Esophagus impedanometry is a diagnostic procedure based on measuring alternating current impedances between several electrodes located on a special impedance probe inserted into the patient's esophagus. It is usually performed in conjunction with the pH-meter of the esophagus (and in this case is called impedance-pH-meter ), for which pH-electrodes located on the same probe are used.
A new diagnostic procedure designed to study non-acidic gastroesophageal refluxes . The first work on esophageal impedanometry was performed by J. Silny in 1990 ( Castell DO , 2005).
Content
Why is esophagus needed?
Currently, the daily standard for the diagnosis of gastroesophageal reflux disease (GERD) is the daily pH meter . The criterion for the appearance of gastroesophageal reflux is considered to be a decrease in pH in the esophagus below 4 units. 5 cm above the upper edge of the lower esophageal sphincter . However, modern studies show that the symptoms of GERD are often caused not by the acidic contents of the stomach, but by the injection of bile from the duodenum into the esophagus with pH β 7 or the passage of gas bubbles from the stomach through the esophagus. To detect acidic reflux or gas bubbles, measuring only the acidity of the esophagus is not enough.
Esophagus methodology
A probe about 2 mm thick is inserted into the esophagus, on which electrodes for measuring impedance and a pH sensor are located at intervals of 2 cm. The occurrence of gastroesophageal reflux (GER) is detected by impedancemetry, and the pH level in the bolus of refluxate is determined using a pH sensor.
Detection of a reflux bolus is based on the fact that:
- The conductivity of liquid refluxate is higher than the conductivity of the walls of the esophagus. Therefore, when liquid refluxate enters the esophagus on the electrodes, it expands the lumen of the esophagus, and due to a change in geometry (increasing the cross section with high conductivity), the impedance between these electrodes decreases.
- The conductivity of a gas bolus is lower than the conductivity of the walls of the esophagus. Therefore, when a gas bubble enters the electrodes in the esophagus, the impedance between these electrodes increases until the electrical circuit breaks.
Using these regularities, the appearance of GER is detected by the dynamics of the impedance, and episodes of liquid GER, gas GER, and a mixture of gas and liquid are detected by the magnitude of the impedance in the refluxate.
Sources
- Silny J. Intraluminal multiple electric impedance procedure for measurement of gastrointestinal motility. J Gastrointest Motil. 1991; 3: 151-162.
- Castell DO , Mainie I., Tutuian R. Non-acid Gastroesophageal Reflux: Documenting its Relationship to Symptoms Using Multichannel Intraluminal Impedance (MII) . Trans Am Clin Climatol Assoc. 2005; 116: 321β334.
- Multichannel intraluminal impedance associated with pH-meter in the study of gastroesophageal reflux disease . Rev Esp Enerm Dig (Madrid) Vol. 100, N. Β° 2, pp. 67-70, 2008.
- Grinevich V. Monitoring of pH, bile and impedance monitoring in the diagnosis of GERD . Clinical and experimental gastroenterology. No. 5, 2004.
- Trukhmanov A.S., Kaybysheva V.O. pH-impedance measurement of the esophagus . Manual for doctors / Ed. Acad. RAMS, prof. V.T. Ivashkina - M .: Publishing House MEDPRAKTIKA-M, 2013.32 p. ISBN 978-5-98803-288-5 .