Gastric Impedance Spectroscopy in Cardiovascular Surgery Patients vs. Healthy Volunteers

Abstract

Impedance spectroscopy has been proposed as a method of monitoring mucosal injury due to hypoperfusion and ischemia in the critically ill. The present study evaluates spectral differences in elective cardiovascular surgery patients compared with the impedance spectra of the gastric mucosa in healthy adults. An impedance spectroscopy probe and nasogastric tube (ISP/NGT) was placed into the stomach of 77 heart surgery and 21 healthy volunteers. The recorded impedance spectra were classified into 3 groups: group 1 for healthy volunteers; group 2 for patients with neither ischemia nor complications; and group 3 for patients with ischemia and complications during the first 3 days in the recovery unit. There were statistical differences in resistance (p<0.001) and reactance (p<0.001) among the 3 groups. The results show that impedance spectra are distinct and significantly different in patients with probable ischemic mucosal injury compared to healthy subjects, and therefore this technology may be a useful prognostic and diagnostic monitoring tool.

In vivocharacterization of ischemic small intestine using bioimpedance measurements

“…The most commonly used electrode setup to measure the electrical properties of the small intestine has been to use an intraluminal 4-electrode ring setup (Bloch et al, 2017, Beltran et al, 2005, Beltran et al, 2013a, Beltran et al, 2007, Beltran et al, 2013b, Beltran and Sacristan, 2015, Gonzalez et al, 2007, Gonzalez et al, 2003, sending a current between the outer electrode rings, while measuring the voltage across the inner electrode rings, with the assumption that some of the current passes through the mucosal layer affecting the measured complex impedance ( Figure 9). As the current with the intraluminal 4-ring electrode setup will only pass through a small part of the mucosa, we estimate that this method is not usable with respect to assessment of intestinal viability.…”

“…To the best of our knowledge, the present work is the first to use trans-intestinal measurements to assess intestinal viability. Recent studies related to bioimpedance and the small intestine have mainly been focused on intraluminal catheters for assessment of changes in the electrical properties of the mucosa, to detect the presence of ischemia (Gonzalez et al, 2007, Gonzalez et al, 2003, Beltran et al, 2005, Beltran et al, 2013a, Beltran et al, 2007, Beltran et al, 2013b, Beltran and Sacristan, 2015. The 4-electrode ring catheter method has been shown to be unreliable (Bloch et al, 2017).…”

Electrical biopsy of irradiated intestinal tissue with a simple electrical impedance spectroscopy system for radiation enteropathy in rats-–a pilot study

“…EIS was also applied for early tumor detection and assessment of muscle radiation injury in rats (Osterman et al 2004, Skourou et al 2004. In human subjects, the EIS technique was applied to evaluate the ischemic status of patients after cardiovascular surgery and to provide a valuable prognostic index for postoperative analysis (Beltran et al 2005). Furthermore, EIS was demonstrated to have the ability to detect breast cancer and to identify the risk of the disease (Morimoto et al 1993, Stojadinovic et al 2005.…”

Gastric impedance spectroscopy in elective cardiovascular surgery patients

“…Impedance spectroscopy provides good information about the tissue structure (Kyle et al 1999) and it has been used in the measurement of changes in ischemia or perfusion in different organs (Gersing 1998, Kun and Peura 1994, Casas et al 1999. Complex impedance spectroscopy also provides phase information, so that resistive and reactive tissue components can be separated, producing more reliable measurements that are appropriate for medical research.…”