on human intestine ex vivo, reporting an association between the value from the bioimpedance data and the viability of the small intestine. Moreover, Hou et al [ 3 ] investigated the use of dielectric relaxation spectroscopy together with machine learning methods (LSTM and CNN) to assess small intestinal viability.…”